On 7/19/2016 10:25 PM, Taxed and Spent wrote:
On 7/19/2016 7:10 PM, Ed Pawlowski wrote:
On 7/19/2016 9:24 PM, Taxed and Spent wrote:


They don't care about that since it is still potable water. The
concern
is contamination by outside chemicals such as lawn chemicals siphoning
back through a sprinkler system. Some heating systems have chemicals
and can have pressure higher than the feed water, etc.

Of course they care. You can add chemicals to your water tank (like to
clean it or something) and your water system could backfeed into the
water tank (not Danny's, since he says it is all downhill from the
tank). They don't write codes for when things go right.

That would be an intentional act. There are many ways to contaminate
your drinking water. The backflow is to guard against accidental
siphoning.


whoosh! It IS possible for backflow to occur into the water tanks,
depending on how your system is set up. And then to the well. Or would
you consider ALL such backflow as to be an intentional act (leaving the
hose in a puddle of water, etc)? Intentional or not is not the issue.

You mentioned adding chemicals to clean the tank. That is unusual and
intentional. Assuming we are talking about the pressure tank and not
some open tank in the yard. The hose in the puddle is the reason for
the added backflow preventer. Some towns are requiring them on all
outdoor faucets, not just sprinklers.

On Tue, 19 Jul 2016 19:19:11 -0700, Taxed and Spent wrote:

from this manual/installation instructions

http://media.wattswater.com/1915346.pdf

It's dark now but here's a full sized pictu

It seems to be a Wilkins Zurn 975XL based on what's stamped on the side.

This is a maintenance video:
https://www.youtube.com/watch?v=ctYonNGogIE

They costs hundreds of dollars each:
http://www.sprinklerwarehouse.com/Wi...ies-s/9537.htm

I think this is the repair kit I used in the past:
https://www.amazon.com/Zurn-RK34-975.../dp/B00D2ZGER8

I need to measure the pipe diameter, but here's a $200 one-inch Wilkins
1-975XL Backflow Preventer:
https://www.amazon.com/Moen-1-975XL-.../dp/B001ASAT48

This seems to have parts diagrams:
http://backflowparts.com/wilkins-model-975xl-975xl2/

Looking at the phantom diagram, I can't figure out how it works yet:
http://www.zurnproducts.com/wilkins-...t-3-4-2-models

On Wed, 20 Jul 2016 00:16:49 -0400, Ed Pawlowski wrote:

You mentioned adding chemicals to clean the tank. That is unusual and
intentional. Assuming we are talking about the pressure tank and not
some open tank in the yard. The hose in the puddle is the reason for
the added backflow preventer. Some towns are requiring them on all
outdoor faucets, not just sprinklers.

Here is a full-sized pictu
http://i.cubeupload.com/8zGy7F.jpg

I "think" the backflow valve is only on the outdoor water, and not on the
water on the outside of the house. I can prove that, tomorrow, if we need
me to, since I had to shut it off again (it blew about two hours ago in the
dark and the wife heard it so I had to go out in my pajamas and turn it off
again).

I think I get the *concept* of the hose or sprinklers being in a puddle of
swamp water being bad if that got sucked back into the water tanks - but
what I don't get is HOW that suction can occur.

What would make a water supply set up on a hill suck swamp water UP that
hill?

On Wed, 20 Jul 2016 04:51:17 -0000 (UTC), Danny D. wrote:

It seems to be a Wilkins Zurn 975XL based on what's stamped on the side.

I forgot to include the picture of the markings:
http://i.cubeupload.com/8zGy7F.jpg

On Wed, 20 Jul 2016 04:53:12 -0000 (UTC), Danny D. wrote:

It seems to be a Wilkins Zurn 975XL based on what's stamped on the side.

I forgot to include the picture of the markings:
http://i.cubeupload.com/8zGy7F.jpg

This video seems to have the same leak as I do:
https://youtu.be/Dn95xCQ89VE

On 7/19/2016 9:52 PM, Danny D. wrote:
On Wed, 20 Jul 2016 00:16:49 -0400, Ed Pawlowski wrote:

You mentioned adding chemicals to clean the tank. That is unusual and
intentional. Assuming we are talking about the pressure tank and not
some open tank in the yard. The hose in the puddle is the reason for
the added backflow preventer. Some towns are requiring them on all
outdoor faucets, not just sprinklers.

Here is a full-sized pictu
http://i.cubeupload.com/8zGy7F.jpg

I "think" the backflow valve is only on the outdoor water, and not on the
water on the outside of the house. I can prove that, tomorrow, if we need
me to, since I had to shut it off again (it blew about two hours ago in the
dark and the wife heard it so I had to go out in my pajamas and turn it off
again).

I think I get the *concept* of the hose or sprinklers being in a puddle of
swamp water being bad if that got sucked back into the water tanks - but
what I don't get is HOW that suction can occur.

What would make a water supply set up on a hill suck swamp water UP that
hill?


your situation is not typical (nor is it unheard of).

of course, if there is enough backflow to put some crud into your house,
not your water tanks, you will be drinking crud.

On 7/19/2016 9:51 PM, Danny D. wrote:
On Tue, 19 Jul 2016 19:19:11 -0700, Taxed and Spent wrote:



Looking at the phantom diagram, I can't figure out how it works yet:
http://www.zurnproducts.com/wilkins-...t-3-4-2-models



https://www.youtube.com/watch?v=NQFrSnm2V6U

On 7/19/2016 9:51 PM, Danny D. wrote:


Periodic relief valve discharge may occur on dead end service applica-
tions, such as boiler feed lines or cooling tower makeup lines. This may
be due to fluctuating supply pressure during a static or no flow condi-
tion. To avoid this discharge, install a spring-loaded, rubber seated
check valve ahead of the backflow assembly.

On 7/19/2016 9:53 PM, Danny D. wrote:
On Wed, 20 Jul 2016 04:53:12 -0000 (UTC), Danny D. wrote:

It seems to be a Wilkins Zurn 975XL based on what's stamped on the side.

I forgot to include the picture of the markings:
http://i.cubeupload.com/8zGy7F.jpg

This video seems to have the same leak as I do:
https://youtu.be/Dn95xCQ89VE


Maybe you need a screen filter on the inlet side. You may have a lot of
rust or crud finding its way to the Zurn, causing repetitive problems.

On Wed, 20 Jul 2016 04:53:12 -0000 (UTC), Danny D. wrote:

It seems to be a Wilkins Zurn 975XL based on what's stamped on the side.

I forgot to include the picture of the markings:
http://i.cubeupload.com/8zGy7F.jpg

I can see a 1" stamped on the side, so, I think it is a one inch Wilkins
Zurn 975XL backflow preventer valve.

http://i.cubeupload.com/8zGy7F.jpg

On 07/20/2016 12:52 AM, Danny D. wrote:
What would make a water supply set up on a hill suck swamp water UP that
hill?

As I recall, there was a farm hand (an illegal Italian guy) that went to
flush out a spray rig. For whatever reason, the guy hooked the fresh
water lines up to the spray pump output and backfed some herbicide into
the farmers water supply.

On 7/20/2016 12:52 AM, Danny D. wrote:


I think I get the *concept* of the hose or sprinklers being in a puddle of
swamp water being bad if that got sucked back into the water tanks - but
what I don't get is HOW that suction can occur.

What would make a water supply set up on a hill suck swamp water UP that
hill?


Unlikely, but it can happen. Ever siphon gas from a car tank? Once you
get the flow started it sucks the gas up, then back down. Think of your
well as the can on the ground as it is maybe 200' lower than the puddle
in your yard. If the well loses power, your bladder tank is no longer
pressured due to use . . .

Taxed and Spent writes:
On 7/19/2016 6:25 AM, wrote:


What happens if the valve leaks is that, overnight, it can create a river,
since once it starts, it never stops.


if you are on well water, I don't think there is a code issue, bypass it if you wish...

or connect a pipe with a valve to the discharge side and set the valve to just slightly open..this way the back pressure valve can still work but if it sticks open, the flow will be limited.

Mark





I have just noticed several wells not too far from Danny D. with
backflow preventers, so maybe it is a code requirement nowadays.

They're required for every lawn sprinkler system as well as any
wells in the state. They're even required for commercial building
water supplies.

On Tuesday, July 19, 2016 at 7:32:05 PM UTC-4, Danny D. wrote:
On Tue, 19 Jul 2016 12:08:58 -0700 (PDT), trader_4 wrote:

He already has two unions, one on each side of the backflow valve.
HomoDepot will cut and thread pipe to length. Or he could transition
to PVC. That is assuming it's not required by code and there is
no chance of backflow into a potable water system.

Ah. Good observation.
Those valves are also unions I guess.
Nice. Very nice.
So a pipe nipple is all that is needed,
right?

The valves on either side are not unions. The unions are in the
vertical pipes that are taped up. And yes, all you'd need is a
nipple of the correct length. If you're lucky, it may be a standard
length. But as others have pointed out, it may be a code violation
to not have a backflow valve.

On Tuesday, July 19, 2016 at 10:03:27 PM UTC-4, Taxed and Spent wrote:
On 7/19/2016 6:44 PM, Danny D. wrote:
On Tue, 19 Jul 2016 17:30:54 -0700, Taxed and Spent wrote:

I would think code should be concerned about backflow from your water
tanks to your well.

I think that this backflow preventer is to prevent a garden hose which is
left open dangling in swamp water from sucking up, like a straw, that swamp
water, into the main water supply.

If that is all it is doing, this would be much simpler and cheaper:


What else is it supposed to be doing, besides being a backflow/siphon preventer?

Now that you've mentioned it, why exactly do any of these backflow/siphon
preventers have to be so fancy or exist at all? Here you need one on a
sprinkler system. It would seem to me that a simple check valve would
do the same thing.

The main reason plumbers have to be licensed is protection of the
public water supplies also certification for water/sewage operators.
We don't want to be drinking our neighbor's sewage or chemicals. You
can wire your house wrong and it might burn your house down but it won't
make the neighbors sick, you do your plumbing wrong and it has the
potential to make them ill. Water will and does run both ways in a pipe.

On 7/20/2016 12:23 AM, Danny D. wrote:
On Wed, 20 Jul 2016 04:53:12 -0000 (UTC), Danny D. wrote:

It seems to be a Wilkins Zurn 975XL based on what's stamped on the side.

I forgot to include the picture of the markings:
http://i.cubeupload.com/8zGy7F.jpg

I can see a 1" stamped on the side, so, I think it is a one inch Wilkins
Zurn 975XL backflow preventer valve.

http://i.cubeupload.com/8zGy7F.jpg

It's a reduced pressure backflow preventer...
https://www.amazon.com/Wilkins-1-375.../dp/B005TU5PRO
If you are on a private well and not connected to public water
supplies you can probably just bypass it. From the looks of it I'd
guess it quit working properly years ago.

On Wednesday, July 20, 2016 at 9:41:34 AM UTC-4, My 2 Cents wrote:
The main reason plumbers have to be licensed is protection of the
public water supplies also certification for water/sewage operators.
We don't want to be drinking our neighbor's sewage or chemicals. You
can wire your house wrong and it might burn your house down but it won't
make the neighbors sick, you do your plumbing wrong and it has the
potential to make them ill. Water will and does run both ways in a pipe.


If you wire your home wrong it can certainly kill people other
than yourself, eg tenants, neighbors in condo or row house next
door, guests, neighbor kid who comes over to use the pool or play
in the house, firemen responding, etc. And while it's theoretically possible that doing
some plumbing incorrectly could somehow contaminate the public
water system and make others sick, I've never heard of a single
actual case. So, if it's happening, it sure is extremely rare.
It's pretty hard to somehow accidently get contaminated water pushed
into a municipal water system with 60 PSI on it.

On 7/20/2016 9:01 AM, trader_4 wrote:
On Wednesday, July 20, 2016 at 9:41:34 AM UTC-4, My 2 Cents wrote:
The main reason plumbers have to be licensed is protection of the
public water supplies also certification for water/sewage operators.
We don't want to be drinking our neighbor's sewage or chemicals. You
can wire your house wrong and it might burn your house down but it won't
make the neighbors sick, you do your plumbing wrong and it has the
potential to make them ill. Water will and does run both ways in a pipe.


If you wire your home wrong it can certainly kill people other
than yourself, eg tenants, neighbors in condo or row house next
door, guests, neighbor kid who comes over to use the pool or play
in the house, firemen responding, etc. And while it's theoretically
possible that doing
some plumbing incorrectly could somehow contaminate the public
water system and make others sick, I've never heard of a single
actual case. So, if it's happening, it sure is extremely rare.
It's pretty hard to somehow accidently get contaminated water pushed
into a municipal water system with 60 PSI on it.

some case histories .. http://www.treeo.ufl.edu/case-histories.aspx

On Wednesday, July 20, 2016 at 10:06:34 AM UTC-4, My 2 Cents wrote:
On 7/20/2016 9:01 AM, trader_4 wrote:
On Wednesday, July 20, 2016 at 9:41:34 AM UTC-4, My 2 Cents wrote:
The main reason plumbers have to be licensed is protection of the
public water supplies also certification for water/sewage operators.
We don't want to be drinking our neighbor's sewage or chemicals. You
can wire your house wrong and it might burn your house down but it won't
make the neighbors sick, you do your plumbing wrong and it has the
potential to make them ill. Water will and does run both ways in a pipe.


If you wire your home wrong it can certainly kill people other
than yourself, eg tenants, neighbors in condo or row house next
door, guests, neighbor kid who comes over to use the pool or play
in the house, firemen responding, etc. And while it's theoretically
possible that doing
some plumbing incorrectly could somehow contaminate the public
water system and make others sick, I've never heard of a single
actual case. So, if it's happening, it sure is extremely rare.
It's pretty hard to somehow accidently get contaminated water pushed
into a municipal water system with 60 PSI on it.

some case histories .. http://www.treeo.ufl.edu/case-histories.aspx

Interesting. It doesn't tell how frequently this actually happens.
The selected cases are from all across the USA and going back to 1964.
Of all the cases, only two were where contaminated water from a residential
system went into the municipal water system.

On 7/20/2016 10:50 AM, trader_4 wrote:


some case histories .. http://www.treeo.ufl.edu/case-histories.aspx

Interesting. It doesn't tell how frequently this actually happens.
The selected cases are from all across the USA and going back to 1964.
Of all the cases, only two were where contaminated water from a residential
system went into the municipal water system.


I don't see this one being much of a problem. I see benefits.

At a winery in the City, someone inadvertently left open a water supply
valve to a wine distilling tank after flushing out the tank. During a
subsequent fermenting process, wine backflowed from the tank into the
City water mains and out of the faucets of nearby homeowners. This
reversal of flow through the water piping occurred because the pressure
in the wine distilling tank was greater than the pressure in the City
water system.

On 7/20/2016 9:56 AM, My 2 Cents wrote:


If you are on a private well and not connected to public water supplies
you can probably just bypass it. From the looks of it I'd guess it quit
working properly years ago.


Is it really a private well? Where does the water come from? Probably
a big aquifer that feeds other homes in the vicinity downstream from
this house.

On Wednesday, July 20, 2016 at 11:37:33 AM UTC-4, Ed Pawlowski wrote:
On 7/20/2016 10:50 AM, trader_4 wrote:


some case histories .. http://www.treeo.ufl.edu/case-histories.aspx

Interesting. It doesn't tell how frequently this actually happens.
The selected cases are from all across the USA and going back to 1964.
Of all the cases, only two were where contaminated water from a residential
system went into the municipal water system.


I don't see this one being much of a problem. I see benefits.

At a winery in the City, someone inadvertently left open a water supply
valve to a wine distilling tank after flushing out the tank. During a
subsequent fermenting process, wine backflowed from the tank into the
City water mains and out of the faucets of nearby homeowners. This
reversal of flow through the water piping occurred because the pressure
in the wine distilling tank was greater than the pressure in the City
water system.

Notice the part where I said "residential systems".

On Wednesday, July 20, 2016 at 11:39:37 AM UTC-4, Ed Pawlowski wrote:
On 7/20/2016 9:56 AM, My 2 Cents wrote:


If you are on a private well and not connected to public water supplies
you can probably just bypass it. From the looks of it I'd guess it quit
working properly years ago.


Is it really a private well? Where does the water come from? Probably
a big aquifer that feeds other homes in the vicinity downstream from
this house.

From what Danny described, it is a private well. There may be places
where a backflow preventer is required on a private well, but even here
in the highly regulated Peoples Republic of NJ you can hook an irrigation
system up to a private irrigation well with no backflow preventer.
So, here they aren't concerned about possible aquifer contamination.
It's only when you connect a sprinkler system to the municipal water
system that you need one.

On Tuesday, July 19, 2016 at 8:09:05 PM UTC-5, Danny D. wrote:
[...]
The pressure on the pump is 70psi:
http://i.cubeupload.com/92IFu3.jpg

How do I *lower* that pressure?

Your maintenance video says that debris in the
check-valves is the most common cause of the relief valve
firing. Have you found internal debris in past tear-downs?

See the online manual...

http://sprinklertalk.com/manuals/wil...5xl_manual.pdf

Notice the part where I said "residential systems".


Contamination from a residence might affect a few neighbors but once
it gets to a city main it's diluted so much it would have to be really
bad to get enough attention to identify and correct it. Free chlorine
residual in public water supplies "should" take care of most bacterial
problems.
If it doesn't seem like much of a problem, it's because people are
doing their jobs and the system is working.

On Wednesday, July 20, 2016 at 1:03:05 PM UTC-4, My 2 Cents wrote:
Notice the part where I said "residential systems".


Contamination from a residence might affect a few neighbors but once
it gets to a city main it's diluted so much it would have to be really
bad to get enough attention to identify and correct it. Free chlorine
residual in public water supplies "should" take care of most bacterial
problems.
If it doesn't seem like much of a problem, it's because people are
doing their jobs and the system is working.

You're ignoring the bigger reason. Commercial locations, factories,
car washes, and similar have all kinds of system that have pressure in
them, pumps, are interconnected, etc. And they have all kinds of
maintenance going on, workers disconnecting things, connecting things,
flushing things, testing things, etc. A residence, not so much.

My 2 Cents writes:

Notice the part where I said "residential systems".


Contamination from a residence might affect a few neighbors but once
it gets to a city main it's diluted so much it would have to be really
bad to get enough attention to identify and correct it. Free chlorine
residual in public water supplies "should" take care of most bacterial
problems.

Of course, not all "public water supplies" chlorinate the water. Mine
doesn't for instance and it serves a portion of the 10th largest city
in the U.S. of A.

On Wed, 20 Jul 2016 08:40:21 -0700 (PDT), trader_4 wrote:

Notice the part where I said "residential systems".

Just to be clear, "this" well is a single-family system.

Even if the water tanks were filled with swamp water, they won't get into
the well because the well fills from the top (and has a shutoff valve set a
good two feet from the top). [Yes, the shutoff valve can fail, I guess.]

So, what I *still* don't get (sorry) is how swamp water is going to get
into the tanks.

1. The sprinklers certainly can be in swamp water, as can the hoses.
2. So, that part I have no problem with understanding.
3. Since the pumphouse is on the highest part of the property, gravity
alone, won't allow the swamp water to make it uphill 20 or 30 feet to the
tanks.
4. So there must be *suction* (a lot of suction!)

I agree that, if suction (a lot of suction) exists, then the swamp water
can be sucked up 2 or 3 or 5 or 10 or 20 or 30 feet (the yard is uneven)
into the bladder tank and then past the pressurizing motor and then into
the bottom of the water tanks.

This next question matters because I'm considering bypassing that valve.

HOW is that suction going to occur?
Is it even possible?
How?

On Wed, 20 Jul 2016 11:39:27 -0400, Ed Pawlowski wrote:

Is it really a private well? Where does the water come from? Probably
a big aquifer that feeds other homes in the vicinity downstream from
this house.

There is no way to contaminate the ground water.

The tanks feed from the top through an open pipe.

They shut off filling two feet from the top.

Even if the shutoff valve failed, water would spill out over the top of the
tank in preference to making its way into a looped pipe which is *above*
the level of the top of the tank. (I think.)

So, even if I filled the tanks with swamp water, I can't see how that swamp
water would ever get back into the 400-foot-deep well itself.

But, maybe I'm wrong, as I don't know this stuff all that well.

On Wed, 20 Jul 2016 09:27:29 -0700 (PDT), Davej wrote:

Your maintenance video says that debris in the
check-valves is the most common cause of the relief valve
firing. Have you found internal debris in past tear-downs?

See the online manual...

http://sprinklertalk.com/manuals/wil...5xl_manual.pdf

Every few years, this valve drives me nuts but there's more information
about the problem over the years, due to youtube's popularity.

For example, last night I watched all the videos on the Wilkins Zern
one-inch 975XL backflow valve, from troubleshooting, to testing, and
installing.

I do agree with you that it seems the main problem is apparently debris in
the seat between a rubber part and a brass part, so, I will disassemble all
three spring-loaded valves, clean, and reassemble - and then report back.

When I search the alt.home.repair archives for my last post on the subject:
http://tinyurl.com/alt-home-repair

I find this 11/21/2012 where I documented the procedure and then forgot
about it over the years.
Pictorial DIY for repairing Wilkins Zurn 975XL Backflow Preventer

Which I reproduce below:
STEP 0: Shut inlet & outlet valves & open #2,#3 & #4 test ports
STEP 1: Repair & clean the #1 check valve on top inlet
STEP 2: Repair & clean the #2 check valve on bottom outlet
STEP 3:Repair & clean the relief valve on the side inlet

http://www2.picturepush.com/photo/a/...g/11462795.jpg
http://www3.picturepush.com/photo/a/...g/11462796.jpg
http://www4.picturepush.com/photo/a/...g/11462797.jpg
http://www1.picturepush.com/photo/a/...g/11462799.jpg
http://www2.picturepush.com/photo/a/...g/11462800.jpg
http://www3.picturepush.com/photo/a/...g/11462801.jpg
http://www4.picturepush.com/photo/a/...g/11462802.jpg
http://www5.picturepush.com/photo/a/...g/11462803.jpg
http://www1.picturepush.com/photo/a/...g/11462804.jpg
http://www2.picturepush.com/photo/a/...g/11462805.jpg
http://www4.picturepush.com/photo/a/...g/11462807.jpg
http://www5.picturepush.com/photo/a/...g/11462808.jpg
http://www1.picturepush.com/photo/a/...g/11462809.jpg
http://www2.picturepush.com/photo/a/...g/11462810.jpg
http://www3.picturepush.com/photo/a/...g/11462811.jpg

IN SUMMARY:
I found all the parts inside the three valves in excellent condition
as you had suggested it would be - but I replaced them all anyway.

The key problem I saw was the #2 check valve was stuck in place
due to light-green corrosion inside the brass cap cavity.

Also there was light-green corrosion in all cavities, which I
painstakingly wire brushed out - as that was the key issue.

On a scale of 1 to 10, this is an easy 1. No surprises. No special
tools. It took me about three hours - one hour for the #1 check
valve on the top inlet, another hour for the #2 check valve on the
bottom outlet, and another hour for the relief valve on the inlet.

It should take you about a half hour in total - maybe 45 minutes,
depending on how well you wish to clean out the green corrosion.
I took my sweet time.

Below is a quick DIY with photographs for the $755 1-inch ID
Zurn Wilkins 975XL Reduced Pressure Principle Backflow Preventer
(http://www.zurn.com/Pages/ProductDet...NodeKey=377206)
after detailing the 11-piece Wilkins Water Works RK34-975XL $43.20
repair kit (855-663-9876) and assembly instructions.

HERE ARE THE KEY REFERENCES:
Wilkins Zurn 975XL Specification Sheet
http://content.zurn.com/web_document...on/ISSM950.pdf
http://content.zurn.com/web_document...-975XL(lg).pdf

Wilkins Zurn 975XL Maintenance Sheet
http://content.zurn.com/web_document...on/ISSM950.pdf

On 7/20/2016 12:53 PM, Danny D. wrote:
On Wed, 20 Jul 2016 09:27:29 -0700 (PDT), Davej wrote:

Your maintenance video says that debris in the
check-valves is the most common cause of the relief valve
firing. Have you found internal debris in past tear-downs?

See the online manual...

http://sprinklertalk.com/manuals/wil...5xl_manual.pdf

Every few years, this valve drives me nuts but there's more information
about the problem over the years, due to youtube's popularity.

For example, last night I watched all the videos on the Wilkins Zern
one-inch 975XL backflow valve, from troubleshooting, to testing, and
installing.

I do agree with you that it seems the main problem is apparently debris in
the seat between a rubber part and a brass part, so, I will disassemble all
three spring-loaded valves, clean, and reassemble - and then report back.

When I search the alt.home.repair archives for my last post on the subject:
http://tinyurl.com/alt-home-repair

I find this 11/21/2012 where I documented the procedure and then forgot
about it over the years.
Pictorial DIY for repairing Wilkins Zurn 975XL Backflow Preventer

Which I reproduce below:
STEP 0: Shut inlet & outlet valves & open #2,#3 & #4 test ports
STEP 1: Repair & clean the #1 check valve on top inlet
STEP 2: Repair & clean the #2 check valve on bottom outlet
STEP 3:Repair & clean the relief valve on the side inlet

http://www2.picturepush.com/photo/a/...g/11462795.jpg
http://www3.picturepush.com/photo/a/...g/11462796.jpg
http://www4.picturepush.com/photo/a/...g/11462797.jpg
http://www1.picturepush.com/photo/a/...g/11462799.jpg
http://www2.picturepush.com/photo/a/...g/11462800.jpg
http://www3.picturepush.com/photo/a/...g/11462801.jpg
http://www4.picturepush.com/photo/a/...g/11462802.jpg
http://www5.picturepush.com/photo/a/...g/11462803.jpg
http://www1.picturepush.com/photo/a/...g/11462804.jpg
http://www2.picturepush.com/photo/a/...g/11462805.jpg
http://www4.picturepush.com/photo/a/...g/11462807.jpg
http://www5.picturepush.com/photo/a/...g/11462808.jpg
http://www1.picturepush.com/photo/a/...g/11462809.jpg
http://www2.picturepush.com/photo/a/...g/11462810.jpg
http://www3.picturepush.com/photo/a/...g/11462811.jpg

IN SUMMARY:
I found all the parts inside the three valves in excellent condition
as you had suggested it would be - but I replaced them all anyway.

The key problem I saw was the #2 check valve was stuck in place
due to light-green corrosion inside the brass cap cavity.

Also there was light-green corrosion in all cavities, which I
painstakingly wire brushed out - as that was the key issue.

On a scale of 1 to 10, this is an easy 1. No surprises. No special
tools. It took me about three hours - one hour for the #1 check
valve on the top inlet, another hour for the #2 check valve on the
bottom outlet, and another hour for the relief valve on the inlet.

It should take you about a half hour in total - maybe 45 minutes,
depending on how well you wish to clean out the green corrosion.
I took my sweet time.

Below is a quick DIY with photographs for the $755 1-inch ID
Zurn Wilkins 975XL Reduced Pressure Principle Backflow Preventer
(http://www.zurn.com/Pages/ProductDet...NodeKey=377206)
after detailing the 11-piece Wilkins Water Works RK34-975XL $43.20
repair kit (855-663-9876) and assembly instructions.

HERE ARE THE KEY REFERENCES:
Wilkins Zurn 975XL Specification Sheet
http://content.zurn.com/web_document...on/ISSM950.pdf
http://content.zurn.com/web_document...-975XL(lg).pdf

Wilkins Zurn 975XL Maintenance Sheet
http://content.zurn.com/web_document...on/ISSM950.pdf


since this is a recurring problem, consider this on the inlet side

http://www.ebay.co.uk/itm/brass-inli...-/121466255185

On Wed, 20 Jul 2016 13:02:59 -0700, Taxed and Spent wrote:

since this is a recurring problem, consider this on the inlet side

http://www.ebay.co.uk/itm/brass-inli...-/121466255185

You are correct that this is a recurring problem.

Given that it keeps happening, I like that idea of installing a flushing
valve!
- Brass Inline 0,5mm Mechanical Water Filter Washer 1/2 3/4 1 inch Dirt
Removal
http://www.ebay.co.uk/itm/brass-inli...-/121466255185

Based on a search of http://tinyurl.com/alt-home-repair, and for the
record, this seems to be when I last rebuilt all three valves:
https://groups.google.com/forum/#!se...o/sAV9vXVibFIJ

Every few years that valve drives me nuts.

Here's what I wrote on 11/6/2012:
https://groups.google.com/forum/#!se...s/4Q5NZCTcwCwJ

I just got off the phone with Wilkins Zurn Technical Support
(aka Wilkins Water Works) at 1-855-663-9876

A new one is over seven hundred dollars.

So, while it may be easy to say to buy one, I would think
a home repair is in order here.

Luckily, they make a 'repair kit', with instructions:

http://www.zurn.com/Pages/ProductDet...NodeKey=377206
Wilkins Waterworks 975XL Repair Kit List Price: $55
Wilkins Waterworks 975XL Repair Kit List Price: $755

-----------------

I called up Wilkins Zurn (Wilkins Water Works) technical support.
They told me those four fittings are for testing purposes, as
you had surmised.

I'm reading all I can on it from the datasheets right now since
it's a $755 part with a $55 repair kit - but, as you know,
repairing (fixing) takes more effort than simple replacement.

Wilkins Zurn 975XL Specification Sheet
http://content.zurn.com/web_document...-975XL(lg).pdf

Wilkins Zurn 975XL Maintenance Sheet
http://content.zurn.com/web_document...on/ISSM950.pdf

I wonder if there is Linux freeware for these CAD drawings?
Wilkins Zurn 975XL CAD drawings (DXL)
http://content.zurn.com/web_documents/dxf/975XL.dxf

Wilkins Zurn 975XL BIM 3d Model
http://tinyurl.com/aj8fh26
------------------------
BTW, I can't tell if it's a 1" or a 1.5 inch opening
because it clearly has a "1" stamped on each opening
but it's just as clearly got a 1" pipe going in and out.

Here, for example, is a ruler next to the pipe and
a yellow circle around the 1.
LARGE: http://www3.picturepush.com/photo/a/...g/11346746.jpg
SMALL: http://www3.picturepush.com/photo/a/...0/11346746.jpg

Notice the pipe is actually about 1 3/8ths in diameter, so it's
neither 1 inch nor 1.5 inch.

Q: What size would you say this Wilkins Zurn 975XL actually fits?
--------------------------------
I called Technical Support again: 1-855-663-9876x2x4
and I detail the answers so the NEXT person with a
similar question can find the answers more easily.

Zurn Wilkins (they don't call it Wilkins Zurn) tech support
confirmed the (1) indicates it's a 1-inch fitting even though
the OD of the pipe going in is clearly (much) greater than
one inch in diameter.

They told me to look for an additional (1") on the body
and lo and behold, there it is (see this picture):
http://www3.picturepush.com/photo/a/...g/11346746.jpg

They only sell one repair kit which is the
RK34-975XL $43.20 (fits 3/4" and 1")

This repair kit comes with the thicker upper check valve
spring, the thinner lower check valve spring, 3 o-rings,
3 seals, etc., and as such is a "complete" repair kit.

They said that Furgeson Enterprises sells them:
http://www.ferguson.com

So, I think we have our solution!
--------------------------
For OP & anyone else who to learn about backflow preventers I offer...
http://content.zurn.com/web_document...on/ISSM950.pdf

That document describes my backflow preventer:
"Zurn Wilkins 1-inch ID Model 975XL Reduced Pressure Principle
Backflow Preventers are for use on potable water lines where a
health hazard could exist if a backflow situation were to occur."

And, that document describes the four test cocks:

1. Start with both shut-off valves closed.
Slowly open the inlet shut-off valve until the backflow preventer is
completely pressurized. A brief discharge from the relief valve may occur
while the device is pressurizing. The discharge should cease by the time
the shut-off valve is fully open. Device should function properly. If the
discharge does not stop, refer to "MAINTENANCE INSTRUCTIONS" for repair
procedures.

2. After the device has been pressurized, vent all trapped air from both
check valve by slightly opening each of the four test cocks.

3. Slowly open the downstream shut-off valve. The Model 975XL Reduced
Pressure Principle Backflow Preventer is now in service.

4. If "spitting" or intermittent discharges from the relief valve are
noted, it could be a result of pressure fluctuation and/or a water hammer
condition in the system. If such conditions exist, install water pressure
reducing valves or water hammer shock arresters in compliance with
industry standards as needed.

5. After the Model 975XL has been properly installed, test the device
(see "TEST PROCEDURES"). If the device fails the test, remove the first
and second check valves and thoroughly flush the device. If the relief
valve fails to operate properly,inspect the sensing passage for clogging
(see "MAINTENANCE INSTRUCTIONS"). Clean rubber seals of all debris and
place unit back in service.

The TROUBLESHOOTING section is apropos for a.h.r.

TROUBLESHOOTING THE MODEL 975XL:
When the relief valve discharges intermittently it can be almost always
assumed that the device is functioning correctly and that the
discharge is caused by systems such as inlet pressure fluctuations or
water hammer due to quick closing valves.

The amount of discharge is proportional to degree of fouling. Most
problems occur in the #1 check which is where debris enters the backflow
preventer first.

1. SUDDEN OR RAPID SPITTING
a. Drop in inlet pressure.
b. Sudden increase in downstream pressure due to water hammer from quick
closing shut-off valve installed downstream.
A. Install an in-line spring loaded check valve upstream of backflow.
B. Install pressure reducing valve upstream of backflow unit.
C. Install in-line spring loaded check valve downstream of backflow as
close to source as possible, but not closer that 4 feet.

2. LIGHT INTERMITTENT DRIP
a. Slightly fouled #1 check.
A. Clean #1 check and turn check valve seal ring over or replace.

NOTE: Continuous discharge of the relief valve signifies a failure of
some part of the device. To help determine the specific area of failure,
close the #2 shut-off valve. If the discharge stops, the #2 check
requires service. If the discharge continues, the #1 check requires
service.

1. CONTINUOUS DISCHARGE
a. Fouled #1 check.
b. Fouled relief valve seat.
c. Fouled #2 check
A. Clean check valves and turn check valve seal rings over or replace.
B. Clean relief valve seat and turn relief valve seal ring over or
replace.

GENERAL MAINTENANCE
1. Clean all parts thoroughly with water after disassembly.
2. Carefully inspect rubber seal rings, diaphragms and o-rings for damage.
3. Test unit after reassembly for proper operation (see "Testing
Procedures").

SERVICING CHECK VALVES
1. Close inlet and outlet shut-off valves.
2. Open No. 2, No. 3 and No. 4 test cocks to release pressure from
valve.
3.Unscrew check valve covers using appropriate size wrench (CAUTION:
Cover is spring loaded).
To avoid injury, hold cover down firmly with one hand while unscrewing.
4. Remove check valve cover, spring and poppet assembly.

5. Inspect the rubber seal ring for cuts or embedded debris. To
remove seal ring, remove screw and seal ring retainer. If the
reverse side of the seal ring is unused, it is possible to invert the
seal ring. This would be considered a temporary solution to fixing
a fouled check and should be replaced with a new seal ring as
soon as possible.

6. Inspect valve cavity and seating area. Remove any debris.

7. If installed with removable seat, unscrew seat from body and
replace with new seat and lightly grease o-ring.*

8. Reverse the above procedures to reinstall check valve assembly.
Care should be taken to make sure the heavy spring is installed in
the No. 1 check valve.

SERVICING RELIEF VALVE
1. Remove relief valve cover bolts and cover. Gently pull on diaphragm to
remove the cartridge assembly.
2. Inspect seal ring for cuts and embedded debris. Turn over or replace
if required.
3. Disassemble cartridge by unscrewing relief valve retaining screw.
4. Inspect diaphragm and o-rings for damage. Replace required
parts and apply a light coat of grease to plunger o-ring.
5. Carefully reassemble cartridge assembly.
6. Inspect relief valve seat for wear on seating surface. If damaged,
replace seat and seat o-ring.*
7. Insert cartridge assembly into relief valve body.
8. Replace relief valve cover and cover bolts.
9. Place device in service and test per "TESTING PROCEDURES".

*For seat removal assistance, consult factory.

WILKINS, a ZURN company
1747 Commerce Way, Paso Robles, CA 93446 Phone:805-238-7100
----------------------------------------
Here is the Zurn Wilkins 950-XL backflow preventer repair kit.

Hard to believe I paid fifty bucks for two springs and a
couple of o-rings!

http://www3.picturepush.com/photo/a/...g/11363276.jpg
-----------------------------

HERE ARE THE KEY REFERENCES:
Wilkins Zurn 975XL Specification Sheet
http://content.zurn.com/web_document...on/ISSM950.pdf
http://content.zurn.com/web_document...-975XL(lg).pdf

Wilkins Zurn 975XL Maintenance Sheet
http://content.zurn.com/web_document...on/ISSM950.pdf

Here is that thread:
https://groups.google.com/forum/#!se...o/sAV9vXVibFIJ

Every few years that valve drives me nuts.

Here's what I wrote on 11/6/2012:
https://groups.google.com/forum/#!se...s/4Q5NZCTcwCwJ

I just got off the phone with Wilkins Zurn Technical Support
(aka Wilkins Water Works) at 1-855-663-9876

A new one is over seven hundred dollars.

So, while it may be easy to say to buy one, I would think
a home repair is in order here.

Luckily, they make a 'repair kit', with instructions:

http://www.zurn.com/Pages/ProductDet...NodeKey=377206
Wilkins Waterworks 975XL Repair Kit List Price: $55
Wilkins Waterworks 975XL Repair Kit List Price: $755

-----------------

I called up Wilkins Zurn (Wilkins Water Works) technical support.
They told me those four fittings are for testing purposes, as
you had surmised.

I'm reading all I can on it from the datasheets right now since
it's a $755 part with a $55 repair kit - but, as you know,
repairing (fixing) takes more effort than simple replacement.

Wilkins Zurn 975XL Specification Sheet
http://content.zurn.com/web_document...-975XL(lg).pdf

Wilkins Zurn 975XL Maintenance Sheet
http://content.zurn.com/web_document...on/ISSM950.pdf

I wonder if there is Linux freeware for these CAD drawings?
Wilkins Zurn 975XL CAD drawings (DXL)
http://content.zurn.com/web_documents/dxf/975XL.dxf

Wilkins Zurn 975XL BIM 3d Model
http://tinyurl.com/aj8fh26
------------------------
BTW, I can't tell if it's a 1" or a 1.5 inch opening
because it clearly has a "1" stamped on each opening
but it's just as clearly got a 1" pipe going in and out.

Here, for example, is a ruler next to the pipe and
a yellow circle around the 1.
LARGE: http://www3.picturepush.com/photo/a/...g/11346746.jpg
SMALL: http://www3.picturepush.com/photo/a/...0/11346746.jpg

Notice the pipe is actually about 1 3/8ths in diameter, so it's
neither 1 inch nor 1.5 inch.

Q: What size would you say this Wilkins Zurn 975XL actually fits?
--------------------------------
I called Technical Support again: 1-855-663-9876x2x4
and I detail the answers so the NEXT person with a
similar question can find the answers more easily.

Zurn Wilkins (they don't call it Wilkins Zurn) tech support
confirmed the (1) indicates it's a 1-inch fitting even though
the OD of the pipe going in is clearly (much) greater than
one inch in diameter.

They told me to look for an additional (1") on the body
and lo and behold, there it is (see this picture):
http://www3.picturepush.com/photo/a/...g/11346746.jpg

They only sell one repair kit which is the
RK34-975XL $43.20 (fits 3/4" and 1")

This repair kit comes with the thicker upper check valve
spring, the thinner lower check valve spring, 3 o-rings,
3 seals, etc., and as such is a "complete" repair kit.

They said that Furgeson Enterprises sells them:
http://www.ferguson.com

So, I think we have our solution!
--------------------------
For OP & anyone else who to learn about backflow preventers I offer...
http://content.zurn.com/web_document...on/ISSM950.pdf

That document describes my backflow preventer:
"Zurn Wilkins 1-inch ID Model 975XL Reduced Pressure Principle
Backflow Preventers are for use on potable water lines where a
health hazard could exist if a backflow situation were to occur."

And, that document describes the four test cocks:

1. Start with both shut-off valves closed.
Slowly open the inlet shut-off valve until the backflow preventer is
completely pressurized. A brief discharge from the relief valve may occur
while the device is pressurizing. The discharge should cease by the time
the shut-off valve is fully open. Device should function properly. If the
discharge does not stop, refer to "MAINTENANCE INSTRUCTIONS" for repair
procedures.

2. After the device has been pressurized, vent all trapped air from both
check valve by slightly opening each of the four test cocks.

3. Slowly open the downstream shut-off valve. The Model 975XL Reduced
Pressure Principle Backflow Preventer is now in service.

4. If "spitting" or intermittent discharges from the relief valve are
noted, it could be a result of pressure fluctuation and/or a water hammer
condition in the system. If such conditions exist, install water pressure
reducing valves or water hammer shock arresters in compliance with
industry standards as needed.

5. After the Model 975XL has been properly installed, test the device
(see "TEST PROCEDURES"). If the device fails the test, remove the first
and second check valves and thoroughly flush the device. If the relief
valve fails to operate properly,inspect the sensing passage for clogging
(see "MAINTENANCE INSTRUCTIONS"). Clean rubber seals of all debris and
place unit back in service.

The TROUBLESHOOTING section is apropos for a.h.r.

TROUBLESHOOTING THE MODEL 975XL:
When the relief valve discharges intermittently it can be almost always
assumed that the device is functioning correctly and that the
discharge is caused by systems such as inlet pressure fluctuations or
water hammer due to quick closing valves.

The amount of discharge is proportional to degree of fouling. Most
problems occur in the #1 check which is where debris enters the backflow
preventer first.

1. SUDDEN OR RAPID SPITTING
a. Drop in inlet pressure.
b. Sudden increase in downstream pressure due to water hammer from quick
closing shut-off valve installed downstream.
A. Install an in-line spring loaded check valve upstream of backflow.
B. Install pressure reducing valve upstream of backflow unit.
C. Install in-line spring loaded check valve downstream of backflow as
close to source as possible, but not closer that 4 feet.

2. LIGHT INTERMITTENT DRIP
a. Slightly fouled #1 check.
A. Clean #1 check and turn check valve seal ring over or replace.

NOTE: Continuous discharge of the relief valve signifies a failure of
some part of the device. To help determine the specific area of failure,
close the #2 shut-off valve. If the discharge stops, the #2 check
requires service. If the discharge continues, the #1 check requires
service.

1. CONTINUOUS DISCHARGE
a. Fouled #1 check.
b. Fouled relief valve seat.
c. Fouled #2 check
A. Clean check valves and turn check valve seal rings over or replace.
B. Clean relief valve seat and turn relief valve seal ring over or
replace.

GENERAL MAINTENANCE
1. Clean all parts thoroughly with water after disassembly.
2. Carefully inspect rubber seal rings, diaphragms and o-rings for damage.
3. Test unit after reassembly for proper operation (see "Testing
Procedures").

SERVICING CHECK VALVES
1. Close inlet and outlet shut-off valves.
2. Open No. 2, No. 3 and No. 4 test cocks to release pressure from
valve.
3.Unscrew check valve covers using appropriate size wrench (CAUTION:
Cover is spring loaded).
To avoid injury, hold cover down firmly with one hand while unscrewing.
4. Remove check valve cover, spring and poppet assembly.

5. Inspect the rubber seal ring for cuts or embedded debris. To
remove seal ring, remove screw and seal ring retainer. If the
reverse side of the seal ring is unused, it is possible to invert the
seal ring. This would be considered a temporary solution to fixing
a fouled check and should be replaced with a new seal ring as
soon as possible.

6. Inspect valve cavity and seating area. Remove any debris.

7. If installed with removable seat, unscrew seat from body and
replace with new seat and lightly grease o-ring.*

8. Reverse the above procedures to reinstall check valve assembly.
Care should be taken to make sure the heavy spring is installed in
the No. 1 check valve.

SERVICING RELIEF VALVE
1. Remove relief valve cover bolts and cover. Gently pull on diaphragm to
remove the cartridge assembly.
2. Inspect seal ring for cuts and embedded debris. Turn over or replace
if required.
3. Disassemble cartridge by unscrewing relief valve retaining screw.
4. Inspect diaphragm and o-rings for damage. Replace required
parts and apply a light coat of grease to plunger o-ring.
5. Carefully reassemble cartridge assembly.
6. Inspect relief valve seat for wear on seating surface. If damaged,
replace seat and seat o-ring.*
7. Insert cartridge assembly into relief valve body.
8. Replace relief valve cover and cover bolts.
9. Place device in service and test per "TESTING PROCEDURES".

*For seat removal assistance, consult factory.

WILKINS, a ZURN company
1747 Commerce Way, Paso Robles, CA 93446 Phone:805-238-7100
----------------------------------------
Here is the Zurn Wilkins 950-XL backflow preventer repair kit.

Hard to believe I paid fifty bucks for two springs and a
couple of o-rings!

http://www3.picturepush.com/photo/a/...g/11363276.jpg
-----------------------------

On 07/20/2016 04:09 PM, Danny D. wrote:
just got off the phone with Wilkins Zurn Technical Support
(aka Wilkins Water Works) at 1-855-663-9876

A new one is over seven hundred dollars.

So, while it may be easy to say to buy one, I would think
a home repair is in order here.


I'd replace that $755 whiz-o-matic valve with an ordinary check valve
and call it a day...but that's just me.

On Wednesday, July 20, 2016 at 2:07:41 PM UTC-4, Danny D. wrote:
On Wed, 20 Jul 2016 08:40:21 -0700 (PDT), trader_4 wrote:

Notice the part where I said "residential systems".

Just to be clear, "this" well is a single-family system.

Even if the water tanks were filled with swamp water, they won't get into
the well because the well fills from the top (and has a shutoff valve set a
good two feet from the top). [Yes, the shutoff valve can fail, I guess.]

So, what I *still* don't get (sorry) is how swamp water is going to get
into the tanks.

1. The sprinklers certainly can be in swamp water, as can the hoses.
2. So, that part I have no problem with understanding.
3. Since the pumphouse is on the highest part of the property, gravity
alone, won't allow the swamp water to make it uphill 20 or 30 feet to the
tanks.
4. So there must be *suction* (a lot of suction!)

I agree that, if suction (a lot of suction) exists, then the swamp water
can be sucked up 2 or 3 or 5 or 10 or 20 or 30 feet (the yard is uneven)
into the bladder tank and then past the pressurizing motor and then into
the bottom of the water tanks.

This next question matters because I'm considering bypassing that valve.

HOW is that suction going to occur?
Is it even possible?
How?

From what we can figure from what you describe, it sounds like in your
case backflow is virtually impossible. However the backflow preventer
may still be required by local code. When they write code, they don't
typically take into account every possible scenario and instead write
code to require something in all installations of concern.

On 7/21/2016 7:25 AM, trader_4 wrote:
On Wednesday, July 20, 2016 at 2:07:41 PM UTC-4, Danny D. wrote:
On Wed, 20 Jul 2016 08:40:21 -0700 (PDT), trader_4 wrote:

Notice the part where I said "residential systems".

Just to be clear, "this" well is a single-family system.

Even if the water tanks were filled with swamp water, they won't get into
the well because the well fills from the top (and has a shutoff valve set a
good two feet from the top). [Yes, the shutoff valve can fail, I guess.]

So, what I *still* don't get (sorry) is how swamp water is going to get
into the tanks.

1. The sprinklers certainly can be in swamp water, as can the hoses.
2. So, that part I have no problem with understanding.
3. Since the pumphouse is on the highest part of the property, gravity
alone, won't allow the swamp water to make it uphill 20 or 30 feet to the
tanks.
4. So there must be *suction* (a lot of suction!)

I agree that, if suction (a lot of suction) exists, then the swamp water
can be sucked up 2 or 3 or 5 or 10 or 20 or 30 feet (the yard is uneven)
into the bladder tank and then past the pressurizing motor and then into
the bottom of the water tanks.

This next question matters because I'm considering bypassing that valve.

HOW is that suction going to occur?
Is it even possible?
How?

From what we can figure from what you describe, it sounds like in your
case backflow is virtually impossible.

Depends on WHERE. His setup can still have backflow into the pipes on
the lower part of his property (not the tank on the hill), which may
serve his drinking faucets for all we know.

On Wednesday, July 20, 2016 at 4:19:32 PM UTC-4, Pierre Piquant wrote:
On 07/20/2016 04:09 PM, Danny D. wrote:
just got off the phone with Wilkins Zurn Technical Support
(aka Wilkins Water Works) at 1-855-663-9876

A new one is over seven hundred dollars.

So, while it may be easy to say to buy one, I would think
a home repair is in order here.


I'd replace that $755 whiz-o-matic valve with an ordinary check valve
and call it a day...but that's just me.

Given the system he's described, which is basically a water tank on top
of a hill, he doesn't even need the check valve. However, a local code
may require it, because the code may not be written just for water tanks
that sit high on a hill.

On Thursday, July 21, 2016 at 10:28:10 AM UTC-4, Taxed and Spent wrote:
On 7/21/2016 7:25 AM, trader_4 wrote:
On Wednesday, July 20, 2016 at 2:07:41 PM UTC-4, Danny D. wrote:
On Wed, 20 Jul 2016 08:40:21 -0700 (PDT), trader_4 wrote:

Notice the part where I said "residential systems".

Just to be clear, "this" well is a single-family system.

Even if the water tanks were filled with swamp water, they won't get into
the well because the well fills from the top (and has a shutoff valve set a
good two feet from the top). [Yes, the shutoff valve can fail, I guess.]

So, what I *still* don't get (sorry) is how swamp water is going to get
into the tanks.

1. The sprinklers certainly can be in swamp water, as can the hoses.
2. So, that part I have no problem with understanding.
3. Since the pumphouse is on the highest part of the property, gravity
alone, won't allow the swamp water to make it uphill 20 or 30 feet to the
tanks.
4. So there must be *suction* (a lot of suction!)

I agree that, if suction (a lot of suction) exists, then the swamp water
can be sucked up 2 or 3 or 5 or 10 or 20 or 30 feet (the yard is uneven)
into the bladder tank and then past the pressurizing motor and then into
the bottom of the water tanks.

This next question matters because I'm considering bypassing that valve.

HOW is that suction going to occur?
Is it even possible?
How?

From what we can figure from what you describe, it sounds like in your
case backflow is virtually impossible.

Depends on WHERE. His setup can still have backflow into the pipes on
the lower part of his property (not the tank on the hill), which may
serve his drinking faucets for all we know.

He told us early on that the backflow preventer is at the top of
the hill with the tank, pump, etc.

On Mon, 18 Jul 2016 22:33:30 -0000 (UTC), Danny D. wrote:

What is it about these backflow pressure valves that makes then blow from
pressure once every couple of years?
http://i.cubeupload.com/sPmg4A.jpg

Is there some "maintenance" I'm supposed to do to prevent it from leaking?
http://i.cubeupload.com/2peIoi.jpg

Do you think it would be easy to just put a pipe in its place instead?
http://i.cubeupload.com/TS0zHT.jpg

The valves look pretty clean inside to me.
http://i.cubeupload.com/cTWAvc.jpg

Top:
http://i.cubeupload.com/uPRI64.jpg

Bottom:
http://i.cubeupload.com/WRwLmb.jpg

I just rebuilt the wider diaphragm part only a year or so ago.

What makes these things constantly blow every year or two?
http://i.cubeupload.com/YBbHfF.jpg

How hard would it be you think to just bypass it?
http://i.cubeupload.com/ulUq4G.jpg

By way of belated update, I thoroughly cleaned out the backflow pressure
valve components about a week or so ago, and the eruptions of water just
stopped.

So I guess it just needed a "tune up" cleaning!

I wire brushed and dremeled out the crud, which was caked on a half
millimeter thick, and that seems to be what the problem was.

I guess one of the three valves were sticking from the corrosion.
SMALL: http://www2.picturepush.com/photo/a/...0/11343535.jpg
LARGE: http://www2.picturepush.com/photo/a/...g/11343535.jpg

To put it back together, I followed my own DIY from many years ago,
archived over he
http://tinyurl.com/alt-home-repair

Which brings you to he
https://groups.google.com/forum/#!forum/alt.home.repair

Where I searched to find this thread from
https://groups.google.com/forum/#!searchin/alt.home.repair/danny$20checkvalve$20backflow|sort:relevance/alt.home.repair/PWa8EZbbyps/PnRfJLPK7SYJ
What would happen if I just bypassed this garden water check valve?
11/5/2012 by Danny D.

No sense in taking new pictures - they look almost exactly the same.
http://www2.picturepush.com/photo/a/...g/11462795.jpg
http://www3.picturepush.com/photo/a/...g/11462796.jpg
http://www4.picturepush.com/photo/a/...g/11462797.jpg
http://www1.picturepush.com/photo/a/...g/11462799.jpg
http://www2.picturepush.com/photo/a/...g/11462800.jpg
http://www3.picturepush.com/photo/a/...g/11462801.jpg
http://www4.picturepush.com/photo/a/...g/11462802.jpg
http://www5.picturepush.com/photo/a/...g/11462803.jpg
http://www1.picturepush.com/photo/a/...g/11462804.jpg
http://www2.picturepush.com/photo/a/...g/11462805.jpg
http://www4.picturepush.com/photo/a/...g/11462807.jpg
http://www5.picturepush.com/photo/a/...g/11462808.jpg
http://www1.picturepush.com/photo/a/...g/11462809.jpg
http://www2.picturepush.com/photo/a/...g/11462810.jpg
http://www3.picturepush.com/photo/a/...g/11462811.jpg

I'll let you know when it leaks next.