Jud McCranie wrote in message . ..
Latest: today we drained the tank again and this time I pumped the
pressure up higher with a tire pump that plugs into a cigarette
lighter, and refilled the tank. Also, right now I'm bypassing a
filter, which was clogged up. (I really should have checked that
earlier, but I replaced it not too long ago.) The air pressure in the
tank is 62 PSI.

At the moment the water pressure and flow is fine - just like it
should be. I'm going to see how it holds over the next few days.

The pump is running for about 15 seconds each time. Should it be
longer?

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Damn. I didn't consider a filter in the system. That is a common
cause of low flow even when the tank is operating correctly.

15 sec is way too short of a cycle time and is very hard on the pump.
You say air pressure in the tank is 62 psi. Is that with the tank
empty or full? If it is empty it is way too much and the pump
shouldn't even be shutting off unless an overload switch is being
activated.

Now that you have a air pump, start over. Drain the tank, add air to
2 psi below cut-off and restart your system. You will then have it
set correctly.

Harry K

If you are going to give advice, at least know what you are talking
about.

Hey Einstein. . could u pleeease highlight the part where i gave advice ? ? ?
pretty sure that i asked a question. . .

In article , Jud McCranie wrote:
Latest: today we drained the tank again and this time I pumped the
pressure up higher with a tire pump that plugs into a cigarette
lighter, and refilled the tank. Also, right now I'm bypassing a
filter, which was clogged up. (I really should have checked that
earlier, but I replaced it not too long ago.) The air pressure in the
tank is 62 PSI.

Too high.

Look, this isn't rocket science. Your pump control is set to come on at 42
psi, and shut off at 58. So shut off the power to the pump and drain the tank,
completely. Pressurize the tank to 40 psi. Turn the pump back on.

That's all.

--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)

Get a copy of my NEW AND IMPROVED TrollFilter for NewsProxy/Nfilter
by sending email to autoresponder at filterinfo-at-milmac-dot-com
You must use your REAL email address to get a response.

On Sun, 14 Nov 2004 18:00:13 GMT, (Doug Miller)
wrote:

Look, this isn't rocket science. Your pump control is set to come on at 42
psi, and shut off at 58. So shut off the power to the pump and drain the tank,
completely. Pressurize the tank to 40 psi. Turn the pump back on.

It is working OK with that pressure. If I drain the tank and
pressurize the tank to 40 PSI and then turn the pump on, the pressure
will be even higher. The first time I drained the tank, I didn't pump
any air in. The second time I pumped it up to 11 PSI, turned on the
pump, and it compressed the air until it was at 46 PSI. The third
time I drained it and pumped it up to 20 PSI, then turned on the pump
and the air pressure went up to 62 PSI.

After using it for more than a day, the air pressure is still at 62
PSI when the pump cuts off. And to check to see if the gauge is
wrong, I used a different one and it reads 63.5 PSI.


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Jud McCranie wrote in message . ..
On Sun, 14 Nov 2004 18:00:13 GMT, (Doug Miller)
wrote:

Look, this isn't rocket science. Your pump control is set to come on at 42
psi, and shut off at 58. So shut off the power to the pump and drain the tank,
completely. Pressurize the tank to 40 psi. Turn the pump back on.

It is working OK with that pressure. If I drain the tank and
pressurize the tank to 40 PSI and then turn the pump on, the pressure
will be even higher. The first time I drained the tank, I didn't pump
any air in. The second time I pumped it up to 11 PSI, turned on the
pump, and it compressed the air until it was at 46 PSI. The third
time I drained it and pumped it up to 20 PSI, then turned on the pump
and the air pressure went up to 62 PSI.

After using it for more than a day, the air pressure is still at 62
PSI when the pump cuts off. And to check to see if the gauge is
wrong, I used a different one and it reads 63.5 PSI.


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No, the pressure will NOT go higher. The control switch is set to cut
off at about 62 psi. It will do that whether you have 1 psi or 40 psi
for the precharge. 62 is where it will cut off. It will also start
at about 40 psi no matter what your precharge is. The precharge is
not what operates the system. The system operates only on the 20 psi
differential that the pump adds on top of the pre-charge. The
pre-charge is there to for two reasons.
1. Air bubble to compress to make the system work.
2. To control the cycle time of the pump. Anything less than the
optimum (2 psi approx below cut-in) makes the pump run more often for
less time. That is hard on pumps.

Trust us. I don't know about Doug but I have been running these
systems since I was 16 and am now 70 still running them. Shut the
pump off, drain the tank and pump the proper amount of air in.

Harry K

On 15 Nov 2004 06:47:15 -0800, (Harry K)
wrote:

No, the pressure will NOT go higher.

Well, it did the other three times.

The first time I drained it, I let the air pressure off and didn't
pump any air in. After I cut the pump back on, the air pressure in
the top of the tank was around 20 PSI, but I don't remember the exact
figure.

The second time I drained the tank, I pumped the air up to 11 PSI.
Then I turned the pump on, and the air pressure went up to 46 PSI.
After the pump went through , it maintained 46 PSI (when the pump cut
off).

The third time I drained the tank, I pumped the air pressure up to 20
PSI. After turning the pump back on, the air pressure went up to 62
PSI. Three days later, when the pump cuts off, the air pressure is
still around 62 PSI.

So, to summarize: air pumped in / final air pressu

before final

0 PSI 20 PSI (approx)
11 PSI 42 PSI
20 PSI 62 PSI (63.5 according to my other gauge)

If I drain the tank, pump up the air to more than 20 PSI, and then
turn the pump on, the final air pressure is going to be higher than 62
PSI. I'm willing to take bets on that.

It has twice been said that this isn't rocket science, but there is
physics involved - Boyle's law. As a gas is compressed onto a smaller
volume, its pressure goes up.

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0 PSI 20 PSI (approx)
11 PSI 42 PSI
20 PSI 62 PSI (63.5 according to my other gauge)

If I drain the tank, pump up the air to more than 20 PSI, and then
turn the pump on, the final air pressure is going to be higher than 62
PSI. I'm willing to take bets on that.

It has twice been said that this isn't rocket science, but there is
physics involved - Boyle's law. As a gas is compressed onto a smaller
volume, its pressure goes up.

Yeah, but the pump is supposed to be cutting off at a specific pressure,
so boyles law or not, the upper limit should be constant. If it's not,
then there's something wrong with your setup. Specifically, if
you pre-pressurise the tank to or beyond what the upper cutoff is,
the pump should never come on at all.

According to Harry K :
Jud McCranie wrote in message . ..
On Thu, 11 Nov 2004 20:04:19 GMT, (Doug Miller)
wrote:

It's cheaper to buy a couple of pipe wrenches at Sears, and rent a truck, than
to pay somebody else to put the tank in for you. :-)

I know it is simple - set it in there and connect one pipe, but I
don't think I'm physically able to do it.

I see google is being very slow again as yesterday's post hasn't shown
yet.

Don't be intimidated by the -size- of the tank. They weigh relatively
nothing. The box they come in and any packing materials almost weigh
as much as the tank. They are awkward to haul and maneuver tho due to
the size.

Interesting.

The reason I say that is that the bladder-style tank we have isn't very big
at all. It's about 14" in diameter, about 24" tall, and probably weighs
about 15 pounds empty. That handles us without any problems whatsoever.
(simultaneously taking a shower, flushing the toilet, running the
dishwasher, and clothes washer when the irrigation system is in operation!
Okay, yeah, we couldn't take the shower without a pressure balance valve...)

A _large_ tank (ie: anything approaching a hot water tank in size) is
suggestive of either an old-fashioned bladder-less tank, or cistern
requirements (ie: very low flowrate well).
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

According to Harry K :
Right. All it takes is two pipe wrenches and one will do if you're
lucky. Just don't do what I did once and forget to empty the tank
before you break the connection. :)

Or what I did once. In a hurry to test whether the new water pump was
working in a new house, I wired it up, and only did enough plumbing to
get it to the tank.

Fired it up.

Hey, cool, it works!

Now _how_ do I empty the tank?

I almost got away with partially cracking open a 1/4" NPT plug on
the meter manifold and deflecting the spray into a bucket. Until
the plug fell out.

FWOOMMP!

There were a number of very upset (wet) people on the other side of the
basement.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

According to Michael Strickland :

Frequent pump cycling - Turn off water where pipe enters house, then check
pressure to see if it stays steady for at least 30 minutes. Turning off water
within the house eliminates pressure drops from leaky toilet valves and
dripping faucets.

As a FYI, another "odd" pump cycling cause: the tubing from the line to
the pressure switch gets plugged with crud.

You'll think the pressure switch or pump was defective, because sometimes the
pump fires up, and sometimes it doesn't.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

According to :

0 PSI 20 PSI (approx)
11 PSI 42 PSI
20 PSI 62 PSI (63.5 according to my other gauge)

If I drain the tank, pump up the air to more than 20 PSI, and then
turn the pump on, the final air pressure is going to be higher than 62
PSI. I'm willing to take bets on that.

It has twice been said that this isn't rocket science, but there is
physics involved - Boyle's law. As a gas is compressed onto a smaller
volume, its pressure goes up.

Yeah, but the pump is supposed to be cutting off at a specific pressure,
so boyles law or not, the upper limit should be constant. If it's not,
then there's something wrong with your setup. Specifically, if
you pre-pressurise the tank to or beyond what the upper cutoff is,
the pump should never come on at all.

Exactly.

He's showing erratic operation. No matter what he precharges the tank to,
the peak pressure _should_ be the pressure switch cut-out pressure.

Which suggests to me that something is wrong with the pressure switch
setup, and the pressure switch isn't seeing the true line pressure.

If the unit has a small hose supplying the pressure switch, take it off, and
ream it (and the fittings) out with a pipe cleaner.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

On Mon, 15 Nov 2004 17:07:45 -0500, "
wrote:

Yeah, but the pump is supposed to be cutting off at a specific pressure,
so boyles law or not, the upper limit should be constant.

The pump does cut off consistently at 57-58 PSI of the WATER. The AIR
pressure at the top of the tank at that point depends on how much air
I put in when the tank was drained. The more initial air, the higher
the air pressure.

If it's not, then there's something wrong with your setup.

The bladder may be broken, but it is holding the air pressure.

Specifically, if
you pre-pressurise the tank to or beyond what the upper cutoff is,
the pump should never come on at all.

Correct me if I'm wrong, but isn't there a diaphragm or bladder made
out of rubber or something like that in the tank, with air above it
and water below it? When the tank is drained, there is no water in
the tank and pressurizing the air in the tank via the valve at the top
pressurizes the air above the diaphragm, but not below, right? (It
doesn't pressurize the whole tank, just the bladder, right?) Then the
pressurized air doesn't affect the water going in until it hits the
diaphragm, right?

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On 15 Nov 2004 22:47:13 GMT, (Chris Lewis)
wrote:

If the unit has a small hose supplying the pressure switch, take it off, and
ream it (and the fittings) out with a pipe cleaner.

There is a 3/4" pipe coming off the main pipe that goes to the
pressure switch, and there is a circular pressure gauge coming off
that pipe. The pump cuts on and off consistently according to that
gauge. I'll have to drain the tank again to clean it out.

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Jud McCranie wrote in message . ..
On Mon, 15 Nov 2004 17:07:45 -0500, "
wrote:

Yeah, but the pump is supposed to be cutting off at a specific pressure,
so boyles law or not, the upper limit should be constant.

The pump does cut off consistently at 57-58 PSI of the WATER. The AIR
pressure at the top of the tank at that point depends on how much air
I put in when the tank was drained. The more initial air, the higher
the air pressure.

If it's not, then there's something wrong with your setup.

The bladder may be broken, but it is holding the air pressure.

Specifically, if
you pre-pressurise the tank to or beyond what the upper cutoff is,
the pump should never come on at all.

Correct me if I'm wrong, but isn't there a diaphragm or bladder made
out of rubber or something like that in the tank, with air above it
and water below it? When the tank is drained, there is no water in
the tank and pressurizing the air in the tank via the valve at the top
pressurizes the air above the diaphragm, but not below, right? (It
doesn't pressurize the whole tank, just the bladder, right?) Then the
pressurized air doesn't affect the water going in until it hits the
diaphragm, right?

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O.K. I think I see why you are misunderstanding the system. The
pressure in the tank is initially set by the pre-charge. The switch
will be set for a specific cut-in/cut-off. The pump starts and will
add about 20 psi to whatever pre-charge you put in and then cut off
when system pressure reaches the cut-off (62psi). Here is a basic
step-by-step.

Tank empty
20 psi
pump starts and pumps 40 psi until it reaches 60
cuts off.

You now have a tank containing water and an air bubble that is now
compressed to 60 psi.

you draw water.
Tank empties down as the air bubble expands
System pressure reaches 40 psi.
Pump cuts off.
At this point the air bubble has decreased only 20 psi
System repeats until something fails.

Your basic misunderstanding in your post is that the water is
compressed. No it is not, water cannot be compressed. The air
bubble, whether separated from the water by a bladder or not is what
makes the system run and is the only thing having pressure. Yes, it
does compress the bladder and thus presses on whatever is in the tank,
i.e, the entire tank both above and below the bladder senses the same
pressure. When the tank is empty the bladder will probably be resting
on the tank bottom with no water at all in the tank.

When you clean out the pipe to the pressure switch (should be a 1/8"
or 1/4" pipe) then re-pressurize the tank to about 40 psi (I think you
said it cuts off at 42psi). Watch the gauge. You will see it happily
cranking along between 40 and 60 psi (okay, a bit higher at your
settingss). Ignore testing teh pressure via the air fill valve on the
top of the tank other than when adding the pre-charge. It will always
be the same as the tank guage within the error range of the
instruments you are using.

Erratic operation could also be caused by a sticking pressure switch.

Harry K

According to Jud McCranie :
On Mon, 15 Nov 2004 17:07:45 -0500, "
wrote:

Yeah, but the pump is supposed to be cutting off at a specific pressure,
so boyles law or not, the upper limit should be constant.

The pump does cut off consistently at 57-58 PSI of the WATER. The AIR
pressure at the top of the tank at that point depends on how much air
I put in when the tank was drained. The more initial air, the higher
the air pressure.

Which is a violation of physics. In a closed vessel with liquid
and/or gas components, ALL of it will be at _exactly_ the same
pressure at any given moment. The presence of the diaphram can
essentially be ignored (if the diaphragm is in contact with both
components).

[There's a couple of teensy imperfections in this "ideal situation",
but we're talking less than .25PSI in this case.]

If you're reading a different pressure for the air and the water,
either your measurements are defective, or the points at which
you measure the air and water do not have a free flow of _pressure_
between them. Ie: there's a plug.

Correct me if I'm wrong, but isn't there a diaphragm or bladder made
out of rubber or something like that in the tank, with air above it
and water below it?

Right.

When the tank is drained, there is no water in
the tank and pressurizing the air in the tank via the valve at the top
pressurizes the air above the diaphragm, but not below, right?

Right.

(It
doesn't pressurize the whole tank, just the bladder, right?)

Right.

Then the
pressurized air doesn't affect the water going in until it hits the
diaphragm, right?

Right. Once the wqater hits the diaphragm, however, the water and air
pressure will be the same (within half a PSI).

So, if you're reading 68PSI on the air, and 50-ish PSI on the water when
the pump kicks out, something _very_ wierd is going on. I"ll bet on the
laws of physics being respected ;-)
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

On 16 Nov 2004 07:03:36 -0800, (Harry K)
wrote:
Your basic misunderstanding in your post is that the water is
compressed. No it is not, water cannot be compressed.

I know that water can't be compressed, I said that as water filled the
tank, it compressed the air at the top.

When you clean out the pipe to the pressure switch (should be a 1/8"
or 1/4" pipe)

It is a 3/4" outside diameter pipe going to it, but it has a connector
like this:
http://www.homedepot.com/prel80/HDUS...m.0& MID=9876

Thank you for all of your help and for being patient. It is working
acceptably well right now, so I'm going to try to wait until the new
year to replace the tank.

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In article , Jud McCranie wrote:
On Sun, 14 Nov 2004 18:00:13 GMT, (Doug Miller)
wrote:

Look, this isn't rocket science. Your pump control is set to come on at 42
psi, and shut off at 58. So shut off the power to the pump and drain the tank,
completely. Pressurize the tank to 40 psi. Turn the pump back on.

It is working OK with that pressure.

Maybe so, but it will work better with correct pressure.

If I drain the tank and
pressurize the tank to 40 PSI and then turn the pump on, the pressure
will be even higher.

Of course it will. The air is compressed by the water being pumped in. When
the pressure reaches 58 psi (the cutoff setting on your control), the pump
will shut off. That's how it's supposed to work.

The first time I drained the tank, I didn't pump
any air in. The second time I pumped it up to 11 PSI, turned on the
pump, and it compressed the air until it was at 46 PSI.

Indicates abnormal operation.

In article , Jud McCranie wrote:


If I drain the tank, pump up the air to more than 20 PSI, and then
turn the pump on, the final air pressure is going to be higher than 62
PSI. I'm willing to take bets on that.

Fine with me. How much do you want to wager?

There's _no_way_ that the pressure is _ever_ going to go higher than the
cutoff setting on the well control, unless the control malfunctions.

It has twice been said that this isn't rocket science, but there is
physics involved - Boyle's law. As a gas is compressed onto a smaller
volume, its pressure goes up.

And as soon as the pressure reaches the cutoff setting on the well control,
the pump shuts off, and the pressure goes no higher. If that does _not_
happen, then you need to replace the control unit, because it's
malfunctioning.

In article , Jud McCranie wrote:
On 15 Nov 2004 22:47:13 GMT, (Chris Lewis)
wrote:

If the unit has a small hose supplying the pressure switch, take it off, and
ream it (and the fittings) out with a pipe cleaner.

There is a 3/4" pipe coming off the main pipe that goes to the
pressure switch, and there is a circular pressure gauge coming off
that pipe. The pump cuts on and off consistently according to that
gauge. I'll have to drain the tank again to clean it out.

When you do, precharge the tank to 2 psi below the cut-ON setting on the
control. Trust me. That's how it's supposed to work.

In article , Jud McCranie wrote:
On Mon, 15 Nov 2004 17:07:45 -0500, "
wrote:

Yeah, but the pump is supposed to be cutting off at a specific pressure,
so boyles law or not, the upper limit should be constant.

The pump does cut off consistently at 57-58 PSI of the WATER. The AIR
pressure at the top of the tank at that point depends on how much air
I put in when the tank was drained. The more initial air, the higher
the air pressure.

You're getting different readings because you're using different gauges. One
or both is not accurate. Which one is "right" doesn't really matter.

The only thing that matters is the reading on the gauge at the well control.
If the pump comes on when *that* gauge reads 42 PSI, then you need to
precharge the tank with air to a reading of 40 PSI on *that* gauge. Forget
about the readings at the top of the tank. They are *not* relevant.


If it's not, then there's something wrong with your setup.

The bladder may be broken, but it is holding the air pressure.

If the bladder is broken, it unquestionably is *not* holding the air pressure,
any more than a broken balloon can hold air pressure. A pressure tank does not
need a bladder at all in order to function; however, without a bladder, the
air will eventually be absorbed by the water, a little at a time, until
there's almost no air left -- which is exactly the problem that prompted your
original post. The purpose of a bladder is to prevent this absorption.

Specifically, if
you pre-pressurise the tank to or beyond what the upper cutoff is,
the pump should never come on at all.

Correct me if I'm wrong, but isn't there a diaphragm or bladder made
out of rubber or something like that in the tank, with air above it
and water below it?

Normally, yes. In your case, though, the bladder has apparently ruptured.

When the tank is drained, there is no water in
the tank and pressurizing the air in the tank via the valve at the top
pressurizes the air above the diaphragm, but not below, right? (It
doesn't pressurize the whole tank, just the bladder, right?) Then the
pressurized air doesn't affect the water going in until it hits the
diaphragm, right?

AFAIK, that diaphragm is pretty near the bottom of the tank, so the air space
below it is so small as to be irrelevant.

In article , (Chris Lewis) wrote:

A _large_ tank (ie: anything approaching a hot water tank in size) is
suggestive of either an old-fashioned bladder-less tank, or cistern
requirements (ie: very low flowrate well).

Disagree. A large tank can also be indicative of a homeowner who likes to have
a really high pressure and flow rate in his shower, without short-cycling his
pump by a small draw-down. :-) At our previous place, we had a high-output
submersible pump (it would fill a 200-gallon livestock tank in about 10-12
minutes), and an 85-gallon pressure tank, with pressures set at 50/90.

On Wed, 17 Nov 2004 14:56:01 GMT, (Doug Miller)
wrote:

The only thing that matters is the reading on the gauge at the well control.
If the pump comes on when *that* gauge reads 42 PSI, then you need to
precharge the tank with air to a reading of 40 PSI on *that* gauge.

IIRC, after I drained the water, that gauge showed 0 PSI after I
drained the tank and still showed 0 after I pumped up the tank, which
seems to make sense if the diaphragm is not completely broken, but
only has a small leak.


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In article , Jud McCranie wrote:
On Wed, 17 Nov 2004 14:56:01 GMT, (Doug Miller)
wrote:

The only thing that matters is the reading on the gauge at the well control.
If the pump comes on when *that* gauge reads 42 PSI, then you need to
precharge the tank with air to a reading of 40 PSI on *that* gauge.

IIRC, after I drained the water, that gauge showed 0 PSI after I
drained the tank and still showed 0 after I pumped up the tank, which
seems to make sense if the diaphragm is not completely broken, but
only has a small leak.

No, it doesn't. Even in a tank with no diaphragm at all, the gauge should read
whatever pressure the tank has been precharged to, provided that:
a) the gauge is operating properly
b) there is no blockage in the tube leading to the gauge
c) all the valves are closed
d) there are no leaks in the system.

On Thu, 18 Nov 2004 01:17:00 GMT, (Doug Miller)
wrote:

No, it doesn't. Even in a tank with no diaphragm at all, the gauge should read
whatever pressure the tank has been precharged to ...

I checked it, and the water pressure gauge does go to 0 when I drain
the tank - even though the air bladder is still pressurized. I just
don't see how that gauge could be affected by the air pressure inside
the bladder, because that gauge is outside the bladder. With the
bladder/diaphragm between them, there is no contact between the air in
the bladder and the gauge in the water line. It is sort of like if
you measure the air pressure in one tire, it doesn't affect the
pressure in another tire.



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On 17 Nov 2004 19:40:44 -0800, (Harry K)
wrote:

Well yes but only after the pre-charge has been set. At least in my
tank and it sounds like in Jud's too the pressure gauge on the
well-trol reads 0 even with the correct precharge when the tank is
empty. I can only assume that the bag blocks the tank outlet.

That's what I think, but isn't the bag supposed to be airtight? (It
holds the pressure.)

Here's my setup. There is a pipe coming from the well, there is a T
off of that. There is a T off of one of those branches, and one leg
of that T goes to the pressure switch and the other goes to the water
pressure gauge. Back to the other leg of the T off the main line, one
leg goes into the house and the other goes into the bottom of the
tank. From what I understand, there is a diaphragm in the tank that
makes an air bladder at the top. On the top of the tank is a valve
similar to a tire gauge except that it is metal. I stick my air
pressure gauges to that, and use it to pump up the air.

When I drain the tank I cut off the pump and open a couple of faucets.
The water pressure gauge goes down to zero. The air pressure drops
down, but it holds at about 20 PSI (checked with 2 gauges). It holds
that way. Then I close the faucets. If I pump air into the top of
the tank, the pressure goes up there, but it has no effect on the
pressure at the water gauge. I think the diaphragm is keeping the air
in the bladder at the top of the tank, but I thought that is what it
is supposed to do.

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In article , Jud McCranie wrote:
On 17 Nov 2004 19:40:44 -0800, (Harry K)
wrote:

Well yes but only after the pre-charge has been set. At least in my
tank and it sounds like in Jud's too the pressure gauge on the
well-trol reads 0 even with the correct precharge when the tank is
empty. I can only assume that the bag blocks the tank outlet.

That's what I think, but isn't the bag supposed to be airtight? (It
holds the pressure.)

It's *supposed* to be, yes. Yours *isn't*. That's how your tank got
waterlogged.

Jud McCranie wrote in message . ..
On 17 Nov 2004 19:40:44 -0800, (Harry K)
wrote:

Well yes but only after the pre-charge has been set. At least in my
tank and it sounds like in Jud's too the pressure gauge on the
well-trol reads 0 even with the correct precharge when the tank is
empty. I can only assume that the bag blocks the tank outlet.

That's what I think, but isn't the bag supposed to be airtight? (It
holds the pressure.)

Here's my setup. There is a pipe coming from the well, there is a T
off of that. There is a T off of one of those branches, and one leg
of that T goes to the pressure switch and the other goes to the water
pressure gauge. Back to the other leg of the T off the main line, one
leg goes into the house and the other goes into the bottom of the
tank. From what I understand, there is a diaphragm in the tank that
makes an air bladder at the top. On the top of the tank is a valve
similar to a tire gauge except that it is metal. I stick my air
pressure gauges to that, and use it to pump up the air.

When I drain the tank I cut off the pump and open a couple of faucets.
The water pressure gauge goes down to zero. The air pressure drops
down, but it holds at about 20 PSI (checked with 2 gauges). It holds
that way. Then I close the faucets. If I pump air into the top of
the tank, the pressure goes up there, but it has no effect on the
pressure at the water gauge. I think the diaphragm is keeping the air
in the bladder at the top of the tank, but I thought that is what it
is supposed to do.

---
Replace you know what by j to email

Yes, your understanding is correct. Actually the bag does not hold
the air, it holds the water (the water is pumped into the bag or it is
in mine anyhow). The bag's only purpose is to separate the air from
the water. Without it (or a 'snifter valve') the air is absorbed into
the water shortly resulting in a waterlogged tank. That is why you
have your problem - the bag is broken allowing the air bubble to
gradually disappear. The reason you get a zero reading on the tank
gauge when you drain it is that the bag is blocking the tank
inlet/outlet. Thus that guage will read zero while the air valve on
top will show whatever pre-charge you have.

Use the gauge on top to establish the pre-charge with the tank empty.
Again that is 2 psi approx under the cut-in pressure. Once you have
that set correctly, use the tank gauge to monitor the system.

Harry K

According to Jud McCranie :
On Thu, 18 Nov 2004 01:17:00 GMT, (Doug Miller)
wrote:

No, it doesn't. Even in a tank with no diaphragm at all, the gauge should read
whatever pressure the tank has been precharged to ...

I checked it, and the water pressure gauge does go to 0 when I drain
the tank - even though the air bladder is still pressurized. I just
don't see how that gauge could be affected by the air pressure inside
the bladder, because that gauge is outside the bladder. With the
bladder/diaphragm between them, there is no contact between the air in
the bladder and the gauge in the water line. It is sort of like if
you measure the air pressure in one tire, it doesn't affect the
pressure in another tire.

This is suggestive that the bladder _is_ working properly.

When you relieve all the pressure off the water line, the diaphragm
"settles" down around the inlet and acts as a pressure dam.

But once the water starts to become pressurized and comes in contact
with the diaphragm and "lifts it off" the bottom, basic physics says
that the water and air pressure will be identical (within a PSI
or so). If they're not, your pressure gauges are simply not being
consistent.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.