Hello, I seem to have some problems with my water pump. If I just run one
home appliance for the water, the pressure drops pretty quickly.

For instance , Im trying to water my lawn now.. the pump gets up to 60 PSI ,
and then drops to about 37 PSI within 2 minutes...then the pump turns on
again. Doesnt this seem to be dropping too quickly? I wanted to run 2
sprinklers at the same time, but it seems impossible with the quick pressure
drops.

I have a picture of my setup here -

http://www.world-news-forums.com/well-water.JPG

maybe I need a bigger resorvoir ?

If temporarily increasing the water pressure just for the sprinklers would
work, im willing to do it. Just not sure which knob increases the pressure.
Any info would be awesome. (And I will be careful if I get some advice here
on increasing the pressure.)

thanks much,

john

----- Original Message -----
From: "Meat Plow"

Sounds like your tank is waterlogged. Have a plumber drain it and pump
some air into it unless you feel capable.

I never knew they needed air in them..is it something I could possibly do?
The container that says "Myers" thats where the water is stored in right?
Maybe I need a bigger one? seems so small.

"john" wrote in message
...
Hello, I seem to have some problems with my water pump. If I just
run one home appliance for the water, the pressure drops pretty
quickly.

For instance , Im trying to water my lawn now.. the pump gets up to
60 PSI , and then drops to about 37 PSI within 2 minutes...then the
pump turns on again. Doesnt this seem to be dropping too quickly?
I wanted to run 2 sprinklers at the same time, but it seems
impossible with the quick pressure drops.

I have a picture of my setup here -

http://www.world-news-forums.com/well-water.JPG

maybe I need a bigger resorvoir ?

If temporarily increasing the water pressure just for the sprinklers
would work, im willing to do it. Just not sure which knob increases
the pressure. Any info would be awesome. (And I will be careful if
I get some advice here on increasing the pressure.)

Put the sprinkler in a 5 gallon bucket and turn it on. How long does
it take to fill the bucket? If it takes about 1/2 a minute or so, you
probably have no problem with the reservoir. Otherwise, check the
pressure in it with the water pressure released. It should be 2 psi
less than your pump cut in pressure (35 psi).

What happens if you run 2 sprinklers? The pump may run full-time, but
does it supply sufficient pressure for the sprinklers? If so, you
again have no problem, unless your well cannot supply enough water
over time. If the pump runs full time but the pressure is
insufficient, then you need a more powerful pump to run two
sprinklers. Just run one at a time, or get lower volume sprinklers.

Bob

If temporarily increasing the water pressure just for the sprinklers
would work, im willing to do it. Just not sure which knob increases the
pressure. Any info would be awesome. (And I will be careful if I get
some advice here on increasing the pressure.)

Put the sprinkler in a 5 gallon bucket and turn it on. How long does it
take to fill the bucket? If it takes about 1/2 a minute or so, you
probably have no problem with the reservoir. Otherwise, check the pressure
in it with the water pressure released. It should be 2 psi less than your
pump cut in pressure (35 psi).

What happens if you run 2 sprinklers? The pump may run full-time, but does
it supply sufficient pressure for the sprinklers? If so, you again have no
problem, unless your well cannot supply enough water over time. If the
pump runs full time but the pressure is insufficient, then you need a more
powerful pump to run two sprinklers. Just run one at a time, or get lower
volume sprinklers.

Bob

Bob, I was already doing something before I came upon your post. I added
air to it so that its at 20 PSI now. Its suppose to be at 30PSI but my air
compressor wasnt strong enough.. It stopped at 20 PSI. (one of those
cigerrete lighter ones..i need to get a real one soon.)

But even at 20 PSI, the pump turns back on after 2 minutes of running the
water from one outlet at full strength. (didnt seem to make much of any
difference..maybe a little but thats it)

Like even if I run my bathroom faucet by itself at full blast (cold water)
the pump turns on anywhere from 90 seconds to 2 minutes. Is this a normal
time or no? Like what is the normal amount of time it should turn on after
one water outlet is running full blast?

The water flows good/strong...but once its at 37 PSI, its barely pumping out
from the sprinkler.

How bout temporarily adjusting the pump so that it cuts off at 70 or so?
I'll make sure I have the sprinklers on at all times when its at that
level.. Is there a way to adjust that or no?

On Jun 17, 1:59 pm, "john"
wrote:
If temporarily increasing the water pressure just for the sprinklers
would work, im willing to do it. Just not sure which knob increases the
pressure. Any info would be awesome. (And I will be careful if I get
some advice here on increasing the pressure.)

Put the sprinkler in a 5 gallon bucket and turn it on. How long does it
take to fill the bucket? If it takes about 1/2 a minute or so, you
probably have no problem with the reservoir. Otherwise, check the pressure
in it with the water pressure released. It should be 2 psi less than your
pump cut in pressure (35 psi).

What happens if you run 2 sprinklers? The pump may run full-time, but does
it supply sufficient pressure for the sprinklers? If so, you again have no
problem, unless your well cannot supply enough water over time. If the
pump runs full time but the pressure is insufficient, then you need a more
powerful pump to run two sprinklers. Just run one at a time, or get lower
volume sprinklers.

Bob

Bob, I was already doing something before I came upon your post. I added
air to it so that its at 20 PSI now. Its suppose to be at 30PSI but my air
compressor wasnt strong enough.. It stopped at 20 PSI. (one of those
cigerrete lighter ones..i need to get a real one soon.)

But even at 20 PSI, the pump turns back on after 2 minutes of running the
water from one outlet at full strength. (didnt seem to make much of any
difference..maybe a little but thats it)

Like even if I run my bathroom faucet by itself at full blast (cold water)
the pump turns on anywhere from 90 seconds to 2 minutes. Is this a normal
time or no? Like what is the normal amount of time it should turn on after
one water outlet is running full blast?

The water flows good/strong...but once its at 37 PSI, its barely pumping out
from the sprinkler.

How bout temporarily adjusting the pump so that it cuts off at 70 or so?
I'll make sure I have the sprinklers on at all times when its at that
level.. Is there a way to adjust that or no?- Hide quoted text -

- Show quoted text -

Increasing the pressure cut-off/on pressure in the tank will
_decrease_ the useable amouint of water it contains. You didn't
specify the procedure you used to check the air pressure (known as
"pre-charge") in the tank.

Proper and only way to do it right.

1. shut off pump.
2. Open a valve (preferably near the same level as the tank) until
water stops flowing.
3. Shut valve and check the pressure. You seem to have it set now at
40-60 (within reason) so the pre-charge should be 38 or 2 psi below
the cut-in pressure.

You might buy a portable air tank and fill it at a gas station for a
source of hight pressure air.

It sounds like your tank is too small. Mine stands almost 6ft high
and will haul 3 heads about 4 minutes (never checked it) between
cycles.

Harry K

Proper and only way to do it right.

1. shut off pump.
2. Open a valve (preferably near the same level as the tank) until
water stops flowing.
3. Shut valve and check the pressure. You seem to have it set now at
40-60 (within reason) so the pre-charge should be 38 or 2 psi below
the cut-in pressure.

I use the same gauge thats on the water tank for the reading right?

and is it possible to check the pressure with a seperate gauge that attaches
to the air valve at the top of the tank?

My tank (thats in the initial post picture) is only about 5 feet high. Im
guessing its the tank then... crap..

On Jun 17, 7:51 pm, "john"
wrote:
Proper and only way to do it right.
1. shut off pump.
2. Open a valve (preferably near the same level as the tank) until
water stops flowing.
3. Shut valve and check the pressure. You seem to have it set now at
40-60 (within reason) so the pre-charge should be 38 or 2 psi below
the cut-in pressure.

I use the same gauge thats on the water tank for the reading right?

and is it possible to check the pressure with a seperate gauge that attaches
to the air valve at the top of the tank?

My tank (thats in the initial post picture) is only about 5 feet high. Im
guessing its the tank then... crap..

I am on dialup so didn't check the picture at first. That looks like
a new installation. The tank looks plenty large to do a reasonable
watering job (2-3 heads at least).

Yes, normally use the same gauge as there is some variance in the
usual ones. You can check it either by the one on the tank or by the
fitting on top but the process is the same in either case.

If you do decide that you need more storeage, you can add another tank
working in conjunction with the one you have. It would just tee off
of the pipe leading in/out of your current tank.

Harry K

"john" wrote in message
...

If temporarily increasing the water pressure just for the
sprinklers
would work, im willing to do it. Just not sure which knob
increases the pressure. Any info would be awesome. (And I will be
careful if I get some advice here on increasing the pressure.)

Put the sprinkler in a 5 gallon bucket and turn it on. How long
does it take to fill the bucket? If it takes about 1/2 a minute or
so, you probably have no problem with the reservoir. Otherwise,
check the pressure in it with the water pressure released. It
should be 2 psi less than your pump cut in pressure (35 psi).

What happens if you run 2 sprinklers? The pump may run full-time,
but does it supply sufficient pressure for the sprinklers? If so,
you again have no problem, unless your well cannot supply enough
water over time. If the pump runs full time but the pressure is
insufficient, then you need a more powerful pump to run two
sprinklers. Just run one at a time, or get lower volume sprinklers.

Bob

Bob, I was already doing something before I came upon your post. I
added air to it so that its at 20 PSI now. Its suppose to be at
30PSI but my air compressor wasnt strong enough.. It stopped at 20
PSI. (one of those cigerrete lighter ones..i need to get a real
one soon.)

Even car tires need more than 20 psi. Are you sure?

Remember, guages may be wrong. Do you have a tire guage? The pressure
in the bladder tank shoud be 2 psi less than the cut-in pressure of
the pump switch, when water pressure is released with the pump off. Do
you have a manual tire pump?


But even at 20 PSI, the pump turns back on after 2 minutes of
running the water from one outlet at full strength. (didnt seem to
make much of any difference..maybe a little but thats it)

How much water is that? Measure it.


Like even if I run my bathroom faucet by itself at full blast (cold
water) the pump turns on anywhere from 90 seconds to 2 minutes. Is
this a normal time or no? Like what is the normal amount of time it
should turn on after one water outlet is running full blast?

How much water is that? Different faucets have different flow. My hose
bibb puts out about 15 gallons / minute. That would cycle your tank
pretty quick.


The water flows good/strong...but once its at 37 PSI, its barely
pumping out from the sprinkler.

You have a differential of 23 psi, which seems pretty large. You can
change it (look for instructions inside the pressure switch cover),
but it will shorten the cycle even more. Is you do this, you also need
to increase your pressure tank pressure.

How long is your hose? What water volume does the sprinkler use per
minute? What diameter is the inside of you hose? Does the sprinkler
work OK if you connect it directly to your faucet. If so, get a bigger
diameter and/or shorter hose.


How bout temporarily adjusting the pump so that it cuts off at 70 or
so?

Don't increase the cut-out pressure. Increase the cut-in to the
minimum usable.

I'll make sure I have the sprinklers on at all times when its at
that level.. Is there a way to adjust that or no?

If your pump can't get it above 39 when it switches on, changing the
settings isn't going to help. If it can, changing the cut-in pressure
will help with the sprinklers, but will shorten the cycle otherwise.

When you run 2 sprinklers, what does the pressure do? Does it get down
to 39, switch on the pump, which then run continuously, gradually
increasing pressure until it stabilizes at something below cut-out? Or
does the pressure increase to cut out, then drop again? Or does it
drop from 39? It all depends on the pumping capacity of the pump and
piping and the sprinkler need. When you run sprinklers, the pump will
either cycle or run continuously. You can add storage, which would
increase the cycle time, but the pump will still cycle if it pumps
more water than you are using.

It's probably better for your pump to pump continuously rather than
cycle on/off when you are watering, if your water supply can keep up
with it. If the pump cycles with 2 sprinklers, try using more and see
if you hit a balance point where the pressure is sufficient but the
pump keeps running.

Bob

On Jun 18, 10:50 am, "Bob F" wrote:
"john" wrote in message

...







If temporarily increasing the water pressure just for the
sprinklers
would work, im willing to do it. Just not sure which knob
increases the pressure. Any info would be awesome. (And I will be
careful if I get some advice here on increasing the pressure.)

Put the sprinkler in a 5 gallon bucket and turn it on. How long
does it take to fill the bucket? If it takes about 1/2 a minute or
so, you probably have no problem with the reservoir. Otherwise,
check the pressure in it with the water pressure released. It
should be 2 psi less than your pump cut in pressure (35 psi).

What happens if you run 2 sprinklers? The pump may run full-time,
but does it supply sufficient pressure for the sprinklers? If so,
you again have no problem, unless your well cannot supply enough
water over time. If the pump runs full time but the pressure is
insufficient, then you need a more powerful pump to run two
sprinklers. Just run one at a time, or get lower volume sprinklers.

Bob

Bob, I was already doing something before I came upon your post. I
added air to it so that its at 20 PSI now. Its suppose to be at
30PSI but my air compressor wasnt strong enough.. It stopped at 20
PSI. (one of those cigerrete lighter ones..i need to get a real
one soon.)

Even car tires need more than 20 psi. Are you sure?

Remember, guages may be wrong. Do you have a tire guage? The pressure
in the bladder tank shoud be 2 psi less than the cut-in pressure of
the pump switch, when water pressure is released with the pump off. Do
you have a manual tire pump?



But even at 20 PSI, the pump turns back on after 2 minutes of
running the water from one outlet at full strength. (didnt seem to
make much of any difference..maybe a little but thats it)

How much water is that? Measure it.



Like even if I run my bathroom faucet by itself at full blast (cold
water) the pump turns on anywhere from 90 seconds to 2 minutes. Is
this a normal time or no? Like what is the normal amount of time it
should turn on after one water outlet is running full blast?

How much water is that? Different faucets have different flow. My hose
bibb puts out about 15 gallons / minute. That would cycle your tank
pretty quick.



The water flows good/strong...but once its at 37 PSI, its barely
pumping out from the sprinkler.

You have a differential of 23 psi, which seems pretty large. You can
change it (look for instructions inside the pressure switch cover),
but it will shorten the cycle even more. Is you do this, you also need
to increase your pressure tank pressure.

How long is your hose? What water volume does the sprinkler use per
minute? What diameter is the inside of you hose? Does the sprinkler
work OK if you connect it directly to your faucet. If so, get a bigger
diameter and/or shorter hose.



How bout temporarily adjusting the pump so that it cuts off at 70 or
so?

Don't increase the cut-out pressure. Increase the cut-in to the
minimum usable.

I'll make sure I have the sprinklers on at all times when its at
that level.. Is there a way to adjust that or no?

If your pump can't get it above 39 when it switches on, changing the
settings isn't going to help. If it can, changing the cut-in pressure
will help with the sprinklers, but will shorten the cycle otherwise.

When you run 2 sprinklers, what does the pressure do? Does it get down
to 39, switch on the pump, which then run continuously, gradually
increasing pressure until it stabilizes at something below cut-out? Or
does the pressure increase to cut out, then drop again? Or does it
drop from 39? It all depends on the pumping capacity of the pump and
piping and the sprinkler need. When you run sprinklers, the pump will
either cycle or run continuously. You can add storage, which would
increase the cycle time, but the pump will still cycle if it pumps
more water than you are using.

It's probably better for your pump to pump continuously rather than
cycle on/off when you are watering, if your water supply can keep up
with it. If the pump cycles with 2 sprinklers, try using more and see
if you hit a balance point where the pressure is sufficient but the
pump keeps running.

Bob- Hide quoted text -

- Show quoted text -

Some minor comments.

23psi is right on the normal pressure differential for residential
systems (allowing for gauge variations). Normal settings a

20/40 - Too low if irrigating.
30/50 - adequate and will run sprinklers. Some sprinklers will have
problems at the 30 psi end of the cycle.
40/60 - No need that I know of for a residence to ever go higher.
Higher ranges are not recommended due to excess wear on fixtures.

The "2psi below cut-in" optimizes the pump run time.

His 20 psi pre-charge is too low but it has nothing to do with the
'delivered pressure'. If the the switch is set 40/60 with 20psi
precharge water will still be coming out of the tank between 40/60
psi.
Pump will cycle more is all.

Harry K

On Jun 17, 12:24 pm, "john"
wrote:
Hello, I seem to have some problems with my water pump. If I just run one
home appliance for the water, the pressure drops pretty quickly.

For instance , Im trying to water my lawn now.. the pump gets up to 60 PSI ,
and then drops to about 37 PSI within 2 minutes...then the pump turns on
again. Doesnt this seem to be dropping too quickly? I wanted to run 2
sprinklers at the same time, but it seems impossible with the quick pressure
drops.

I have a picture of my setup here -

http://www.world-news-forums.com/well-water.JPG

maybe I need a bigger resorvoir ?

If temporarily increasing the water pressure just for the sprinklers would
work, im willing to do it. Just not sure which knob increases the pressure.
Any info would be awesome. (And I will be careful if I get some advice here
on increasing the pressure.)

thanks much,

john

Just a quck thought. Do you have a filter after the pressue tank? If
so when was the last time you changed it. My sprinklers would not work
properly due to lower pressure after about 20 seconds of being on.
This kept on happening.

I changed the filter to dump out all the clogged earth etc. Then
sprinklers worked fine.

Best, Mike.

I appreciate all the advice here.

Alright, adding that 20 PSI air to the tank seems to have helped alot....BUT
I still cycle about once every 80 seconds. the sprinkler I have is the
largest the store had...im not sure on the exact size but it covers the most
amount of land out of all others..and is one of those sprinklers that goes
back and forth. I was never even able to get this amount of pressure out
of my sprinkler before.. It shoots out very good now and continues like that
all the time...even when the pressure is down to 37 PSI. The sprinkler
covers about a 1/8 acre of land. pretty powerful. That is estimated of
course. Im sure if I was able to get 30 PSI into it, it would be even
better...but i'll have to buy one of those power washer things for that.
(with the powerful air compressor)

So im guessing it worked...because before when I was down to 37 PSI, the
water would barely come out of the sprinkler. So it fixed it, even though
it still short cycles...the water comes out really good now and stays like
that throughout. Im proud of this.

I guess the next question is...is it normal to cycle once every 80 seconds
when so much water is being pumped out like this? I still dont think
anybody answered what is the general normal time that a pump cycles if a
cold water faucet is on full blast ? Mine doesnt seem to go past 90
seconds.

Just a quck thought. Do you have a filter after the pressue tank? If
so when was the last time you changed it. My sprinklers would not work
properly due to lower pressure after about 20 seconds of being on.
This kept on happening.

I changed the filter to dump out all the clogged earth etc. Then
sprinklers worked fine.

Best, Mike.

wow hobbes...thats crazy that you recommended that.. because I also did that
yesterday while adding the air to the tank. Maybe thats what fixed
everything. My sediment filter was clogged pretty good.

"john" wrote in message
...
I appreciate all the advice here.

Alright, adding that 20 PSI air to the tank seems to have helped
alot....BUT I still cycle about once every 80 seconds. the
sprinkler I have is the largest the store had...im not sure on the
exact size but it covers the most amount of land out of all
others..and is one of those sprinklers that goes back and forth. I
was never even able to get this amount of pressure out of my
sprinkler before.. It shoots out very good now and continues like
that all the time...even when the pressure is down to 37 PSI. The
sprinkler covers about a 1/8 acre of land. pretty powerful. That
is estimated of course. Im sure if I was able to get 30 PSI into
it, it would be even better...but i'll have to buy one of those
power washer things for that. (with the powerful air compressor)

So im guessing it worked...because before when I was down to 37 PSI,
the water would barely come out of the sprinkler. So it fixed it,
even though it still short cycles...the water comes out really good
now and stays like that throughout. Im proud of this.

The filter fixed the sprinkler problem. More air in the tank will
lessen the short cycle problem.

I guess the next question is...is it normal to cycle once every 80
seconds when so much water is being pumped out like this? I still
dont think anybody answered what is the general normal time that a
pump cycles if a cold water faucet is on full blast ? Mine doesnt
seem to go past 90 seconds.

Again (the third time) how much water is the sprinkler using? How big
is the pressure tank? The combination, along with some factor for the
amount of the tank that going from 39 to 60 psi fills, will tell you
if the tank is working right. Probably, adjusting the air in the tank
correctly will make a significant difference.

I'd guess that factor would be .25, since filling the tank half way
should double the initial pressure to 80. Pressurizing the water to 60
should take it to half that. So your tank would supply 1/4 its volume
of water between pump off and pump on. Someone correct me if I'm
wrong.

http://www.doh.wa.gov/ehp/dw/Publica...42_4-18-06.pdf

Bob

Doing a little more mental calculation, Having the tank pressurized to
20 initially would mean that when it gets to the 40 psi cut-in, the
tank is already half full, so you are only getting half its useful
volume during a pump cycle.

Bob

On Jun 18, 3:27 pm, "john"
wrote:
I appreciate all the advice here.

Alright, adding that 20 PSI air to the tank seems to have helped alot....BUT
I still cycle about once every 80 seconds. the sprinkler I have is the
largest the store had...im not sure on the exact size but it covers the most
amount of land out of all others..and is one of those sprinklers that goes
back and forth. I was never even able to get this amount of pressure out
of my sprinkler before.. It shoots out very good now and continues like that
all the time...even when the pressure is down to 37 PSI. The sprinkler
covers about a 1/8 acre of land. pretty powerful. That is estimated of
course. Im sure if I was able to get 30 PSI into it, it would be even
better...but i'll have to buy one of those power washer things for that.
(with the powerful air compressor)

So im guessing it worked...because before when I was down to 37 PSI, the
water would barely come out of the sprinkler. So it fixed it, even though
it still short cycles...the water comes out really good now and stays like
that throughout. Im proud of this.

I guess the next question is...is it normal to cycle once every 80 seconds
when so much water is being pumped out like this? I still dont think
anybody answered what is the general normal time that a pump cycles if a
cold water faucet is on full blast ? Mine doesnt seem to go past 90
seconds.

With that low a pre-charged and such a big sprinkler I am not
surprised at the short cycle time. You do not need an expensive
compressor, a hand pump will do 40psi. There are also small 'non-
tank' compressors which is what I have. Very useful and not very
spendy. Campbell-Hausfeld Power Pal.

Pump cycle time is not a one-size fits all. It depends on:

Tank size
Pre-charge pressure
Pump output (how much water does it pump/how fast)
How much water is going through the sprinklers.

Without knowing all of those, no one can give a meaningful answer.

Someone else has asked (and I meant to) whether you have a filter in
the system. If it is after the tank it can cause the 'just dribbling
effect' and low pressure. Any whole system (filters all the water)
should be installed in the line between the pump and the pressure
tank.

Harry K

On Jun 18, 6:41 pm, "Bob F" wrote:
Doing a little more mental calculation, Having the tank pressurized to
20 initially would mean that when it gets to the 40 psi cut-in, the
tank is already half full, so you are only getting half its useful
volume during a pump cycle.

Bob

You are still missing how the pre-charge works. When the system
reaches cut-in (40 in this case) the tank will be empty no matter what
the pre-charge is. The pre-charge has no effect on delivered
pressure, only on the useable volume of water per cycle.

Harry K

"Harry K" wrote in message
ups.com...
On Jun 18, 6:41 pm, "Bob F" wrote:
Doing a little more mental calculation, Having the tank pressurized
to
20 initially would mean that when it gets to the 40 psi cut-in, the
tank is already half full, so you are only getting half its useful
volume during a pump cycle.

Bob

You are still missing how the pre-charge works. When the system
reaches cut-in (40 in this case) the tank will be empty no matter
what
the pre-charge is. The pre-charge has no effect on delivered
pressure, only on the useable volume of water per cycle.


If the precharge is 20, at 40 the tank will be half full, to compress
the precharge to 40, leaving less than desirable volume. I have no
disagreement with the second sentence - I never said otherwise.

Bob

On Jun 18, 9:31 pm, "Bob F" wrote:
"Harry K" wrote in message

ups.com...

On Jun 18, 6:41 pm, "Bob F" wrote:
Doing a little more mental calculation, Having the tank pressurized
to
20 initially would mean that when it gets to the 40 psi cut-in, the
tank is already half full, so you are only getting half its useful
volume during a pump cycle.

Bob

You are still missing how the pre-charge works. When the system
reaches cut-in (40 in this case) the tank will be empty no matter
what
the pre-charge is. The pre-charge has no effect on delivered
pressure, only on the useable volume of water per cycle.

If the precharge is 20, at 40 the tank will be half full, to compress
the precharge to 40, leaving less than desirable volume. I have no
disagreement with the second sentence - I never said otherwise.

Bob

After thinking about it a bit...well quite a bit. I think you are
correct.

Harry K

Harry K wrote:
On Jun 18, 9:31 pm, "Bob F" wrote:
"Harry K" wrote in message

ups.com...

On Jun 18, 6:41 pm, "Bob F" wrote:
Doing a little more mental calculation, Having the tank pressurized
to
20 initially would mean that when it gets to the 40 psi cut-in, the
tank is already half full, so you are only getting half its useful
volume during a pump cycle.
Bob
You are still missing how the pre-charge works. When the system
reaches cut-in (40 in this case) the tank will be empty no matter
what
the pre-charge is. The pre-charge has no effect on delivered
pressure, only on the useable volume of water per cycle.
If the precharge is 20, at 40 the tank will be half full, to compress
the precharge to 40, leaving less than desirable volume. I have no
disagreement with the second sentence - I never said otherwise.

Bob

After thinking about it a bit...well quite a bit. I think you are
correct.

Pardon me for butting in, and I haven't seen the earlier portion of the
thread so I may be missing the point but just in case I didn't...

These last several repartees are based it seems on the assumption the
precharge volume is the same as the total tank volume but it isn't.

Thus a

On Jun 19, 5:39 am, dpb wrote:
Harry K wrote:
On Jun 18, 9:31 pm, "Bob F" wrote:
"Harry K" wrote in message

roups.com...

On Jun 18, 6:41 pm, "Bob F" wrote:
Doing a little more mental calculation, Having the tank pressurized
to
20 initially would mean that when it gets to the 40 psi cut-in, the
tank is already half full, so you are only getting half its useful
volume during a pump cycle.
Bob
You are still missing how the pre-charge works. When the system
reaches cut-in (40 in this case) the tank will be empty no matter
what
the pre-charge is. The pre-charge has no effect on delivered
pressure, only on the useable volume of water per cycle.
If the precharge is 20, at 40 the tank will be half full, to compress
the precharge to 40, leaving less than desirable volume. I have no
disagreement with the second sentence - I never said otherwise.

Bob

After thinking about it a bit...well quite a bit. I think you are
correct.

Pardon me for butting in, and I haven't seen the earlier portion of the
thread so I may be missing the point but just in case I didn't...

These last several repartees are based it seems on the assumption the
precharge volume is the same as the total tank volume but it isn't.

Thus a- Hide quoted text -

- Show quoted text -

Oh? Since the precharge is added with the tank empty, why wouldn't it
be the 'total tank volume'? Of course it isn't once the pump kicks in
and adds water into the tank compressing that air bubble.

Harry K

Harry K wrote:
On Jun 19, 5:39 am, dpb wrote:
Harry K wrote:
On Jun 18, 9:31 pm, "Bob F" wrote:
"Harry K" wrote in message
ups.com...
On Jun 18, 6:41 pm, "Bob F" wrote:
Doing a little more mental calculation, Having the tank pressurized
to
20 initially would mean that when it gets to the 40 psi cut-in, the
tank is already half full, so you are only getting half its useful
volume during a pump cycle.
Bob
You are still missing how the pre-charge works. When the system
reaches cut-in (40 in this case) the tank will be empty no matter
what
the pre-charge is. The pre-charge has no effect on delivered
pressure, only on the useable volume of water per cycle.
If the precharge is 20, at 40 the tank will be half full, to compress
the precharge to 40, leaving less than desirable volume. I have no
disagreement with the second sentence - I never said otherwise.
Bob
After thinking about it a bit...well quite a bit. I think you are
correct.
Pardon me for butting in, and I haven't seen the earlier portion of the
thread so I may be missing the point but just in case I didn't...

These last several repartees are based it seems on the assumption the
precharge volume is the same as the total tank volume but it isn't.

Thus a- Hide quoted text -

- Show quoted text -

Oh? Since the precharge is added with the tank empty, why wouldn't it
be the 'total tank volume'? Of course it isn't once the pump kicks in
and adds water into the tank compressing that air bubble.

Because there's a diaphragm or bladder that isn't symmetric...

--

On Jun 19, 7:16 am, dpb wrote:
Harry K wrote:
On Jun 19, 5:39 am, dpb wrote:
Harry K wrote:
On Jun 18, 9:31 pm, "Bob F" wrote:
"Harry K" wrote in message
egroups.com...
On Jun 18, 6:41 pm, "Bob F" wrote:
Doing a little more mental calculation, Having the tank pressurized
to
20 initially would mean that when it gets to the 40 psi cut-in, the
tank is already half full, so you are only getting half its useful
volume during a pump cycle.
Bob
You are still missing how the pre-charge works. When the system
reaches cut-in (40 in this case) the tank will be empty no matter
what
the pre-charge is. The pre-charge has no effect on delivered
pressure, only on the useable volume of water per cycle.
If the precharge is 20, at 40 the tank will be half full, to compress
the precharge to 40, leaving less than desirable volume. I have no
disagreement with the second sentence - I never said otherwise.
Bob
After thinking about it a bit...well quite a bit. I think you are
correct.
Pardon me for butting in, and I haven't seen the earlier portion of the
thread so I may be missing the point but just in case I didn't...

These last several repartees are based it seems on the assumption the
precharge volume is the same as the total tank volume but it isn't.

Thus a- Hide quoted text -

- Show quoted text -

Oh? Since the precharge is added with the tank empty, why wouldn't it
be the 'total tank volume'? Of course it isn't once the pump kicks in
and adds water into the tank compressing that air bubble.

Because there's a diaphragm or bladder that isn't symmetric...

--- Hide quoted text -

- Show quoted text -

Any diagram of a bladder tank that I have seen (I haven't cut one open
to check) shows the bladder collapsed against the bottom of the tank
when it is empty.

Harry K