Home water pump system short cycling

[JHZR2]

I have municipal water, so are not sure what this means. Say water is pulled to a diaphragm storage vessel, filled via a pump. No idea on quality or status of the storage tank... But it is the same kind of a tank that folks on wells have.

Say the pump short cycles and runs often. What does this mean? Not enough air pressure in the diaphragm?

I assume checking the pressure via the schrader valve would give indication?

Thanks!

 

[Carbon]

It could be water is being used. Maybe the flapper in the toilet needs replacing.

 

[Rand]

you probably have a booster pump to increase pressure.


just checking the pressure wont tell you anything.. Its probably waterlogged.


I can explain more if that doesnt make sense..


basically if there is too much water and not enough air it will short cycle because the air compresses and the water doesnt. but the pressure will be the same.(waterlogged or not)

you can sometimes tell by timing the system if its waterlogged.

for example a system has an old water tank and when properly filled will take about 2m25s to cycle
when water logged its usually 45s or less.

I usually end up taking my air compressor over about once every 6-8 monthes... its alot cheaper than buying a new tank.

 

[doitmyself]

I didn't know that they use home pressure tanks with municipal water supplies.

One possibility is that the vinyl bladder or diaphragm (depending on design) in the pressure tank is broken.

 

[strongt]

Maybe this info in this article will help you:

Link

 

[JHZR2]

Originally Posted By: doitmyself
I didn't know that they use home pressure tanks with municipal water supplies.

One possibility is that the vinyl bladder or diaphragm (depending on design) in the pressure tank is broken.


This isn't in my home. It's in another home in a place where water conservation is VERY necessary, so no leaks.

The waterlogged thing sounds plausible. Is there a diaphragm in there or just air? Can I just pump air in (assuming the pressure is low or just water comes out) to fix, or are other steps needed?

 

[spasm3]

If it was an inground well pump id say the foot valve, but on municipal system i have no idea. I know on the old bladderless tanks you had to add air when it got water logged. If i remember, my father added air about once a year.

 

[Rand]

http://www.thisoldhouse.com/toh/video/0,,20305378,00.html

shows them installing a booster system.


depends on the tank if you can just add air or not.

it shouldnt hurt anything to add some air and see if it helps any but I'm not a plumber

What I do if I'm in a hurry is shut off pump (in your case incoming water too)
turn on the water somewhere.. sink shower whatever.
when the water pressure gets low I turn off the water

then turn off the water at the tank exit.

then air it upto near design turn on pressure

in my case the pump kicks on at 30psi and stops at 50psi

so when the tank was nearly drained I aired it upto 28psi

then turn all the water back to normal.. ie pump on.. all valves open etc.

let pump fill the tank.. then time the drawdown and fill up.

and if I mangled any terms in there.. sorry professionals

not sure how this works with some of the newer bladder systems but the one I work on loses air and What I do fixes it for 6-8 monthes or so.

 

[JHZR2]

This is NOT a municipal system. As I personally have municipal water, that's why I'm not familiar for this alternate location.

Rand - thanks for the great write-up!

 

[spasm3]

Originally Posted By: JHZR2
This is NOT a municipal system. As I personally have municipal water, that's why I'm not familiar for this alternate location.

Rand - thanks for the great write-up!


Is is cycling with no water use? If you can watch the gauge and the pressure drops right after the pump stops with out water usage, then the water is leaking back into the well via a bad foot valve. In other words, the bladder air tank is pushing the water back into the well after the pump stops. This wears the pump motor as it is simply shuttling water back and forth. If the pump is rapid cycling only with water useage then it needs air in the tank/bladder.

 

[JHZR2]

Good stuff. There is no well, it's a cistern and is roughly the same level but will try to pay attention to this tomorrow.

 

[Rand]

Originally Posted By: JHZR2
Good stuff. There is no well, it's a cistern and is roughly the same level but will try to pay attention to this tomorrow.


yea some more details would help us .. help you

maybe a couple cell phone pics or something.

 

[Rick in PA]

Originally Posted By: doitmyself
I didn't know that they use home pressure tanks with municipal water supplies.

One possibility is that the vinyl bladder or diaphragm (depending on design) in the pressure tank is broken.


Likely this. If the bladder breaks, the water in the system will start to absorb the (compressed) air. At some point, no more compressed air, just water in the accumulator and it short cycles. You can add more air and it will work again for a while, but over time the air absorbs (diffuses) back into the water and the system resumes short cycling. The only long term solution is to replace the accumulator tank.

 

[JHZR2]

Here is what happens. Had a shower on during the time.

 

[rjundi]

Short cycling may indicate the pressure tank needs more air in the bladder in it or is leaking. It also can be a leak in the line leading into the home (my recent case).

Actually watching your video, the pressure switch is bad is the first step. Don't bother adjusting it, just replace it. It is very inexpensive (I think <$30).

 

[JHZR2]

Originally Posted By: rjundi


Actually watching your video, the pressure switch is bad is the first step. Don't bother adjusting it, just replace it. It is very inexpensive (I think div>


Can you explain how you determined that?

I'm pretty sure the pressure gauge is stuck, btw.

 

[rjundi]

Originally Posted By: JHZR2
Originally Posted By: rjundi


Actually watching your video, the pressure switch is bad is the first step. Don't bother adjusting it, just replace it. It is very inexpensive (I think div>


Can you explain how you determined that?

I'm pretty sure the pressure gauge is stuck, btw.


Is there a bladder tank somewhere down the line? If yes it should sound hollow and clinking when you hit with knuckle. If its solid then its full and either needs air added/water purged or replacement.

The pump will cycle just like that if the pressure tank is not working OR if the pressure switch is defective as the slight variance in pressure is simply turning the pump on/off. These systems are quite simple typically.

 

[Rick in PA]

Replace the pressure gauge.

If the pressure relatively quickly swings between the anticipated set-points. I'd say it's accumulator time. It's been a while since I've worked on this type of system, maybe a 20 to 30 PSI differential (somebody who knows, feel free to chime in).

If the pressure doesn't change that much, go for the pressure switch.

 

[JHZR2]

Added air to the tank and the pump runs much longer between cycles.

Much better.

Next step is fixing the gauge and some wiring.

 

[Rick in PA]

Hmmm... pointing towards the accumulator. We had a well at our last house and I ended-up replacing everything between the well (with an in-well pump) and the house pluming system. About 20 years ago. Basically, the accumulator was shot, but everything else was due for replacement. The one thing I remember was our water smelled like PVC plastic for a while after the work. I guess the accumulator had a vinyl bladder.