well pump pressure switch

[Bradfurd]

Our shower has been kicking off after several minutes of use...I've been researching possible causes, and I think it's either the pressure switch or the tank. I'm thinking I'll replace the switch first, and if the problem isn't solved, try the tank. There is visible damage (hard water) and a miniscule leak near the baseplate of the switch. I'm thinking this isn't good!

The pressure gauge is reading 38 psi, but the switch is a 30/50 and the tank is rated for the same, meaning that the system should be set at 28 psi (2psi below the 30 rating), right? Could the previous owner have adjusted the switch?

Should I buy a new 30/50 gauge and set the pressure to 28 or should I buy a 40/60? If I buy a 30/50 and set the system to 28psi, will that noticeably impact my pressure throughout my home and at my RO drinking water system upstairs?

[Syonyk]

I think you should do more troubleshooting before you throw parts at the problem.

A well pump and pressure tank setup is pretty simple to troubleshoot.

Go watch the gauge while someone runs the water.  It should swing between your low point and high point, with a few minutes of normal water flow between the two.  If it's cycling very rapidly, your tank is probably shot.  If the pressure drops, and drops, and drops, and the pump doesn't kick on until 10 psi or something, your pressure switch is bad.

[Bradfurd]

Thanks for the tips...I will do that.

Hopefully my gauge isn't shot as well.

[trammatic]

The pressure gauge is reading 38 psi, but the switch is a 30/50 and the tank is rated for the same, meaning that the system should be set at 28 psi (2psi below the 30 rating), right? Could the previous owner have adjusted the switch?

You're right, but did you relieve the pressure from the system before checking the pressure?  Pretty easy to do--cut the breaker for the well, then open a tap until water stops flowing.  THEN the pressure should be 28 psi.

[Bradfurd]

Ahh, I see. Makes sense. I haven't done that yet, but I will. Thanks!

[Syonyk]

You're right, but did you relieve the pressure from the system before checking the pressure?  Pretty easy to do--cut the breaker for the well, then open a tap until water stops flowing.  THEN the pressure should be 28 psi.

Huh?

If I turned off my well pump and opened a tap, the pressure would get to nearly zero.

Maybe I'm misunderstanding the system in question.  My system description:
- Fixed speed 240V well pump down at the bottom of the well.
- A pair of pressure tanks in the crawlspace (based on what I could fit through the man access door).
- A pressure switch to control the well pump.
- A pressure gauge/drain/etc.

My pressure switch is set to 60/40.  It'll turn the well pump on somewhere around 40psi, and turn it off somewhere around 60psi.

I'm not sure I understand either the exact nature of problem or the system in question at this point.  More details would be useful.

[BudgetSlasher]

You're right, but did you relieve the pressure from the system before checking the pressure?  Pretty easy to do--cut the breaker for the well, then open a tap until water stops flowing.  THEN the pressure should be 28 psi.

Huh?

If I turned off my well pump and opened a tap, the pressure would get to nearly zero.

Maybe I'm misunderstanding the system in question.  My system description:
- Fixed speed 240V well pump down at the bottom of the well.
- A pair of pressure tanks in the crawlspace (based on what I could fit through the man access door).
- A pressure switch to control the well pump.
- A pressure gauge/drain/etc.

My pressure switch is set to 60/40.  It'll turn the well pump on somewhere around 40psi, and turn it off somewhere around 60psi.

I'm not sure I understand either the exact nature of problem or the system in question at this point.  More details would be useful.

I believe what he is getting at is that the air pressure behind the diaphragm in the pressure vessel should read 28 PSI (in this 30 PSI system) without the domestic water system being pressurized and pressing against the diaphragm thus increasing the pressure on the air side of the diaphragm.

Some other points.

Yes, the prior owner could have adjusted the pressure cut in and cut out points (dependent on the switch) I raised ours from 20/40 to 40/60 when we moved it. (as a side not we love the increased pressure in the shower, though, I believe, a properly size pressure vessel for 40/60 is larger than 30/50 or 20/40)

Kicking off? Do you mean that the shower goes completely dead? Does the shower go from full pressure to off or does it taper from full pressure to low pressure to dead? How big is your pressure vessel? What is the GPM of your shower head? Does this problem occur anywhere else (for example an exterior house or high GPM laundry sink)? Has anyone watched to see if the pressure drops below 30 PSI when the shower is in use or have you just looked at the gauge after you get out of the shower, dry off and dress?

I would suggest having someone watch the pressure gauge when a low GPM fixture is in use (or any fixture on low). Does the well behave as expected drop to 30 kick on and climb to 50 and cut off; all while the fixture is running. If so your pressure switch is likely fine.

If your pressure vessel has 28 PSI when there is 0 PSI on the domestic water system the diaphragm is likely intact and that is about the only thing that could go wrong.

This problem reoccurring for the shower (I assume) and no mention of it with lower flow or lower volume uses, coupled with what you have told us doesn't particularly sound like a switch or vessel issue to me; the only thing I can think of is if the contacts on the pressure switch are dirty. If you can provide additional information perhaps we can help formulate a theory.

[paddedhat]

Budget slasher, I tend to agree that absent any other issue, a shower running out of water, doesn't immediately make me think of the pressure switch being shot. I usually troubleshoot by killing the power, and opening a tap. Once the gauge shows zero I check the schrader valve on the bladder with an air gauge. If that's good, I turn the circuit back on, and see if it comes up to a reasonable high pressure before cutting out, as in 50-60lbs. Then I open up a tap to get the pump cycling. If you open anything up too wide, you risk running the pump without cycling, so a kitchen tap on a moderate flow is fine. Then it's time for the exciting job of watching the gauge and listening for the contacts to open and close, while noticing the pressure readings while that happens. I don't know if it's useless anecdotal info. or not, but it seems that the few times one failed at my house, the high side cut off still worked fine, but it would allow pressure to drop unacceptable low before it "woke up" and started the pump. A switch that's operating in a 5-60 range, is pretty irritating. The other thing the OP mentioned, is the seepage at the switch and the hard water. Several switches I have swapped out were shot since mineral build-up had totally clogged to small riser pipe that connects the switch to the manifold.

[Bradfurd]

The other thing the OP mentioned, is the seepage at the switch and the hard water. Several switches I have swapped out were shot since mineral build-up had totally clogged to small riser pipe that connects the switch to the manifold.

paddedhat - Thanks! This is exactly why I had an inkling that the switch may be the culprit. Obviously, I still want to troubleshoot the system to make sure nothing else is going on.

Thanks for the thorough input, everyone. FYI - the shower does cut out immediately and without warning.

[Syonyk]

I believe what he is getting at is that the air pressure behind the diaphragm in the pressure vessel should read 28 PSI (in this 30 PSI system) without the domestic water system being pressurized and pressing against the diaphragm thus increasing the pressure on the air side of the diaphragm.

Ahh, that makes sense.  I was thinking about the pressure gauge on the actual water lines (that's where I start with troubleshooting).  Forgot the tanks had their own tap.

[Bradfurd]

UPDATE

I followed paddedhat's steps...cut the power, drained the house piping, drained the tank...Schrader valve on top of the tank read right around 28psi.

I couldn't get the old pressure switch nut/plate off of the standpipe/riser, but I could unscrew the standpipe/rise assembly. After an hour or so of messing with that seized beast, I ended up just cleaning the riser out (it was completely packed with sediment) and reusing it by attaching it to the new pressure switch.

When I turned everything back on, the pressure gauge downstream of the tank is reading at 21 psi (it was around 40 before) but the Schrader valve on top of the tank is reading about 48psi.

Could my pressure gauge on the piping be bad? I turned on all faucets and fixtures in my house and everything seems to be working properly. Could I have bumped some of the adjustment components when installing the new switch?

Thanks again!

[Syonyk]

Did you adjust the new pressure switch to your desired pressures?

If the tank is 28psi empty, and 48psi when full, I'd entirely expect about 20psi of water pressure in the system.  Tweak the pressure switch set screws until you get it cycling where you want.

[Bradfurd]

Not yet...that was going to be my next step. I guess I assumed it would default to somewhere between 30 and 50 out of the box.

[Syonyk]

I don't assume much about out of the box settings. Your pressure tank and pressure gauge agree, so set it where you want it now.

[Bradfurd]

If I dial up the pressure switch to the 40psi it was at before, what should happen to the air pressure on the top side of the tank?

[Syonyk]

It should rise to 68psi...

There's a static 28psi plus whatever the water pressure currently is.

[Bradfurd]

And what is the max that the air side of a pressure tank is rated for? I saw somewhere that 100psi was common. I'm sure it's in my owner's manual. I just don't want to immediately start adjusting things without knowing exactly what's happening to everything else in the system, possibly putting my tank at risk.

Thanks again for your insight, Syonyk.

[Syonyk]

I have no idea what your well tank is rated to...

There's probably a data plate on the side that tells you.  That sort of thing is almost always on the physical tank, not in the owner's manual.

I think you really need to sit down with Google and "How does a pressure tank well system work?" type queries.  They're a super simple system, but I don't have the impression you really understand what's going on it at all, which is not a good state to be in when you're adjusting things.

You need to understand your pressure tank(s), your pressure switch, what your plumbing is designed to work with, etc.  I know how my system works because I put it together (and acquired a burning hatred for lead free brass before switching to pex), but that doesn't help you much.

[Bradfurd]

I have done research and do understand how it works, but every situation is different. I'm just looking for any similar experiences, things to watch out for, things I might be overlooking...and if nobody replies, that's OK too. I just figured I would grasp in the direction of the combined knowledge of this community to fix an issue myself without spending hundreds on a plumber.

[Syonyk]

Every system is different.

My inlaws up the hill have a continuously variable well pump with a tiny pressure tank and an inverter drive system.  I've got an old pump with a simple mechanical pressure switch.

[Bradfurd]

Just glanced at a photo I had taken, and I think I can see a 100psi tag on there. Specs I found online state 125. Sounds like I'm fine at around 68 either way. I will verify tonight! Really appreciate the guidance.

Funny how I didn't think to look for that tag last night at midnight...it appears that it was right in front of my face!

[Bradfurd]

I broke down and called a plumber/pump service.

GOOD NEWS:
The gauge was faulty, which explains all the random, confusing readings. New working gauge is nice. My pressure switch installation was good.

BAD NEWS:
The motor on the pump was on its last leg. Amp readings showed it being overworked. $1500 and a new well pump later, the problem is solved. Not the outcome I hoped for, but it had to be done! Thanks again to everyone who chimed in.