Understanding PSI - how low can you go?

[mainerr]

Hi folks.

I've submersed myself in reading well system articles and watching youtube videos for a few hours now.

Here's my setup:

Tank: WX-202 (20 gallons). Drained the tank, measured in at 28psi.
Pump: Goulds 2 Wire 1/2 HP 230V 4" Submersible Water Well Pump with Motor
Pressure switch: Square D 30/50

Problem:

Pump runs continuously. The pump is over 15 years old and I knew it was EOL. I dialed back the pressure switch to cutoff in the low 40's a while back trying to get more life out of the pump (and for budget reasons). Now it seems like the pump is having trouble building pressure beyond 33/34 PSI.

Going to soon bite the bullet and get the pump replaced. In the meantime, for the sake of electricity savings and to make sure the pump doesn't go belly up from running and running before I can get it replaced, what should I do? Is it out of the question to put in a 20/40 switch and set the well tank to 18psi? Can I set my 30/50 to 20/40 somehow?

Thanks for any help you can offer. Please let me know if there's anything I missed in my post or can clear up.

Signed,
Pump running in a snowstorm in Maine on a budget


edit: We are a low flow household. No dishwasher, low flow showerheads and low flush toilets, not much of a multiple source demand situation as far as I understand them - in case that makes any difference as to the situation.

 

[Reach4]

To lower the cut-in and cut-out settings while keeping the differential between those two settings constant, adjust the range nut. The range nut is the 3/8-inch nut that adjusts the larger of the two springs in Models FSG, FYG, FRG, and Type G Pumptrol switches.

Turn the range nut counter-clockwise to lower the cut-in pressure. Three and a half
revolutions of the range nut will change both the cut-in and cut-out settings by approximately 10 psi.

Then reduce the precharge accordingly.

 

[Sponsor]

 

[mainerr]

If I retain the range of 20 and set it to 13/33, and set my well tank to 11psi - is that bad for the well tank?

I feel like there must be something wrong with operating the well tank at such a low pressure - but my options are either that or shutting off the power to the pump to stop it from running... ?

 

[Reach4]

If I retain the range of 20 and set it to 13/33, and set my well tank to 11psi - is that bad for the well tank?

No.
If the pump has trouble hitting that 33 cut-off, you might have to turn the other nut a little CCW. There usually is not much to be had that direction. Once the pressure is off of the little spring, turning futher is not going to help. This should reduce the differential a bit, but as long as the pump still runs for almost a minute, you would be OK.

Adjust the differential nut if you want to raise or lower the
cut-out setting while keeping the cut-in pressure constant. The
differential nut is the 3/8-inch nut that adjusts the smaller of
the two springs in Models FSG, FYG, FRG, and Type G switches. Turn
the differential nut clockwise to increase the cut-out pressure and
counter-clockwise to lower the cut-out pressure. Adjusting the
differential nut will change only the cut-out setting while the
cut-in setting remains unchanged.

I think it is common that you cannot
adjust the differential to much, if any, lower than the 20 PSI differential
that the switch comes pre-set to. You can widen it.

pumptrol adjustment.

 

[mainerr]

Thank you. I will perform those changes in the morning and see how it goes.

 

[mainerr]

Couldn't wait (or sleep) so I'm in the basement working on it now.

When you say this:

"as long as the pump still runs for almost a minute, you would be OK."

Do you mean that 1 minute is the preferred time? Would going under that be considered 'short cycling' or are you more concerned with the pump struggling at the end to reach a PSI and going on for 2-3 minutes?

 

[mainerr]

Interestingly, lowering the psi on the well tank seems to have a direct correlation with the pressure the pump can build up (unless there's some margin of error in my dial). When the tank was at 28 psi the pressure could build to 33/34psi. Now with it down around 10psi it tops out at 26psi. Seems like a race to the bottom. I guess the new pump can't come soon enough.

 

[mainerr]

Ok, the pump is no longer running continuously. I have it in the 16 to 26 psi range, which seems ridiculous. The water pressure at the faucets seems passable, we can do dishes ... but it's definitely in limp mode.

 

[Reach4]

One minute is par, but 3o seconds is not terrible. Two or 3 minutes would be great if that would stay. But if it gets to 5 minutes on a 2o gallon pressure tank, that would seem to be a short step to infinity.

Incidentally, there is no problem with the precharge being a little high, other than the stutter in pressure before the pump catches up.

If you keep a constant 2o PSI differential, the amount of water delivered each cycle is more at a lower pressure, 10/30 for example, than at 30/5o. That is not important to know, but you might find it of interest.

 

[Texas Wellman]

It's toast. The one minute time is out the window. Just make sure it can turn on and off and baby the water as much as you can.

 

[mainerr]

Thanks guys.

I will search the forum for tips on pulling a well pump in the snow. Probably make a new thread on it, but while this has momentum - what's the risk of a fresh faced novice of doing it myself with no experienced help on the first go?

I appreciate your advice.

 

[Valveman]

I run pressure switches as low as 10/30 for some Geo systems. You can go as low as you need, but that pressure is certainly in "limp mode".

The biggest risks of pulling you own pump is dropping the pump in the well and/or getting hurt. It all depends on what kind of pipe and how deep the pump is set. 100' on plastic pipe is a DIY job. 50' on steel pipe or 200+ on plastic is not a DIY job.

 

[Texas Wellman]

There may be a hole in the drop pipe as well.

 

[Cacher_Chick]

What he said. If you have an above ground check valve, it might be masking the possibility that you have a leak in the drop pipe or pitless adapter.

 

[mainerr]

To close this thread - I had the family business out that drilled our well. They checked the pressure at the well, the pump was only pushing 30psi.

I paid them to replace the pump in between the snow storms.They put in a Berkeley 1/2 HP ( http://store.kgpowersystems.com/b7p...ackage-7-gpm-1-2-hp-10-stages-1-ph-230-v.aspx ) to replace the Goulds that was there. They also tested and replaced the electrical wire.

Running at 40/60 now, and the overall price was very fair considering. I'd like to do it myself next time during warm weather... hopefully in 15 or 20 years.

Thanks again to everyone who helped me in this thread.

 

[Reach4]

I paid them to replace the pump in between the snow storms.

Good move. Thanks for the follow-up. It's nice that the pump gave you a soft fail, so that you could get the work done between snow storms.