Thanks for the info that you gave me about the questions I had about a drop in water pressure to our house - the what is it with me and wells? post. If you can help a bit more I would appreciate it.
I checked the pressure reading at the well and observed the following:
* Full (available) water pressure w/pump off was 65psi. Pressure gauge is located on the same pipe outlet that the pressure switch is on (between well and pump).
* I turned on hose bib at tank outlet until pump kicked on.
* Pressure cut-off was 35 psi.
* I adjusted cut-on to 40 psi, and cut-off to about 62 psi.
Here's what happens as water pressure drops - I can see the pressure switch diaphragm move slowly as the pressure drops until the contact finally trips. At that point, the pressure gauge reads about 40 psi so that seems OK.
However, right after the cut-on trips, the pressure drops to almost nothing - like 10 psi - then there is a second or two until the pressure comes right back up, finally cutting the pump off at about 60 psi. That's the lag that we are experiencing in the house - water dwindles to almost nothing. then quickly increases to regular pressure. It's annoying because it always makes me wonder if the water's coming back [img]/forums/images/icons/crazy.gif[/img]
Why does the pressure drop so dramatically? I have not yet checked the tank charge pressure, but it seems that at the 40 psi cut-on there should only be a mild ripple in the supply rather than a big drop, then back up. Is the pump losing its prime (new 1.5hp pump) and then having to make up the head?
Almost sounds like a check valve gone bad. Is there a check valve at the pump (question for the experts). What holds the pressure in the system when the pump kicks off? [img]/forums/images/icons/smile.gif[/img]
My guess (I'm no expert, but have a well system that I maintain) is that you're getting flow back into the pump. That would leave me to believe that there may be a problem with the pump, but you might consider installing a one way valve - I do that in a few places with my gravity fed irrigation water.
I'll check the air pressure in the tank first to ensure that it's where it needs to be - about 2 psi below pressure switch cut-on psi.
As far as what holds pressure in the system, I assumed that it was the air pressure in the tank. There is no bleed down of pressure during times of no water usage - pressure remains at the upper range of the limit - about 55-60 psi. I have no idea if the pump itself has a check valve (submersible, about 280' down), but if it did not have something then wouldn't the water pressure bleed down during off-time (no water usage).
I like the one way check valve suggestion - would it simply install into the supply line that comes out of the well, between well outlet and pressure switch?
<font color="blue"> I like the one way check valve suggestion - would it simply install into the supply line that comes out of the well, between well outlet and pressure switch? </font color>
That's what I'd do. Like I said (or should have) I'm no expert, but it seems to make sense to me. I figure if your pump is already starting to flake out that you won't loose anything by trying this and that you're pressure tank, etc., won't notice a difference.
My well comes in through PVC pipe, and before it hits the pressure tank is filtered for sediment. I don't have a one way valve on my well, but if I were to try one I'd probably put it right after the sediment filter.
But do bear in mind that I'm an unlisenced, uneducated amature... Hopefully some more experienced folks will jump in.
Forget my comment on checking the tank bladder pressure.I did not pay enough attention to your comments.
There should be a check valve at the pump. This appears to be holding as the tank maintains pressure when there is no water being used.
My quess is the well produces some gas. When the pump kicks on the check valve opens and the pump becomes temporary vapour locked till the gass passes thru. Tthis allows the pressure drop to almost zero. When the pump picks up water the pressure will again start to increase.
I checked the tank pressure and it is right on 38 psi, which makes sense for the 40/60 pressure switch that's being used.
In order to check the air pressure in the tank, I turned off the power and ran the water until there was no water pressure. What I observed was that as I ran the water (no power - just pressure from the tank) the gauge reading slowly fell as you would expect it to. When the psi hit the cut-on level at the pressure switch instead of a continued slow drop in pressure, the pressure immediately fell to nothing and that was the end of the water out of the hose bib.
What puzzles me is that it's as though the well either has 40-60 psi of water pressure or nothing - there does not seem to be any pressure below 40 psi. But - I don't lose water pressure during times non-use. I was anticipating that as the water ran the pressure would continue to slowly drop to nothing, not fall from 40 to nothing, like off of a cliff. I just don't get it. I am tempted to replace the pressure switch since it's cheap, but I don't want to start just throwing parts at the problem.
I don't want to pester you with all this, but I would sure like to figure out what's going on before calling the well company. I'm not so sure that I'll call the ones that installed the pump, so I wanted to get some good knowledge before talking to anyone else. [img]/forums/images/icons/tongue.gif[/img] Thanks!
Here's my theory: If you have two check valves in your system and the one down at the pump has failed, then most of the water between check valve #1 and checl valve #2 would drain back down through the pump creating a partial vacuum between the head of water and check valve #2. When the pressure switch cuts in, the pump pushes the head of water and the partial vacuum up and it's this partial vacuum (now compressed to your 10 PSI up through the system. As soon as the "slug" of air/vaccum passes the pressure guage, it reads the true pressure of the water.
Does the water you draw in the house seem to have small air bubbles in it?
Yeah, it sure sounds like a check valve problem of some sort. Imagine a spring type check valve at the pump. It holds as long as the pressure is enough to overcome the spring (a normally open valve in this case). As soon as the pressure drops to the spring load it opens and dumps everything out.
It was also mentioned that the pump is 280 feet down. That is a tremendous amount of pressure head to the pump. That may be a factor of some sort too [img]/forums/images/icons/smile.gif[/img]
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