Water pressure issues


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Old 12-20-14, 08:29 AM
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Water pressure issues

Recently, the brass pressure relief valve on the pressure tank cross tee started going off when the well pump was almost cut off. I figured it needed replacing, so I put a new one on there (same 75psi activation) and it didn't change anything. So, I found this forum (very cool and informative, btw) and read a few threads that suggested making sure the pressure tank was within 2-3psi of the cut-out pressure. I checked the pressure on the pressure tank and sure enough, it was low by about 15-20psi. I drained the tank, put air in to 2-3psi within the cut-out, and turned the pump back on. It worked and stopped the pressure relief valve from blowing water all over the basement floor, but created a new problem in the process.

Now the water pressure drops to almost zero before the pump kicks on. It has a 40/60psi switch which was replaced a few years ago (same 40/60 pressure). I'm a little worried about how the plumbing will react in this 30 year old house by increasing the cut-in pressure on the switch. What should I do?

Thanks in advance. I really like this forum.
 
  #2  
Old 12-20-14, 09:49 AM
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Welcome to the forums.

If the pressure is that low and the pump hasn't started you have a defective switch or a plugged water supply line. Usually the pressure switch connects to a manifold of 1/8" pipe. That pipe gets clogged and rusted up causing the pressure switch not to see the proper pressure.

If that is unclear post a picture or two of your setup. http://www.doityourself.com/forum/el...rt-images.html
 
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Old 12-20-14, 12:30 PM
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The symptom of pressure slowly dropping as you use water and then dropping quickly to zero, just before the pump kicks on is quite often a problem of having a little too much air in the pressure tank.

The reason for the air to be 2-3 psi BELOW cut in pressure is so that some water remains in the tank at all times. If the air pressure is ABOVE the cut in pressure, then all the water leaves the tank and since the diaphragm cannot keep pushing water past the exit hole of the tank, the pressure will quickly drop to zero once the tank is completely empty (which it will be, at some point, if the air pressure is higher then the water pressure).

So I would look at removing 5 psi or so of air to confirm if this is your issue or not before I did any structural fixes. If this is not your problem, just put the air back in.

I know you said you did this but getting good measurements of water/air pressure can be more of an art then a science. Most likely you have a combination of the two problems as I and PJ have identified.
 
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Old 12-20-14, 02:35 PM
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put air in to 2-3psi within the cut-out, and turned the pump back on.
hi guys. Is that correct 2-3 within cut-out? Shouldn't it be 2-3 within cut-in?
 
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Old 12-20-14, 03:26 PM
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Yes, it should be 2 psi less then your cut in pressure. So if you have a 40/60 pressure switch your tank pressure should be 38 psi. This should be measured with no water pressure on the system.
 
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Old 12-21-14, 06:31 AM
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Didn't notice that. Yes. 2-3psi below CUT IN pressure. If he did use cut out pressure then disregard my 5 psi removal of air. It will need a lot more then that removed to work properly. Just do it again, the right way, and see how the pump works.
 
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Old 01-02-15, 08:15 AM
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Thanks for the replies, all. I have to clean out the sediment in the filters on the water-in connections on the washing machine, so it's very possible the switch could have sediment too. Looks like I'm gonna have to get a new one (and install a sediment filter on the water line).
 
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Old 01-02-15, 09:13 AM
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Verify the pressures first. Your pressure gauge on the tank or the gauge you're using to set the tank pressure may be slightly off. That in itself could cause the incorrect air charge in your tank.

Relieve some air pressure from the tank, see if the issue goes away.
 
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Old 01-02-15, 11:56 AM
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I let a little more out and the pressure doesn't drop off to a trickle before the pump kicks in, but now the switch cuts out at 65psi. Fixed one but got another. 😝
 
 

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