Delay in getting water after pressure switch cut-in

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cribbj

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We recently bought a summer/retirement home in MT that had been used by 2 PO's as a part time, seasonal vacation home. It and its plumbing, and well pump are all 40 years old. Everything worked OK, but "just" OK. Enter the new owner who's a DIY'er and an engineer and decides he wants to make everything work better and that's where this story begins. BTW, well is about 30 deep and has a 3/4 HP submersible pump.

Replaced the pressure tank with a new Water Worker 20 gal unit (same as before) and its piping tee and fittings with new SS, also a new Square D 30-50 pressure switch, new check valve ahead of the pressure tank, etc.

The precharge on the bladder in the new tank was 38psi, and shame on me, I initially forgot to bleed it down to 2psi below the pump cut-in, so the first few pump starts were accompanied by a fair amount of water hammer. Realising what I'd done, I drained the system, bled the bladder down to 28psi, then started things back up again and monitored the system & system pressure closely.

Now, at 30psi, when the pressure switch contacts closed, I had 240v on the load side of the contacts, going to the pump, but the pump acted like it wasn't starting, because I had no pressure buildup for a few seconds - possibly 3-5. Meanwhile, the pressure kept dropping in the system, due to the water usage in the house, until it fell to 0psi once it was below the bladder pressure. Then, after a few seconds, the water "arrived" to the pressure tank with a water hammer bang, and we had pressure again.

Bled some more pressure out of the bladder until it was at 25psi, and tried again and got the same symptoms, although not quite as severe. Although I was tempted to bleed more pressure out of the bladder, I'd run out of time and we had to close the system down for the winter and head back to TX.

Really wish I'd had my clamp-on ammeter with me, as that would have told the story, but based on the above, does it sound like my 40 year old pump is on its last legs? Particularly since it probably didn't take kindly to the initial or subsequent water hammer in the system?

BTW, when the pump did come on, and built up pressure, there was no air being expelled out the taps in the house, so this would probably eliminate the possibility of corroded pipe and air in the suction line allowing the water to drain back to the well, wouldn't it?

I've searched the forum and read both these threads:
https://terrylove.com/forums/index....y-in-getting-water-after-pump-kicks-in.47856/ Don't think my problem is quite the same as SmokingTundra, and of course, my well is nowhere near as deep.

https://terrylove.com/forums/index....essure-switch-clicks-and-pump-turns-on.48169/ I think my problem is similar to BillEBob's, but unfortunately, he didn't publish the resolution of his issue.

Thanks in advance for your thoughts & suggestions!
 

Tom Sawyer

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Couple of things, the first would be to see if there is a big leak at the pitiless adapter. Next on the list would be a bad check valve on the pump and finally, a bad pump. But, make sure the contacts close on the pressure switch and power is going to the pump at cut in pressure.
 

LLigetfa

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Start by getting rid of the checkvalve at the bladder tank. Bladder tank systems should only have the one checkvalve in the pump. The checkvalve may be the cause of the water hammer and the cause for the delay in the water arriving.
Put an ammeter on the pump wire and see if it is pulling full amps before the water arrives. How far down the well to the water?
 

cribbj

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Tom: Thanks, I did confirm the pressure switch contacts are definitely closing and 240v is getting to the pump side contacts. What I don't know is whether the pump starts drawing current immediately, or if it's having trouble starting.

I don't think there's another check valve at the wellhead or pitless adapter, or if there is, it's no longer functional. I put a 1/8" NPT air bleed valve on the pump side of my pressure tank check valve, and when I open that bleed, it sucks air for perhaps 30 seconds, until the water drains back to the well. (This air bleed was recommended for our area to keep the line from the pump from freezing in the winter.)

Don't know about a check at the pump either, but I do know the water is being allowed to drain back into the well when I open that air bleed, so either there's no other checks, or most probably they've failed over time, (or perhaps there's a Flomatic drainback valve in the drop pipe).

LLigetfa: Thanks for your input, I really wish I'd had my clamp-on ammeter with me up in MT as that probably would have cleared this problem up fairly quickly. Also, as there was an existing check valve in the system at the incoming line from the well to the pressure tank, I replaced it when I did this upgrade.

I was mistaken about the depth of the well. The total depth is unknown, but the height of the ground water is supposedly 45 feet below ground according to a well test report that was run in 1996. At that time, with the well making around 7 GPM for 25 minutes, the drawdown in the level was 7 feet. So I'm assuming the total depth of the well is at least 75 to 100 feet?

You're saying that check valves aren't recommended for these incoming lines at the pressure tanks? Could you expand on that a little more, as most of the diagrams I've seen, including the one provided with my new pressure tank showed multiple checks; one at the pump and one at the tank?

Many thanks for all the input.
 
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Tom Sawyer

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There should be a check valve at the pump. Most of the guys here will too you not to have one at the tank too but most of the pump manufacturers and most cords requires one at the tank. I suspect that your drain back valve is allowing most of the water to drain from the pipe in the off cycle which would cause the daly and water hammer issue.
 

Craigpump

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Water Worker tanks are diaphram tanks made by Amtrol to compete against the other lousy tanks sold by big box stores. They do NOT have a provision to vent off excess air, which is what you have because of a faulty check valve, bleeder hole in the pipe or broken pipe/ rotted fitting.
 

Tom Sawyer

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I think he's talking about a valve that he out in. Not the one on the tank. At any rate though, I too suspect he has a leak in the line somewhere or the check valve on the pump is shot.
 

cribbj

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Craig, thanks; unfortunately the Water Worker was the only tank available on a Saturday, within an hour and a half drive in a remote area of MT :).

Here's a pic of a new surface setup from Dean Bennett which is very similar to what I installed. The only difference between this and mine, is that I substituted a check valve that had a 1/8" NPT tap on the pump side so that I could install my manual air bleeder valve (it's just a little icemaker valve, but seems to work well so far.) Plus I put a SS union upstream of the check so I could work on the line in the future without having to cut the poly pipe coming from the well (it's already a bit shorter than I'd like).

There doesn't appear to be any leaks with this setup (judging by all the air the icemaker valve sucks in when I open it), and the absence of any drips under the pressure tank and/or around this piping.

I haven't touched anything upstream of this.

709U114SSDFK.gif


I think the next steps will be:

1. Get a clamp-on ammeter on the pump leads and confirm when the motor actually begins to pull amperage, and how much.

2. If #1 points to the pump, then I'll pull the old pump & replace all the downhole equipment, as I'd rather do it all once, rather than piece meal it.

3. If #1 indicates the pump is OK, then I'll eliminate that check valve shown in the pic above. May still pull the pump to see if any of the piping or other downhole stuff isn't working right. The system may well have a drainback valve in it that's leaking. Everything upstream of the pic above is a mystery, as I have no record of what was installed, or what the depth of the well is, etc.
 

LLigetfa

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If the system was deliberately setup with a drain-back then the checkvalve at the tank may be an integral part of it. There then should also be a bleeder in the drop pipe but sometimes the checkvalve in the pump is removed instead. Removing the checkvalve in the pump could in some cases cause the pump to spin backwards and if it were to restart while it is spinning backwards, it can be damaged. Removing the checkvalve can also draw too much vacuum if the water level is far down. Think of how a mercury barometer works.

The bleeder should be placed high enough so that it doesn't draw too much vacuum. It just needs to drain to below the frost line. The checkvalve in the pump then should hold the weight of the water column if it is working. If enough of a vacuum is created from the weight of the water column, then you can have water hammer when that column of water hits the topside checkvalve.

A drain-back system can be setup without a topside checkvalve provided the checkvalve is in the pump and a bleeder is used. A bleeder is designed to close and stay closed under normal pressure but open under low/no pressure. Two manual valves can be put on the pump side of the tank; one inline and another as a drain. The handle should be removed in normal use so that someone does not inadvertently close the valve and deadhead the pump.
 

cribbj

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Updating this thread from last year as we've just arrived to the cabin for a week and are continuing to have water hammer issues at pump startup.

To me, it's pointing to a faulty downhole check valve at the pump. The following is why I think this, but my logic may be flawed, so would appreciate others' opinions & advise. First here's a summary of the well and equipment:

The well was drilled in the mid-70's and we think it's around 60-75 feet deep. A 3/4 hp Valley submersible pump was installed in May 1977, and as far as we know, it's still down in the well. It was rated for 12 gpm, but I don't know at what head, etc. and Valley have since apparently gone out of business and I can't find performance curves for it. For anyone who might have old Valley data, it's a model S1211-MF2072 and is a 2 wire setup.

In 1996 the state of MT tested the well, and the results showed the ground water to be 44 feet below the surface. The well flowed 7 gpm for 25 minutes with a drawdown of 7 feet. So presumably the pump is hung somewhat deeper than 51 feet, but we really don't know how deep.

Surface equipment originally installed in the home's crawl space consisted of an incoming check valve, ball valve, tank tee with Square D 20-40 psi pressure switch, a pressure gauge, and a 20 gal Water Worker bladder tank. This was all done in 1" galvanised pipe and it was pretty rusted and nasty looking, so when I bought the home last year, I replaced it all with a 1" SS tank tee & fittings, new pressure relief valve, new Square D pressure switch, and a new brass check. The check had 1/8" NPT ports up & downstream, so I plugged the downstream port, and put a manual valve on the upstream port so I could admit air and allow the well to drain back for the winter.

The original system did not have any noticeable water hammer, however after I replaced all the surface equipment as mentioned above, the water hammer issues began. After some initial hiccups getting the precharge of the bladder tank adjusted correctly, the hammer diminished somewhat, but it's definitely still there at pump startup and very noticeable/audible from inside the house.

Here's what happens when the water hammer occurs:

1. Pressure switch cuts in at 29-30 psi, motor amps spike to 20-25 momentarily, then settles back to 6-7 normal running current.

2. 4 seconds after pressure switch cut-in, there's a noticeable movement and hammer in the incoming line from the pump.

I believe the newly installed surface check valve is holding/sealing, but the downhole check valve at the pump is not. Although there's no air in the lines when I turn on taps in the house, I think there's loss of pressure and loss of water column between the 2 checks, so when the pump starts, it's having to partially refill the line, and when that water arrives to the surface and meets the 25-30 psi house pressure behind the surface check valve, it creates the hammer. That theory is also reinforced because when I shutdown the system last summer, I opened the 1/8" manual air bleed valve on the upstream side of the surface check, and air entered the system for about 30 seconds, which leads me to believe the water column in the pipe was draining back through the downhole pump. This shouldn't have happened if the downhole check had been holding, correct?

I'm still not understanding why replacing the surface equipment caused the problem to begin, other than perhaps the original surface check was passing, as well as the downhole one?

I've made a couple of videos of the system and the problem here:

This one describes the surface equipment:

This one shows the pressure switch cutting in, the ammeter indications, and the water hammer:

Just as an FYI, currently, the pump is only producing 3 GPM at the surface (as measured by filling a 5 gallon bucket from the bathtub spout in about 100 seconds.) Since the whole downhole system is still original, and is now 38-40 years old, I'm leaning towards pulling it and replacing it all, to get better delivery, as well as hopefully sorting out this hammer issue.
 

Reach4

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Replacing the pump makes sense. So does replacing as much steel (pipes and fittings) as you can with PVC, stainless steel, and brass. Your new pump should be a 1/2 HP maybe 12 GPM pump. 3/4 HP is too big of a pump for you for the pump to be in its sweet range. That should have a much larger pressure tank with a drawdown that will let the pump run at least a minute each time. An alternative would be to use a smaller tank with a Cycle Stop Valve.

For now, you may be able to get some more life by removing the top-side checkvalve. That should get rid of the water hammer and may let the bottom checkvalve perform better.
 

cribbj

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Thanks Reach4; I'm still not clear, however, why the water hammer is even occurring?
 

Reach4

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cribbj

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Thanks for that link; still not clear why the water hammer began occurring after installing new parts, however. The only thing I can come up with is that the old surface check must have been completely nonfunctional, which I suppose is understandable after nearly 40 years of service :)
 

cribbj

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Took the surface check valve out of the system this morning and the water hammer is gone!

Now to continue with the replumbing project (in PEX).
 
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