Well pump cycling on and off

[Guitar God]

Any ideas why our 1 year old well pump started cycling on and off. We had our well re drilled deeper because it had to be reprimed all the time and it worked fine for a few weeks but now when it's refilling the tanks it's cycling on for 2-3 seconds and the off for 2-3 seconds. A few times I noticed it stopped for a few minutes and then restarted when it should have been on constantly until the float switch turned it off.

It's not even warm so I doubt it's a thermal breaker, I think it got hot enough to turn off when it was running dry with the shallower well. No apparent loose connections. It sounds noiser at the bore hole after the well drillers removed a grey attachment to the two inlet holes and replaced it with two pvc pipes going down the hole but I don't know how or if they connect under the ground. Any ideas?

Edited December 6, 2015 by Guitar God

[Crossy]

Assuming it's a jet-pump the 'grey attachment' is the jet and is now in the correct location at the bottom of the bore (on the end of the two pipes).

I'm also assuming that it does NOT have a pressure tank (flooded pressure tanks cause the symptoms you describe) so we need to look deeper.

Suggest looking at the capacitor (single-phase pump) although after only one year it should still be OK. They are inexpensive to easiest test would be to replace it.

[happynthailand]

check your inline check valve sounds like the valve is not opening and closeing like it should

sounds like the valve has dirt or some thing stuck in the valve not letting the check valve work as it should

Edited December 7, 2015 by happynthailand

[Guitar God]

Correct, no pressure tank. It could be the motor cap but that I don't think would explain it sitting off for a while entirely.

Sand is definitely a possibility, they pumped a lot out and then accidentally pumped even more into my tanks with they bypassed the sediment filter. That could be it.

Thanks for both the ideas, I'm going to meter out the float switch just in case and check a few other things before I head back to the store.

[Artisi]

Is there any control in the system other than the float switch - and how does the float switch operate - in circuit with power to the pump or thru' a relay- could be a fault in the float switch / relay. Can you operate the float switch manually external to the tank?

[Artisi]

Is there any control in the system other than the float switch - and how does the float switch operate - in circuit with power to the pump or thru' a relay- could be a fault in the float switch / relay. Can you operate the float switch manually external to the tank?

or eliminate the float switch as a check of its integrity

[Guitar God]

I was going to do that today but got sidetracked. From what I saw when the float is vertical it completes the circuit from the breaker box to the pump, when the tank is full and the float is horizontal, it breaks either line or neutral. To the motor terminal block on the pump are just supply voltage from the breaker through the float switch, and a high pressure shutoff.

There was a device with a water line from the impeller housing that had a rubber diaphragm and spring inside (inline check valve?). It was totally packed with fine sand and I was sure that was the problem. I cleaned it out and reassembled and reinstalled it but it made no difference.

I discovered it's the pressure switch that's turning on and off. I'd have to disconnect the two wires to spin it off and had to leave so that I'll do tomorrow.

The pump is a HitachiHTC-D325GX.

My wife said the guy at Home Pro was an idiot and only wanted to get 500 to come look at it or wanted to sell another pump so she'd prefer to call the guy who redrilled the well but that will probably take a month before it moves up his priority list, he's busy drilling wells and there's nothing in it for him really.

[Artisi]

Ok could be a problem in the pressure switch, has "anyone" played with it, maybe the on/ off settings are incorrect.

[Crossy]

Since you have a float switch (and assuming no float valve in the tank) a pressure switch is superfluous apart from preventing over-pressure from a blocked pipe (maybe you have just that if the check was full of sand).

Maybe some adjustment would solve the issue, or bridge the beast out until a new one can be procured.

[Guitar God]

The blocked pipe suggestion sounded like a good lead but when I disconnected the pump from the piping to the tanks I back-flushed it and nothing but clean water came out. I ran the pum while it was disconnected and no sand or dirt came out of the pump tank either.

I disconnected the over pressure switch and jumpered it out with my ammeter and it worked like it's supposed to. Ah-ha, it's got to be the switch.

I took the over pressure switch out, flushed the pump again and then disassembled the switch assembly. Nothing had been adjusted, the varnish seal (can't recall the real name) was unbroken. I saw nothing wrong with the pump or diaphragm. I reassembled it, put it back together and the pump has been working perfectly all day. Not the first time I've fixed something by not fixing anything. Sometimes I think machines just need some attention.

I know it's possible that the problem might come back but I have a feeling there was a grain of sand in the wrong place or something in the switch that needed reseating and I think this problem's fixed. I spent many years working on IBM, Cray and Amdahl mainframes and peripherals, one of my accounts was Nasa mission control in Houston (Clear Lake by League City actually) and I know about intermittent problems but many times just taking things apart and reassembling them is the solution.

Thanks for the help and lessons about water pumps. I learned more about pumps and wells than I ever thought I would know.

[Crossy]

GG, you're not the only one by a long chalk.

I've lost count of the number of times I've "fixed it by doing nothing". Take it apart, look at all the (perfectly fine) bits, put it back together, problem solved.

These things (like our ladies) do indeed like attention.

[Artisi]

Good result, do you think there might have been an "airlock" in the system which you cleared by disconnecting pipes etc?

[Guitar God]

Anything's possible. I doubt there is any place in the short run from the pump to the tanks that could happen but the well pump has a 5-10 L chamber under the pump motor that I opened and flushed out. The over pressure sensor sits on the top of it.

[Crossy]

Anything's possible. I doubt there is any place in the short run from the pump to the tanks that could happen but the well pump has a 5-10 L chamber under the pump motor that I opened and flushed out. The over pressure sensor sits on the top of it.

Ah-ha, a pressure tank!

I'll bet it was water locked (see my post #2), draining it solved the issue.

[Artisi]

Anything's possible. I doubt there is any place in the short run from the pump to the tanks that could happen but the well pump has a 5-10 L chamber under the pump motor that I opened and flushed out. The over pressure sensor sits on the top of it.

Ah-ha, a pressure tank!

I'll bet it was water locked (see my post #2), draining it solved the issue.

Beat me to it.

[Artisi]

Anything's possible. I doubt there is any place in the short run from the pump to the tanks that could happen but the well pump has a 5-10 L chamber under the pump motor that I opened and flushed out. The over pressure sensor sits on the top of it.

Actually it is not really an over pressure switch, it should correctly be called a pressure control switch - its function is to shut the pump off at a predetermined upper pressure and bring the pump back online at a predetermined lower pressure. Unfortunately bladderless tanks are a pain in the arse as they become "waterlogged", the air above the water in the tank is gradually displaced by water resulting in insufficient air pocket to be pressurised for the upper /lower limits and the pump will then cycle on/off constantly.

Bladderless tanked pumps are not the best selection for these applications for the above reason, although there are probably hundreds of thousands around the world doing a reasonable job if you understand that the tank should be drained often.

[Guitar God]

I bet that was the fix for the cycling. I didn't know that chamber needed an air pocket to work properly. I figured once it started pumping it would just run until the float switch signaled it to stop. It did have upper and lower limited in Kpa,which makes more sense now. I thought it was to shut off the pump if the float valves in the tank shut off due to a float switch malfunction or if the line to the tank was plugged or shut off with a ball valve. You learn something new every day.

[Artisi]

Are you pumping from the well too holding tank from which you then repump to the house?

If this is the case you could forget about the pressure tank and switching - the ideal set up is to have water level control in the tank using a lower level switch on float and a higher level switch off float switch. This will start the stop the well at the levels you set and negate the pressure tank and switch.

[RakIsaan]

I bet that was the fix for the cycling. I didn't know that chamber needed an air pocket to work properly. I figured once it started pumping it would just run until the float switch signaled it to stop. It did have upper and lower limited in Kpa,which makes more sense now. I thought it was to shut off the pump if the float valves in the tank shut off due to a float switch malfunction or if the line to the tank was plugged or shut off with a ball valve. You learn something new every day.

But, as Hitachi advises, you will need to clean the 'aerator', the little unit connected to the pump with a black tube or directly fitted to the pump. I have to do this once a year.

http://www.hitachi-th.com/hitachi2014/product/catalog/pdf/WP_WT-P_WM-P_GX2.pdf