Pump intermittently won’t build pressure

[Ian Wright]

Hello everyone:
I have a problem with my well that has me stumped. I recently replaced my pressure tank, pressure switch, and all the tank fittings, etc. The original switch was a 30/50 and I replaced it with a 40/60 to get a little more pressure in the house. After the install I flipped the well on it built up to 60 in a minute or so and was fine. The next day I was in my basement and noticed the well was running. Pressure was just sitting at 50 PSI and wouldn’t move. I flipped the switch off waited about 2 minutes and then pressure raised at a normal rate right up to 60. Today I came home and after flushing toilet I ran downstairs to check and it was doing the same thing. Flipped it off and waited turned it back on and bam 60psi again. After I drained the tank down it was stalling out around 40psi.

I started doing some trouble shooting and found tank pressure at 38psi still so new tank is fine. I checked the capacitor and it was fine. Pump run winding resistance spec is 4-5 and I’m at 4.5. Start winding is 18-20 and I only have 7. My hypothesis is the start winding has gone bad or weak and the relay isn’t engaging the run winding all the time. Does this sound right? It’s a 1/2hp submersible 3 wire pump. Well depth is 130’ pump at 80’. Not sure on age but the tank I replaced was about 29 years old.

I am thinking it’s been like this a few months as my electric bill went up $30-49 the past few months so I think the pump has been running like that a lot.

Thanks for any input.

 

[Valveman]

If the water level gets down to 69', a 1/2HP, 10 GPM pump will not be able to build to 60 for shut off. Probably should lower the pressure switch setting back down to 30/50. (Loosen big adjustment screw about 3 turns to the left and reduce tank air charge to 28 PSI).

 

[Sponsor]

 

[Ian Wright]

If the water level gets down to 69', a 1/2HP, 10 GPM pump will not be able to build to 60 for shut off. Probably should lower the pressure switch setting back down to 30/50. (Loosen big adjustment screw about 3 turns to the left and reduce tank air charge to 28 PSI).

I was thinking the same so I tried adjusting the cut off pressure down to 30/50 and I still have the same issue. Pump comes on at 30 runs and runs only gets to 40ish and stops building. I turn the pump off waited a few minutes and turned it back on and it was fine built right up to 50.

The well depth I am going off the original well installation details from the township. I have not verified the pump depth myself.

 

[Valveman]

You need a clip around amp meter to see what is happening. 1/2HP is 5 amps. If it starts that way then quickly drops to 3 amps, you are pumping the well dry. When you turn it off the water level increases and the pump can again supply water. Another good way to see this is to open a hose fully. Turn off the pump for a few minutes. When you turn it back on the hose will have full flow for a short time then drop off quickly. If this is the case you need to lower the pump in the well if possible, and/or get a cistern storage tank and booster pump to be able to take advantage of a low producing well. Even 1 GPM is 1440 gallons per day. You just have to store the 1 GPM so it can be used at 5-10 GPM as needed.

 

[Ian Wright]

You need a clip around amp meter to see what is happening. 1/2HP is 5 amps. If it starts that way then quickly drops to 3 amps, you are pumping the well dry. When you turn it off the water level increases and the pump can again supply water. Another good way to see this is to open a hose fully. Turn off the pump for a few minutes. When you turn it back on the hose will have full flow for a short time then drop off quickly. If this is the case you need to lower the pump in the well if possible, and/or get a cistern storage tank and booster pump to be able to take advantage of a low producing well. Even 1 GPM is 1440 gallons per day. You just have to store the 1 GPM so it can be used at 5-10 GPM as needed.
View attachment 45286

So I just threw an ammeter in it. When the pressure is not building I’m pulling about 6.8 amps. When it builds pressure fine it’s pulling 7.5 amps so not a huge difference. When I checked it today I came home and the pressure was at 0 since I had well off and the ice maker was running and I think I have a leaky toilet flapper. I flipped the switch and it shot up to 30 then stalled. Waited a few minutes and turned it back on and it ran up to 60 in 40 seconds. I am noticing I have a lot of rust colored sediment in my filter after only having it in for 4 days.

 

[Ian Wright]

Was just playing with it some more. Found a better spot to put my ammeter. When problem is there and when it’s not there 5.5 amps. I did notice that when it doesn’t happen amps spike to 9 when it kicks on and then to 5.5. When problem is there it is just a steady 5.5. I’m gonna try a new control box to rule out a problem relay (I know it’s solid state and not likely) since it’s only $50 and looks original. Thanks for the advice valveman. I’ll let you guys know what happens. Hopefully I figure it out and it helps someone else out.

 

[Ian Wright]

I think I got it. Relay in control box is rated for a 1hp pump. This is a 1/2. Ran out to Menards put a 1/2 control box and seems to have done the trick. It’s cycled at least 20 times by now all good. I’ll keep an eye on it next few days but I’m fairly confident that did it.

 

[Reach4]

I think I got it. Relay in control box is rated for a 1hp pump. This is a 1/2. Ran out to Menards put a 1/2 control box and seems to have done the trick. It’s cycled at least 20 times by now all good. I’ll keep an eye on it next few days but I’m fairly confident that did it.

Cool. Didn't see that coming. I think keeping an eye on it makes sense.

Did the old control box have a run capacitor?

 

[Valveman]

I think I got it. Relay in control box is rated for a 1hp pump. This is a 1/2. Ran out to Menards put a 1/2 control box and seems to have done the trick. It’s cycled at least 20 times by now all good. I’ll keep an eye on it next few days but I’m fairly confident that did it.

Maybe? 5.5 to 6 amps is good. 7.5 Amps is not. Usually when the relay is out it will draw more than 7.5 and shut off. Still may have a problem with the motor so do keep an eye on it to see if it is shutting down when it should not.