# Not Enough Demand For Pump To Keep Running



## Redtwin (Feb 9, 2019)

I am working on an irrigation project at my church and am running into problems with the pump cycling on and off when the zones are running. The submersible pump system starts with a 2" pipe coming out of the well and into a closet that holds the pressure switch and the pressure tank. The switch is set to 40/60 and the 80-gallon pressure tank is set to 38psi when completely drained. There is a long run to get to the irrigation system where the pipes step down to 1 1/2" and then down to 1" by the time it gets to our area. It runs under several parking lots and roads so digging it up and running new pipe is not an option. We did a flow test at our end and could get 25 gallons per minute, so we sized all our zones to that. The problem is that is not enough demand to keep the pump running the whole time. We can't add more heads or run zones together because we would lose too much pressure at each zone. I am 99.99% sure the switch and the pressure tank are functioning correctly. The pump will cut on and run for 7 seconds and then cut off for 17 seconds. 7 on, 17 off, over and over. We are considering getting a cycle stop valve but I have never dealt with one before. Getting a larger pressure tank came up but I still don't think that is going to solve the problem.

Another idea I had was to install a shutoff valve on the 2" pipe coming out of the well and close it halfway to limit the output of the pump. I'm not sure if this would be bad for the pump but I think it would slow down the tank filling and would allow the pump to run continuously while the system is on. There is only one toilet and one sink still on this system other than our irrigation.

Any help from anyone experienced in dealing with this would be very appreciated.


----------



## Monocot Master (Feb 28, 2021)

Is this a new irrigation system, or an existing one? You may have a bad bladder in the tank. When they rupture, the tank will completely fill with water, and can cause short cycling. _Disclaimer_ - I am no expert in irrigation or plumbing, but have dabbled quite a bit in both :thumbup:


----------



## Redtwin (Feb 9, 2019)

We are ripping out the old and putting in new. Our source pipe was 1" so we ran 1" all the way through the valves and to each head. The tank is not full of water or waterlogged. When tapping on it, it almost sounds completely empty to be honest. I could hear the bladder working when we were cycling the pump and when we drained the tank all the way out so not sure that is normal either.


----------



## Monocot Master (Feb 28, 2021)

Ok, I see that in your original post now, that your tank is fine. Have you searched here?:

https://www.lawnsite.com/forums/professional-discussions.16/


----------



## Brodgers88 (Feb 26, 2017)

@Redtwin I worked through a similar situation with my irrigation system on a well after burning up the contacts on two different pressure switches from all the cycling. I had to make my zones put out enough flow so the pressure tank will never fill up while running. My well has a 50 gpm flow and the pump will output around 25 gpm with a 40/60 pressure switch and 50 gallon tank, 1" mainline and 3/4" lines from sprinkler valves to heads. Initially my zones were putting out around 15-16 gpm. The pump was cycling on and off about every 2 minutes. I changed nozzles on all heads first decreasing the flow which made the cycling worse then increased flow until the cycling stopped. Through trial and error came up with a nozzle setup running around 23-25 gpm. This setup keeps my pump running continuous without filling the pressure tank during the entire irrigation cycle. The other option would be a cycle stop valve you mentioned. I don't have direct experience with these but I think you have to make sure the pump and plumbing can handle the back pressure the valve creates.


----------

