View Full Version : Low pressure cutoff.
Jack D Davis
06-27-2005, 05:06 PM
We own a duplex on well water. When using sprinklers we occasionally will draw more than the pump can supply and pressure drops. This usually happens when the tenant turns on outside water at the same time we are watering lawns, etc. Even flushing toilet or washing clothes can cause the pressure to drop too low if sprinklers are on. My solution would be to use a normally open solenoid valve and pressure switch to stop the flow of water to sprinkler lines when the pressure drops below a preset point and turn back on after pressure rises to another preset point. The problem is; I can't find a normally open solenoid valve in a price range I can afford. All I find run several hundred $$$. There must be a reasonably priced normally open solenoid valve or pressure actuated valves that would solve my problem, but I'll be danged if I can find one. I'm thinking the water (to the sprinkler lines) should shut off at about 45# and back on at about 55# =/-. The well pump comes on at 50# and off at 60# +/-.
First you may want to look into any possible reasons the pump cannot meet the required needs. Could be beyond it's capacity, or something else.
If you end up trying to shut the sprinklers down, take a look at what pressure your system is holding when the sprinklers are on, in order to determine shut off pressure.
Would it not be easier to just cutoff power to the existing sprinkler valve(s) rather then adding a new valve. Possibly could be done with just a pressure switch alone, or at most a pressure switch and relay.
06-29-2005, 06:37 PM
IMO sprinklers should be timed and run at times when household water use isn't being used. It sounds to me as if the problem is that you are drawing the well down too far for the pump to move water. Or IOWs, you're using too much water in too short a time frame, and then when someone wants water for the houses, there isn't any. And IMO, tenant happiness is more important than plants and grass...
Quality Water Associates
Reverse acting valves are not a common usage item, therefore they are by definition expensive. Shutting power to the sprinkler system would also affect the timers time setting and programming. Depending on your abilities, if you wired a normally closed relay into the "C", common" wire to the valves and interupted that circuit when the pressure dropped it would shut down the valves for the duration of the low pressure. If you powered it from the pump circuit and added a "holding" function, then the system would not cycle rapidly as the pump restored pressure and then lost it again as soon as the system turned on, but would stay off until the pump restored full pressure to start over..