Water Pump Runs on City Water With Switch Off

[capt.morgan58]

need advice : water pump cycles on when faucet is opened, on city water and switch is off, this just started yesterday, but I don't want an overflow or flood also turn off tap pump stops ???

 

[Gary RV_Wizard]

You say the pump switch is OFF? Obviously it should never come on if that's the case. But if it's not OFF (or the On/Off has failed), that simply means your city water pressure is low, probably less than about 45 psi.

Background: The water pump is pressure controlled, so if the water pressure goes below the threshold (usually 45 psi), it tries to come on to boost pressure. The pump switch opens/closes the 12v ground (negative) side of the pump power. If your pump has two or more switch locations for On/Off, it probably has a "pump controller" module rather than the switches directly switching 12v power. Your Off switch just tells the controller that the pump should be Off, but another switch might be saying On at the same time. Or the control module itself has failed. Check those two things for possible problems.

 

[Kirk]

Gary has covered it well. Unless you have some additional questions, there really isn't much to be added. But if you do still have a question, by all means ask.