Low-Pressure Cutoff Switch: How to Reset It
To reset a low pressure cutoff switch, fix whatever made the pressure drop, then hold the side lever in the Start position until the pump builds pressure and let it go. If you let go too early the pump stops again, and if it keeps tripping, the switch is warning you about a real problem in the well, the pump or the tank.
How a low-pressure cutoff works
A standard pressure switch turns the pump on at the cut-in pressure and off at the cut-out. A low-pressure cutoff switch adds one more job. If pressure keeps falling to about 10 psi below the cut-in, the switch opens and stays off. Schneider says the feature is used to protect pipe from low-pressure collapse in booster pump applications.
You can spot one by the lever on the side. Boshart lists the approximate trip points for common settings:
| Switch setting | Cutoff trips at about |
|---|---|
| 20-40 psi | 10 psi |
| 30-50 psi | 20 psi |
| 40-60 psi | 30 psi |
The cutoff point can't be set on its own. On Square D switches it stays 10 psi below the cut-in and moves whenever you change the cut-in. It also won't work if the cut-in is set below 10 psi. And there's no automatic restart: Schneider says plainly that there is no automatic way out of the cutoff.
Don't confuse it with the plain manual lever some switches have. On Square D switches that's the M1 option, an off lever for long shutdowns, while M4 is the low-pressure cutoff.
Why it tripped
The switch trips when pressure falls below the cutoff point. The usual reasons:
- The well ran low. Heavy use, a long irrigation run or a dry spell can draw the water level down to the pump. Boshart gives a low water condition as an example.
- The pump can't keep up. Boshart says a pump without enough capacity to hold pressure during heavy demand can trip the cutoff.
- The tank's air charge is too close to the cut-in. Boshart wants at least 2 to 5 psi between the tank pre-charge and the cut-in. Warm weather raises the pre-charge, so a gap that was fine in winter can vanish by summer.
- A leak or a broken pipe. A burst line or a failed drop pipe drains pressure faster than the pump can make it.
- The power was off. After an outage, pressure can drop while the pump is dead. Schneider says there's no automatic way out of the cutoff, even if pressure is restored from another source.
Tools
- A flashlight
- Your eyes on the pressure gauge near the tank
- Patience. The reset itself takes no tools.
How to reset it, step by step
Check the power
Make sure the pump breaker is on. If it tripped, see whether it holds before you go further.
Look for the cause
Walk the house and yard for running water, a burst pipe or an open hose. If you've been watering, give the well some time to recover first.
Find the lever
It's on the side of the switch box. It usually has three marked positions: Off, Auto and Start.
Lift the lever to Start and hold it
The lever is spring-loaded toward Start, so you have to hold it there by hand. You should hear the pump start.
Watch the gauge
Keep holding until pressure climbs above the cutoff point. Boshart's guidance at first start-up is to hold it until pressure is within 10 psi of the cut-in setting.
Let go
The lever returns to Auto and the switch cycles on its own as long as pressure stays above the cutoff.
Watch one full cycle
Run a faucet until the pump kicks on, close it, and check that the pump shuts off at the cut-out.
If pressure doesn't climb while you hold the lever, stop. A pump that runs without building pressure is either out of water or has a broken pipe, and holding the lever longer can damage it.
A new switch with open contacts isn't broken
People replace an old standard switch with a cutoff model, wire it up, and nothing happens. Boshart says a new low-pressure cutoff switch ships with its contacts open, and that's normal. Hold the lever at Start until the pump reaches the cut-in pressure, which on a 30-50 switch is 30 psi, and it will run on its own after that. Schneider gives the same instruction for first power-up.
Mistakes to avoid
- Resetting over and over without a cause. Each trip means pressure fell for a reason. Find it.
- Taping or wiring the lever in the Start position. That defeats the protection and lets the pump run dry.
- Setting the tank pre-charge right at the cut-in. Leave the gap Boshart recommends.
- Lowering the cut-in to stop nuisance trips. The cutoff moves with it, so you've only moved the problem lower.
When it's a pro job
Call a well contractor if the switch trips several times a week, the pump runs without building pressure, or pressure falls with every faucet closed. Those point to a weak pump, a low-yield well or a leak below ground. If you need a new switch, our page on how to replace a well pressure switch covers the swap. To change the range itself, see adjusting a well pump pressure switch.
FAQ
How do I reset a well pump pressure switch?
If it has a lever, hold the lever in Start until the pressure gauge climbs past the cutoff point, then let it go. If it has no lever, there's nothing to reset. Check the breaker, the pressure gauge and the switch inlet instead.
How do I reset a pressure switch on a well pump without a lever?
You can't, because standard switches have no lockout. When one stops working, the usual causes are a tripped breaker, a clogged inlet nipple or a worn switch. Our pressure switch problems page goes through them in order.
Why does my low-pressure cutoff switch keep tripping?
Boshart names two causes: a tank pre-charge too close to the cut-in, or a pump that can't hold pressure during heavy use. A well running low on water causes it too. Check the pre-charge first, since it's free.
Does a low-pressure cutoff switch work with a jet pump?
Yes. Boshart says its low-pressure cutoff switches work with both shallow well and deep well jet pumps. The reset is the same.
Can I adjust the cutoff point on my switch?
Not on its own. The cutoff stays a fixed amount below the cut-in and follows it when you adjust the range. Adjust the cut-in and the cutoff moves with it.
Sources
- Schneider ElectricHow does the M4 option on a 9013 F Pressure switch work? (opens in a new tab)
- Schneider ElectricIs the low pressure cutoff option on a 9013 pressure switch adjustable? (opens in a new tab)
- Boshart IndustriesWhat is a Pressure Switch with Low Pressure Cut-Off feature? (opens in a new tab)
- Boshart IndustriesWhy is my low-pressure cut-out switch nuisance tripping? (opens in a new tab)
- Boshart IndustriesIs my low pressure cut-off switch defective? The contacts are open on my new switch (opens in a new tab)
- Schneider Electric9013: What is the difference between M1 and M4 options? (opens in a new tab)
- Telemecanique Sensors (Schneider Electric)Pumptrol Pressure Switch Instruction Sheet 65013-005-39 (opens in a new tab)
- Boshart IndustriesCan I use a low pressure cut-out switch with my jet pump? (opens in a new tab)