Pump still running after power outage?

[Isabella]

So this is weird. We had a quick power outage in my neighborhood yesterday evening. When the power came back on, my pool pump started running immediately on its own, even though the timer switch was technically off. I tried turning the breaker off/on, but the pump just kicks back in like it has a mind of its own. Water’s moving fine, but I don’t like that it’s ignoring the timer. Has anyone ever seen this happen? Is it a bad relay, or am I about to fry my whole system?

 

[Freddie]

So this is weird. We had a quick power outage in my neighborhood yesterday evening. When the power came back on, my pool pump started running immediately on its own, even though the timer switch was technically off. I tried turning the breaker off/on, but the pump just kicks back in like it has a mind of its own. Water’s moving fine, but I don’t like that it’s ignoring the timer. Has anyone ever seen this happen? Is it a bad relay, or am I about to fry my whole system?

That’s definitely not normal behavior. Sounds like your pump timer relay might be fused closed from a surge during the outage. I had a sprinkler timer do that once basically it was stuck in the “on” position no matter what. If that’s the case you’ll probably need to replace the timer box, otherwise the pump will just keep running until it burns out.

 

[Zephyr]

So this is weird. We had a quick power outage in my neighborhood yesterday evening. When the power came back on, my pool pump started running immediately on its own, even though the timer switch was technically off. I tried turning the breaker off/on, but the pump just kicks back in like it has a mind of its own. Water’s moving fine, but I don’t like that it’s ignoring the timer. Has anyone ever seen this happen? Is it a bad relay, or am I about to fry my whole system?

Could also be that the surge messed with the electronics in the pump motor itself if you’ve got a variable speed model. Sometimes they default to “on” after losing power. I’d unplug the timer completely and see if the pump still kicks on when the breaker is reset. If it does, the motor’s onboard control might be the culprit.

 

[Olivia Reed]

I’ve seen something similar happen once after a short power cut, and it turned out the timer relay had partially fried during the surge. It basically welded itself in the “on” position, so the pump ignored the timer completely. You can test this pretty easily, disconnect the timer or remove the control wire and see if the pump still powers on when you flip the breaker. If it does, the relay or timer box is toast. If not, then the issue might be with the pump’s internal controller, especially if it’s a variable-speed model. Either way, I’d keep it shut off at the breaker until you can check it properly.

 

[Edward Williams]

Most likely, your pump timer relay is stuck in the 'on' position after the power surge. Try checking if the timer still turns or not, if it’s stuck in the 'on' position, you’ll probably need to replace the timer box to stop the pump from running continuously.

 

[Matthew Collins]

I’ve seen something similar after a short outage and it ended up being the timer contacts sticking rather than the pump itself. On those mechanical timer boxes the little metal contacts can arc during a surge, and sometimes they basically weld together. When that happens the pump keeps getting power even if the dial says it’s in the “off” window.

One quick thing you can check is whether the timer dial is still rotating normally. If the clock motor is turning but the pump never shuts off when it passes the off tab, that’s usually a sign the contacts inside are stuck closed. My pump did exactly that after a storm and the filter pressure stayed normal because the system was just running nonstop.

If you’re comfortable opening the timer box (with the breaker off), you can sometimes see the contact points inside. In my case they were visibly darkened and slightly fused together. Replacing the timer mechanism fixed it and everything went back to normal scheduling.

At least the good news is the pump running constantly for a short time won’t hurt anything, it just means the system is filtering more than usual. The bigger concern is the timer not controlling it anymore.