Summer is coming -- help me fix my swamp cooler?
January 24, 2014 10:39 AM   Subscribe

I have a weird, vexing problem with my swamp cooler. Electricity is involved. Short version: when I turn it on, it blows the circuit breaker. Details below.

Last year, we refurbished our ancient swamp cooler, and installed a new motor and a new pump. Initially, everything seemed to work fine. But shortly after the installation, we found that when we turned the switch (standard five settings -- high/low cool and high/low fan and pump only), it would trip the circuit breaker. I'm not sure why it worked fine initially, then developed this issue.

My online research into this problem suggested that it could be a worn out switch box (possible, since it was very old), a wiring issue inside the box, or maybe something worn out in the plug. So I replaced the switch box, redid the wiring in the box, and took off the old plug and installed a new one.

Afterwards, everything worked -- mostly. If I turned the switch on clockwise one click, to pump only, it would trip the circuit breaker. But if we turned the knob the other way, to the high/low fan settings, it would NOT trip the circuit breaker, even if the switch was then turned all the way through high cool to low cool. (This was not consistent -- sometimes, we could turn it to pump only from off, and it would just work.) When it would trip, we were able to reset the breaker and turn the cooler on again.

We were willing to live with this, so everything was OK for a while, but one day I wasn't thinking and turned the switch to low cool, once again tripping the circuit breaker. This time, though, resetting the circuit breaker didn't work. If I turn it on at all, either direction, it trips the breaker. Thinking maybe something had come loose in the switch box or plug, I opened it all up and redid everything to make sure everything was connected right, but it didn't help.

I'm at a loss as to what the problem is. My wife thinks the pump is the culprit, that it might be too powerful and drawing too much juice. I suppose that's possible -- the cooler is on the same circuit as our TV and computers, and if I plug in something power-sucking like a space heater or portable air conditioner, it will trip the breaker. But it seems like if that were the case we wouldn't have been able to run it for weeks without issues. Or not? I'm also puzzled by the erratic nature of the problem (up to the point where it completely failed). Any thoughts on what's happening here?
posted by Mo' Money Moe Bandy to Home & Garden (8 answers total)
What prompted the overhaul? Are these the same problems you had before, or new ones?
posted by jon1270 at 10:44 AM on January 24, 2014

I work for an electrical contractor, although I am not an electrician. I showed your question to one of our service electricians and he suggested the breaker might have weakened with age, and the problem has been exacerbated by the refurbishment of your cooler. He says if he was called in to troubleshoot the problem, first place he would look is the breaker.
posted by Sternmeyer at 10:57 AM on January 24, 2014

Response by poster: What prompted the overhaul? Are these the same problems you had before, or new ones?

Before the overhaul, we had two problems going on -- first, we couldn't get the pump to work consistently. Sometimes it would turn on -- sometimes not. We'd replace the pump, but it didn't help. We tested it on the ground on an outlet, and it would be fine, but once installed, it would work occasionally, but mostly not.

Second, the motor seemed to be wearing out -- in order to get it to work at low (fan or cool) setting, I had to first turn it to high, then to low. Eventually it stopped working altogether on low.

For the overhaul, we (I'm saying "we" but this is mostly my neighbor helping us out -- I unfortunately have a bad fear of heights so I don't go up on the roof myself) replaced the motor and pump, and for some reason the pump just worked after that.
posted by Mo' Money Moe Bandy at 11:00 AM on January 24, 2014

Could be a weak breaker.

Now that you have the problem happening repeatedly you have a chance of tracking it down. If it is the pump disconnecting it and then starting the unit would let you know.

Is the breaker a GFCI? With a unit as old as yours it's possible some of the wiring has deteriorated such that there is enough leakage across to trip the GFCI.
posted by Mitheral at 11:02 AM on January 24, 2014

Response by poster: Thanks, Sternmeyer, I appreciate your doing that! Perhaps a worn breaker would explain why the problem has been intermittent and progressive?
posted by Mo' Money Moe Bandy at 11:03 AM on January 24, 2014

Response by poster: Mitheral, I unfortunately am not very familiar with circuit breakers, and I'm not at home to look at it, but I believe it is not GFCI -- it doesn't have any kind of test or reset button.
posted by Mo' Money Moe Bandy at 11:16 AM on January 24, 2014

Response by poster: I'm wondering if I could test to see if the breaker was the culprit, by plugging the swamp cooler into an outlet that runs to a different breaker?
posted by Mo' Money Moe Bandy at 12:17 PM on January 24, 2014

Yes that would work. And yes a GFCI should have some sot of obvious test and reset button.
posted by Mitheral at 1:15 PM on January 24, 2014

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