TheSamba.com :: View topic - Heat pump trips circuit breaker after a while

Tue Feb 04, 2014 12:07 pm

I thought I'd tap into the brain trust here. I think some here have some specialized experience with this.

I arrive home from work Monday, and poor Mrs. Cusser is cold (was like 59F high Monday), and the heat pup isn't working, nothing when I set blower fan to "on" at the control. So I brave the cold weather and go out and flip the heat pump breaker, and everything works, for about 15 minutes (meanwhile, Mrs. Cusser enjoyed warming up in the jacuzzi, can't detail that though). Anyway, about 10pm, we notice that it's not working again, so I have to keep her warm all night.

Anyway, this morning, again I flip the heat pump breaker, and it works for like 15 minutes.

Question: does this sound like first step for me is to just replace the 60-amp Cutler-Hammer breaker? It seems - because I'm a heat pump dummy - that if the heat pump was really having issues that this would happen within a few seconds of start up.

I believe that the heat pump circuit breaker is 34 years old, and if I've replaced it, was over 24 years ago. And I think that Ace stocks them.

Any help here before I have to call some service company? Help me take care of Mrs. Cusser's needs !!! Thanks.

Tue Feb 04, 2014 12:51 pm

Have you tried just manually running the system for say, 10 minutes (then lower the temp setting)? I'm wondering if the "trip" is happening after it's heat-up cycle- like when it just switches to fan. Of course, that would mean internal vs. breaker problem. Perhaps a bad cycling relay is to blame.

(I'm hard-wired to believe all fuses and breakers trip for a reason, 1st- but I've been wrong already 17 times this week!)

Tue Feb 04, 2014 1:04 pm

Iv'e seen more that one older breaker get weak and trip prematurely but one of those clamp ammeters on the line first would confirm the unit isn't suddenly drawing more than it's fair share.

Tue Feb 04, 2014 1:18 pm

odds are it is not the breaker either the fans, a relay and/or a heat element is tripping it
heat pumps are pretty simple once you figure them out it just cycles heat from one area to another by using a compressor and condenser

think of it as like a bus wiring system and you have something grounding out and blowing the fuse

so you will either have to test all the electrical controls yourself or call a heat guy

a easy way to test the breaker is to find another breaker in the panel with the same rating and switch the wires on them
just long enough for a test if the same breaker trips still then it's the breaker but if the other one trips then it's something in the unit tripping it

Tue Feb 04, 2014 6:44 pm

Update: I borrowed a clamp-on ammeter and got off work a little early, so had some daylight.

I got home and measured the amps draw with the breaker on (heat pump on), read about 12 to 13 amps on each leg (what we "electrical guessers" used to call wires) coming from the heat pump dual 60-amp breaker.

[QUOTE=applianceguy;146181]Check to make sure all the wire connections/lugs are tight at the breaker. Sometimes, especially with aluminum wiring the connections get loose and you simply need to tighten the connections. [/QUOTE]

So I switched off the breaker and tightened the two screws for the wire attachments. It looks like some of the larger wires like for the heat pump indeed are aluminum, but lots of others are copper.

Heat pump breaker at top in this photo.

Other side, copper wires.

After tightening the two screws, and switching on the breaker, the amps reading was about 29.6 amps in each leg.

So I took my cordless phone along, with instructions for Mrs. Cusser to call me if it shut off, and went off to Ace. At Ace, there were several types of dual 60-amp breakers for $14, then I found the Eaton CH260 which apparently is made for Cutler Hammer breaker boxes, for $20, no returns. Since Mrs. Cusser hadn't called, and I'd only do such repair during daylight, I didn't get it (they stocked two). So far, so good....

Tue Feb 04, 2014 7:54 pm

Does just the outside unit shut down, or both the inside and outside units shut down once the breaker trips?

Believe it or not, poor airflow through the indoor unit can cause excessive head pressure/amp draw during the heat mode. Hell, even a dirty filter could cause this condition, among many many other things...

Tue Feb 04, 2014 10:53 pm

Nice job. Good pics too.
The breaker may have failed, but CH are good quality, so you may want to check the connections at the pump as well.
The other thing I see, is there should be oxide inhibitor on all AL connections. At the breaker, disconnect, and pump.
If it still trips with a new breaker and good connections, the pump is failing.

Wed Feb 05, 2014 12:58 am

It almost looks like there is deox residue under the first lug in the first pic. The old stuff looks like brown bakelit.
Those are good breakers.
I would pop the breaker off to check the busing for damage and also check resistance through the breaker

It seems almost like something comes on at 15min tripping the breaker

How does the breaker feel when you snap it on and off?

It should have some resistance to it but not be really hard or sloppy loose

Does it draw 29 amps when it trips?

Have you opened up the heat pump yet?

I think the condenser should have its own breaker.

Wed Feb 05, 2014 7:11 am

Update, 15 hours later: still working perfectly. Mrs. Cusser is warm.

Apparently after 34 years, the two screws needed tightening.

Note to self: tighten again in 34 years if still here - and if able to lift a screwdriver....

Wed Feb 05, 2014 9:26 am

69 Jim wrote: Believe it or not, poor airflow through the indoor unit can cause excessive head pressure/amp draw during the heat mode. Hell, even a dirty filter could cause this condition, among many many other things...

X2. A couple of houses ago, my heat pump would shut off and in the summer it was due to ice buildup on the inside coils. The installer did a poor job of sizing and ducting, and if the filter was the LEAST bit dirty, airflow slowed and the ice would come, and soon after, the breaker would blow. It can also do this if it is low on Freon (or whatever they are using these days), or if a fluid filter is clogged.

Wed Feb 05, 2014 9:28 am

You should check all the other lugs to see if they are loose.

Tue Feb 11, 2014 9:23 am

tncsparky wrote: You should check all the other lugs to see if they are loose.

Agree, the buss bar may need a little clean up too...

Tue Feb 11, 2014 12:02 pm

Well, I replaced the circuit breaker, moved it down the bar too. Turns out I had replaced that breaker myself over 20 years ago. Fifteen hours later it had tripped.

So I'm having a service call scheduled.

Tue Feb 11, 2014 12:18 pm

Cusser wrote: Well, I replaced the circuit breaker, moved it down the bar too. Turns out I had replaced that breaker myself over 20 years ago. Fifteen hours later it had tripped.

So I'm having a service call scheduled.

Do you have good air flow over the indoor coil? During heat mode, it's crucial. If you have poor airflow over the indoor coil(dirty filter, etc.) during cooling mode, it will frost over but wouldn't cause a breaker to trip. Having say a dirty filter during heat mode would be the same as blocking airflow over the outside unit during A/C use. Excessive compressor head pressures will usually draw more amps than the breaker can hold. There are so many other culprits it could be. A good technician will get to the bottom of it. It may be a good idea to let the unit run for a while before the tech arrives to help with the diagnosis, hourly rates are killer. Another thing to try is to run just the indoor fan for a while to see if it overheats and goes out on thermal overload. Seen that one a few times. Good luck to you Cusser...

Tue Feb 11, 2014 12:23 pm

Cusser wrote: Well, I replaced the circuit breaker, moved it down the bar too. Turns out I had replaced that breaker myself over 20 years ago. Fifteen hours later it had tripped.

So I'm having a service call scheduled.

depending on the model of the heat pump it could have anywhere from 4 to a dozen sensors in it that could fail
one of those failing could cause the breaker to trip or cause the compressor to over heat which would trip it or the fan overheat which could trip it etc...

heat pumps are like new cars a $5 sensor could make the whole thing not work

Tue Feb 11, 2014 8:10 pm

Not a fan of aluminum wiring.

Tue Feb 11, 2014 9:26 pm

Millions of feet of Al wire have been installed. Its not all Aluminum, its an alloy. The old stuff that they put in trailers was junk but the new stuff is just fine
Most of the sub feed wiring will be done this way because of the huge cost savings

Wed Feb 12, 2014 1:04 am

I had a 400 foot underground run to power my shop. Aluminum was the only choice. Copper would have cost over $1000 more. Its all in the connection materials and deox paste. Perfectly safe if done properly.

Wed Feb 12, 2014 6:54 am

Cusser get ready for a new compressor if you have never changed it. More then likely that will be the outcome.

Wed Feb 12, 2014 10:17 am

Jon Schmid wrote: Not a fan of aluminum wiring.

I worked for a electrical supply store in the mid-2000's and back then they were saying that copper wiring was to be fazed out in the next 10-15 years

even back then we rarely sold any copper stuff that was bigger then 8 gauge

if you got more then 15 years out of that compressor then you got a good one
those are sealed units and most were never build to last more then 5-10 years unless it's a higher end unit then 15 year is about average
(I also worked in HVAC supply stores for several years)