Educate me about circuit breakers, please!

I’m posting here in hopes that someone with a vast knowledge of heat pumps and air handlers can give me a clue as to what’s going on. I figure MPSIMS is better than GQ for this question, as it’s pretty specific and probably won’t fight anyone’s ignorance but my own.

We’ve had our house for almost 3 years now. For the last two winters, every once in awhile, the air handler circuit breaker will trip, apparently randomly. It happened only a couple of times the first winter, then several last winter. The heat will work just fine for weeks, then all of a sudden it will trip every few cycles for a couple of days.

Now this winter, it’s happening WAY more often. The heat isn’t staying on for more than an hour or two. Around 2 am, it’s pretty darn cold in the house.

The specific model is:

Trane Air Handler - Convertible Variable Speed
Model: TWE031E130A0
Installed in 1994

It seems to be Circuit Breaker 1 that is tripping.

The people who owned the house before us were scary-organized, and left a gigantic notebook of documentation for everything that ever happened here. According to the Book of the House, it seems that at one time, circuit 1 was serviced, and the original 50 Amp circuit breaker was replaced with a 60 Amp circuit breaker. I take that to mean that the serviceguy saw that it was drawing more amps than the circuit would allow, and “fixed” the problem by just putting in a larger breaker without finding out why this air handler is pulling more than 50 Amps.

So it seems that the air handler is now pulling more than 60 Amps on occation. I suppose that I could try to replace the breaker itself with another 60 Amp breaker, or I could try to put in a larger breaker, but I’m afraid of doing that because the overcurrent rating on the air handler is 60 Amps. I don’t want to accidentally allow the blower to pull too much current and catch on fire and burn the house down.

It doesn’t seem to be a full short circuit, since this is an intermittent problem. Maybe the blower motor is getting old and is just pulling more current, but that doesn’t make much sense to me. Does anyone have any ideas? It’s one of those things that gets annoying, but it takes 20 seconds to reset the breaker, so it doesn’t get much priority in the house. On the other hand, if the house is going to go up in flames soon, I should probably deal with it.

Any theories or ideas would be appreciated!

Maisy

It could be a bunch of things. It could just be a bad breaker. It could be a fault in the heater that’s causing it to occasionally draw too much current. And if it is the heater, it could range from the innocuous to the really bad. It could, for example, be a bad bearing or overtight belt on the fan that’s causing it to draw too much current. Or it could be a fault in the heating element – maybe a few coils have shorted out, causing it to have too low a resistance.

Have you had a technician in to look at the system? Does it get yearly maintenance?

As noted by Finagle, it could be a faulty breaker. Doubtful, but if the replacement breaker is not marked HACR (Heating, Air Conditioning and Refrigeration), it may trip owing to inrush current.

The change of a breaker from 50 to 60 amps is only permissible if the circuit conductors are rated for that ampacity under that application.

Sorry to be the bearer of bad news, but you need to hire a competent technician to evaluate the system, and it may take a few hours, and it won’t be cheap. Needle in a haystack service calls are that way.

Yeah, I’m planning to call for service tomorrow morning. It’s the time of year when everybody’s got heating problems, so I’m sure it’ll be a few days before anyone can come out to take a look. I thought maybe there would be an easy fix or obvious answer. Besides, I always like to at least have a basic understanding of the problem when I talk to a repairman. But it sounds like there are quite a few possibilities on this, and obviously I’d much rather be safe than sorry.

I appreciate your taking the time to reply - I will check on a couple of your suggestions.

M