Heat Pumps and Electric Heating - Trane XL1200 tripping cb on air handler

This looks like a great forum. I hope someone can give me some help.

The circuit breaker on the air handler used to trip every few months or so and I would take it as a sign the air filters needed to be cleaned and I would clean them and it would work for several more months without a problem. Now that it is starting to get cold the breaker seems to trip whenever the heat is on for more than 10-15 minutes or so.

Steps I've taken so far. Thoroughly cleaned the air handler and inspected for loose/bad wiring. Thoroughly cleaned the outside unit and looked for anything suspect. I did find some wires in the air handler that looked pretty oxidized so I sandpapered them and the contacts. Also found one of the ionizer wires was broken, but I've taken the electric cleaning units (not sure what the right name is) out while troubleshooting.

The system worked for two nights after I cleaned up the wire on the air handler, but tripped again this morning. I also noticed that the aux ht light has been on a lot lately when the system is working.

Questions: How do I narrow down the problem? What are the most common reasons for the circuit breaker on an air handler to trip? I'm pretty good with electronics (soldering and voltage testing, etc...) and can take pictures if it would be helpful. Any help would be appreciated.

Here's a pic of the inside of the air handler (also a trane)
http://img206.imageshack.us/img206/3632/wiresvz8.th.jpg (http://img206.imageshack.us/my.php?image=wiresvz8.jpg)

The wires you point to are low voltage control wires.

When the breaker would trip every few monthes was it always in heat?

Does the breaker also serve the blower?

What is the breaker rated at?

Can you take an amperage reading through the breaker?

What is the model and serial of the air handler?

Thanks for the response. I'll answer your questions the best I can.

1) When the breaker would trip every few monthes was it always in heat?

No, I'm pretty sure it happened this summer as well.

2) Does the breaker also serve the blower?

I'm not sure, but when the breaker trips everything turns off, the blower, the air cleaner, and the heat pump.

3) What is the breaker rated at?

It's says 60

4) Can you take an amperage reading through the breaker?

Probably, but I'm pretty nervous to go near the thing when there is power to it. Is it relatively safe?

What is the model and serial of the air handler?

Model: TWE030P130A0 Serial: H22890353

I'm sure this unit is over 10 years old (I'm thinking closer to 15). It came with the double-wide when we bought it and I guess those "it's hard to stop a trane" commercials got to me because I didn't even think about it until it quit working so it has been neglected.

Thanks for your time. Aaron

4) Can you take an amperage reading through the breaker?

Probably, but I'm pretty nervous to go near the thing when there is power to it. Is it relatively safe?


I mean with a clamp on amp meter, not actually disconnecting wires and letting the current go through the meter.

The fact that it happened without the heat on makes me think weak breaker. Amps will tell the tale.

A meter like this will work and be handy for years to come:
Clamp On Meter (http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100138499)

I didn't see it in the specs, but we want to know what the amps through the breaker are when it trips. A "Max Hold" button would help. This will hold the max value read if you are not there or looking when the breaker trips.

I'm thinking 22 week of 1989.

I'm thinking 22 week of 1989.

Ah, that's why you wanted the serial number... That link to the clamp on meter isn't working for me.

Is this the right one?

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100628710

Good meter if your going to make a living with it. I send Store SKU# 263732, costs 50 bucks.

You are correct, serial number is the clue to age. Sometimes easy to get, sometimes like hyroglyphics.

I forgot that the elec heater is an accessory with a different model number. Mute point now, the parts list for that air handler is only available as an Xcell file. No pretty pictures to look at.

Anyway, you don't need a big expensive meter around the house. Cheap and sufficient is just fine.

I had originally thought a problem with the heater itself until you verified that the breaker tripped every so often in A/C also. This point to the breaker itself.

Hi Jarredsdad,

Sorry for the long delay. Had to put this project on the back burner until payday. I bought the meter you suggested, but it doesn't seem to have a max hold button (it has a hold button, but that just seems to hold whatever reading is on currently). I'm not exactly sure what I'm doing at this point, but I tried measuring the amps on the breaker (I've included pictures) and it seemed like it started out well below the 60 limit (around 35.1) and then slowly crept up. I walked in the house to see if the auxillary heat light was on and it tripped so it may have jumped up, but I thought it was strange that it was going up steadily .1 amp at at time. I also measured the voltage and it's 123.3ish on both sides.

I'm not even sure I'm measuring things right, maybe you could have a look at the pictures and let me know. If the breaker is tripping below 60 amps is that definatively a bad breaker? Should I be concerned about the upward crawling amps? Thanks for your help.

http://img160.imageshack.us/img160/6364/ampsxk9.th.jpg (http://img160.imageshack.us/my.php?image=ampsxk9.jpg)http://img160.imageshack.us/images/thpix.gif (http://g.imageshack.us/thpix.php)

http://img513.imageshack.us/img513/3160/voltsok0.th.jpg (http://img513.imageshack.us/my.php?image=voltsok0.jpg)http://img513.imageshack.us/images/thpix.gif (http://g.imageshack.us/thpix.php)

Good. But read L1 and L2 together (146 volts).

35 amps is a lot without heat on.

You only have a 1/3 Hp motor there maybe 5 amps.

Something is drawing it. Can you check the fan motor and the different legs going to each heater coil?

Yes tripping below 60 is a bad breaker. A 60 amp "must trip" around 90 not 40.

Thanks again. Glad you're still around. I had the heat on when I was measuring the amps. With the fan only on I get a 1.2 reading and it's the same with emergency heat. I only get up in the 40 amps when the outside unit kicks on. The breaker just tripped using only the emergency power and the amps are like 1.2 with that... Time to swap the breaker?

I don't really know what I'm looking at out there. Could you take a look at the picture and let me know where to measure L1 & L2? It's too tight a space to use the clamp meter on the left side (red and blue wires) are the fat black wires on the right side going to give me a valid reading for amps? Thanks again. Aaron

http://img134.imageshack.us/img134/1051/breakerqb3.th.jpg (http://img134.imageshack.us/my.php?image=breakerqb3.jpg)http://img134.imageshack.us/images/thpix.gif (http://g.imageshack.us/thpix.php)

Just wanted to write and say that I replaced the 60a circuit breaker and everything seems to be working fine now (knock on wood). Thanks Jarredsdad for all your advice and help. I'm really excited about having the clamp on meter and I'm sure it will come in handy for years. It will be nice to wake up and not see my breath! Beer 4U2

In the last pic your clamp on was reading L1 or L2 (L meaning line), the thick black wires coming into the unit.

The red and blue are called T1 and T2 or the load side of the contactor.

Remember electricity runs in a straight line, with respect to circuits, find the stopping point and you've found the problem.

But it also likes short cuts to ground. Don't be a short cut, as soon as you disrespect it It will zap you.