Breaker Tripping

terrynistler

I have a rent house with a ten year old electric hvac system. The 60 amp breaker on the furnace is tripping every 3-4 hours. Checked everything electrical out seems to be fine. Where can I get these Siemen furnace breakers at it is a 60 amp Special purpose seimens with the spades off the load side regular lugs on line side? The breaker is right next to the 30 amp breaker on the hvac unit. The breaker in the panel box has never tripped. I disconnected one strip temporarily and seems to work fine.

mdshunk

The breaker is not the problem. It never is. Besides, it appears you havn't taken amp draws of the system or the elements yet.

Take out the heat packs and visually examine them, and you will find your problem. Also, check the resistance of the sequencers and all connections for signs of heating. Your problem will be visual or measurable, but you havn't done enough troubleshooting yet.

Or, you can save the trouble and call the Landlord. That's the advantage of being a renter.

terrynistler

MD Thanks. However I did do individual amp draws on each coil. They total 45 - 47 amps Individually they are within the schematics on furnace. I pulled the plate and inspected via flashlight each coil. I expected to see something burnt or signs of arcing none of these were present. Sequencer working according to specs. This problem started a week ago and would trip every other day. I am the landlord . It is my tenant that is not happy lol. The breaker is spongy not crisp at all. It is my last option. But none of my supply houses carry it. Checked a few online as well and still cannot find it. Was wondering if the hvac guys have ran into this problem. I am a licensed Master electrician and Master plumber and can usually fix my own hvac as well but this one has me stumped. Are you aware of any other problem that could cause this I sat there in the attic for 2 hours with my ammeter waiting but of course it worked fine but tripped 2 hours later after having been through 3 heat cycles. I am stumped and the other HVAC guy in town is also an electrical contractor and Plumber with HVAC don't want to resort to calling him.

Thanks

mdshunk

The Square D "QO-U" is the typical replacement. It mounts the same way.

terrynistler

Thank You.
I have located the breaker online and will install it when it arrives. I am in Texas so it is not often we need Heat. This unit is in an attic and the temps get pretty high during the summer. I see lots of premature failure here. I appreciate your help....

faber307

Almost every time I have run across a sporatically tripping breaker, with amp draws within limits, there is a loose connection somewhere. And it may not be extemely evident but at the minimum there should be some discoloration at the bad terminal, whether it be the conductor or the terminal. Like MD said, It's never the breaker.

One of those little infrared thermometers can reveal alot when you compare terminal temperatures