I am an unhappy owner of a Water Furnace geo unit. It has been running for about a year, and we've had many problems.

I will try to spare the details, and go straight to my current problem.

There is something wrong with the electrical connection. The loop compressor is trying to start, but it just buzzes for about 3 seconds (house lights dim) and gives up. We had this problem last winter when the unit was running for just one month. I had the installer out several times and together we finally pinned the problem down to a faulty breaker.

After about a year, the problem is back. The loop compressor isn't working, we're on expensive electric aux heat tonight, and tomorrow morning I'm heading out to the electrical dealer to get new breakers. Add $90 more to the energy costs!!

There are some things that don't quite add up. First, there is a 90A circuit and a 60A circuit. The compressor is on the 60A circuit. The 90A circuit is wired for 100A because a 90A breaker is not available. We have a 200A Cutler Hammer BR panel dedicated for the geo. The thing that doesn't make sense is that the problem was solved by replacing the 100A breaker (the aux heat), and NOT the 60A breaker (the compressor). It should be the reverse.

Another strange thing is that the 100A breaker tests OK. But it is 100% reproducable to recreate the behavior by restoring the original breaker. Now I have two failed breakers apparently.

And the problem seems to be brought on by heavy use of aux heat. Over the last month, it was very cold. The geo has run 24 hrs since early December.

[In fact, we were so uncomfortable last year with the fan on high that we put in 50K btu more heat via a gas boiler/radiant heat in our favorite rooms.]

According to the installer, the compressor checks out fine.

Are there ways the breaker can fail by getting too much heat through the wiring when aux heat is running a lot? Any suggestions on tests to further isolate the problem?