chuckconnie Report post Posted March 30, 2014 Furnace blower starts and when roof unit tries to start the breaker trips. Any input would be appreciated. Share this post Link to post Share on other sites
dickandlois Report post Posted March 30, 2014 Chuckconnie, Sounds like the problem is in the area of the compressor motor. Motor starter block, bad starter cap or something in the motor. kind of a circuit that is a little different to trouble shoot if your not familiar with AC compressor circuits. Rich. Share this post Link to post Share on other sites
wolfe10 Report post Posted March 30, 2014 First confirm that voltage is at least 108 when the compressor tries to start. If is does this on shore power, but not on generator, it may be a shore power issue. If not a voltage issue, look into the things Rich mentioned-- pay particular attention to the capacitor. If you are not comfortable working when charged capacitors, have a professional do it. You CAN do a visual check (on-roof inspection)-- if it is leaking or deformed, assume it is bad. Share this post Link to post Share on other sites
dickandlois Report post Posted March 30, 2014 Good point Brett! I have a voltage and frequency monitor connected, so checking the voltage and frequency comes as intuitive as walking to me. So I tend to go into equipment diagnostic mode when I'm posting. Rich. Share this post Link to post Share on other sites
chuckconnie Report post Posted April 15, 2014 The air conditioner still works. Share this post Link to post Share on other sites
dickandlois Report post Posted April 16, 2014 A working AC compressor takes that out of the equation. That leaves the heating element if your equipped with one and the circuit that reverses the cooling and heating coils. Should have asked before, but could post the make and model numbers of you AC and heat pump system? Rich. Share this post Link to post Share on other sites
wigginsjsr Report post Posted April 16, 2014 If the furnace motor is coming on before the heat pump it may mean that your thermostat is set to more than 5 degrees below the ambient temp inside the motor home. In the case of my rig if you try to use the heat pump to raise the temp with more than a 5 degree difference the furnace will come on to help the heat pump make up the difference until the heat pump can handle the ambient temp on its own. Both will run during that time. That could mean that the start up load of both is too much for the breaker, or as pointed out above the voltage may be too low to handle the load. I would try turning on only the furnace until the ambient temp reached the desired setting, and then turn off the furnace and on the heat pump. See if that sequence works. Share this post Link to post Share on other sites
wolfe10 Report post Posted April 16, 2014 "That could mean that the start up load of both is too much for the breaker, or as pointed out above the voltage may be too low to handle the load." Not sure I understand. The furnace fan (actually whole furnace) operates on 12 VDC. The heat pump on 120 VAC. The furnace should only very indirectly affect 120 VAC appliances/breakers (just the small additional load of the charger to replenish the battery). Share this post Link to post Share on other sites
wigginsjsr Report post Posted April 16, 2014 Yes, as usual Brett is correct. My bad! Share this post Link to post Share on other sites
