turning off auxiliary heat during defrost - need help
I need some help. I have a single stage heatpump with demand defrost (3-tons) and a 90% gas furance (100BTU input). This is a dual fuel setup.
I have it controlled by a focus-pro wireless t-stat kit. It works great EXCEPT FOR.
When my heatpump goes into defrost it initiates the gas-furance. Sometimes during a longer defrost their is significant heat left in the plenum when it switches back to heatpump and there is annoying vibration until all the leftover heat produced from the gas furnace during the defrost cycle is gone. I'm sure this vibration is not good for the heatpump. This has been happening since I had the system install 2.5 years ago. It hasn't caused any problems but I'm sure it might take life off the system. Its also annoying hearing the vibration after it comes out of defrost.
This happens because my furnace is single stage and it produces way to much heat then necessary to temper the cool air of defrost and the heat comes from below the coil.
Can I disconnect a wire from my t-stat base by my furance so when it goes into defrost it doesn't start my furnace? I tried disconnecting the aux/E wire. This solves the problem - but I can no longer activate the gas furnace if I were to switch to emergency heat or for when it drops below the balance point that I have set on the t-stat.
Or do I have to disconnect the W wire at the heatpump because I read on other forums that this is energized during defrost?
I'm looking for some type of solution. I can live with a short spurt of cold air during the defrost cycle.