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HZ432 and TH8320R1002 Setup
This is a new house and I am not sure the contractor has the thermostats set correctly. Before I bother him, I would like to learn a little how my system operates and if it is correct, move on.
I have a Goodman DSZC16036 2 stage Heat Pump, a Goodman GMVC96060 2 stage gas furnace, a HZ432 zone control with DATS and OAT sensors and 2 zones.
The HZ432 seems correct: It is set up for Dual Fuel: 2 stage compressor and 2 stage dual fuel. The system is set to use the OAT to switch off the heatpump below 25*.
The question is around the TH8320R1003. That is setup as a 2 stage air-air heatpump, with gas/oil backup ( but there is no option for a 2d stage backup in ISU 207? Do I need to specify commercial in ISU 101 to get 2 backup stages?? )
Anyway the main question: there is no outside sensor on the thermostats and the ISU 219 is set to "No Fossil Fuel Kit". This would imply that the thermostat was handling the switch between Fossil fuel and Heat Pump. BUT I thought the HZ432 would do this using it's OAT???
So should ISU 219 be set to "External Fossil Fuel"
What is the problem if it is not set to "Yes" ?