I have an xv 90 furnace with comfort R enabled. I was wondering if comfort R works the same way in heat mode as it does in cooling mode. Does anyone know the time that the unit stays on low verses higher blower speeds during the heating mode, and what determines the blower speed. Also, is it recommended to operate the unit in Comfort R mode for heating, or is there a more efficient setting for heat?
I am not a Tech and I only have a XV80, but wiring and operation should be the same as with your XV90.
Comfort-R, or 'enhanced mode' works in 'cool' only and the setup has no effects on heating.
Operation in 'heat' depends on whether you have a single stage or 2-stage thermostat. If you have a 2-stage TS, which you should, it's up to the TS to govern the furnace. It tries to stay in 1st stage unless the setpoint is two- or more degrees higher then the room temp, or when during 1st stage mode the temp drops.
In case of a single stage TS, W1 and W2 on the XV90's Control Board is jumpered and the mode of operation is set: Furnace starts in 1st stage and after a given time (about 10 min, or so which is set at installation) it goes to high fire and stays there until the TS is satisfied. Of course, if the TS is satisfied during 1st stage operation, it won't go to 2nd.
Blower speeds are also set at installation. There are Low, Medium and High settings with different CFMs in 1st and 2nd stage. You may want to read the Installer's Guide if you still have it.