wlape3 wrote:The 140's air return is tied into the cold air return for the propane unit. It ties in just before the downcomer segment which goes into the propane hot air circulation fan. The only problem with this is the propane fan has a higher air flow than the 140 fan so the air coming out of the registers is rarely more than slightly warm.
I've been thinking about your statement and want to share with you a way you may be able to improve on your air temperature.
When we installed our Koker last year we also ran the heat duct into the propane furnace cold air return duct just ahead of the air filter, so the propane furnace blower was pulling the heated air from the Koker and moving it upstairs.
Here's what may help you: my propane blower has a circuit board that allows me to set different motor speeds. We used the "cooling" mode to run with the Koker and turned it down to match the Koker 1500 CFM. So when we ran the propane furnace to heat the house, the blower motor ran at normal speed. When we heated with the Koker the motor ran at 1600 CFM to match the Koker.
The only drawback to this modification is that in the spring, I needed to reset the circuit board to run the motor at full speed for the A/C (2000 CFM).
Since you have a high efficiency propane furnace, you may also have the ability to slow your motor down.
Just a thought.