I am running a central heat system that uses a heat pump as stage 1 and a gas furnace as stage 2. The thermostat used is the White-Rodgers 1F82-261 which supports 2 stages of heat.
When using regular heat mode on the thermostat and setting the temperature to 1 degree Celsius above actual temperature, I noticed that the thermostat was consistently switching to stage 2 heat after about 10 minutes running the heat pump. The manual of the thermostat mentions that stage 2 should only be used when the set temperature on the thermostat is 4 degrees above the actual temperature.
Is there another reason why the stage 2 would kick in prematurely? For example, I suspect that my ventilator is not pushing enough air for the heat pump and therefore may require lots of time before an actual temperature increase is noticeable. Would that be possible that the thermostat triggers stage 2 if no temperature increase is noticed for 10 minutes? There is no mention of that in the manual though.