it is -5 degrees outside. Our thermostat is set at 70 degrees and the house heat is 58 degrees. the fan blade on the unit outside is not moving. the hvac system inside has a sticker on the unit. the empty box says unit has electric resistance. the checked box says 'may install' electric resistance. I see no mention of auxillary heat on the thermostat. Last summer hvac man was here and he said our thermostat is the correct one for the system.
is everything ok and we just need an auxillary heat, or is something broken?
Heat pump condenser fan not running in winter
heatpump
Related Solutions
I believe it's easiest to say that you need to get an HVAC maintenance company to come check on it. The auxiliary heat is entirely separate from the heat pump, that is why it's also used as an emergency system.
However, how cold has it been recently? A heat pump will only work to around 34 degrees or so outside and then it should switch off and allow the auxiliary to heat the home alone. Without going into too many details about the various possibilities, it could be that it's too cold outside for the heat pump, but the auxiliary isn't taking over (an issue with the thermostat and it's wiring to the system.) In regular heating mode, your heat pumps runs until it's too cold outside, and then the auxiliary takes over. In emergency heating, the auxiliary runs only. However, if it's been below say 34 degrees for those last two days, then your auxiliary would have been running entirely anyway and you wouldn't be saving any.
Again though, it's an advanced system and this could be caused by multiple issues - have someone come look at it.
There's a flame sensor (as opposed to a heat sensor) that can become coated with combustion products. These can be cleaned, or it may need replacement.
Best Answer
-5 (I assume °F) is a too low temperature for heat pump to work properly (usually those stops working at -15°C [+5°F]), so outer unit is simply 'locked due to excessive cold'. Auxiliary heat, in some units, is controlled directly by the HVAC controller and not by room T-STAT.
Anyway, check if auxiliary heat is connected BOTH on HVAC unit and Tstat, if it's connected only at unit side, connect it to the t-stat, if it's not connected, probably auxiliary heat is not present on your machine (if it was ECU controlled you won't have that cold in your house).
For now, you can just buy a couple of kerosene heaters and use those in case of emergency, look for 'zibro kamin' (I suggest a model that can work in case of power failure).