cold weather heat problems (heat pump, gas, furnace)

[dougl613]

when the temps get below 30 outside my heater starts to act up. The heater starts up but the fan doesn't come on. If you turn the heater off and on a few times it might start working. I have changed the gas valve and the main board. Above 30 and it seems to work fine. Any suggestions?

[MalteseJane]

who did you use for those changes ? something is wrong with your furnace or even more so with your thermostat.

I re-read your post. You don't make sense. You don't go with an outside temperature. You set your thermostat to the temperature you want inside and you certainly don't want only 30 or below inside. I set my thermostat to 73 during the day and at 62 during the night. It's set that the heater comes on at 7 am to get the temperature up to 73. At 10 pm it shuts down for the night. Even with 30 outside, the inside never goes below 62.

[dougl613]

My unit is an a/c heater all in one that is outside the house. I set the thermostat to stay at 73 and put it on hold so that it stays that temp all the time. The heater will fire up but when its time for the fan to kick on sometimes it will and sometimes it won't. It just seems to not start up more often when it gets colder outside.

[AZgarden]

So, it's a heat pump? How old? Have you done any checkups with a HVAC co. recently? I can't give you any help but maybe you should have it looked at by a pro.