Our Central Heating System has been on the "fritz" lately. It will work for a few hours, sometimes days kicking on and off like nomral then it will suddenly stop blowing warm air. The air is usually VERY cold, but its set on heat. There is a red light that usually starts flashing "em heat", we were told (by a repair person) that we needed to "reset" the system when this happened, which worked the first two times. The A/C works fine, never any problems with it. How do we fix this?? :confused: If anyone can help it would be greatly appreciated.

Is this a heat pump system? With a heat pump, the outside compressor runs for heating as well as cooling, and you do not use gas or oil. It sounds to me like it is a heat pump getting its signals crossed and setting the control valves to cooling when it should be heating. When it fails to heat the house, then the resistance elements, ''em heat'', kicks on. There could be several things causing the problem. If you are lucky, it could be bad connections between the thermostat and system. Check them paying particular attention to orange, black, and brown wires and anything connected to a O or O/B terminal.

The control valves could also be bad or the control board for the system. The control board isn't too bad to change, but it could be an expensive gamble if you aren't sure it is the problem.

I am afraid if you don't find a loose wire or something, you may have to call back the repair man. You could post back here with any more info you have, but I am not sure anybody here will be able to help.

Hi, Mmassi,
As the other answer said, possibly call a repairperson.
The "em heat" is the strip heaters, which kick on when the "normal" heat isn't working, or is too cold (like 10 degrees F), if this is a heat pump.
When the emergency heat kicks on, the small wheel in the electric meter outside the house goes crazy! It really uses a lot of electricity.
Mine did the same type of thing two years ago. The repairperson found a "switch" that was not working properly.
If you are as I am, and not a "do it yourself" person looking a thermostat wiring, or suck, then I do suggest you call a different, reliable, repairperson.
I'm not saying the one who looked at it isn't reliable, but another person might be able to detect the problem better.
I do wish you the best of luck.

The unit could possibly going into the defrost cycle which usually happens on the coldest days. When a heat pump goes into defrost cycle the unit automatically switches back into the cooling mode and the electric heat strips are supposed to come on to compensate for the cold air. The heat strips may not be activating in the defrost mode.

I want to know how to fix my heat all it is doing is blowing cold air I want to know what's wrong with it

My electric furnnace blows warm air in half of my house but not in the other... any ideals? :/