We have a heat pump (without auxiliary heat strips, straight heat pump,) that just started blowing air that smells like burning plastic. I had just replaced the filter and the temp dropped again and the heat started running again.

The vent nearest the outside unit is the only one that really blows the smell. I do not (really) smell it in any other rooms, I get a hint sometimes, but I cannot tell if it because I just left the "smelly" room. I have gone outside to the unit when it has smelled the strongest inside and there is no hint of a smell. The motor operates like always and I have stuck my nose right up to it and smelled nothing.

I removed the new filter and the smell dissipated, but now and then I get a strong whiff of the burning plastic smell.

Any suggestions?

Thanks
Steve

Only thing I can think of is maybe something got onto the coil. If it is a package unit, sitting entirely outside, getting to the coil to clean it could be a real task.

Now it is not blowing any air at all.

Maybe the smell you were getting was the motor going bad.

Ok. I opened the unit and checked everything. The motor spun by hand fine. There were no burnt wires or anything. The fuse by the motor had tripped. I reset it and started the unit and everything ran fine. Warm air blew and I was happy. About two hours later, I started smelling the burning smell again and the blower had quit blowing. It did not cycle off or run through a defrost cycle the entire 2+ hours. The blower blew for over 2 straight hours.

Any suggestions or ideas?

Thanks

Steve

You said you reset the "fuse by the motor". Fuses are not resetable. They must be replaced when they blow. Was this a small button on the motor itself?