Gas and Oil Home Heating Furnaces - Heat Pump Icing

Hello,

I have an old heat pump, somewhere around 15 years old, that until yesterday had a large, dense bush growing on one side of it that was effectively blocking air flow through that side. While I was hacking the bush back from that side, I noticed that the "radiator" looking heat exchangers? were all iced over and restricting any flow through them. I banged on the sides of the unit as best I could, without doing any damage, to knock the some of the ice off. I was unable to knock it all off. I even turned the unit off for a while yesterday to see it would melt...it didn't...too cold. My question is... what is causing this?, and what should I do about it? I can hear the unit working harder because of the restricted air flow. We still seem to be getting heat.

Thanks for any tips, suggestions, and insight.

Jonathan Kendig
Reisterstown, MD

It is normal for HP to ice over during heat. However, the unit should automatically defrost by switching to AC either on a time set up or by temp of the condenser coil ( the outside radiator). You might even notice steam blowing out of unit when this happens. You may want to try to do it manually and see how it work.
Turn unit off at thermostat
Wait about 5 minutes
Switch temostate to cool and lower it so it starts unit
Go outside and watch the action.

If the unit doesn't do this automatically then you need service.