Is a frosted heat pump normal

[looking1234]

I have a ducane ac/heat pump. In heat mode it is frosted over. Is this normal or does it need servicing? System is only 2 years old at most.

[duxinaroe]

This is normal. In the heating mode your outdoor coil becomes your indoor coil. It runs at temperatures below freezing 32F. Condesation starts to frost on the unit, then every 60-90 minutes the unit will go into defrost. The outdoor fan will stop, you will hear a woosh as the reversing valve shifts and the ice will begin to melt. Steam will rise up from the unit. when it is done it will start heating again. Or you could tell you neighbor his units on fire that's always fun.

[jared]

Frosting is normal and after about 60-90 minutes it should defrost...however if the ice builds and builds there is a problem.

[lentz]

If to much frost(Or Ice) buildes up on the unit you can lower the time setting.