Heat pump, age 2010, operating on normal heat mode. Observed coil freezing. Thoughts on cause, possible low on refrigerant? any other possibilities
I have found it to usually be low on refrigerant, or a dirty furnace filter.
Low refrigerant seems to be the most common reason I see.
What Frank said
I am sorry to inform you guys a dirty filter does not make the outside coil freeze up in the normal heat mode. Its not uncommon to see ice on the exterior condensing unit of a HP as that is why they have a defrost cycle;-)
Thanks William, good info
I think you may have observed the unit during its defrost cycle