Part 1 in this series covered defrost cycle problems in heat pumps. Now, let's discuss the second major winter issue: heat pumps stuck in one mode. The customer calls and says the system won't switch ...

Your phone rings at 7:00 a.m. in January. The homeowner says their heat pump quit, and the house is freezing. When you pull up, there's ice everywhere on the outdoor unit — a solid block covering the ...