I ahve a GE Zoneline 5100. I believe it is the heat pump model. in the summer it cools well but last winter, the heat stopped working properly. this year, i turned it on and the heat worked fine but now it has stopped again. it sounds like the compressor is working but then it shuts off. I had a guy in to look at it and he said it would cost a lot just to take it apart to find out what is wrong. Is he telling the truth? Has anyone experience with this model that can help? I don't have a lot of cash to sink into it but need it to work if I can make it that way. thanks in advance to anyone with suggestions.