I have an 8 year old Carrier heat pump. Yesterday, it stopped blowing cold air and began blowing heat. With the thermostat set to cool. I had a non-carrier technician check it today, he said it was not freon that the pressure there looked fine. He mentioned that it cold be the heat strips or a reversal valve. Has anyone ever heard of such a thing? Or does anyone have any other suggestions?

He must not of been a very good technician, most of us service all makes and models. It very well may be a bad reversing valve or it could be in the thermostat. I'd call another company and get a second opinion, I wouldn't pay the first bill because he didn't even attempt to fix the problem.

Could be the coil for the reversing valve

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Originally Posted by hvacservicetech_07

He must not of been a very good technician, most of us service all makes and models. It very well may be a bad reversing valve or it could be in the thermostat. I'd call another company and get a second opinion, I wouldn't pay the first bill because he didn't even attempt to fix the problem.

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He was a friend in the HVAC biz who just happened to be on call yesterday. Works on YORK units and just didn't have any Carrier parts. He didn't charge me anything to look at it, so no payment.

Thanks for the advice though.

Any idea what a reversing valve costs?

Reversing valves are not cheap, lots of braze joints, reclaiming, evacuating and charging of A/C are also required, and a filter drier. If unit is over 10 years old you will probably be better to replace the unit. Your friend really should have been able to tell for sure if it was reversing valve or strip heat, problem should have been fully diagnosed so the correct parts could be ordered, not many companies are going to have a reversing valve lying on their shelf.

A quick test to find out if the reversing valve is stuck in heating mode. The larger diameter freon line at the out side unit would be hot while running, cool air would be blowing out the top of the unit above the condenser fan. If it was in cooling the lager line would be cool and the condenser fan would be blowing out hot air. If your friend says the freon level is fine(If he knows what he is doing, because its pretty easy to know if the reversing valve is switching or not). I would say your heat strips are coming on with the A/C but its hard to say with out more info.

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Originally Posted by T-Top

A quick test to find out if the reversing valve is stuck in heating mode. The larger diameter freon line at the out side unit would be hot while running, cool air would be blowing out the top of the unit above the condenser fan. If it was in cooling the lager line would be cool and the condenser fan would be blowing out hot air. If your friend says the freon level is fine(If he knows what he is doing, because its pretty easy to know if the reversing valve is switching or not). I would say your heat strips are coming on with the A/C but its hard to say with out more info.

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Yep, the large line is hot and there is cold air coming out of the top.

You can jumper R to O (red and orange wires) on the low voltage wires on the heat pump. You should hear a click and then a loud swishing noise. If you hear the click but no swishing noise it's a bad reversing valve. If you do not hear a click it may just be a bad coil. Give it a try I'll try to help if I can. Good luck.