Gas and Oil Home Heating Furnaces - Heat Pump - Not Cooling

I started my heat pump today to check it for summer. I let it run for quite a while (hr+-) and it was still blowing warm air. I went to the inside unit and check the incoming line. The line was cold (I didn't want to leave my fingers there too long) and the coils were cold. They were removing moisture from the air and water was running out. It just wouldn't blow cold air. I had it checked this winter and the pressures were fine and it heated fine (as well as heat pumps do) all winter. Is this a freon problem or something more expensive?

Check your second stage heat. Sounds as though it may be on with the heat pump in the cooling mode. Easy check. Shut off power to outdoor unit at the outdoor disconnect, turn t'stat to cool and turn down temp setting. After the blower is on check air at the register. If it is hot, then your 2nd stage heat is on with the a/c. May be a stuck sequencer.

I briefly remember smelling "that smell" when the electric backup heat kicks in, but I didn't pay much attention to it. Is the "stuck sequencer" related to the inside or outside unit or is it a thermostat malfunction? The thermostat was just replaced this winter, that is why I ask.

Is inside at blower assembly.It takes 24 volts,warms up to make a klixon,that supplys 220 volts to your heat strips.MARK EVERY WIRE before you remove it,take part to a supply house and get exact replacement.PDF

It could be a t'stat miswire, but I would try PDF's suggestion and check the sequencer as suggested.

A recently discovered sneaky source of this problem that is particular to certain models of Trane and it's kissing cousins. There is a temp sensor in the condensing unit that can fail and send a false signal that the unit is in defrost mode, kicking on the heat strips.

It took a careful reading of the unit schematic to catch on to that one...(after much frustration).

Hi,

I always first check each sequencer for 24 volts and if any found,I trace back to find failure/faulty control that is sending the 24 volts.

If there isn't any 24 volts present, then I check for 220 volts from sequencers to heat strips.If any found w/o 24 volts present,the sequencer is stuck closed and is replaced.

I've also heard of the problem that MrRonFla posted about.

Take Care and keep us posted if you would.

CoolBreeze

is this a thermister we are taking about?

I don't have the schematic handy, but I think that is was a thermister symbol. I've only run into it once since I started working this complex, but my predecessor had a stock of the parts stashed away.

I'll pull my files and get specific later.