After many months of running our air-to-air heat pump in AC mode, we’ve run into a cool stretch of weather so I switched it to heat mode last night. In the middle of the night we were wakened by a sound best described as a shopvac caught in a leghold trap. Kind of like the compressor rotor was locked. I immediately turned it off and went back to bed.
I cautiously switched it on this morning and it seems fine now. Anyone have an idea what the problem was (is)?
Thx,
Scott.
Replies
Whatever you do , DO NOT tap on the side of the reversing valve.
How long after it had been running as heat did it make the sound??
No breaker tripped? If not, not likely the compressor siezed.
May be unrelated to heat per se - check to see if the squirrle cage fan on the blower is tight to the shaft, if a belt, see if the belt was yelling at you - re0place me or tighten me please......
>>>Whatever you do , DO NOT tap on the side of the reversing valve. Like I know what that is. ;) But OK, I won't tap on anything.>>>How long after it had been running as heat did it make the sound??Must have been an hour or two.>>>No breaker tripped?Nope. Mind you, it's a 50A breaker. >>>May be unrelated to heat per se - check to see if the squirrle cage fan on the blower is tight to the shaft, if a belt, see if the belt was yelling at you - re0place me or tighten me please...... No, this wasn't the air handling unit (inside the house), it was the pump itself (outside our bedroom window, hence the rude awakening). Glad I heard it though, who knows what kind of damage would have happened if it were left all night.Thanks,Scott.
Check the bearings and lube and the fan on the outside unit.
The reversing valve is a 2" dia cylinder with 4 to 6 pipes going into and out of it and a couple of elec wires. The insides of this slides from one side to the other depending on heat or cool. If the side gets dented, it wont switch too well anymore.
It is possible that it was stuck, and made noise while becoming 'unstuck', in which case you are good for heating season <G>
Had a similar noise once when a branch and leaf fell into the outside unit, turn it off and the branch falls out, no more noise.
>>>Check the bearings and lube and the fan on the outside unit. Watching it run this morning, I'd say the fan isn't the problem. It was spinning quietly and freely. Are the bearings/lube on the compressor easily servicable?
There is a fan in the outside unit as well, generally an axial flow unit (like a standard room fan). These can, if the bearings go bad, make that noise like a "Shop Vac in a leghold trap" (I like that description!) -- a sort of growling, whining sound. Then turn them off for a few minutes and start them back up and they sound perfectly normal -- until the next time they decide to do their thing.The other thing that might possibly squeal is the reversing valve. It could (in theory at least) "chatter" if it didn't complete its cycle properly, or if there was a worn seal/seat. Similarly to the fan it could operate completely fine if the unit is recycled. And in the case of this valve the problem might never recur (at least for the season), once the valve is "loosened up" a bit.The compressor, if seized, will make a loud humming noise, very steady, with no variation in pitch or loudness.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
>>>until the next time they decide to do their thing.Might be, but I'd be surprised if that (relatively small) motor could make that much noise. My first suspicion is the compressor motor, which is a fairly large (4 ton) unit. I'll let you know.>>> And in the case of this valve the problem might never recur (at least for the season), once the valve is "loosened up" a bit.Here's hoping... What you (and Art) say makes sense. This was the very first time that it was switched from AC to heat.Thanks,Scott.
You've never heard a 4" computer cooling fan scream. You can hear it across a room crowded with other computer equipment.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
> No breaker tripped? If not, not likely the compressor siezed. But some (all?) systems have an over-pressure switch. If the reversing valve was stuck mid-cycle, the OP switch could have tripped before the breaker did.Of course, either one would cause the compressor to fall silent, and a tripped breaker would kill the condenser fan as well. It's not always easy to tell if the compressor has stopped, with the fan running, but if both have stopped that's hard to miss.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
BTW, a locked compressor or any other electric motor, won't make a screaching noise.
It will be a loud hum or buzz.
William the Geezer, the sequel to Billy the Kid - Shoe
>>>It will be a loud hum or buzz.Perhaps my description is a bit off (mid-night stupor). You're right, it was a VERY loud buzzing, nasty sound coming from the compressor motor.