Compressor Noise During Low Ambient Cooling

[LibertyTree]

I went on a call where a customer was having compressor noise issues with his York 18 SEER heat pump in cooling mode at low outdoor temperatures. I haven't had much experience with cooling at low ambient, I seemed to be able to reduced the noise a bit by raising the head pressure. If low temps are indeed the cause of the noise, is there an easy way to boost head pressure? I tried to install a low ambient kit a while back to slow fan speed but was either too stupid to make it work, or the equipment might not have been compatible.

[ckartson]

Was it a scroll compressor and 410a refrigerant? They do get louder with low head.

[54regcab]

Customer is concerned about high energy bills so he buys a 18 seer AC. Wont open windows on a cool day....

[LibertyTree]

Yes it is a scroll with 410a. Opening windows won't do. He works for the university and does some sort of plant research. He's got a space with some pretty decent heat load from high powered lights that run year round (and no it's not weed haha). Any help for me guys?

[LibertyTree]

Double post

[beenthere]

That unit is not designed to be used with any type of head control. It says that in the install instructions.

Sounds like you are getting flood back. Might want to see if you can increase the indoor blower speed to evaporate more of the refrigerant.

[Core_d]

could installing a crank case heater help this problem?

[Rob_in_WV]

Would putting a heater on the accumulator(if equipped) be an option to speed up the boiling off of excess refrigerant? Just have one on the compressor that energizes on contactor open and one on the accumulator that energizes when the contactor closes.

[SBKold]

Don't think liquid flood is the issue here. I hope you have a txv indoors. Even then with low ambient the valve should be wide open and still have higher than design SH due to ultra low head.

[jim bergmann]

I have heard a pinging noise/rattle when there is not enough pressure difference across the compressor. The scrolls will start to separate. Happens when the head is to low and the indoor air temp to high. The high efficiency of the coil becomes to high. The equipment might be outside of its design specifications.

[LibertyTree]

This unit has a factory installed crankcase heater. There is also an indoor TXV. Beenthere, I will try to increase blower speed, its certainly worth a shot. Ron, thats an interesting idea. Do they even make such a heater? Jim, I'm afraid you're probably right. At this point I'm just trying to figure out a way to raise the head pressure without getting too ghetto... Thanks for the replies fellas

[VTP99]

What type of low ambient did you try ?

[terpfan_]

A common fan cycle switch would work to control head pressure. Johnson sells a bunch of models compatiable with 410a. A hot gas bypass could also help problem with solenoid to close bypass in heating mode. A combination of both might help as well.