Help! Cover on compressor of outside Heat Pump

[Erby]

Anybody ever see an outside heat pump unit with an insulated cover over the compressor. Nine year old American Standard unit.

Click to Enlarge

82.42 KB

Click to Enlarge

43.08 KB

Click to Enlarge

38.86 KB

-

[Terence McCann]

My new Carrier has a cover on it as well. It's there for sound deadening.

[Bill Kibbel]

Quite common on scroll compressors as they're quite loud. Some others have an insulated compartment for the compressor.

[Marc]

Not to disagree with Terry or Bill but the insulation blanket on heat pump compressors also serves the purpose of conserving heat for the house when the system is functioning in heat mode. Air conditioners may have one also to retain heat within the hermetic unit, which promotes the condensation of refrigerant gases to locations other than the compressor crankcase. If too much liquid refrigerant is mixed with the oil in the crankcase when the compressor starts up, the rapidly vaporizing refrigerant may carry too much oil with it through the compressor. Compressor are intended to pump gas, not liquids. Too much liquid through a compressor may damage the valves, though today's scroll units are more tolerant than reciprocating units.

It's not in the interests of a homeowner to remove that blanket.

Marc

[Bill Kibbel]

Not to disagree with Terry or Bill but the insulation blanket on heat pump compressors also serves the purpose of conserving heat for the house when the system is functioning in heat mode. Air conditioners may have one also to retain heat within the hermetic unit, which promotes the condensation of refrigerant gases to locations other than the compressor crankcase. If too much liquid refrigerant is mixed with the oil in the crankcase when the compressor starts up, the rapidly vaporizing refrigerant may carry too much oil with it through the compressor. Compressor are intended to pump gas, not liquids. Too much liquid through a compressor may damage the valves, though today's scroll units are more tolerant than reciprocating units.

It's not in the interests of a homeowner to remove that blanket.

Marc

That seems to make sense, but I've never read that from any manufacturers documentation. I have read several that stated the insulation was installed specifically to "minimize operating sounds".

[Bain]

Not to disagree with Terry or Bill but the insulation blanket on heat pump compressors also serves the purpose of conserving heat for the house when the system is functioning in heat mode. Air conditioners may have one also to retain heat within the hermetic unit, which promotes the condensation of refrigerant gases to locations other than the compressor crankcase. If too much liquid refrigerant is mixed with the oil in the crankcase when the compressor starts up, the rapidly vaporizing refrigerant may carry too much oil with it through the compressor. Compressor are intended to pump gas, not liquids. Too much liquid through a compressor may damage the valves, though today's scroll units are more tolerant than reciprocating units.

It's not in the interests of a homeowner to remove that blanket.

Marc

That's what I've been taught, as well, though the sound issue is another reason for the jacket (my own term 'cause they're nearly always that ugly, bright orange that seems reserved for life jackets). When a scroll compressor goes into defrost mode, what is essentially a big screw spins around like the Tasmanian devil, which is why the things are so loud.

[Marc]

Interesting. I googled quite a bit and couldn't find anything to substantiate my post but I've had that understanding for many years from working in the field and have discussed it with other techs many times. Even my Trane Air Conditioning Manual ('65 edition) didn't even mention blankets (need a new one). Anyone have a Carrier Manual, recent edition?

Marc

[Terence McCann]

The problem with the new 410 machines is that they operate at a much higher pressures and make a hell of a racket. Carrier has some marketing lingo in which they describe their efforts to mask the noise as a feature and benefit.

You may have heard some "urban legend" Marc.

[Bain]

Interesting. I googled quite a bit and couldn't find anything to substantiate my post but I've had that understanding for many years from working in the field and have discussed it with other techs many times. Even my Trane Air Conditioning Manual ('65 edition) didn't even mention blankets (need a new one). Anyone have a Carrier Manual, recent edition?

Marc

Marc, I found this by Googling. Read the second FAQ from the top.

http://www.brinmar.com/faqs_sound_blankets.html

[Marc]

Thanks John.

Marc

EDIT: It's just kinda humbling to have some information that you've relied on for so long to suddenly and instantly turn into smoke...or 'urban legend' as Terry calls it (good term). I guess it's a good thing, as long as the truth has been finally arrived at.