AC Compressor Swap

[NJ Sailor]

Hello new to this forum. Interesting question someone asked me and I have no idea. Can you change a 12000 BTU compressor with a 6000 BTU and leave all the other components the same, will it become a 6000 unit?? He has a 6000 compressor available and would use the unit in a smaller boat. Is this possible?

 

[Turtle Blues]

First thought is that it can't move enough gas to condense in the larger coil, but I will certainly defer to folks with some letters behind their name for a better answer.

 

[NJ Sailor]

Thanks, I did not know enough to give him a reply.

 

[DavidM]

Well, I have a few letters behind my name, but probably not the ones you are thinking of .

But yes I think it will work if all you need is 6,000 btu/hr which ain’t much.

The extra coil area will actually make it more efficient. Kind of like an inverter compressor running at half load.

But how are you going to charge it up. You can’t use Freon weight as it should be somewhere between a 6 and 12 k unit, closer to the 12 I suspect. You will have to do it by pressure I suppose.

David

 

[SIBERNUT]

You may find the juice is the expensive part. If R-12, $tandby if you/he can find it. May need certification just to purchase.

 

[NJ Sailor]

You may find the juice is the expensive part. If R-12, $tandby if you/he can find it. May need certification just to purchase.

 

[NJ Sailor]

I believe it is R410a

 

[O C Diver]

My guess would be no. There is an orifice in the system that in conjunction with the condenser controls pressure. If you're not building enough pressure to turn the gas completely to a liquid, when it goes through the orifice, you won't get the chilling effect for adequate cooling. I would suspect this would be like a car air conditioner that's lost enough of its freon and is no longer really cooling. My guess is the orifice is sized to match the compressor.

Ted

 

[dvarholy]

HVAC tech here. For the following reasons, I suggest the purchase of a replacement system of the correct size: A fixed expansion device (capillary or orifice) calibrated for 12,000 may not produce enough discharge pressure to allow proper operation. Even an automatic expansion device such a TXV still may not have the range to "hold back" enough discharge pressure. If I were to install such a compressor, the existing expansion device would be replaced with a TXV matching the capacity of the new compressor. However, Sporlan, a major supplier of TXV's does not make one in such a small size for R-410A refrigerant. Also, for use in a reverse cycle system, the replacement compressor would need to be rated for heat pump operation, which requires a lower suction pressure. There are heat pump rated 6,000 btu compressors which use R410a. However, a compressor taken from a window AC unit will not likely have this rating. Another thing to consider is the mounting pattern may be different and the piping connections will be different.

Daniel Varholy
HVAC journeyman
'89 Tradewinds 43' MY