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View Full Version : using one insulation for High and Low pressure pipes



piashaw
27-07-2009, 04:50 PM
I'm seeing more and more here in Greece, engineers using a single insulator, with both high and low pressure pipes inside, instead of seperate insulators for each pipe, for small split type a/c's - 9000 to 24000Btu. I was always taught that it was a no no. Is there a time when it is acceptable? pipe runs are normally 3-6m and gas is R407C or 410A.

Comments and thoughts appreciated.

superswill
27-07-2009, 05:30 PM
very common practice in Asia too on domestic splits/multi splits

piashaw
27-07-2009, 05:37 PM
But does it make a big difference to efficiency? If not on small units and small runs, then I might as well do it as well. I'm not interested however in lowering my reputation just to save a few cents, but if it doesn't affect the end result, then why not save a few cents on materials and some time!!

sedgy
27-07-2009, 09:19 PM
piashaw,in the old dayswhen a-c was just a-c, the insulation of both pipes together would have been a no . no, cos there would have been a great loss of motor cooling- one hot pipe - one cold pipe=loss of motor cooling.
nowadays most a-c is heat pump and withthe liquid restrictors being fitted to the discharge line, to save the amount of refrigerent in the system. when the unit is on heating both pipes are hot, when on cooling both pipes are cold, so what do you think of that?

Gary
27-07-2009, 09:27 PM
I'm wondering if insulating them together might cause problems with electrolosis?

marc5180
27-07-2009, 09:29 PM
If it is the liquid and suction pipes that are together, wouldn't this act just as a suction/liquid heat exchanger?
Subcooling the liquid and superheating the vapour?

Gary
27-07-2009, 10:04 PM
If it is the liquid and suction pipes that are together, wouldn't this act just as a suction/liquid heat exchanger?
Subcooling the liquid and superheating the vapour?

The systems in question are those which have the metering device(s) in the outdoor unit, thus the two pipes are at roughly the same temperature.

Goober
28-07-2009, 04:13 AM
Electrolosis between metals that are the same?? copper/copper, doesn't elctrolosis only happen between dis similar metals....