heat pump refrigerant piping 1

[arp08]

Is it necessary to insulate the smaller (liquid) refigerant pipe for a residential size air-cooled heat puump?

 

[pennpoint]

arp08
The liquid line should be isolated/insulated from any hot surfaces such steam or hot water pipes, but does not "normally" need to be insulated its full length. The reason for insulating the suction line is becaues it can and will sweat and this can cause mold problems among other things.

Regards

pennpoint

 

[MintJulep]

But in a heat pump sometimes the liquid line is the suction line and the other way around.

 

[pennpoint]

MintJulep
Well, I'm not so sure.
The liquid refrigerant in the line does change directions when the evaporator becomes the condensor and the condensor becomes the evaporator, but the liquid line is always the liquid line and changes its job. Thus the reason for the two way filter/drier.
It's the discharge and suction lines that reverse their rolls.

Regards
pennpoint

 

[imok2]

Mintjulep, forgive me but I have never seen a liquid line on a heat pump become a suction line. You may be confusing the suction and discharge lines off the compresor which change flow direction accordinf to the position of the four way valve. I would not insulate the liquid line as leaving it exposed may help in some sub-cooling.

 

[pennpoint]

MintJulep;
I offer you this:

http://www.refrigerationbasics.com/1024x768/heat_pumps1.htm

Regards
pennpoint

 

[pennpoint]

My previous post;

but the liquid line is always the liquid line and changes its job.

Should have read: "but the liquid line is always the liquid line and does not change its job."

Regards
pennpoint

 

[MintJulep]

Thank you all for refreshing my memory.

I half remembered that one of the lines to the indoor coil was hot for heating and cold for cooling, and misremembered the rest from there.

 

[pennpoint]

MintJulep
No problem, but you did have me questioning myself there for a while. A little searching and I was assured to be on track.
It's good to go back once in a while, review the data and find that your either on the mark or 180 degrees off. I was fortunate this time, the next time I'll be off. Is this what humility is all about?
Good on ya!
Best Regards
pennpoint

 

[arp08]

MintJulep & Pennpoint:

Thank you for the helpful & timely discussion. Hope you have a good weekend!