Line set sizing?

[J Hayes1978]

What affects or damage can occur when running smaller diameter lines for a discharge or suction line? I know deff higher head pressures. I'm new to the field experts please chime in..Also new to the site hello everyone..

[beenthere]

Lower capacity
Lower efficiency
Possible shortened compressor life.

Welcome

[heatingairman]

If the suction line is too small, you may not get proper oil return to the compressor. You also can have a reduced capacity.

[beenthere]

An undersize vapor line doesn't hurt oil return.
Too large of a vapor line can.

[heatingairman]

WOW! I hope you don't do refrigeration! OOPS... Read it wrong Beenthere! Need to assure proper velocity Horizontal increase size, vertical decrease.

[beenthere]

Both A/C and refrigeration.
A vapor line 1 size undr will never hurt oil return.
The next size up however can on installs with the condenser vertically above.

Recommended min suction line velocity is 1000 FPM. I have vapor line sizing charts for unit that allow the vapor line to be sized for up to 3000 FPM.

I don't have any that approve less then 800 FPM. And they don't want a vertical rise to the condenser.

If you have line set sizing charts that allow 500FPM velocity in the vapor line, post them.

[heatingairman]

I don't think anyone will go out on a limb with 500fpm

[BigJon3475]

So is it safe to say it's a trade off of capacity for smaller sizes and velocity is not so much a concern or oil return......and the LL is way more important to capacity?

Also how important are traps in vertical rises of 50+ ft? I might be subjecting myself to these before to long. Not sure if they even put traps in @ the recommended heights.....for oil return?

[beenthere]

Involved topic Jon.

Within reason, you can compensate a little for a slightly smalled liquid line, more then a vapor line.

Did you get that email I sent you. It has some line set sizing info in it.

[BigJon3475]

I'll check....I didn't think this was the right forum to get to involved.


was that just now or recently in the past?

[heatingairman]

I sent yo an email too bigjon.

[beenthere]

Within teh last few days..
I don't remmember which.

[BigJon3475]

i'll go back over I'm sure i got it.

[beenthere]

Just checked. I sent it on the 4th.

[BigJon3475]

Just checked. I sent it on the 4th.

Sorry not trying to be annoying.....Do you remember the name of the file...maybe I put it in my storage and mean to go back and go over it and forgot. I don't doubt I would have saved it....been about a case of beer thrown in theirbecause of the whole fourth (looks around with a kinda guilty look)


Thanks heatingairman for the Lennox line set guidelines.

[beenthere]

LMAO.

You won't believe the topic.

Its called.
Line set sizing.

[BigJon3475]

Okay I found it sorry

[beenthere]

Goes into pressure drop/increase for vertical lines.
Not too deep.
Also piston size increase/decrease for excess vertical heigth.