pump down line-set for replace outdoor unit

Users who are viewing this thread

Chevsky

Member
Messages
33
Reaction score
5
Points
8
Location
Massachusetts
Asking for a sanity check...

Can I pump down this line-set into the outdoor unit? Gree Flexx heat pump condenser, 4/5 ton, with 50-ft 3/8 liquid, 7/8 vapor lines. I would close the coil service valves (isolating the coil), and close the liquid line at condenser, and then bridge the coil's two service ports with a charging hose (liquid and vapor ports, also remove shrader valves). The idea is that the liquid refrig would flash into the vapor line and get compressed/collected into the condenser unit, just as old R22 AC-only units do.

Some say "no -- scroll compressors can't pull a vacuum" and/or "can't pump down an inverting HP system into condenser like the old single-mode/cooling-only systems -- they can't store as much refrig". But... I'm only trying to capture 410A in the lineset, not whole coil too, and I'm not worried about 'damaging the compressor'.

Why? I'm replacing an outdoor unit, and I don't have a working reclaim pump handy. (((Compressor is noisy in heating mode (since the beginning--install last winter--but only when ramping up or down--weird, it's sometimes ok, like when running at certain/constant speeds, and always quiet in cooling mode))). Anyway, the new outdoor unit comes pre-charged (good for 25ft), but not having a working recovery setup, I want to keep the charge in the coil, but pump-down the line-set into the outdoor unit.

I figure the 60ft lineset has 35-38 oz (depending on source for calculation) Originally the condenser unit must've stored more than half of that. I added 12oz on install for the extra 29ft (upped recommended .32oz/ft just a bit due to larger 7/8 vapor line--maybe too much).

Does this seem like a ok plan? I guess I could try--it'll either pump down to zero or not--but I'm not going to damage anything, right?
 
Last edited:

Fitter30

Well-Known Member
Messages
5,194
Reaction score
1,031
Points
113
Location
Peace valley missouri
Rotary compressor and a micro channel condenser coil they don't pump down like a recip compressor with a older style condenser coil.There isn't very much extra room for the refrigerant. Just valve both sides off and reclaim. Swap out condenser. Before attacking the suction line run nitrogen through liquid line to blow out any oil. Connect line, pressure test to 500 lbs, evacuate to 500 microns or below, open valves, start unit and add the 12 oz of refrigerant.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks