Pumping down Mini Split

[infoseaker]

Is it OK (correct) to pump down mini split system in "Heating mode". Or should I pump down unit only in "Cooling mode"?
I know, there is button on indoor unit for forced cooling, but...
Thanks

[stufus]

If you don't know the answer you should probably not be doing it.
But with the benifit of doubt.....In cooling!!!!!
Cheers
Stu

[infoseaker]

Sorry for stupid question. Never did it in heating mode. Just still learning.
Is it because there is not "enought space" for all refrigerant between compressor and 3way valve? Or any other reason? diagram.jpg

[Brian_UK]

It is because the liquid should be stored in the condenser.

Close the liquid line valve, run it in cooling and when the suction pressure gets to +1psig, 0.1barg, then switch the unit off and close the suction valve.

[taz24]

Sorry for stupid question. Never did it in heating mode. Just still learning.
Is it because there is not "enought space" for all refrigerant between compressor and 3way valve? Or any other reason? diagram.jpg

If you are in heating mode and try to pump it down the refrigerant
will have no where to go to, so the refrigerant needs to be in liquid
form and the only way to do that is to have the system in cooling mode.
Then shut the smaller of the two outdoor valves and wait for the system
to pump all the refrigerant into the correct location (inside the condenser).

taz

untitled.JPG

[gicungchoi]

Taz24 has the above diagram is in HEATING mode, instead of Cooling, isn't it? I believe he meant to point out the pumping down cycle need to be done in the cooling mode only. some body check please!

[taz24]

Taz24 has the above diagram is in HEATING mode, instead of Cooling, isn't it? I believe he meant to point out the pumping down cycle need to be done in the cooling mode only. some body check please!

I was atempting to show him what he described.

Yes the drawing I did is in heating mode and my explanation on the drawing
was regarding the space he would have to pump the refrigerant into.

He already stated there was not enough space to store the refrigerant and Brian
has explained how to pump the system down.

So to avoid confusion....

To pump down an AC it needs to be running in cooling mode.

Gauges need to be fitted to the suction (largest) valve. The saturated liquid (smallest)
valve needs to be wound fully in.

The refrigerant will be returned to the condenser and stored there, after a short time the
suction gauge will start to drop. When the suction reaches just above zero the suction (largest)
valve then needs to be wound fully in also.

The gauge should continue to read zero which will prove no refrigerant is in the
pipework or evaporator.

All the best

taz

.

[infoseaker]

thnaks for answers