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View Full Version : need help r410a mitsubishi mini split not cooling



srryan1
24-07-2011, 05:22 PM
indoor unit will only cool to 82F.

small line is frozen.
big line is cold.
compressure & fan run on high for 10 mins than will shut off for 5 mins than back on again.

here are some pics of it running full speed.

olinewts
24-07-2011, 07:59 PM
S.O.G , did you need to add additional charge for the pipe run. Its cutting out cos its tripping on frost protection.

srryan1
24-07-2011, 08:40 PM
line set was 15 ft and did not have to add any ***** but i do have some.

what is S.O.G.?

Tayters
24-07-2011, 09:19 PM
Short of Gas.
Refrigerant is boiling of in the small pipe before it reaches the indoor unit thats why it's frosting. Suction pressure for R410A around the 110psig mark not the 50psig mark the gauges indicate.
The other unlikely cause would be a restriction before the liquid pipe such as faulty expansion device, blockage, service valve not open fully.

Cheers,
Andy.

srryan1
24-07-2011, 09:57 PM
charged it to 100 psi and it seems to be working right. now to find the leak

JoeAT50A
25-07-2011, 10:43 AM
Precharged 2-lb 9-Oz will cover for 25 ft piping length.
Most important thing is that you must find the leak first and fix it.
Guide line for working pressures are depends on mode and ambient temperature check here.
6894

mohommadkauser
25-07-2011, 11:52 AM
pls chack the discharge prasser and proper flasing the nitrozan .proper vacum the mashin (5 micron) then gas wil charge

JoeAT50A
26-07-2011, 11:11 AM
proper vacum the mashin (5 micron) then gas wil charge

5 micron ???? who wanted to do to achieve 5 microns deep evacuation vacuuming process for 1.5Hp single split.
Deep but 500 microns (it's is not easy to achieve either) will do the job.