mitsu pulling a vac

[philjd26]

hi

have an intermitting problem with a mr slim 407c puh-5kygaa... i keep getting a uh ,u2 error which is a compressor abnormal fault...due to possible high amps or insufficent cooling to compressor

checked pressures and found suction in a vac and liquid line cool in cool mode ....there is an lev on the outdoor unit which i suspect may be a bit dodge...

however i switched unit into heat mode and the pressures/temps where fine so switched back to cool and away it went...has anyone have something simular like this happen?do you reckon moisture ? this system has been running for years until now...

rgrds phil

[superswill]

ok i had a few of these years ago and the lithium expansion valve head(think thats what they call it) on the condenser was over tightened to the body,half a turn and wosh!! pressures back to normal! they didnt show on commissioning (funny that) but on the first service one month after,failing that it could be a blocking? or 4 way vavle?

iam well out of practise with mitsi but sure one of the mitsi will be along soon

[Brian_UK]

Hi Phil

Next time it happens get down to the evaporator and check the flare connections inside the unit.

You'll probably find that it is frozen/frosted over.

If you have both gauge lines connected on the downstream side of the condensing unit then shut the liquid line, open your gauges and pump down the evaporator.

Open the flare connector and remove the frozen waxy ice from the strainer inside the male flare.

Ideally blow through with some OFN, fit a filter/drier, vac out and open your service valves and you could be OK.

[edit] If not then try the LEV.

[AcidSlasher]

could be a blockage, when u switch the unit onto heating, the refrigerant starts flowing the other way which dislodges whatever is causing the blockage, just an idea