samsung ac split in vacum

samsung ac split m/n aqv18nsdxkcv trips on low refrigerant in cooling mode with the lowside pulling into a vacum, yes you would think its low on gas but on off cycle equalizing to 150lbs. i really wish there was a high side port but there is not. looks to me like there is no pumpdown solenoid aand the only restrictions could be in the 4way valve (yeah its a heatpump) or the exspansion valve. i hate a/c splits never worked on a samsung anyone out there have aany words of wisdom, it would be much appreciated

Just because it equalizes to 150 lbs in off cycle doesn't mean it's not low on gas. Checking the subcooling will determine if its low on gas or a restriction.

Moved to Tech to Tech.

Pull the gas out. See if it's close to nameplate.

Sounds like a classic restriction to me. You are no doubt aware the metering device is in the ODU. When you pull the refrigerant out, you can put your pressure taps any where you want them.
Good luck
Coolairman

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Originally Posted by targetman

Pull the gas out. See if it's close to nameplate.

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Agreed, also there may well be another gauge port inside the unit, take the cover off and see. Make sure all the plugs are inplace on the circuit boards and the head is on the EEV (assuming its an inveeter unit). Does it work ok in heating mode?

Used to see a few problems with blocked strainers just before the capilary tube on older R22 splits (various makes) but not really had the problem with the R410A stuff.

I ran into this same exact issue with a mitsubishi mini split and we found out it was a stuck exv and had to replace the coil in the head.