Mitsubishi pury 250 ymf

[Aritcrazz]

I have a problem with an outdoor Mitsubishi outdoor pury250ymf I can't get the discharge pressure above 16 bar I'm loosing heating capacity at the indoor units the refrigerant charge is to spec it like a discharge sensor or transducer is holding the compressor from ramping up but there is no fault code on the system I'm at my witts end does anyone have any ideas ??? Thanks

[Thermatech]

The YMF only had HP sensor so easy to monitor live HP sensor data on the outdoor circuit board using SW1 dips & compare to gauge reading.
Also monitor inverter output HZ to see if its ramping up to max about 104 hz I think is flat out on that model.
The outdoor unit has target of about 20 bar in heating mode so would expect compressor flat out at 16 bar.

If you have more than 250 capacity of indoor units connected & they all call for max heating then HP will be lower than ideal in low ambient conditions.

If you are sure correct refrigerant charge then possible high to low bypass at some location in the system.
One or more indoor units with LEV failed in fully open possition or LEV 1/2 failed fully open at BC box or outdoor unit SV7 or SV5 leaking to low side are all possible problems which could make depressed HP & poor heating performance.

[Aritcrazz]

Thanks thermatech you were on the ball it was sv5 it was jammed I rocked it with a solenoid tester and a few smacks of a hammer everything opperating now thanks again