Daikin HP and LP dropping after closing HP valve

[Contactor]

Called out to old Daikin Split RY125FJW1C-EO code.

Reset unit, brought on cooling.

Low superheat, Low LP (3 bar), Low HP (9.5 bar) R22

6.2 amps per phase.

Freezing up on low side outdoor unit.

Cleaned dirty filters, no change.

Shut HP valve to check compressor - immediately both the HP and LP dropped, re-opened valve before LP switch could open.

Decided compressor was about to conk but now wondering if am I right. Can't think whats happened inside the compressor to cause this.

One of two units installed 1998 in a gym running 0700-2300 every day, possibly left 24/7.

Any comments welcome, thank you

[Cofreth]

what is your on coil and off coil air temperature? Thermostat setting etc.

[chillyblue]

Hi

If you mean the valves on the condensing unit, shutting the HP one will drop both pressures because its clearing the evap of refrigerant (same as a pumpdown)

[cool#9]

Hi
Sounds like indoor unit problem causing wet operation to the compressor.
Is the indoor unit ducted or cassette type ?
Maybe the indoor coil is dirty or the air flow's not enough.
If you succeed in pump down why will you change comp first !
Be careful to take hp from the inside of the outdoor unit (not from service valve)
rgds
cool#9

[Brian_UK]

I would double check the evaporator coil.

You say that it is a gym and by past experience I have found that coils in a disgusting state.