Sub cooled r22 still flashing?

[The MG Pony]

Well if the insulation lagging is old there is your first thing to attend to, get that right, then start again!

On a TXV I personally would tune it till I saw about 10K super heat at the compressor (This ensures the evap is well flooded as it should be, after ensuring the pipe lagging was as sound as I could get it.

All ways start simple, is the evap clean? Are the fans running well? it all starts there, as your suction line pressure and density ultimately control mass flow and compressor loading, not enough we get an under performing system, too much we cook the compressor.

If the lagging on the suction line is poor then we are getting to much super heat where we do not want it, this increases discharge temps, lowers compressor loading, and reduces mass flow.

Start with the simple but not so obvious things. 16K is good on a cap tube system, not so good for a TXV system!

So check the pipe lagging then ensure all evaps are running correctly and clean. check the TXV's sense bulb, is it making good contact and mounted at the top of the pipe? The truest saying I have ever heard is: The devil is in the details! non are too small.

Once the evaps and TXV's are dealt with then we can look on the condensing side of the equation.

The discharge temp can help tell us how our charge and system are behaving, to dense suction gass, or to much super heat raises our discharge, it will all so tell us the ruff quality of our oil in the system tell us if we are burning it or damaging the valves, it is often over looked as your statement shows us.

Discharge temp is another valuable measure that tells us allot about what is going on inside the compressor