Hi!

I am currently servicing some old Tricool QR-25 AC units (25000BTU) on top of an television OB van.
Basically these are on the roof of the truck and cools the installations and the people operating inside. My problem is these units operate with very high head pressures, always above 22 bars, even when outside air temperature is below 30degC (or 86F) which is very high for R22.
After few days of working, the HP protection set at 28 bar trips.
They have mechanical TXV's and manual valves in series with it. Since these are very old, I don't know how may stuck their fingers in them.

Previously I have had the same problem with some very similar Noske Kaesser units on other vans; these units are working poorly even today.
Do you think the condensers aged so their capacity reduced too much? Of course I washed thoroughly the coils, the fan motors are working good and running capacitors are new.
I need to make these work or, better, to install other new units but I can't find something like this.
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