BX 19D air-con

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white exec
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BX 19D air-con

Post by white exec »

Have come up against a hiccup on converting the AC on my BX to R134a.

All has gone well, except for finding a serious leak on the original Sanden compressor, so the comp was replaced with a new one, and the system garage regassed this morning.

No more leaks, but...

- new Nissens (=Sanden SD709) compressor, pre-loaded with PAG46
- new O-rings throughout, except for TXV (not so far removed)
- new dryer
- new pressostat
- system regassed, 680cc R134a (85% of OE 800cc of R12)
- no leaks now showing

But
Compressor (and rad fans) correctly operate when AC selected, but NO COOLING.
After a few minutes of idle-speed running, with compressor remaining on all the time, still no cooling, or any temperature rise on the HP output union/pipe from comp to condenser. Would expect to feel this pipe/hose get warm.
After 5 mins running, compressor body has got appreciably hot, but no noticeable temp rise of the HP output pipe/hose.
Still no cooling delivered.

My guess is that the TXV is blocked (blocked shut), so no refrigerant entering the evaporator.
The 3-way pressostat is allowing comp to run, so dryer (HP) is neither under- or over-pressure, which seems a good sign.

Reckoning my next move should be to replace the TXV.
Does that seem sensible?

Any advice welcome.
I've also posted this on BX-Club.