13 April 2019


Because we had to dump the R134 from the system to get the fan/radiator/condenser assembly back in the car...

We took the opportunity to flatten the bow that had formed in the condenser.

This created a chance for additional worry that I'd broken it.

Last night we attached the vacuum pump to the now resealed AC system.

Dragged it down to -30 psi and gave it a five minute wait.

Gauge had fallen back to -25 psi.


Happily I have a supply of strong drink to shut The Hated Brain up to allow sleep.

Marv's the AC guy here, so I've been blindly watching him run his gauges.

Duck-Duck-Go to the rescue.

I read up on how the gauges work and what readings you're supposed to be seeing.

Turns out, when there's moisture in the system, it's not unusual to see a dramatic drop in vacuum on the first go as the water is evaporated out.

So, I hooked up the gauges and pump again and cranked it down to -30 psi again.  After 20 minutes, still showing 30.  Ten minutes to go on this initial run.  After 30 minutes, still holding!


  1. On a previously running system that's been opened I usually pull a 30mm Hg vacuum for 60 mins to evaporate any moisture absorbed and trapped in the refrigerant oil and dessicant, then isolate the system and watch for a rise indicating a leak.

    1. Our two little test shots were to see if there was some gross damage from flattening it.

      Marv, the voice of calm, kept restating that we would let the pump run for 30+ minutes to get that moisture.

      I did that on my own while I waited for him to show up and it was still showing -30 (-28 indicated because his gauge reads high consistently) three hours later.


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