HVAC reseach!

ChuckBlack · Post by **ChuckBlack** » Sun May 07, 2017 9:13 pm

Hello guys!

I'm about to service my HVAC system and I'm wondering if anyone has done it before...?

I have L300 1993 dual AC system.
Shows R-134a post 91 but some still used R-12...?

If so... To whom do you know what type of refrigerant was inside (R-12, R-22, or R-134a)?
Also, to whom, did you have to add fittings so that a R134a Manifold gauge shreder valve could fit on?
And finally, did you have to replace the CCOT valve?

Thanks to anyone who can answers those!!!

Post by **Growlerbearnz** » Sun May 07, 2017 10:31 pm

I serviced mine: rebuilt the compressor, replaced all the O-rings, flushed the lines, and replaced the receiver-dryer, switched to R134a at the same time (Mine's a mid-'91, originally R12).

Mine had a service sticker under the engine cover saying "R12". The definitive way to check would be to look at the fill ports:

: ac_service_fittings_ea974b840e89240e911c2e49ba10981c28d7dd90.gif (6.8 KiB) Viewed 3811 times

I had to add R134a adaptor fittings. They just screwed right on.

Mine has expansion valves (TXV) rather than a CCOT, so no worries there. I don't see any mention of CCOT in the workshop manuals so I imagine yours has too.

I don't know how much oil or refrigerant was added- I left that (and the drain/flush/refill) to the AC shop. They also supplied the compressor rebuild kit and receiver-dryer.

deskinthewoods · Post by **deskinthewoods** » Fri May 25, 2018 3:10 pm

Growlerbearnz wrote:..., switched to R134a at the same time (Mine's a mid-'91, originally R12).

So, am I to understand that you can just replace R12 with R134a? That it doesn't matter which refrigerant you use?

Post by **Growlerbearnz** » Fri May 25, 2018 6:53 pm

Correct, though you have to flush all the R12 out before putting R134a in, and you need to change the fill ports (R12-to-R134a adapters just screw right on). It's a good idea to flush out the old oil too- R12 oil is allegedly compatible with R134a oil, but your oil is 25 years old. It's a good time to replace it.

deskinthewoods · Post by **deskinthewoods** » Sat May 26, 2018 5:13 am

And how does one flush the lines?

Post by **Growlerbearnz** » Sat May 26, 2018 1:42 pm

I've always had the AC shop do it after they've removed and safely disposed of the R12 (we Kiwis are a little touchy about ozone depletion and the resulting skin cancers).

...though it looks like you can buy flush kits online. Not sure how they work, it looks like a cannister of solvent, perhaps propelled by compressed air. AC shops usually have a machine that does it.

deskinthewoods · Post by **deskinthewoods** » Sat May 26, 2018 3:17 pm

Thanks for that info, Growlerbear