Date: Wed, 28 Aug 2013 22:05:03 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: RedTek and the Sight Glass
In-Reply-To: <COL125-W799868EA6685A46D716FCCF340@phx.gbl>
Content-Type: text/plain; charset="us-ascii"
What is the high side pressure? 40-50 psi is way too high for any R12 type
replacement. Keep in mind that the AC systems relies in recirculating sir to
cool things down. With the engine compartment open and the AC sucking all
that engine heat you will need see a 40 degree discharge especially with the
fan on high speed. You need to measure both the high and low side pressures
to make sure the compressor and expansion valve is working. The gauge set
will indicate pressure and ~ coil temperatures. Automotive systems should
be filled by volume, and then tested for proper pressures. Too many
variables to just fill by pressure unless you really know what you are
doing. An overfilled system will damage the compressor in short order. Not
being able to pull down the low pressure side is usually a sign of a bad
compressor. Busted valve parts!
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Mike Finkbiner
Sent: Wednesday, August 28, 2013 9:29 PM
To: vanagon@GERRY.VANAGON.COM
Subject: RedTek and the Sight Glass
I'm running into conflicting advice about what the sight glass should look
like after switching from R12 to RedTek.
I had the R-12 in my '87 Westy system removed and a vacuum pulled, then put
the adaptor on the low side plug and started installing the RedTek. After a
couple of cans and the can of leak stop, with the AC running full bore I was
getting low-side pressure above 40, but according to my calibrated hand, no
significant cooling from the vents. The AC fan was running and the
low-pressure tube out of the compressor was chilly, but not really cold.
Looking at the sight glass I saw lots of bubbles, so I assumed I needed to
add more coolant, and did a bit more, but no more cooling.
Shut down after about half an hour and noticed the low pressure valve
adapter was hissing. When I unscrewed it, that stopped, but I wondered how
much coolant had leaked out.
I called the RedTek help number and a man in tech support said he wasn't too
familiar with the automotive side, but on some Vanagons I might need low
side pressures over 50 psi. They also recommended running it again after it
sat overnight in case there was some crud floating in the system that needed
to settle. They are shipping me a replacement adapter and some more
refrigerant.
I borrowed a digital thermometer the next day, started the engine and ran
the air conditioning to see if there was any difference. With an air
temperature in the garage of 74, the AC was blowing 54, so it is cooling
some. I thought it should drop 40 degrees below ambient if it's running OK.
Again, lots of bubbles in the sight glass.
Then I ran into a note which indicated that the sight glass is not reliable
for RedTek, because it's much lighter. They said I should expect bubbles,
and might actually have too much refrigerant in the system. They
recommended letting enough out to get the low side pressure down to below 40
and see what happened.
So - if you are running RedTek, what does your sight glass look like?
- Mike
Mike Finkbiner
'87 Westy
Moscow, Idaho
mike_l_f@hotmail.com
You can't see a thought, you can't measure, weigh, nor
taste it - but thoughts are the most real things in the Galaxy.
- Richard Baslim