Date: Fri, 30 Sep 2016 16:12:31 +0000
Reply-To: Keith Hughes <keithahughes@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Keith Hughes <keithahughes@YAHOO.COM>
Subject: Re: '91 Carat AC - again!
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Some aftermarket Trinary switches also contain a high pressure blowout plug. Basically a lead filled orifice that is the final fail-safe in the event of severe overpressure. They can fail occasionally over time though. Take a close look at the switch and see if that's what you have. Should be a nice clean hole if it had a blowout plug. Generic trinary switches are available at most mobile A/C places. AZKits.com has them if you don't have any locally. I've used theirs before without issue.
Keith Hughes
'86 Westy GenV (Marvin)
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Date: Thu, 29 Sep 2016 20:30:43 -0500
From: John Rodgers <jrodgers113@GMAIL.COM>
Subject: Re: '91 Carat AC - again!
Thanks guys. Now this is beginning to make sense. It
really helps to
understand to know when to quit.
John
On Sep 29, 2016 19:58, "Dennis Haynes" <d23haynes57@hotmail.com>
wrote:
> That trinary switch does a number of functions. It is
both a safety limit
> and it operates the radiator fan intermediate speed
based on pressure on
> the high (condenser) side of the system.
>
> The first function is to ensure there is some pressure
in the system to
> allow the compressor to turn on. Since it is on the
high side once the
> compressor turns on this switch will continue to be
satisfied even if onl=
y
> air is in there. At around 275 PSI it should put the
radiator fan into th=
at
> intermediate speed. This is done operating the relay (I
think space 5) in
> the fuse box to apply power through the other side of
the fan resistor to
> bring up the speed. At some higher pressure it should
turn the compressor
> off.
>
> The fact that you blew the back off the switch
indicates that you have a
> blockage in the system and that the safety circuit
didn't do its job. You
> probably also compromised other parts of the system. My
bet if the system
> was just cleaned and flushed and whatever is that there
was too much oil
> that couldn=E2=80=99t pass through the port in the
Receiver dryer and the=
system
> went into hydraulic lock up. The compressor is probably
toasted also. Loo=
k
> for bubbles in the hoses, cracks in the condenser and
distortion or the
> blow port on the dryer failing.
>
> Summer is over so you some time to recuperate. It is
time you get a pro t=
o
> do this complete and pay your dues. Someone can get
hurt here.
>
> Dennis
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