[DeTomaso] use sight glass in AC that has been retrofitted to 134a?

[Doug]

Jeff,

What do you mean by a heater "liquid test"?

Doug Braun
Blue73L #5505

-----Original Message-----
From: DeTomaso [mailto:detomaso-bounces at server.detomasolist.com] On Behalf Of JEFFREY COBB
Sent: Friday, August 05, 2016 3:37 AM
To: Pantdino <pantdino at aol.com>; detomaso at detomasolist.com
Subject: Re: [DeTomaso] use sight glass in AC that has been retrofitted to 134a?

Jim,
All cars use different  pressures and for examples this week we did a/c work on a 124 Fiat, many Benz-Bmws-Toyotas, a 71 e-type, Ford +Chevy trucks, a Cobra kit car and a Mangusta.
But basic pressures at 1,500 rpm with cooling fans on and on high, with both windows open, rear and front hatch closed, high fan and not on recirc should be about 35 + - low side and 250 + - high. Seems like a 7:1 ratio works the best. Converted systems do need different numbers but never too much of a change. So your low range should vary from 20 to 38 psi and the high 210 to 260 psi as long as above written parameters are meet. The proper pressures will equate to the coolest temps. You have to note that and remember you are just setting the vent output for the coolest temp not some pre-considered ideal temp you hope for.
About 30 % of all of our a/c fixes are fixing the stuck on heaters. We are in hot Louisiana, make sure your heater is truly shut off by doing a liquid test.  
Do use the correct oil and add 2 oz if you are not sure of how much is in. You can always expel the working high side into a cloth or jug for 2 seconds to get an idea if you are oily enough. A lot of spit indicates fine but dry expelled gas needs oil.
 Keep cool,

Jeff

Jeff Cobb- I pad
W-225-343-7525
C-225-907-4514
Jeff Cobb Auto Works
1316 S. Acadian Thruway
Baton Rouge, La.
70806
www.LiveOakConcours.org

On Aug 4, 2016, at 11:05 PM, Pantdino <pantdino at aol.com> wrote:

> Hi, Jeff,
> 
> What should the pressures be?
> 
> Thank you,
> 
> Jim
> 
> 
> -----Original Message-----
> From: Jeff Cobb <jeffcobb1 at me.com>
> To: Pantdino <pantdino at aol.com>; detomaso <detomaso at detomasolist.com>
> Cc: Jeff Cobb <jeffcobb1 at me.com>
> Sent: Thu, Aug 4, 2016 6:55 pm
> Subject: Re: [DeTomaso] use sight glass in AC that has been retrofitted to 134a?
> 
> The sight glass is always used as a reference point. You must go by the dual gauges.
> Never by the low side only.
> 
> Jeff Cobb
> 
> On Aug 4, 2016, at 8:44 PM, Pantdino via DeTomaso <detomaso at server.detomasolist.com> wrote:
> 
> > After switching the AC system to 134a, do you use the sight glass in 
> > the dryer or go by the pressure at the low pressure port like with 
> > modern cars?
> > 
> > Sorry, but I don't recall what I learned several years ago when I 
> > switched the system over.
> > 
> > Jim Oddie
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