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

Jeff Cobb jeffcobb1 at me.com
Sat Aug 6 13:14:02 EDT 2016


Doug, 

    The heater may not be off and not warm just because you have turned to off the heater control, screwed in the mechanical heater valve or shut off the heater on some level.

A liquid test is where you make sure the heater is not getting warm water by:

-1-Feeling the cabin heater hoses which should be cabin temp. If warm then do to #2. If ok then heater is off unless high rpm = w/p velocities leak past the valve.
-2-Using large radiator hose pinchers to pinch them closed, if warm, to see if a/c gets colder. If so the # 3.
-3-If diff is noted then inspect valve cable closure device to see if fully closed.
-4-If so closed and 1, 2 and 3 were followed, then remove valve and test its closure ability against pressured air or garden hose water for leak test.
-5-Or just say the hell with all of the above and just install another heater valve out of view so you can totally shut off the hot water and be cool.

Jeff Cobb
Cell 225-907-4514
			

On Aug 6, 2016, at 11:59 AM, Doug <doug351c at gmail.com> wrote:

> 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
>>> _______________________________________________
>>> 
>>> 
>>> Detomaso Email List is not managed by POCA Posted emails must not 
>>> exceed 1.5 Megabytes DeTomaso mailing list 
>>> DeTomaso at server.detomasolist.com 
>>> http://server.detomasolist.com/mailman/listinfo/detomaso
>>> 
>>> To manage your subscription (change email address, unsubscribe, etc.) use the links above.
>>> 
>>> Members who post to this list grant license to the list to forward any message posted here to all past, current, or future members of the list. They also grant the list owner permission to maintain an archive or approve the archiving of list messages.
>> 
> 

-------------- next part --------------
   Doug,

       The heater may not be off and not warm just because you have turned
   to off the heater control, screwed in the mechanical heater valve or
   shut off the heater on some level.
   A liquid test is where you make sure the heater is not getting warm
   water by:
   -1-Feeling the cabin heater hoses which should be cabin temp. If warm
   then do to #2. If ok then heater is off unless high rpm = w/p
   velocities leak past the valve.
   -2-Using large radiator hose pinchers to pinch them closed, if warm, to
   see if a/c gets colder. If so the # 3.
   -3-If diff is noted then inspect valve cable closure device to see if
   fully closed.
   -4-If so closed and 1, 2 and 3 were followed, then remove valve and
   test its closure ability against pressured air or garden hose water for
   leak test.
   -5-Or just say the hell with all of the above and just install another
   heater valve out of view so you can totally shut off the hot water and
   be cool.
   Jeff Cobb
   Cell 225-907-4514
   On Aug 6, 2016, at 11:59 AM, Doug <[1]doug351c at gmail.com> wrote:

     Jeff,
     What do you mean by a heater "liquid test"?
     Doug Braun
     Blue73L #5505
     -----Original Message-----
     From: DeTomaso [[2]mailto:detomaso-bounces at server.detomasolist.com]
     On Behalf Of JEFFREY COBB
     Sent: Friday, August 05, 2016 3:37 AM
     To: Pantdino <[3]pantdino at aol.com>; [4]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
     [5]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
     _______________________________________________
     Detomaso Email List is not managed by POCA Posted emails must not
     exceed 1.5 Megabytes DeTomaso mailing list
     DeTomaso at server.detomasolist.com
     http://server.detomasolist.com/mailman/listinfo/detomaso
     To manage your subscription (change email address, unsubscribe,
     etc.) use the links above.
     Members who post to this list grant license to the list to forward
     any message posted here to all past, current, or future members of
     the list. They also grant the list owner permission to maintain an
     archive or approve the archiving of list messages.

References

   1. mailto:doug351c at gmail.com
   2. mailto:detomaso-bounces at server.detomasolist.com
   3. mailto:pantdino at aol.com
   4. mailto:detomaso at detomasolist.com
   5. http://www.LiveOakConcours.org/


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