92 F250 AC problem

I reciently had a shop convert my AC over to the new R134. It worked for about an hour then stopped. 2 days later it worked fine for two days and now it stopped working. Is there some sort of a relay or something that would cause this to work, then not work.....?

Reply to
Treetop
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Pressure is probably wrong. Take it back.

Reply to
JimV

Would not having the correct amount of freon in the system cause it to work sometimes and not other times?

Reply to
Treetop

Yes, depending on the underhood temp.

Reply to
JimV

I don't think the R14 system uses freon.I'm not an expert though. Geoff.

Reply to
GeoffP

I am not either. I meant the R-134, but I thought it was also called freon, just a different formula. Sorry for my lack of knowledge.

Reply to
Treetop

They are both refrigerants. Retrofitted systems are a hack unless they are done right. Very few people do them right. The pressures are different for R134 and R12. Systems designed for R12 often work poorly and/or fail soon after the retrofit.

Reply to
JimV

R134A is a refrigerant, and a replacement for R12 Freon. It operates normally at about 10% higher pressure, and at about the same percentage less efficiency as R12.

What JimV was referring to is thermal expansion, which causes the base pressure in your system to be higher in the engine compartment, due to ambient and engine temperatures. Your system has a low and a high pressure safety switch, to protect the system from damage as the pressure increases past a predetermined point. It is common for a garage to overcharge the system when performing a retro-fit, because it doesn't take quite as much R

134 as it did the R 12.

.....in any case, follow JimV's advice, and take it back.

Spdloader

Reply to
Spdloader

When you say it stopped do you mean stopped cooling, the compressor stopped running or what stopped. R134a will hits higher pressure on a warm day than R12 will and can cause a over pressure kick out on some systems. Most conversions go fairly smoothly but some do not as R134a does have a diferent pressure curve than R12 and is a marginal replacement at best in a system desigened for R12. If compressor does not run, check charge pressures to see if they are too high (or too low) In a conversion you want to error to a slight undercharge with R134a in a R12 system, not a overcharge.

Reply to
SnoMan

When it stopped, the vents stopped putting out very cold air. The AC air was the same temp as the vent air, using a very scientific process involving putting my hand in front of the vent to check.

The compressor was kicking in a out like it should, however it seemed to me that it was kicking in an out a bit more frequently.

It seems to work when it is warmer outside than when it is cooler out, over

80 degrees F.
Reply to
Treetop

Take it back.

Spdloader

Reply to
Spdloader

"Treetop" wrote: > SnoMan wrote: > > "Treetop" wrote: >  >> I reciently had a shop convert my AC over to the new > R134. It worked >  >> for >  >> about an hour then stopped. 2 days later it worked > fine for two days >  >> and >  >> now it stopped working. Is there some sort of a > relay or something >  >> that >  >> would cause this to work, then not work.....? > >

Try changing/upgradin the cutout switches. There is shrader valve under them to prevent freon loss. Does sound like it might be just a bit under charged though. If it was overcharged it would kickout prematurely in hot weather.

Reply to
SnoMan

SnoMan wrote: :: "Treetop" wrote: ::: SnoMan wrote: :::: "Treetop" wrote: :::  >> I reciently had a shop convert my AC over to the new ::: R134. It worked :::  >> for :::  >> about an hour then stopped. 2 days later it worked ::: fine for two days :::  >> and :::  >> now it stopped working. Is there some sort of a ::: relay or something :::  >> that :::  >> would cause this to work, then not work.....? :::: :::: When you say it stopped do you mean stopped cooling, the ::: compressor :::: stopped running or what stopped. R134a will hits higher ::: pressure on a :::: warm day than R12 will and can cause a over pressure kick ::: out on some :::: systems. Most conversions go fairly smoothly but some do ::: not as R134a :::: does have a diferent pressure curve than R12 and is a ::: marginal :::: replacement at best in a system desigened for R12. If ::: compressor does :::: not run, check charge pressures to see if they are too high ::: (or too :::: low) In a conversion you want to error to a slight ::: undercharge with :::: R134a in a R12 system, not a overcharge. ::: ::: When it stopped, the vents stopped putting out very cold air. ::: The AC air ::: was the same temp as the vent air, using a very scientific ::: process involving ::: putting my hand in front of the vent to check. ::: ::: The compressor was kicking in a out like it should, however it ::: seemed to me ::: that it was kicking in an out a bit more frequently. ::: ::: It seems to work when it is warmer outside than when it is ::: cooler out, over ::: 80 degrees F. :: :: Try changing/upgradin the cutout switches. There is shrader valve :: under them to prevent freon loss. Does sound like it might be just a :: bit under charged though. If it was overcharged it would kickout :: prematurely in hot weather. ::

I finally got a chance to take it back to the Mechanic. He checked for leaks and drained and recharged the system. He took it out for a few test drives and worked for him just fine. I picked it up. It worked for about 5 miles. While driving home and thinking of finding a new mechanic, I turned the temp to hot for a bit then back again and it worked the rest of the way home. Is there such a thing as a faulty temp switch? Is it something that I can replace?

Reply to
Treetop

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