If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
AC pressure switch field replaceable?
Hi all,
I have a 92 Chevy Astro van 4.3 w/ factory AC. My pressure switch for the AC compressor went out and since it hasn't been running real cold anyway, I bought an R-134a retrofit kit for it. I also bought a conversion R-134a switch since it doesn't run at the same pressure and the conversion kit is kinda sparse on extra parts. I still have to find a place to evacuate the R-12 in there now. I'm not going to just void it to the atmosphere. My question is this: I noticed the conversion switch that threads onto the back of the accumulator has a little button on the inside-center of the fitting. It looks like it's supposed to open a valve similar to the service port on the AC system when it's threaded all the way on. If this switch fails again some time in the future, can I just turn this off and put another on on it or do I have to have the system vacuumed out again? Thanks, - Jeff G |
Ads |
#2
|
|||
|
|||
AC pressure switch field replaceable?
Keep YerSpam wrote: > Hi all, > I have a 92 Chevy Astro van 4.3 w/ factory AC. My pressure switch for > the AC compressor went out and since it hasn't been running real cold > anyway, I bought an R-134a retrofit kit for it. I also bought a > conversion R-134a switch You may want to read this about the switch: http://www.acdelcotechconnect.com/pd...sb_03D-128.pdf If low Freon is your only problem, consider shelling out money for some new seals and an R-12 recharge because the results from R-134a retrofit kits like the one you describe have been poor, unless you go beyond their instructions and remove all the old oil. R-12 may seem expensive, but it's still much cheaper than a poor R-134a retrofit that fails. See also: www.aircondition.com www.acresource.com |
#4
|
|||
|
|||
AC pressure switch field replaceable?
"Don" > wrote in message ... > EACTLY! And the conversion will NEVER cool as well as R12 in a > system designed for R12. Also, however much a system leaks R12, it > will leak HC134 considerably worse. I have to disagree. I've had three systems converted from R12 to R134 (1992 F150, and two farm tractors) and all three performed at least as well as when charged with R12. In fact, the last conversion is actually too damn cold. I have one tractor that was converted to R134 over 7 years ago. I have not had to recharge it once in that time. For my F150, all that was done was to replace the accumulator, suck the system down and recharge it with R134 (about 75% as much as for R12). Other than the oil that when with the accumulator, no attempt was made to remove oil from the system. System worked fine for 3 years and was still working fine when I sold the truck. Ed |
#5
|
|||
|
|||
AC pressure switch field replaceable?
"C. E. White" > wrote in message news:44ad09db$1@kcnews01... > > "Don" > wrote in message > ... > > EACTLY! And the conversion will NEVER cool as well as R12 in a > > system designed for R12. Also, however much a system leaks R12, it > > will leak HC134 considerably worse. > > I have to disagree. when I sold the truck. > > Ed Actually, Ed, I have not had my older unit converted yet, but intend to do so. The local shops here say that the 134a conversions, when properly done, are very successful and cool just as well as the Freon systems. I respect Don's expertise and good advice on this board, and will comment from a personal perspective when my conversion is complete. (The shop here is locating the leaks in the old system right now - most likely the GM compressor shaft seal - and then we will proceed.) |
#6
|
|||
|
|||
AC pressure switch field replaceable?
> wrote in message .com... > > "C. E. White" > wrote in message > news:44ad09db$1@kcnews01... > > > > "Don" > wrote in message > > ... > > > EACTLY! And the conversion will NEVER cool as well as R12 in a > > > system designed for R12. Also, however much a system leaks R12, it > > > will leak HC134 considerably worse. > > > > I have to disagree. when I sold the truck. > > > > Ed > > Actually, Ed, I have not had my older unit converted yet, but intend to do > so. > > The local shops here say that the 134a conversions, when properly done, are > very successful and cool just as well as the Freon systems. > > I respect Don's expertise and good advice on this board, and will comment > from a personal perspective when my conversion is complete. (The shop > here is locating the leaks in the old system right now - most likely the GM > compressor shaft seal - and then we will proceed.) > > Condenser size and air flow is the main issue on r134a retro fits. R134a has a higher operating pressure and the condenser runs much hotter than on R12. In larger vehicles like pick up trucks and large cars the R12 condenser is usually large enough and the airflow is sufficient to handle the conversion well. On small cars with tiny condensers and electric fans there is often not enough condenser cooling to remove the excessive heat and the system performs accordingly. The issue of oil is also less of a problem on systems that have a larger capacity. You can leave some of the old mineral oil in the system and it just separates from the refrigerant and settles down in the condenser and accumulator. The adder PAG oil is picked up by the r134a and lubricates the compressor well enough. On a small system, if any old oil is left it displaces enough total volume that the system is less efficient due to the lower volume of refrigerant that will fit in the system.. Non-barrier hoses on older systems are not usually a problem because the mineral oil has permeated the pores in the hose and keeps the smaller r134a molecules from seeping through. Bottom line, r134a retro fits can and do work, but depending on the make and model, you may have to make some modifications for it to work well. -- Kevin Mouton Automotive Technology Instructor "If women don't find you handsome, they should at least find you handy" Red Green |
#7
|
|||
|
|||
AC pressure switch field replaceable?
Kevin wrote: > > wrote in message > .com... > >>"C. E. White" > wrote in message >>news:44ad09db$1@kcnews01... >> >>>"Don" > wrote in message ... >>> >>>>EACTLY! And the conversion will NEVER cool as well as R12 in a >>>>system designed for R12. Also, however much a system leaks R12, it >>>>will leak HC134 considerably worse. >>> >>>I have to disagree. when I sold the truck. >>> >>>Ed >> >>Actually, Ed, I have not had my older unit converted yet, but intend to do >>so. >> >>The local shops here say that the 134a conversions, when properly done, > > are > >>very successful and cool just as well as the Freon systems. >> >>I respect Don's expertise and good advice on this board, and will comment >>from a personal perspective when my conversion is complete. (The shop >>here is locating the leaks in the old system right now - most likely the > > GM > >>compressor shaft seal - and then we will proceed.) >> >> > > > Condenser size and air flow is the main issue on r134a retro fits. R134a has > a higher operating pressure and the condenser runs much hotter than on R12. > In larger vehicles like pick up trucks and large cars the R12 condenser is > usually large enough and the airflow is sufficient to handle the conversion > well. On small cars with tiny condensers and electric fans there is often > not enough condenser cooling to remove the excessive heat and the system > performs accordingly. The issue of oil is also less of a problem on systems > that have a larger capacity. You can leave some of the old mineral oil in > the system and it just separates from the refrigerant and settles down in > the condenser and accumulator. The adder PAG oil is picked up by the r134a > and lubricates the compressor well enough. I thought that on retrofits where there was NOT a complete system flush and dryer replacement that Ester oil was recommended? Bob On a small system, if any old oil > is left it displaces enough total volume that the system is less efficient > due to the lower volume of refrigerant that will fit in the system.. > Non-barrier hoses on older systems are not usually a problem because the > mineral oil has permeated the pores in the hose and keeps the smaller r134a > molecules from seeping through. Bottom line, r134a retro fits can and do > work, but depending on the make and model, you may have to make some > modifications for it to work well. ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#8
|
|||
|
|||
AC pressure switch field replaceable?
"Bob Urz" > wrote in message ... > > Condenser size and air flow is the main issue on r134a retro fits. R134a has > > a higher operating pressure and the condenser runs much hotter than on R12. > > In larger vehicles like pick up trucks and large cars the R12 condenser is > > usually large enough and the airflow is sufficient to handle the conversion > > well. On small cars with tiny condensers and electric fans there is often > > not enough condenser cooling to remove the excessive heat and the system > > performs accordingly. The issue of oil is also less of a problem on systems > > that have a larger capacity. You can leave some of the old mineral oil in > > the system and it just separates from the refrigerant and settles down in > > the condenser and accumulator. The adder PAG oil is picked up by the r134a > > and lubricates the compressor well enough. > > I thought that on retrofits where there was NOT a complete system flush > and dryer replacement that Ester oil was recommended? > > Bob > Ester oil will mix with the old mineral oil and will circulate with the r134a, but many manufacturers recommend using only PAG. Experience has shown that leaving a small amount of mineral oil in the system is not detrimental as long as a sufficient amount of PAG has been added with the retrofit. The old mineral oil just separates and settles out. It is not circulated, but it does take up some space in the system and on small systems may reduce total system capacity for the refrigerant and PAG. Of course, it is always best to flush the system, but on minimal retrofits it is not absolutely necessary in all cases. BTW, it has also been my experience that on small systems with an orifice tube the low pressure clutch cycling switch can be retained. The r134a does have a slightly different optimal evaporator pressure, but it is such a small difference that no noticeable improvement is gained by switching to a r134a pressure switch. However, on several small cars I have had to replace the expansion valve to one that is r134a compatible to get maximum cooling efficiency. It might just be that the old TXV was just not operating correctly, though. I never tried going back with an original R12 TXV during a retrofit where I was replacing the valve anyway. -- Kevin Mouton Automotive Technology Instructor "If women don't find you handsome, they should at least find you handy" Red Green |
#9
|
|||
|
|||
AC pressure switch field replaceable?
"Bob Urz" > wrote in message ... > I thought that on retrofits where there was NOT a complete system flush > and dryer replacement that Ester oil was recommended? > > Bob On my system, there will definitely be a complete flush, and the recommended PAG lubricant will be used. I will most likely replace the compressor with a new aftermarket one, replace the O-tube, and the filter/dryer. I had considered replacing the condenser too, with one of the newer high efficiency designs, but probably will forego that unless the present one is damaged. |
#10
|
|||
|
|||
AC pressure switch field replaceable?
Don wrote:
> On 6 Jul 2006 01:18:59 -0700, wrote: > > >>Keep YerSpam wrote: >> >>>Hi all, >>> I have a 92 Chevy Astro van 4.3 w/ factory AC. My pressure switch for >>>the AC compressor went out and since it hasn't been running real cold >>>anyway, I bought an R-134a retrofit kit for it. I also bought a >>>conversion R-134a switch >> >>You may want to read this about the switch: >> >> http://www.acdelcotechconnect.com/pd...sb_03D-128.pdf >> >>If low Freon is your only problem, consider shelling out money >>for some new seals and an R-12 recharge because the >>results from R-134a retrofit kits like the one you describe >>have been poor, unless you go beyond their instructions and >>remove all the old oil. R-12 may seem expensive, but it's >>still much cheaper than a poor R-134a retrofit that fails. > > > EACTLY! And the conversion will NEVER cool as well as R12 in a > system designed for R12. Also, however much a system leaks R12, it > will leak HC134 considerably worse. > > Don > www.donsautomotive.com > > > > > >>See also: >> >> www.aircondition.com >> www.acresource.com > > Thanks for the info, good stuff. I plan on having the entire system taken down to a complete vacuum. Can I remove the low-pressure switch from the accumulator without exposing the system to atmosphere? The jumper test confirmed that the switch was the problem before I originally posted about this. I'd hate to have to pay a shop's standard fee in a rate book (just the way they do it around here) for unscrewing a switch if I can easily & safely do it in my driveway before I fill the system. Cheers, - JJG |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
'99 Intrepid pwr window controls | Randy | Chrysler | 8 | September 20th 05 05:31 AM |
Tire Pressure Monitor | Luke | Corvette | 56 | September 3rd 05 10:11 PM |
Tire Pressure Monitor | Luke | Technology | 58 | September 2nd 05 06:47 AM |
Climatronic Diagnostic Controls | Luís Lourenço | Audi | 1 | November 12th 04 08:22 AM |
Ign Switch Failure examination 91 B3 | dave | VW water cooled | 0 | October 2nd 04 04:46 PM |