Originally Posted By: tdi-rick
440Magnum said:
Adding 134a refrigerant
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Originally Posted By: benjamming
Originally Posted By: 440Magnum
[snip]2) Put a manifold gauge set on the system so you can monitor high-side and low-side pressures. [snip]
Like this? CPS Products R134a Pro-Set® Aluminum Block Manifold Gauge Set with Hoses
You can buy a nice set at harbor freight for $60.00
Originally Posted By: 440Magnum
[snip]2) Put a manifold gauge set on the system so you can monitor high-side and low-side pressures. [snip]
Like this? CPS Products R134a Pro-Set® Aluminum Block Manifold Gauge Set with Hoses
You can buy a nice set at harbor freight for $60.00
Originally Posted By: tdi-rick
You will contaminate the system with air/whatever is in the gauges and lines if you don't purge the hose at the manifold end (if using a commercial refrig/a-c type manifold) regardless of the system being under pressure.
The refrigerant under pressure just pushes the non-condensables and moisture (if present) up to the gauge end of the hose, then just mixes with the refrigerant in the line, so there's a fair chance that by the time you take your gauges off the service valve the mixed contaminants have mixed enough for a % to make their way into the system.
That was a big problem with old manifold and hose sets without schrader valves in the hose ends and positive cut-off ball valves right behind the fittings. I always purge if the gauge set doesn't still show internal pressure from its last use, but it usually does. I've got one manifold set that shows 50 psi in all the hoses after hanging in the garage for 6 months- these new hoses are very refrigerant-tight.
Originally Posted By: tdi-rick
It's also a good idea to connect the suction line up while the compressor is not running, otherwise you will contaminate the system if it is running on a vacuum (liquid line blockage, faulty or internally iced up TXV, very short of refrigerant, iced up FDC, FDC fan failure, etc)
Another one of those nit-picky anal things that *I* always do, but the tech at PepBoys who's younger than my car probably does NOT do...
Originally Posted By: tdi-rick
BTW, it's illegal for non licensed people to work on or service any a/c or refrig system over here, and impossible to buy refrigerant without a Federal 'Refrigerant Trading Authorisation' thanks to federal EPA dictates.
That's how it is with R-12 here and has been for years. Although I paid my $30, took the on-line course, and got my certificate years ago... I've never actually used it to buy R-12 though, because R-134a conversions (when done RIGHT) work so much better than we were all afraid they would.
You will contaminate the system with air/whatever is in the gauges and lines if you don't purge the hose at the manifold end (if using a commercial refrig/a-c type manifold) regardless of the system being under pressure.
The refrigerant under pressure just pushes the non-condensables and moisture (if present) up to the gauge end of the hose, then just mixes with the refrigerant in the line, so there's a fair chance that by the time you take your gauges off the service valve the mixed contaminants have mixed enough for a % to make their way into the system.
That was a big problem with old manifold and hose sets without schrader valves in the hose ends and positive cut-off ball valves right behind the fittings. I always purge if the gauge set doesn't still show internal pressure from its last use, but it usually does. I've got one manifold set that shows 50 psi in all the hoses after hanging in the garage for 6 months- these new hoses are very refrigerant-tight.
Originally Posted By: tdi-rick
It's also a good idea to connect the suction line up while the compressor is not running, otherwise you will contaminate the system if it is running on a vacuum (liquid line blockage, faulty or internally iced up TXV, very short of refrigerant, iced up FDC, FDC fan failure, etc)
Another one of those nit-picky anal things that *I* always do, but the tech at PepBoys who's younger than my car probably does NOT do...
Originally Posted By: tdi-rick
BTW, it's illegal for non licensed people to work on or service any a/c or refrig system over here, and impossible to buy refrigerant without a Federal 'Refrigerant Trading Authorisation' thanks to federal EPA dictates.
That's how it is with R-12 here and has been for years. Although I paid my $30, took the on-line course, and got my certificate years ago... I've never actually used it to buy R-12 though, because R-134a conversions (when done RIGHT) work so much better than we were all afraid they would.
Originally Posted By: Buffman
Originally Posted By: benjamming
Originally Posted By: 440Magnum
[snip]2) Put a manifold gauge set on the system so you can monitor high-side and low-side pressures. [snip]
Like this? CPS Products R134a Pro-Set® Aluminum Block Manifold Gauge Set with Hoses
You can buy a nice set at harbor freight for $60.00
I've yet to see anything at China Freight that was made in USA.
Originally Posted By: benjamming
Originally Posted By: 440Magnum
[snip]2) Put a manifold gauge set on the system so you can monitor high-side and low-side pressures. [snip]
Like this? CPS Products R134a Pro-Set® Aluminum Block Manifold Gauge Set with Hoses
You can buy a nice set at harbor freight for $60.00
I've yet to see anything at China Freight that was made in USA.
Originally Posted By: swalve
These are some of the silliest rules I know of- you know those spray cans of "air" that you use to remove dust out of computers, printers and the like? Most of them contain... r134a. Not a little bit as a propellant, but the whole can is r134a.
They aren't here, the 'Federal Department of the Environment and Water Resources' had anything that contained any 'listed' refrigerant banned too.
...and you should see my license fees, (two Federal, one to purchase and one to use, and one State contractors license) and you had to prove years of Technical College and industry experience to gain a license too.
These are some of the silliest rules I know of- you know those spray cans of "air" that you use to remove dust out of computers, printers and the like? Most of them contain... r134a. Not a little bit as a propellant, but the whole can is r134a.
They aren't here, the 'Federal Department of the Environment and Water Resources' had anything that contained any 'listed' refrigerant banned too.
...and you should see my license fees, (two Federal, one to purchase and one to use, and one State contractors license) and you had to prove years of Technical College and industry experience to gain a license too.
Originally Posted By: benjamming
Originally Posted By: Buffman
Originally Posted By: benjamming
Originally Posted By: 440Magnum
[snip]2) Put a manifold gauge set on the system so you can monitor high-side and low-side pressures. [snip]
Like this? CPS Products R134a Pro-Set® Aluminum Block Manifold Gauge Set with Hoses
You can buy a nice set at harbor freight for $60.00
I've yet to see anything at China Freight that was made in USA.
I didn't know we were that picky. Just trying to help save money. They work good.. I have a set and so does the guy who does restroations and other car work next door.
Originally Posted By: Buffman
Originally Posted By: benjamming
Originally Posted By: 440Magnum
[snip]2) Put a manifold gauge set on the system so you can monitor high-side and low-side pressures. [snip]
Like this? CPS Products R134a Pro-Set® Aluminum Block Manifold Gauge Set with Hoses
You can buy a nice set at harbor freight for $60.00
I've yet to see anything at China Freight that was made in USA.
I didn't know we were that picky. Just trying to help save money. They work good.. I have a set and so does the guy who does restroations and other car work next door.
One quick additional check for R134 systems is a cold check. At around 70f, with the car sitting overnight, simply hook up the low side gauge [car off and never started]. It will read around 80 [because the 2 sides are equalized]. A hotter day will read a bit higher.
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