AC gauge lines for different refrigerants?

[TheEquineFencer]

AC GAUGE LINES, THE ONES YOU INSTALL REFRIGERANTS WITH. NOT SYSTEM LINES for different refrigerants. Mainly I'm looking for what gauge lines I need for R-410A. Are lines the same as R-12? I'm wondering what other refrigerants share the same type lines.

But, it's probably be nice if an HVAC REPAIRMAN chimed in and listed the differences between the different types of refrigerants and lines, or any "work arounds."

TIA

TEF

 

[fitter30]

Never have i worried about the refrigerate but the oil especially now that systems are critical charge and don't hold much refrigerate. Hoses and gauge manifolds get purged but there could be a drop or two of oil coating a hose. 40 years ago compressors held qt of oil in a piston compressor and piping held oil. Now 3 ton compressor is a thermos bottle size 8-10 oz of oil. Hoses with the valves on the ends make purging easier with a drum of refrigerate by screwing on the hose before it's tight can purge the hose end as it is tighten to open the schrader.

 

[TheEquineFencer]

I understand about oil compatibility and such. PAG oil and such. I haven't really used a set of gauges in several years. With all the different types of refrigerants now, R12, R22, R134, R410A, the list goes on.

I'm looking information on Gauges and Line compatibility for Refrigerants. But thanks for the input...

Never have i worried about the refrigerate but the oil especially now that systems are critical charge and don't hold much refrigerate. Hoses and gauge manifolds get purged but there could be a drop or two of oil coating a hose. 40 years ago compressors held qt of oil in a piston compressor and piping held oil. Now 3 ton compressor is a thermos bottle size 8-10 oz of oil. Hoses with the valves on the ends make purging easier with a drum of refrigerate by screwing on the hose before it's tight can purge the hose end as it is tighten to open the schrader.

 

[The Metric System]

I'm a design engineer in the industry and I'm very familiar with how to select line sizes from first principles.

It is not possible to give a simple blanket answer because line sizing will vary with several factors, primarily:

• Refrigerant
• System capacity
• Total line length and routing

In practice there is actually a range of line sizes that will be satisfactory for any given installation and all lines within this range will give about the same results. If you are not in this range it is usually better to be a bit too small (reduces system efficiency) than it is to be a bit too large (reduces oil return and increases thermodynamic dead volume).

To answer your specific question, I would generally expect an R-12 and R-410A system with the same capacity and layout to use piping within the same size range. However, if I were replacing an existing R-12 system I would also replace the existing lines if at all possible, because they are likely:

• 30+ years old, approaching end of life, and in unknown condition
• Selected/built for R12 pressures, rather than the much higher pressures of R-410A. Leaks on startup are a real concern.
• Either uninsulated or poorly insulated
• Possibly full of **** that you don't want to bring back to your nice new system

 

[bonneyman]

When I was doing HVAC I had separate manifold and hose sets for R22 and R410A. (Just got out ahead of the game and eliminated cross-contamination issues by having completely separate service tools). I guess this would be one place where those Maglite-sizes electronic gauges would come in handy - no hoses that hold gas/oil mixtures.
I got out before having to do many refrigerant repairs on the 410A so didn't have a separate vacuum pump for those.

The main thing I saw was the higher pressure for the 410A. Most of my hoses were around 10 years old, and were rated for 22 (I could do 12, 500, and 502 with them if I needed). Didn't want to risk blowing a hose on 410A so got a brand new set. Probably used them 5 or 6 times. Plus the synthetic oil didn't always play nice with older, R22 polymers like seals and gaskets. If I'd stayed in past 2018 I would have had to invest in more 410A equipment.

Now R32 is out, and I have no clue - or desire to research - what kind of oil it uses. Might have had to buy ANOTHER gauge set to work on those. Geez - I'm gonna need a bigger truck! lol

 

[Snapped-off]

You can use the same lines and gauges as long as they match your pressure range. Clean them alcohol if using with a different refrigerant.

The temperature ranges won't match if you're using a gauge intended for a different type of refrigerant. Will have to manually calc.

A2L lines are left hand threaded, something to keep in mind.

I would personally just buy a dedicated set though.

 

[TheEquineFencer]

I'm a design engineer in the industry and I'm very familiar with how to select line sizes from first principles.

It is not possible to give a simple blanket answer because line sizing will vary with several factors, primarily:

• Refrigerant
• System capacity
• Total line length and routing

In practice there is actually a range of line sizes that will be satisfactory for any given installation and all lines within this range will give about the same results. If you are not in this range it is usually better to be a bit too small (reduces system efficiency) than it is to be a bit too large (reduces oil return and increases thermodynamic dead volume).

To answer your specific question, I would generally expect an R-12 and R-410A system with the same capacity and layout to use piping within the same size range. However, if I were replacing an existing R-12 system I would also replace the existing lines if at all possible, because they are likely:

• 30+ years old, approaching end of life, and in unknown condition
• Selected/built for R12 pressures, rather than the much higher pressures of R-410A. Leaks on startup are a real concern.
• Either uninsulated or poorly insulated
• Possibly full of **** that you don't want to bring back to your nice new system

I'm not talking about system lines I'm talking about the gauges and lines to check add freon/refrigerants.

Please do not make this more complicated... I thought it was a simple question.

I live with a civil engineer... She seems to make things more complicated than needs to be when I ask simple questions too. It must be something about how engineers think...

 

[Aileron]

I think I know what your asking . Most as still 1/4' flair. The mini splits however use a 5/16 flair and you can buy adapters for your old 1/4' hose ends. Pressure is pressure. You don't need a 410 gauge as long as you can convert pressure to temperature for the specific refrigerant. i will back up a second and say the suction gauge has a higher reading than the older 12,22,502 gauge.

 

[fitter30]

I understand about oil compatibility and such. PAG oil and such. I haven't really used a set of gauges in several years. With all the different types of refrigerants now, R12, R22, R134, R410A, the list goes on.

I'm looking information on Gauges and Line compatibility for Refrigerants. But thanks for the input...

R12,22,134 500 lb high side/ 200-250 low side
R410 800lb high side/350 low side
Can for R134 since the oil is the same as R410
R12 &22 use mineral oil
R134 &410 POE oil
Mini splits need a 1/4" male x 3/8" female Schrader adp common fitting.

https://www.supplyhouse.com/Yellow-Jacket-19102-1-4-Female-Quick-Coupler-x-3-8-Male-Flare?utm_source=google_ad&utm_medium=Shopping_Tools&utm_campaign=Shopping_X_Tools_X_SSC_New&utm_campaignid=22230238988&utm_adgroupid=173601024886&utm_targetid=pla-2348645108560&utm_product_id=19102&utm_matchtype=&utm_keyword=&utm_adtype=pla&utm_category=Tools&gad_source=1&gad_campaignid=22230238988&gbraid=0AAAAAD_WAyuYdYWnNeyi5-yRDpMOhsLtx&gclid=Cj0KCQjw-NfDBhDyARIsAD-ILeDXv5MBxiUComoW3_Yy-MRs7S3sOEm2ICDdggQUXUGuu-voHGlHbdAaAqCEEALw_wcB

 

[TheEquineFencer]

R12,22,134 500 lb high side/ 200-250 low side
R410 800lb high side/350 low side
Can for R134 since the oil is the same as R410
R12 &22 use mineral oil
R134 &410 POE oil
Mini splits need a 1/4" male x 3/8" female Schrader adp common fitting.

https://www.supplyhouse.com/Yellow-Jacket-19102-1-4-Female-Quick-Coupler-x-3-8-Male-Flare?utm_source=google_ad&utm_medium=Shopping_Tools&utm_campaign=Shopping_X_Tools_X_SSC_New&utm_campaignid=22230238988&utm_adgroupid=173601024886&utm_targetid=pla-2348645108560&utm_product_id=19102&utm_matchtype=&utm_keyword=&utm_adtype=pla&utm_category=Tools&gad_source=1&gad_campaignid=22230238988&gbraid=0AAAAAD_WAyuYdYWnNeyi5-yRDpMOhsLtx&gclid=Cj0KCQjw-NfDBhDyARIsAD-ILeDXv5MBxiUComoW3_Yy-MRs7S3sOEm2ICDdggQUXUGuu-voHGlHbdAaAqCEEALw_wcB

Best answer yet!

 

[TheEquineFencer]

I think I know what your asking . Most as still 1/4' flair. The mini splits however use a 5/16 flair and you can buy adapters for your old 1/4' hose ends. Pressure is pressure. You don't need a 410 gauge as long as you can convert pressure to temperature for the specific refrigerant. i will back up a second and say the suction gauge has a higher reading than the older 12,22,502 gauge.

Another best answer. Between you and Fitter30, I think I have what I'm looking...I think all I need are a standard set of gauges. For R-134, I'll need adapter or a different line set for all my present and future needs.

 

[Aileron]

I retired 3 years ago over my back. All my gauges where basically the same with maybe a favorite set. Some 4 port with a glass but unless a install they stayed in the truck. I did keep one set seperate for working on oil free centrifugul chillers. They operate with magnetic bearings which lift the shaft off the touchdown pads and spin midair. Oil contaminates those touchdown pads.

 

[PoorUB]

Most service techs do not have gauges dedicated for each refrigerant, some do, but most will not. When R410 first came out everyone was screaming that you had to have separate gauges. It was not long before even manufacturers were saying it didn't matter. Purge your gauges when you go from one gas to another. The tiny bit of oil in your hoses will not matter and chances are the oil will not leave the gauge anyway.

 

[65ranchero]

I used my R12 gauges many times on R134 systems with adaptors and used a scavenged R12 vacuum pump from a retired / broken recovery machine.

 

[KenC]

I used my R12 gauges many times on R134 systems with adaptors and used a scavenged R12 vacuum pump from a retired / broken recovery machine.

My first vac pump was a scavenged compressor from an ancient refrigerator., 1970 or so. Sweated a fitting to the suction line, pumped a little oil in it with a squirt can on every use. Did a lot of older R12 car work with that.

 

[bonneyman]

My first vac pump was a scavenged compressor from an ancient refrigerator., 1970 or so. Sweated a fitting to the suction line, pumped a little oil in it with a squirt can on every use. Did a lot of older R12 car work with that.

Do you still have it? I for one would love to see how you made it work.

R12 was like the best refrigerant. It was so forgiving from a maintenance standpoint. I remember when we had a R22 units that were having oil return problems we'd add about 10% of R12 and the problem disappeared. Totally miscible, compatibility with existing seals and o-rings were no problem, didn't hurt the pressures. It was great.

 

[KenC]

Do you still have it? I for one would love to see how you made it work.

R12 was like the best refrigerant. It was so forgiving from a maintenance standpoint. I remember when we had a R22 units that were having oil return problems we'd add about 10% of R12 and the problem disappeared. Totally miscible, compatibility with existing seals and o-rings were no problem, didn't hurt the pressures. It was great.

I no longer have it, upgraded to a real vacuum pump years ago. The conversion is simple. I used a 1/4" male/male flare coupling with one end drilled out to fit the OD of the suction line, a short copper tube brazed to the compressor. Sweated that fitting on. The electrical part was just as simple. It had 3 connections, common and two hots, one for run and one for start. Since the start relay was in the fridge cabinet I substituted a momentary push button. And used a on/off switch in the cord. Plug it in, turn it on and push the button.

I can't take credit for the idea. A local furniture and appliance dealer used one just like it for all his appliance and a/c work. He told me about it and even gifted me the compressor from an old fridge.