Automotive Air Conditioning Information Forum (Archives)

my2monkeys on Sat June 30, 2012 11:17 AM

Year: 1989
Make: Jeep
Model: Cherokee
Engine Size: 4.0
Refrigerant Type: OE r-12
Ambient Temp: 75
Pressure Low: 25-30
Country of Origin: United States

1989 Cherokee 4.0L



My brother got ahold of some HotShot 414B (he's a res./comm HVAC tech).

We are replacing the r134a that replaced the OEM r-12 with r414b.

The reason for the HotShot is the 134a doesn't seem to cool the rig at low speeds like the r-12 used to.

So after some internet study, and my brother's a/c shop happening to have a 30 lbs bottle of HotShot we're in the process of charging the system.

My question is, Do you guys like the 414b in autos and what Low and High psi should I be looking for at 80* F?

We put the system in a vaccuum.

Do you add the "liquid" to the High side valve on comp. with engine off and vaccuum established?

Thanks Colin

mk378 on Sat June 30, 2012 12:05 PM

Any PAG oil that has been used must be removed before reverting to a chlorinated refrigerant. There is chemical incompatibility and the PAG will turn to sludge.

Always remove blends from the cylinder as liquid.

The main problem with these is that the R-22 component can seep through intact rubber hoses, causing loss of refrigerant, the remaining refirgerant becoming an improper blend.

Why not just use R-12?

iceman2555 on Sat June 30, 2012 12:06 PM

Responses:

1.) Never let family work on your car! When they screw it up...with whom can you become angry!

2.) Appears as if one experiment did not work...lets try it again and install a chemical that we know nothing about.

3.) R12 cars were never designed to operate with a refrigerant like 134a and the increased operational pressures. So accept that it may not cool as well. My advice for my customers was to stay with R12. The system will function as it should.

4.) Conduct more internet study on the Hotshot!

5.) NO, NO, and once more NO. Not sure about the pressures....pressures are not an indication of a fully charged system.....never were.....never will be....so pressures are pressures....see #4

6.) How do you 'put a system into a vacuum.' But understand.

7.) See more of #4. Since this refrigerant (?) is a blend..it must be charged as a liquid. The chemical will fractionate if not. Be very careful adding liquid to an operating system. This could result in serious compressor damage. Contact HOTSHOT for compressor warranty issues.

Check out MSDS info for HOTSHOT

Material: CAS Number Typical Wt. %
Chlorodifluoromethane (HCFC-22) 75-45-6 50%
2-Chloro-1,1,1,2-tetrafluoroethane (HCFC-124) 2837-89-0 39%
1-Chloro-1,1-difluoroethane (HCFC-142b) 75-68-3 9.5%
Isobutane (HC-600a) 75-28-5 1.5%

Conduct a bit of research on pressures points of the different chemicals....one will leak from the system more rapidly than others....which one will it be...and does this chemical cool or migrate lubricant ? These chemicals tend to fractionate within the system during operation.....got a leak...means the system can not be topped off...gotta be completely recharged once more....mmmm...seems like operational cost is going to be more expensive...or perhaps this system does not have any leaks....great.

Why not simply redo the retro and do it properly and charge the system to charge amount.... not pressures (do not work with a retro). Accept that some vent loss is acceptable and go for it. Forget all the sales BS about HOTSHOT and all the other magic in a can solutions to this issue.

Service your system properly and it should perform in an acceptable manner.

Good luck!!



-------------------------
The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

my2monkeys on Sat June 30, 2012 12:44 PM

Quote
Originally posted by: iceman2555
Responses:



1.) Never let family work on your car! When they screw it up...with whom can you become angry!



2.) Appears as if one experiment did not work...lets try it again and install a chemical that we know nothing about.



3.) R12 cars were never designed to operate with a refrigerant like 134a and the increased operational pressures. So accept that it may not cool as well. My advice for my customers was to stay with R12. The system will function as it should.



4.) Conduct more internet study on the Hotshot!



5.) NO, NO, and once more NO. Not sure about the pressures....pressures are not an indication of a fully charged system.....never were.....never will be....so pressures are pressures....see #4



6.) How do you 'put a system into a vacuum.' But understand.



7.) See more of #4. Since this refrigerant (?) is a blend..it must be charged as a liquid. The chemical will fractionate if not. Be very careful adding liquid to an operating system. This could result in serious compressor damage. Contact HOTSHOT for compressor warranty issues.



Check out MSDS info for HOTSHOT



Material: CAS Number Typical Wt. %

Chlorodifluoromethane (HCFC-22) 75-45-6 50%

2-Chloro-1,1,1,2-tetrafluoroethane (HCFC-124) 2837-89-0 39%

1-Chloro-1,1-difluoroethane (HCFC-142b) 75-68-3 9.5%

Isobutane (HC-600a) 75-28-5 1.5%



Conduct a bit of research on pressures points of the different chemicals....one will leak from the system more rapidly than others....which one will it be...and does this chemical cool or migrate lubricant ? These chemicals tend to fractionate within the system during operation.....got a leak...means the system can not be topped off...gotta be completely recharged once more....mmmm...seems like operational cost is going to be more expensive...or perhaps this system does not have any leaks....great.



Why not simply redo the retro and do it properly and charge the system to charge amount.... not pressures (do not work with a retro). Accept that some vent loss is acceptable and go for it. Forget all the sales BS about HOTSHOT and all the other magic in a can solutions to this issue.



Service your system properly and it should perform in an acceptable manner.



Good luck!!



After posting on here I did a search on this forum for 414b and I see your expert knowledge and experience is the first place I should have looked!

I do understand now about the blend refrigerants and how they break down differently and how the "amount" of refrigerant is the only way to properly fill a system with any certainty.

Thanks for the replies. BTW, my brothers boss won't let him use the r-12 bottle because it cost him 1200 dollars for 30lbs

iceman2555 on Sat June 30, 2012 4:01 PM

If he is paying 1200 for/30lb of R12, have him give me a call....have access to this stuff for lot less.

-------------------------
The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

Leggie on Tue July 03, 2012 5:13 AM

I asked something like this before. In theory, it would work, but realistically, I wouldn't recommend it.

It contains HCFC-22 which has a tendency to diffuse through elastomers and that refrigerant has a 15degrees of glide. The combination of this would make this refrigerant very susceptible to fractionation.

If you pour a glass full of vodka and wait a few days until its almost dry, the remaining liquid is no longer 40% alcohol. It's richer in water, because alcohol selective evaporated. To avoid this, you need to move the mixture in liquid phase rather than evaporating the gas.

If you keep topping it off with vodka, it won't maintain 40% alcohol.


It is not an issue in hermetic machines like R12 refrigerator as they're very tight and almost never leak.

my2monkeys on Sat July 21, 2012 12:23 AM

Thanks for the good info.

UPDATE: The HOTSHOT has been in for a few weeks and it cools about the same as the 134a at Hwy speed.

Vent temps down to 44*F outside 85*F, so not too bad.

Bad thing is that at low RPM's or idle the compressor makes a surging sound like it's loading up and pulsates.

When we were charging the system with the liquid ofcourse we had no scale so my brother was "guesstamating" the charge wt.

We were adding until vent temps bottomed then started to rise. Got down to 42.3*F.

Then Bro decides to hit it with "a little more" and the comp. goes ROAR ROAR ROAR.

So he evacs some pressure and the ROAR mellows out some but still comes back on occasion.


So now I can't even dial the system in because it has the Blend Refrig. in it and in gas form it doesn't leave (the system) in the same ratios as in a liquid state?

Is that a true fact that once charged you can't adjust the press. with any certainty?


I'm not sure the system will last with this HOTSHOT.

I'm thinking of getting some of that R-12 my Bro's boss has stashed and putting it back to stock specs.

Like I should have done to begin with!

Would it be hard to get all that 414B HOTSHOT out of there?

Do you change the dryer very often on a simple recharge and when compressor destruction is not an issue?

Leggie on Sat July 21, 2012 1:14 AM

Yes... you'll need a dedicated "trash" cylinder meant for recovering contaminated refrigerant. So, you're going to have to visit a shop... or find a HVAC tech who will recover contaminated residues into his waste bottle.