R134a refrigerant

[owen-cox]

I wil probably get shot down, but what would happen if I used some of this F gas exempt automotive refrigerant to top up a heat pump that is supposed to use R410A

Would it work? Would it work but not as eficciently? Would it wear out quicker? Would it be dangerous?

R410 has completely different properties to R134a as it is designed as an air conditioning gas for domestic and commercial use. R134a was designed as a refrigeration gas for fridges ( although it is also used in car air conditioning) R410 runs at double the pressures of R143a and so adding R134a will completely change the way the system works and possibly burn out the compressor.
definitely not advised. there is a reason refrigerants are all different. if they could make one that did all applications they would do it would be much cheaper to manufacture.

 

[Heckler]

There is a difference in the molecular weights according to Wiki:-

R134a 102.03 g/mol
R12 120.91 g/mol

Engineering Toolbox has fuller details:-

https://www.engineeringtoolbox.com/dichlorodifluoromethane-R-12-d_972.html

and

https://www.engineeringtoolbox.com/r134a-properties-d_1682.html

Now all that means little to me, apart from a passing understanding of what appear to be quite different physical properties of R12 and R134a.

What does concern me is the apparently cavalier approach of a couple of the forum mechanical practitioners in advocating re-filling practices which are at best inefficient, and at worst illegal and environmentally unacceptable.

There are presumably very good technical and compliance reasons why proper refrigeration engineers have to be licensed, and their use of the gases tracked. Shade tree mechanic practices following some of the dubious (but physically possible) charge/change procedures outlined in car forums should not be part of our boating environment.

We should appreciate and encourage the forums' engineers in all disciplines for the value they add to boating knowledge, and for the time they spend making positive posts to help other members. Without their input, the forums would be far less interesting and far less of a rich technical resource.

Oh dear me, a farmer who knows all about refrigeration. A pop at me again? Again got it wrong dear boy, somewhere I have a certificate from the course that the Oilfield Company sent me on to certify me!
Stu

 

[superheat6k]

I don't think it is safe to draw too many parallels between the industrial systems that you work on and automotive air-con systems. Whereas commercial systems and indeed domestic refrigeration don't generally have quick fit style connections automotive air-con has several on a single installation.

When cars were built with systems running R12 it was unheard of to have to replenish the refrigerant unless there was a physical problem, such as a damaged pipe etc. Since changing to R134a it's well known that the air-con will need periodic servicing and re-charging. I'm talking of systems that were filled with either R12 or R134a from new, not retrofitted systems.

You asked me to provide evidence to back up my claim that molecular leakage was a myth. This I have provided from a decent and authoritative source from a simple Google search, and indeed on a paper concerning vehicle applications - not general industrial.

It is interesting however you now explain other reasons for it being OK for vehicle systems to leak as being acceptable, whilst others on here have explained quick connectors are a leak in progress.

I have explained in some reasonable level of technical detail why R134a seals leak, and nothing you have presented contradicts these reasons. My own opinion here is that poor service practices = trace quantities of air in systems and hence moisture in systems = seal damage.

I appreciate it is not so commonplace to pressure test with dry nitrogen and evacuate to < 3 torr vacuum, but not applying standard refrigeration practices more widely in the automotive air-con service industry does not mean such practices are right. Indeed a good deal of responsibility for the stringent F Gas Directive phase down targets can be directly laid at the door of the automotive industry gas losses. OK so each system only holds a cupful of the refrigerant, but with many millions of them slowly leaking, the combined negative environmental effect is massive.

 

[sarabande]

Oh dear me, a farmer who knows all about refrigeration. A pop at me again? Again got it wrong dear boy, somewhere I have a certificate from the course that the Oilfield Company sent me on to certify me!
Stu

You can't resist being condescending can you ? In one of the most informative threads for ages, you get personal.

Does the certificate you have "somewhere" relate to the refrigerants and current compliance procedures under consideration, and is it valid for the activities that are being discussed, or is it related to your rigpig life a few years ago with gases that are now illegal ?

 

[PaulRainbow]

You asked me to provide evidence to back up my claim that molecular leakage was a myth. This I have provided from a decent and authoritative source from a simple Google search, and indeed on a paper concerning vehicle applications - not general industrial.

You provided no evidence whatsover. Where has anything that you have posted stated that refrigerant in automotive air-con does not escape past the seals ?

It is interesting however you now explain other reasons for it being OK for vehicle systems to leak as being acceptable, whilst others on here have explained quick connectors are a leak in progress.

Firstly, i never said it was OK (or otherwise). It's well known that non brazed or silver soldered connections leak, it's what i have said all along, both here and in other threads, i have not just added that. It's the reason automotive systems leak. They did not leak when they were filled with R12.

If anyone has any doubts, just Google. It is an absolute fact that R134 molecules are smaller than R12. I bet everyone on this forum has had older cars with R12 air-con, can anyone remember having to have it periodically re-filled ? We all know that our modern R134 systems need doing every few years.

I have explained in some reasonable level of technical detail why R134a seals leak, and nothing you have presented contradicts these reasons. My own opinion here is that poor service practices = trace quantities of air in systems and hence moisture in systems = seal damage.

You keep saying this, but that's nonsense. Cars that have not had the air-con touched since he car was built will still need the refrigerant re-filling, how can that be down to poor servicing ?

 

[Heckler]

You can't resist being condescending can you ? In one of the most informative threads for ages, you get personal.

Does the certificate you have "somewhere" relate to the refrigerants and current compliance procedures under consideration, and is it valid for the activities that are being discussed, or is it related to your rigpig life a few years ago with gases that are now illegal ?

Rigpig? Oh dear me! more insults. Pot calling kettle black?

 

[sarabande]

Don't evade the question. What are you certified for in terms of refrigeration work ? Let us know, and I will listen to your suggestions about how to deal with systems currently requiring an appropriately qualified person to work on them.

I make no claims to have any a/c quals, so your pot/kettle comment is pointless and vapid.