Re: Painful safety lessons
R 404 a for leak testing?!! Try nitrogen...As for the US being able to use 10% R22,I believe they signed on to the Montreal Protocol which forbids this.Then again U.S. seems to make their own rules with most things!
Re: Painful safety lessons
Pressure and strength test on new installations are conducted with OFN, Leak testing of systems with OFN with a trace of R22 is still allowed as leak detectors cannot detect OFN. Technically speaking R134a and R404a (Hfc's with an ODP of 0) are not included in the Montreal protocol but are in the Kyoto protocol (limits on GWP)(and F-gas) which the aussies and yanks wont sign up too. :rolleyes:
Re: Painful safety lessons
I can honestly say I could not believe what I have just read. Leak testing with any refrigerant is dangerous particularly in a kitchen. I have only leak tested with nitrogen where the system is new or devoid of gas for the last 15 years and I can honestly say I don't know any one who would use a refrigerant in any mix or quantity.
Good Brazing Good Practice and proper pressure testing with OFN is the only way it should be done unless the system is just short of gas and then a good leak test with an electronic locates the leak. If this doesn't work reclaim the gas and pressure testing using OFN. If that fails I have used florescent die, you do find the leaks although on open screw or recip compressors you can get a lot of mess around the shaft and the clean up can take forever.
Re: Painful safety lessons
My first post was a long time ago. The technician is no longer with us and upon further analysis and questioning, he was only saying he was leak testing. He was, in fact, charging the system after having failed to perform a leak test. Which also speaks poorly of any vacuum he claimed to pull.
As far as the UK not allowing the use of a refrigerant for leak testing, that is a stringency that goes beyond the Montreal Protocol. Montreal protocol permits using trace amounts of a refrigerant combined with nitrogen in order to effectively use electronic leak detectors. Using a trace amount of refrigerant in the example I cited at the beginning of the discussion would not have caused any harm. The technician was not being truthful.
Re: Painful safety lessons
Hi Guys,
Surely its about time that someone (BOC,Rhone,Gasco ect) came up with some kind of gas that can be added to OFN when pressure testing so any leak can be picked up with an electronic detector and that doesn't contravine any legislation on emmisions
Regards
Raymond
Re: Painful safety lessons
Hi Guys,
For me, I always prefer using N2 with trace refrigerants. As for safety and economic measures I do gradual increase of test pressures by using the regulator and perform leak test in between.
Big leaks can be easily identified at low pressure test. Contamination of the surrounding can be minimized, saving of the pressure test gas can be considered depending on the equipment size and above all-surprises can be elliminated if ever there is a pressure break.
The best formula for safety = observation+common sense+precautionary action/measures.
But, sad to say, we sometimes forget.
:cool:
Re: Painful safety lessons
With regard to producing a gas with a substance in it which can be picked up by electronic detectors, I believe that one of the manufacturers produce one with a trace of helium in it. (I would guess it is OFN with a trace of helium).
So you can get electronic leak detectors which pick up helium, although they are quite expensive. :rolleyes:
Re: Painful safety lessons
does anyone remember the pipework guys who leak tested a multisplit system in the north east of uk with water?
seemed like a good idea at the time----LOL
Re: Painful safety lessons
Using refrigerant to do a pressure test actally cost higher than using dry nitrogen gas, especially 404a. But to carry the bottle of dry nitrogen cylinder around makes the job tougher.
Re: Painful safety lessons
I'm quite amused when I see people saying that watching a vacuum gauge rise will indicate whether or not a system is leak tight.
Bear in mind that a system under absolute vacuum will only be subjected to 1 bar atmospheric pressure (14.9psi) and is mainly used to indicate the presence of water vapour.
If you apply nitrogen (OFN) at multiples of atmospheric pressure then you stand a much greater chance of seeing if your system is leak tight and capable of withstanding working pressures. :confused:
Re: Painful safety lessons
Quote:
Originally Posted by fridge51
does anyone remember the pipework guys who leak tested a multisplit system in the north east of uk with water?
This is not too surprising. I heard of a large centrifugal chiller that was hydrotested. Not the water piping mind you, the chiller package...:eek:
The compressor and refrigerant piping were completely filled with water and then pressurized to find the leaks.
Someone always has to get creative and have a "better" way of doing things. Similar to the crimped tubing used as an expansion device in another post for the propane refrigerator.
Who knew refrigeration could be so difficult?:p