Repairing a 3 way motorhome fridge

[MrFluffy]

As title, anyone welded up a ammonia leak on a 3in1 fridge, eg dometic etc?
I want to go out in it this weekend but when we fired up the fridge it stank of ammonia although it got cold so odds are its got a pinhole somewhere.
Ive been told to just weld it up or patch over if its too bad, although Ive been told elsewhere that its packed full of highly flammable gas along with the amonia?
Am I risking my neck doing this, or is it really someone scaremongering and its full of a inert liquid. Im certain we used to get the ammonia fridges repaired by someone who brazed them up, but thats going back 20 years now, and Im not certain enough to risk blowing myself up finding out...

Yes I know a weld patch will be at best a temporary repair...

 

[R Kraft]

Should be ammonia and a little hydrogen in the thing.
Robert

 

[MrFluffy]

Hydrogen, so thats a no for mig'ing on a patch then if theres any left lurking around or there will be one hell of a bang. They must have evacuated the units first before brazing them that we had sent out...

 

[madkayaker]

time for metal glue?

 

[arceyered]

Be carefull? If it as the same liquid as in car aircons then welding can create
a chlorine gas which can be very BAD

 

[MrFluffy]

Never mind the hydrogen I just googled for ammonia refridgerent welding and got back "purge all lines with inert gas before starting to avoid risk of explosion" and a lot of osha and other horror stories about ammonia fires out of control and all sorts like that.

I think Im going to go slap the person who said to just mig a patch on it, it makes welding up a petrol tank look safe...

New fridge freezer time I guess... I would go the chem metal route but Ive been reading about asphixiation by leaks too while i was reading about welding it :O

 

[MrFluffy]

I know osha go overboard, but *shudder*

http://www.osha.gov/SLTC/etools/ammonia_refrigeration/emergency/index.html

 

[R Kraft]

A pinhole leak is an unusual failure, most fail because they have not been leveled before use.
Tipping them just a little during use will make scaling inside from hot spots.
The scale falls from the walls and plug the small orifices .
Robert

 

[Omniata]

Wikipedia link: Ammonia


Not a good idea to heat at all unless your experienced, I've been caught in the middle of a release of about 20 litres of anhydrous ammonia because of an idiot mucking about...
Really not pleasant stuff... If it doesn't ignite when you start patch welding/brazing the fumes will pretty much knock you out and burn your nose and throat if the cylinder ruptures...
Bear in mind when it dissolves in water it's comparable to caustic... Water being the majority of the coating of all your internals...

A bit of a horror story extreme, but get a professional to do it, unless you really are confident enough...


An old refrigerant techy ought to be able to do it... It was one of the better refrigerants...

 

[MrFluffy]

Omni, no job abandoned. Making enquiries about having a new one shipped over as Ive decided its past it anyway as its pretty badly corroded so no point attempting to repair it as it will just go again somewhere else and we're going to be overnighting in the van quite often and dont want to put the kids/mrs at risk of a fire/asphixiation etc.
We just dragged a camping gaz 3in1 coolbox out of storage, and a dometic smaller 3in1 fridge both the same age with a view to using one just for this weekend. The fridge is also starting to rot significantly on its elements but the coolbox is still shiney and new despite being stored in the same conditions. But the camping gaz unit is galvanized on the condensor etc instead of some cheap paint like the fridge. Built in obsolescence eh?

Robert, in case of the blockage, you don't get the strong ammonia smell outside as the system is supposed to be a sealed system. If it didnt stink of ammonia then I would have had a go at "burping" it like you suggest. As soon as I smelt that I knew it was going to be major...