Soldering Expansion Valves

[Abe]

I am now starting to use soldered type expansion valves as opposed to flare.

What is the correct manner to solder or braze, without damaging the bellows .

Do i wrap a wet cloth around the body?

Any help appreciated

[Abe]

I saw an engineer recently fix a leak on a soldered expansion valve with the orifice still in place.

I asked him wouldnt it damage the seat, he said.......the valve bodies can take a lot of heat...........

Im not so sure

[cruzeiros]

i always work with solder connection..it's better because the most loss of refrigerant appeareas at the flare connections. but the orifice it's better to stay out...and always a wet cloth...you can do this also with the elecrovalve but it's always better to open it before brazing.

[slingblade]

Yes, use a wet rag and point the flame away from the valve body when soldering.

[paulcollis]

Hi, depending on what sort of valve you are installing, if alco, or sporlann, we always wrap with wet cloth, or remove internals of valve and reassemble after brazing, but the new Danfoss TUAE series state not to wrap the valve as these valves are stainless steel, just heat the copper tails and let the silphos run into the copper plated stub of the valve, then after valve cools install orifice.

[Argus]

Good for you Aiyub. I hate bloody flares.

Some valves come with detatchable flanges - no problem there.


On some larger valves you may even be able to unscrew the element as they were designed to be interchangeable across a range of refrigerants.

Take out all the guts that are meant to come out and lots of wet rag, flame pointing away from the body, clean all surfaces before you start and be quick.
Avoid quenching silver solder, because if you have a tiny leak, the capillary action will draw moistrure into the system.

Good luck.
________
Ferrari 312PB history

[Brian_UK]

I'll go along with the rags and water Aiyub but there is also a product called PyroCool which can be used.

It comes in a pump action hand sprayer and is a type of cooling gel which dissipates the heat away from the area.

I have used it in the past and can be easier than water depending on the location.

[Abe]

Pyrocool..............Hmmm
I must go look out for it

Thx

[botrous]

Hi Abe and mates , how are you doing guys . . . .

I was searching the Danfoss fitters notes to find what they say about soldering a tev , but didn't find anything , I found how they advise that the KV have to be soldered , I think the process is similar .

The source of this documents is danfoss fitters note file PFH00A102.pdf page 8 , accessible with more files at :
http://www.danfoss.com/BusinessAreas...ters+Notes.htm

Regards

[chillin out]

Just out of interest in case someone doesnt know, a KV has got soft solder inside it. So if there is too much heat it will run out.

I found this when I tried to repair one that was damaged.

Chillin

[botrous]

Just out of interest in case someone doesnt know, a KV has got soft solder inside it. So if there is too much heat it will run out.

I found this when I tried to repair one that was damaged.

Chillin

thanks , good info at least for me

[tony_rich]

The best thing to ues is safty sil solder it can be uesde on steel, coper or brass melting point higher then sofet solder and lower then brazing you will never burn a valve or drier

[Abe]

The best thing to ues is safty sil solder it can be uesde on steel, coper or brass melting point higher then sofet solder and lower then brazing you will never burn a valve or drier

Thats intresting...............please can you provide more details Tony........

Where are you, in USA???

[Ikkii]

i can't speak for the dude but perhaps he was referring to silver solder and silfos rods (canadian thing). silver solder applications are the same as what he lists and requires 400-500 f less heat to flow than silfos (copper to copper only). as for flares, they are just as effective as sweat joint if you flare that copper tube accordingly.

[Rob S]

Personally I mostly sweat everything.. can't stand flares.
But if its a case were I have to use a flare. The flare is always a double and I use Nylog on it.

[JimmyMurphy]

Anyone who would reccomend using damp rags anywhere around a refrigeration system should switch to plumbing and get out of this trade. Moisture is incompressible and use of water anywhere near an opening in a system should be avoided as much as possible. There are tons of products that can be applied before and after the valve that will sufficiently absorb the heat and protect your valve. Some of them are puddy and some of them are spray on as mentioned before.

[US Iceman]

Anyone who would recommend using damp rags anywhere around a refrigeration system should switch to plumbing and get out of this trade.

A little harsh don't you think. What did everyone do before all of these fancy heat absorbing compounds were developed?

If this scares you off, I won't tell some of the things I have done with water and ***** systems.

Moisture is incompressible and use of water anywhere near an opening in a system should be avoided as much as possible.

The compressibility of water has nothing to do with this. Water by itself is a problem with most refrigerants. Ice problems in TXV's, or motor insulation problems due to acid, or when hi-potting motors.

[JimmyMurphy]

Water is a compressor is definately a problem and there are tons of things we "used to do" that were incorrect. I think that giving the BEST advice on here would be better then simply providing 1 easy solution.

[Brian_UK]

I think that giving the BEST advice on here would be better then simply providing one easy solution.

Agreed Jimmy but before you go leaping all over us refer back to some of the TXV manufacturers instructions which recommend using wet/damp rags around the TXV heads.

Considering the the adjacent joints have already been made prior to the addition of a wet rag around the TXV head then there shouldn't be any major routes for the moisture to get inside the system. Any that does would no doubt be carried away with the low pressure nitrogen being used.

[Dan]

Also, keep in mind that Sporlan Q-body valves have rubber o-rings sealing the cartridges to the body. These are more sensitive and I would recommend removing the cartridges. I don't think Sporlan says to do so, but I think it is a good idea.

Sweat valves are the only way to go. Much more reliable as far as leakage goes. In fact, sweat everything as opposed to mechanical fittings in refrigeration systems.

[JimmyMurphy]

absolutely

[US Iceman]

...there are tons of things we "used to do" that were incorrect.

True. And a lot of them are still being done by inexperienced people. I think most of the people here will suggest the best course of actions for any purpose.

Of course these are usually based on solid information founded on basic principles. When it comes time to "cut some corners" not knowing the difference can land someone in a world of problems.

[The MG Pony]

Alberta doesn't know every thing, this may be a shock to you, but I'm afraid it is true.

A wet rag does a wonderful job, it's thanks to a little thing known as nitrogen that keeps the inside at a slightly higher pressure then the out side whowudathunk it?

[Tycho]

Anyone who would reccomend using damp rags anywhere around a refrigeration system should switch to plumbing and get out of this trade. Moisture is incompressible and use of water anywhere near an opening in a system should be avoided as much as possible. There are tons of products that can be applied before and after the valve that will sufficiently absorb the heat and protect your valve. Some of them are puddy and some of them are spray on as mentioned before.

[sarcasm] why yes indeed, beacuse we dont have nitrogen going through the pipes we are soldering to prevent oxidizing, thereby having higher pressure inside the pipes... nor do we pressuretest the pipes with dry nitrogen after soldering... and pulling a vacuum... sheesh, do you think we have time for that? heck... lets just purge the system for a few minutes, get the air out and we'll be good to go...[/sarcasm]


having said that, I'm not a big fan of soldered TEV's... mostly because I work on industrial plants and from time to time look at provision plants and the like... and when a TEV has failed, you bet your hiney that the evaporator has been placed so close to the wall, you can only just squeeze your head sideways through to take a look, no room for your arms or hands... so you can either look at it, or touch it, no combination of the two.

everytime one of our office guys have ordered solder TEV's for the rare occasion where I have to build and comission a provision plant I've called up the wholesaler and told them our office guy made a wrong order and got them to sen me a flare valve instead... it's just about the only valve you cant service in place... why make it so that you can break it while installing it?