VRV III - 4 way valve replacement

[Harvestman]

Hi All

We have a 10 year old VRV III where one of the 4 way valves has split. It is a complete pig to get to, right there in the middle of everything surrounded by pipes.

Does anybody have any suggestions as to how to go about removing the old one. No idea what slack or movement is available on what pipe once it is free of the valve connection. Is there an order to un-braze? There is no way a pipe cutter would fit in there plus it cannot be hacksawn out.

Personally I would scrap the damned thing because of the age and amount of work. But we have been asked to repair it. I'm not a brazing person. I can do it but not confident and I have access to somebody who can so why not abuse it??

My next question is - unsure of what material is inside the new valve - how would you prevent all that heat from transferring into the valve.

I'm not convinced this job is do-ableTBO. I think that the old valve is going to cause damage coming out and the new valve will get heat damaged going in.

Any advise please???

Cheers

[cadwaladr]

Some jobs are just not economical to repair,at ten years old I would replace the kit why will the client not give the go ahead is it the cost and what refrigerant is the system using, I have done similar valve replacements on small transport equipment and most times you have to remove extra piping to get to the valve which can be done on a bench wrapping the valve in wet rags should stop the heat transfer and a second person drip feeding cold water onto the cloths works for me

[Harvestman]

Unfortunately the company I work for stupidly negotiated a fully inclusive contract upto a vast sum. The manager decided that as the company has to pay for it the cheapest option counts.
Pointless in my opinion. Going to cost more in the long run I think.
Agree with your idea - so cut where the pipe cutter fits, extend the new valve ports and retrofit new valve with longer ports into condenser. At least that way the valve is protected.
Going to be a sh1te job tho. Not looking forward to it.

[Brian_UK]

I have in the past removed the fans and top covers to improve access into some of these units, might be something to think about.

You can also get spray on cooling gel to dissipate heat, I'll have a look for the name.

Something like this.... https://www.wickes.co.uk/LA-CO-Cool-Gel-Heat-Barrier---973ml/p/138024

[cadwaladr]

it's like working on a musical instrument sometimes stand back and dismantle the problems,as I said ealI erlier transport stuff is tough but cutting out the obstacles is easier

[Brian_UK]

I don't see the problem really, according to a Daikin manual it's all covered in about six short paragraphs.

A screwdriver a couple of cable ties, unbraze 4 pipes and then just braze in the new one without getting it too hot, 120°C.

A job for the apprentice by the sounds of it, so simple even your manager could do it.

:) Sorry, did i just say that out loud? :D

[Harvestman]

Retired 2015. How I envy you

[Brian_UK]

Retired 2015. How I envy youIt's okay for you workers, I don't weekends or bank holidays off any more you know. ;)

[Rob White]

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Remove as much of the surrounding equipment as possible
then unbraze the top pipe first. Don't worry about protecting the
Old valve just protect the surrounding area with lots of wet rags.

Then unbraze the bottom 3 pipes.

When fitting you will have to protect the valve from prolonged heat.
Wrap it tight with wet rags, braze the three bottom pipes first.
Braze the centre one first then the two outer ones. Use the heat from
brazing the centre pipe to preheat the outside two.

Make sure your flame is always pointed away from the bottom of the valve.
Get in with maximum heat and get it done quickly, messing around will overheat
The valve and damage it.

Be confident, do a few practice braze first and when you do it do it once and don't
mess about. Unless you go in confident, with a powerful flame and maximum heat
you will overheat it and damage it.

I can't enforcise enough, you must go in quickly and braze from the middle out. You
must be confident and do it once. If you mess around and keep returning with flame
you will damage it.

Rob

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