Not using Nitrogen for brazing VRF

[Contactor]

H

Would be interested to hear from anyone who has not used nitrogen for brazing and has had any problems as a result.

Particularly if manufacturers have refused warranty claims etc...

Thanks

[Toosh]

H

Would be interested to hear from anyone who has not used nitrogen for brazing and has had any problems as a result.

Particularly if manufacturers have refused warranty claims etc...

Thanks

Hi Contractor, If you don`t use nitrogen there will be damage to system long term there is nothing to be gained by this it all adds up to losses

Norm

[cool_tech]

hello,
do daikin units have a contamination alarm when carbon is in oil?
only a theory i have heard

[Argus]

hello,
do daikin units have a contamination alarm when carbon is in oil?
only a theory i have heard

.



Yes.

All units have a built-in alarm to show abrasive contamination in the oil.

It's an audible tone in the outdoor unit that sounds a lot like a bag of nails.




.

[raz5]

.



Yes.

All units have a built-in alarm to show abrasive contamination in the oil.

It's an audible tone in the outdoor unit that sounds a lot like a bag of nails.




.

like it ROFLMAO

[Thermatech]

At least one VRF manufacturer sends all warrantee claim compressors to a compressor remanufacturer for a strip down inspection.
If the oil is contaminated warrantee refused.

Any carbon from joints brazed without ofn purge gets flushed back to the compressor sump & acts as grinding paste on the bearings.

Was on a site a few months ago sytem only 2 years old, the contractor had changed the comp twice. The oil contamination was so bad that the complete outdoor unit was replaced & system clean up procedure with shell & core filler drier fitted to the suction.

The major manufactures can trace the installing contractor from commissioning sheets which is one reason why the sheets have to be sent in for the warrantee.
So sooner or later short cut on ofn purge brazing will prove to be expensive.

[The MG Pony]

No OFN when Brazing = You fail. Plain and simple, no reasons not to, and every reason to do so!

[2007eng]

Hi Contractor, If you don`t use nitrogen when you brazing the bubbles will stay inside the pipe causing damage in the compressure.

[brunstar]

no use of nitrogen is just trouble, be clean and do it rght and you should have a trouble free system

[US Iceman]

Without the use of nitrogen during any brazing operation you will form copper oxide in the pipe. It is very thin and forms in the area of the heated joint, so it is just not the joint but also the pipe itself where this can form. If this is allowed to remain in the system, the oil and refrigerant will eventually loosen this, so it will collect on strainers in the inlets to TXV's and driers causing a restriction.

After some time this oxide will find it's way to the compressor where it mixes with the oil Without any test lab results my concerns would be a change in oil viscosity or potential bearing damage and possibly acid formation due to high temperatures and pressures found in the compressor.

From the manufacturers perspective, if you do not follow their directions the warranty would be voided and the contractor would have to assume all costs.

[Contactor]

Presumably this all depends how many joints and how big the pipes are?

[US Iceman]

Not at all. If you braze, you should use nitrogen to purge the piping.

[Brian_UK]

Presumably this all depends how many joints and how big the pipes are?

That just varies the quantity of oxides inside the piping.

[BritCit_Juve]

Virtually all manufacturers will after multiple compressor failures require a few randomly selercted brazed points to be cut out of the system and returned to them. Once they have view of the oxide residues both waranty compressors become chargeable and warranty is terminated.
One manufacturer reserves the right to request joints be cut out if the attend to provide commissioning assistance.
It is not as expensive to braze the joints with nitrogen as it would be to have to replace all the joints, stainers and compressors once you are found out!
Brit

[Tycho]

Presumably this all depends how many joints and how big the pipes are?

if it's one 1/4" joint on a plant with 2 tons of *****, you should still be using OFN.


It's not about if it's necessary or not, it's about what's the right thing to do...


sure, it takes a few minutes extra, but at least you can walk away from it and say that you did it according to the book, and nobody can say you made a bad job about it. Sure, the customer might ask why it took so much time, but when you explain the procedure, he should be happy as well.


You will not find one single serious refrigeration engineer that will tell you that brazing without OFN is "Ok if it's just two or three bends" on a system of some size... you should look in the cowboy forum for that.

[cool#9]

Hello
Have about it an experience with 10 VRV HR + 122 indoor unit + 120 BS boxes (DAIKIN) from another company, brased without nitrogen...
No problem since '2004 !
I don't mean it's a good thing to do that but i'm asking to myself sometimes...
rgds
cool#9

[R1976]

Hi,

I always use ofn on vrf systems.

I often speak to other engineers about it and I would say that in 14 years of this I have never found an engineer who actually uses it. Some smile , some say they don't get paid enough for the job to use it, some set it up to look like they're using it but don't, some use it incorrectly, some don't understand, but the majority don't care.

Education is the key!

[Daikin=Overated]

I don't braze using OFN either because I'm using the Lockring kit which guarentees my installations are squeeky clean internally plus the manufacturers can't say squat should I make a compressor claim! Although theres not currently a handtool for larger pipesizes,it's in the pipeline to allow for VRF installs.

Prior to this I always purged OFN whilst brazing. As the last post mentions it's down to education. Anyone undertaking a pipework/brazing course these days will have this drummed in to them from the offset.

The difficulty is theres a lot of old school engineers out there stuck in there ways, stuck in the past, thinking they know best- when actually they don't and in my view there simply out of touch with the best practise.

Theres no denying the damage that oxidisation causes to compressors. You just shorten the life of the system, or kill the compressor completely. What's not to understand?

[Greengrocer]

Take a look at this.

[Contactor]

Agreed, OFN should always be used.

I am interested in hearing from anyone who has had a problem as a result of not using Nitrogen on one or two joints.

It seems nobody has (here at least).

[US Iceman]

I think it would be difficult to state two joints brazed without nitrogen would lead to any negative effects. At the same time, how could you argue with the need to keep contaminants out of the system?

It has been an industry standard for a long time to minimize contaminants such as copper oxide and water, so the only recourse I could offer is to proceed at your own risk.

That's the best advice I can offer.

[Greengrocer]

It's quite simple really.
As a "rule" we all know that OFN should always be used for any brazing work. In "reality" OFN is hardly ever used on splits and less than 30% on VRV/VRF jobs up to approx 30kW. Above 30kw (mainly specified work) OFN will be used more regularly.
How do I know this? I employ install sub contractors and despite our requirenments / specs for the use of OFN while brazing on every job very rarely do I see engineers with OFN on site while installing pipe-work. OFN seems only to be present on site (and invoiced for) during pressure testing. Our terms state that if system failures occur due to lack of OFN during installation the installer (read sub contractor) must repair the system at his own cost - up to 3 years down the line.

In reality, sub-contractors do not care and take the risk in order to get the work with lower rates or quotes. In general we can see through this and tend to stick with a select group of subbies to do our work to our specs.

Footnote.
Recently we have employed our 1st engineer (big investment) and, to his credit and without any co-ertion or pressure, he has insisted in doing installs by the book. On average it takes him approx 10-20% longer to do an installation than a subby and our use of OFN has increased considerably. Whilst our engineer may take longer to do an install the difference is that I know that the install is "pucker" and there should be no issues that will come back to bite us.
Problem is there are still a load of cowboys out there that don't even know what OFN is let alone how to use it.

Heh Ho.

[tonyhavcr]

how do you put the
nitrogen in. I have to braze on taps first be for I can start brazing.
Then I can purge with nitrogen

[nike123]

how do you put the
nitrogen in. I have to braze on taps first be for I can start brazing.
Then I can purge with nitrogen

If you purchasing pipes with plastic caps on them (you should) then just puncture hole in cap and stick this in to hole!


Or you could buy copper caps for every pipe diameter and braze this to cap!

[Brian_UK]

Or just put a small bleed tube into the end of the copper tube and seal it with tape.

[tonyhavcr]

your funny h a h a h a ha

sometime back I saw someone selling a crimp on type kit for this and want to see if any one tried it or if there was a better way to do it then the old way.