Porus pipework

[Latte]

Hi Guys,

I Have read on previous posts that engineers have come accross pipework leaking THROUGH the pipes due to lack of copper in it. Well this week i have come accross something similar.

Linde Pack (OLD)!!! running on R22 and the suction header tank is leaking like a sieve. Done all the usual, covered it in soap solution but doesn't show anything up but put a leak detector anywhere near it and it goes divvy.
Cleaned all the oil off of it but the next morning when i went back to site it was covered again.

I have spoken to another engineer has he has said he has heard of this before on suction headers.

Anyone else out there come accross it, whats the answer. obviously the pack has to be shut down and reclaimed as its leaking (Montreal) but do you make up your'e own, order one from the manufactures if still available. The header has 12 stubs coming out of the top

Regards

Fatboy

[chemi-cool]

leaking THROUGH the pipes due to lack of copper in it.

Are these copper tubes??

Steel pipes and stainless steel do not leak, maybe the oil drips from above?

Anyway, this is intersting thing. Can you get some photos?

Chemi

[WebRam]

yea, lets see some photos on that one please

[Latte]

Hi Chemi,

I am back up north monday and tuesday next week (Joy of joys, 3 hours on the A1) I will take photo's and post them.

I am not sure what the header is made of, it's not copper as it's covered in rust. I have washed the pack down twice and the oil keeps coming back and there is nothing leaking above it

Regards

Fatboy

[Brian_UK]

Might be a silly question Fatboy but what is the pressure within the suction header ?

If near or below atmospheric then you may not always get a good leak-bubble; does the pack shut down at all allowing the leak to do it's thing while you're not looking ?

Is there a leak towards the end of the header and the oil is migrating along the pipe via capillary action through the rust surface ?

If you make your own header then at least you will sure of the quality

[Argus]

.... Stange to relate I have come across porous steel compressor body castings.

Very rare, I'll admit, only a couple in twenty odd years on the tools, but they do exist.

They can get through a factory water tank test with a good paint job on, which wears off later.
________
Ferrari F2004 history

[Peter_1]

Bitzer has on their website some good info/technical guidelines about making headers and packs.

[chemi-cool]

Hi Mark,

Why would you use steel headers and not copper ones??

Chemi

[chemi-cool]

Hi Mark,

Fine thanks. After a week under the British weather, 22°C over here with blue sky, seems like summer


I do not agree with that method from a few reasons,

1, steel and copper expand and shrink different in temperature changes, which doe's not help.

2, Steel will have to be protected against moisture and acids more then copper.

3, Most techs do not carry steel handling tools (welders, grinders....)

5, On semihermetic packs, vibration can be eliminated by turning each compressor to a different direction. Can not be done with scrolls.

6, I like copper more, nice metal

Chemi

[Peter_1]

We already had twice a leak on the steel discharge headers of a Profroid pack.
The main reason why they use steel headers - they said this to me during a visit at Profroid Marseille - is because it is cheaper and it goes much faster to fabricate headers by welding instead of soldering.
They also have a tube bending machine to eliminate soldering, so they have to use this technique as much as possible.

I don't fully understand what you meant about insurance but we made a pack some months ago with 5 compressors and with copper headers on LP and HP.
We pressurized it on 25 bar for leak checking, so it (LP side) can withstand more pressure then never needed.

Copper the size of most headers range from 18,16,14 to 12 gauge etc.This can be of a precaution against most incidents.But dosent rule out every variable working condition and factor.

What do you mean with this Mark?

Chemi has a point that steel becomes rusted when it's wet all days.

BTW about Profroid.... some Eurovent certified evaporator and condenser manufacturers complained to Eurovent that Profroid was stating that they were Eurovent certified.
As you maybe know, Profroid is owned by Carrier and the Finncoil units - also Carrier - were Eurovent.
So Carrier stated that all their evaporators and condensers were Eurovent certified.
To stop the rumors, AIA of Sweden bought a condenser and paid Eurovent to test it independent. So Profroid didn't asked for a certification, a competitor did if for them.
The results were amazing: the given capacities of some units was exaggerated with 51%!!!
I have copies of the results from the Eurovent tests.

[Latte]

Hi Guys.

It is a hot gas system (Why use hotgas on HT Packs) ambient DF is surely more energy efficient than pumping hot gas aroung and more reliable as it cut out pipework and valves.

I have done all the usual, shutting the pack down ect to leakcheck but still nothing shows, it must be p'ing out though because even when it's all washed down and running with the suction at 35psi the leak detector on LOW still goes divvy.

I am back up there next week to do a maintainence, something i think was alien to the last contractors, oil and driers last changed in 2000, oil not moving about sytem and in poor state. We have got the contract for 3 years so the plan is to blitz everything from the start, it's going to cost but hopefully it will cut out most of the call and on a fully comp contract that will help.

I plan to add dye when i change the oil and driers so i can check it with a light to see if i can trace the leak.

I have already done the LT pack but i will take pictures before and after doing the HT pack. the difference is amazing

Regards

Fatboy

[Mark]

We already had twice a leak on the steel discharge headers of a Profroid pack.
The main reason why they use steel headers - they said this to me during a visit at Profroid Marseille - is because it is cheaper and it goes much faster to fabricate headers by welding instead of soldering.
They also have a tube bending machine to eliminate soldering, so they have to use this technique as much as possible.

I don't fully understand what you meant about insurance but we made a pack some months ago with 5 compressors and with copper headers on LP and HP.
We pressurized it on 25 bar for leak checking, so it (LP side) can withstand more pressure then never needed.


What do you mean with this Mark?

Chemi has a point that steel becomes rusted when it's wet all days.

BTW about Profroid.... some Eurovent certified evaporator and condenser manufacturers complained to Eurovent that Profroid was stating that they were Eurovent certified.
As you maybe know, Profroid is owned by Carrier and the Finncoil units - also Carrier - were Eurovent.
So Carrier stated that all their evaporators and condensers were Eurovent certified.
To stop the rumors, AIA of Sweden bought a condenser and paid Eurovent to test it independent. So Profroid didn't asked for a certification, a competitor did if for them.
The results were amazing: the given capacities of some units was exaggerated with 51%!!!
I have copies of the results from the Eurovent tests.

Peter
Iam not able to visit profroid and ask them myself.I was informed that as standard the headers are copper unless specified by the customer.So if you are correct i have learnt something out of this discussion

Copper the size of most headers range from 18,16,14 to 12 gauge etc.This can be of a precaution against most incidents.But dosent rule out every variable working condition and factor.

What i mean peter is that whatever step we take to prevent as far as practible acts of god LOL.S*it happens.

Best regards.Mark

[Mark]

Hi.Ray

If you have a substantial leak as explained then you should be able to pinpoint it.

Me personally havent had the need to add dye to a system,but i will never say never.

Alot of hot gas packs suffer from oil weapage from the hot gas isolation and solenoid valves,when on defrost.Seal/repair kits are nearly as much to buy as complete valve assemblys and most makes are still available.

Linde packs are notorious for having oil starvation problems.Cant remember what linde recommend to set this too,25 psi above Highest suction pressure??,the problems may be elsewhere.

[chillyhamster]

Simple answer.. Steel was used to manifacture suction headers as it was a cheaper option ( stupid idea called value engineering from a buyer who is not an engineer). Steel / iron headers rust and become porus if the header is contantly wet. A copper header will not corrode to the same effect but can suffer microscopic fractures due to thermal expansion / contraction associated with gas defrost systems. If the header is copper then you can float silver solder over the fracture (old enough not to come under PED), if its steel quote to replace with copper, Beacon or DCI can supply.

[chillyhamster]

rdocwra,

Hot gas was used on lind'e packs built in germany as the Ht case evaperating temprature was -12 to -14 deg C in the meat cases. This requires assisted defrost. Current crop of cases evap at -6 to -8 deg C to achieve the same shelf temps so do not need assisted defrost.

[aus-bound]

Hi Guys,

I Have read on previous posts that engineers have come accross pipework leaking THROUGH the pipes due to lack of copper in it. Well this week i have come accross something similar.

Linde Pack (OLD)!!! running on R22 and the suction header tank is leaking like a sieve. Done all the usual, covered it in soap solution but doesn't show anything up but put a leak detector anywhere near it and it goes divvy.
Cleaned all the oil off of it but the next morning when i went back to site it was covered again.

I have spoken to another engineer has he has said he has heard of this before on suction headers.

Anyone else out there come accross it, whats the answer. obviously the pack has to be shut down and reclaimed as its leaking (Montreal) but do you make up your'e own, order one from the manufactures if still available. The header has 12 stubs coming out of the top

Regards

Fatboy

Had the same problem twice now, both at scabby co-op stores no matter how much pressure we put into the header we never could get it to bubble anywhere, but as you said running at normal pressures leak tester was going daft all along the header. In the end i think we had a local engineering company make up new headers (from steel again) and replaced them, i think we may even have had them enamel or zinc coated and then insulated. Never had anymore problems from them the last i heard.

[Latte]

Hi Aus-bound,

Thorne !!!!!!.

Looking at your'e location this will mean something to you !!!

If so PM me


Regards

Fatboy

[Comms1]

Hi Fatboy

I've worked on several Linde R22 packs myself and had the same problem.
The cause is normally a fine hairline crack in the header which can be hard to pin point or the silver solder joint where the Suction service valve connects.
For our client we have been replacing with copper header's.

Regards

Comms1