Disolved copper pipe!

[monkey spanners]

Got called out to a maggot store today, the system had a stainless evaporator but the copper expansion line had rotted through. Replaced a section of liquid line and equalising line also.
Now to the question, does anyone have any suggestions for preventing it happening again? Was thinking of that 'denso' tape, but have never used it.

Cheers Jon

[Grizzly]

Got called out to a maggot store today, the system had a stainless evaporator but the copper expansion line had rotted through. Replaced a section of liquid line and equalising line also.
Now to the question, does anyone have any suggestions for preventing it happening again? Was thinking of that 'denso' tape, but have never used it.

Cheers Jon
Hi Jon.
If I remember from my coarse fishing days, don't maggots produce ammonia based poo?
If they did is this why the pipework rotted?
If so then you would probably succeed in insulating
the copper pipework with denso tape. A very messy job though as it's an extremely tacky hessian based tape. The compound it is soaked in gets everywhere.
But it does seal and is waterproof.
An alternative may be the yellow tape that you can purchase from a plumbmers merchants. Designed to seal ordinary copper pipe before sinking it in a solid concrete floor. The lime in the concrete also attacks copper. The yellow is just so that it is highly visable also cheaper than buying the yellow coated gas pipe.
Provided you tape it tightly you might even get away with ordinary Electrical insulation tape.
After all I assume that you are only creating a vapour resistant seal.
Or have I got completely the wrong end of the stick?
cheers Grizzlyhttp://www.refrigeration-engineer.com/forums/images/icons/icon14.gif

[nike123]

Got called out to a maggot store today,

I am just curious, what is purpose of such store?:confused:

[Latte]

Hi all,

Am having the same sort of problem with some upright fridges. They are all in the same pub chain, the sites use these fridges to store sauces and after a year the evaps begin to rot and the pipework goes green.
i assume its something to do with the acid in the sauces.
has anyone come accross this before and is there a solution, possibly some kind of spray to put on the evap when changing them.

Regards

fatboy

[Plank!]

there was a similar thread recently - something about "ant nest corrosion"
The organic acids secreted by the ants destroy the copper at a molecular level.
I think there was a link to some technical papers, may be worth searching for it.

Steve

[Grizzly]

Just a outside the box thought guys.
But would not the plastic spray that waterproofs ignition (ht) leads do the trick.
Worth a try and easy to apply.
Grizzly

[monkey spanners]

Hi Grizzly,

Yeah its the ammonia from the maggots thats eaten the copper, forgot to mention it:rolleyes:
Hopefully it won't be me tapping it up as i was covering for a mate who's on holiday:)

nike123,

The coldstore was in an angling shop, the maggots are sold live for fishing.

fatboy,

Have seen the same thing with a fish fridge, all the aluminium had gone to dust too. I think Advanced engineering do a condenser spray coating kit, don't know if it suitable for evaporators, thinking about it that may work on the pipework i'm on about too, cheers:)

Jon

[nike123]

Hi Grizzly,

Yeah its the ammonia from the maggots thats eaten the copper, forgot to mention it:rolleyes:
Hopefully it won't be me tapping it up as i was covering for a mate who's on holiday:)

nike123,

The coldstore was in an angling shop, the maggots are sold live for fishing.



Here in Croatia, for fishing, we use sea worms, and they are excellent when stored in jar with salt on sun for few days. So, you could see, why I ask this question.
[/quote]

[Brian_UK]

I am just curious, what is purpose of such store?:confused:Maggots are kept at a set, cool, temperature to prevent growth into flies for use by fresh water fishermen to use a bait.

edit: Seen answer included above but hey, I've written it now ;)

[nike123]

Thanks, I am sure that I have all needed informations now! ;)

[Abby Normal]

adsil, heresite , electrofin, bronzglow

[WCC73]

Bait coldrooms and mortuaries.Probably the two worst breakdowns you can have. Both can be a bit whiffy and i always have the desire to go home for a shower and change as the smell seems to linger.
God I love being a fridgy!!

( for the attn of any kids out there. Try hard at school, do your homework, get a degree and then you wont suffer the ****e that we engineers have to on a regular basis)

[Grizzly]

Bait coldrooms and mortuaries.Probably the two worst breakdowns you can have. Both can be a bit whiffy and i always have the desire to go home for a shower and change as the smell seems to linger.
God I love being a fridgy!!

( for the attn of any kids out there. Try hard at school, do your homework, get a degree and then you wont suffer the ****e that we engineers have to on a regular basis)
WCC73.
If you check out my link Cold Store Cons in the chit chat & stories section. You will find that a lot of the guys have been there to.
Grizzlyhttp://www.refrigeration-engineer.com/forums/images/icons/icon14.gif

[Eski]

I have used Denso tape before to wrap Chilled water valves that were rusting in a high humidity environment. First, I had to apply the primer, a grease like substance, all over the valve. Then I had fill in any gaps and smooth off any edges that might tear the tape with a denso paste with the consistency of clay. And then finally the tape was put on covering this concoction. These valves are still sweating and the denso tape is not an insulator however it has stopped the rusting.

[monkey spanners]

Cheers Eski,

I'll try our local Pipelinecentre as they sell the tape. Sounds like we could wrap the tev as well as its brass bodied and will no doubt go the same way as the pipework.

Jon

[Brian_UK]

Just one thought MS, how about self-amalgamating tape for wrapping the pipework ?

[monkey spanners]

Cheers Brian,
Got a call from them today (company i was subbying to) as the controler has gone wrong and frozen all the maggots:confused:. Hopefully thier engineer will be back from holiday before any pipe covering gets done:p

Its one of those when you think if i'd put it in when new i'd have done it differently;)

Jon

[The MG Pony]

What about conformal coating, the type used on electrical circuit boards? You can get spry on cans and it is very resistant to near every thing, or even a ultra thin coat of Varnish?