Gas Leak!

[Chunk]

Hi all.

For the past 2 months i have been losing a 50 kg cylinder of r404a in one of my supermarket stores on average every 4 days from a h/t pack with 28 cases and 6 coldstore blowers.

As usual the first thing to do is give the whole system a leak test with my electronic leak detector and surprise,surprise could`nt pick up anything.
Now not being one to whack a load more gas in and hope for the best,and by going by the gas leaks i`ve had in this store since it opened 7 years ago,i arranged to have all cases emptied so i could access valves and coils.
NOTHING not a whiff.All pipework is accessible,leak tested everywhere and got nothing.

So i arranged for a pressure test,which i did over 2 weekends and having not lost pressure on any pipework i decided to pressure the cases even though i was told not bother as i had not picked up a leak with my detector.
4 lads spent all night cutting all evap coils out of cases and pressured each one with 200psi of ofn only to find not one dropped any pressure.

By now i`m getting a bit puzzled as to where this gas is going,even the gas detection system was clear.

So long story short i have spent all friday night and all saturday night cutting the coils out again,but this time i added some refigerant to the ofn and repressured,this time we found 3 coils p**sing out.
So to prove a point we just pressured back with ofn and it didnt leak.

My point is with these f-gas regulations are we not allowed to pressure test like this(gas/ofn mix)as the only way to empty the coil is to blow it off.

And be carefull when leak testing with d-teks and tec-mates detectors as it seems they can only pick up anything that isnt r404a.

[Tesla]

Hi ChunkyMonkeyI read in a book which showed the ASHRAE guidelines, to pressurise system to 15 psi with R22 as a trace then the rest with ofn. Could be old info. Good to see you regulary on this forumTesla

[The MG Pony]

Unfortunetly Tesla this is Banned both in the Uk and Canada, and can only be don with R-134a on automotive gear.

[Chunk]

Hi guys,Thanks for the replies.

The problem i have is that these gas leaks can only be found when cases are on their defrost cycle and when the evaporator has sufficiently warmed up(taking around 15 minutes)and then they start to leak as the pipework expands.

Now when i lose gas,i have to put 28 cases onto defrost for 15 minutes and try with a special leak detector to find and pinpoint leak.Bearing in mind i work for a company with about 100 engineers and we only have one of these detectors:mad:.

Does anyone else have problems trying to detect r404a gas leaks?

P.S I always seem to be replacing my charging lines as after a few uses this gas seems to cause perferations in them.

[bernard]

Hi

I find the D teck and teck mate very good,try new batteries and new tip.We have a lot of them in use with great results.When I have a leak like this I would firstly switch of the pack to allow the suction pressure to build up, then leak test or make a list of all the cases and stick them on a defrost 2 at a time then tick them off as you go.This can be done over a few days if need be.

Regards Bernard

[Chunk]

Thanks Bernard.

As part of our new initiative with js we have to attend a different store each day and we have to leak test everything DAILY and it seems that these sensors lose their efficiency very quickly with 404 and no-one wants to keep paying for them,which is nice.
This roughly equates to 20 hours a week leak testing and we are told that a sensor should be replaced every 40 hours.

This is my companies policy not js so they only have themselves to blame when we have not got the tools to do the job.

[Kp3]

you not thought about puttin uv dye in the system. works well

[Chunk]

Yeah i have but they wont pay.Which brings me to a funny story.

A few years back another engineer wanted some dye and the company refused to buy it as it was deemed too expensive,so we all forgot about it.....

...until a week later when we started to get moisture problems with the said system and that engineer was on holiday.
I removed pack driers and found they were pink.Upon further investigation i found a bucket hidden in the corner containing 2 small bottles of food colouring that must have slipped into the pack.Nice 98% water.

[Grizzly]

Yeah i have but they wont pay.Which brings me to a funny story.

A few years back another engineer wanted some dye and the company refused to buy it as it was deemed too expensive,so we all forgot about it.....

...until a week later when we started to get moisture problems with the said system and that engineer was on holiday.
I removed pack driers and found they were pink.Upon further investigation i found a bucket hidden in the corner containing 2 small bottles of food colouring that must have slipped into the pack.Nice 98% water.

And I thought the only thing in fridge that was pink,

was some of the gas cylinders of the newer refrigerants.

Or as was refereed to me recently by another "stinky"

Girly Gas because it comes in Pink Cylinders!

If it's any help you are not alone Chunky the newer gasses are a nightmare to find.
And most electronic detectors go off if you blow on them!
Cheers Grizzly.

[Brian_UK]

I don't work on cases so forgive my thoughts if they are way off...

If, assuming that the cooling air is drawn/blown over the evaporator and some pipework could a sensitive leak detector be used by simply putting it in the air stream? Or is this what you do now?

No doubt some of the pipework would have to be checked separately, but.........


I'll get me coat...;)

[Chunk]

Hi Brian

Yes normally the first thing we do is run a leak detector across the air off vents in the cabinets,which was great when working with r22 and r408 as these gasses were easily picked up by our detectors.

The problem we are facing now is (in my opinion) that r404 is extremely difficult to pick up unless its hammering
out,the sensors dont last as long when detecting 404.

We`ve invented a new way of leak detecting,if you lie down in the case while its on defrost for 30 minutes,and you can get out and walk in a straight line,you know that one don`t leak.

[bernard]

Thats ok until some old biddy comes looking for some meat and two veg LoL,your scream would sound like a leak detector with a huge leak.plus the heat from your body would terminate the defrost far two quickly.Try standing in the freezer coldroom for half an hour prior to this.


Regards Bernard:D

[Chunk]

HaHa i wont mind,anything to brighten up winters day.:)

[BobbyDazzler08]

Hi All,

The company I work for manufacture and install refrigeration counters (butchers, deli's, bakers, farmshops) etc ..... We will not be undertaking leak detection tests for our customers, instead we are looking to appoint either one or a number of companies who can cover the UK that can carry out the required leak detection tests annually/bi-annually. We would simply recommend these particular companies to our clients. Whatever the charge is, we would discuss any introductory values at a more pertinent time.

My question is, is there anyone out there that carries out these tests and doesn't simply supply either the equipment or software?????

Any pointers would be gratefully appreciated.

For the record we work throughout the UK.

Many Thanks

Bobby D

[The MG Pony]

Any well equipped Outfit can do that, no special leak detecting contractors out there that I know of.

[BobbyDazzler08]

Hi MG,

Any well equipped refrigeration engineers presumably. Wasn't too sure so thought i'd ask. Easier to use a forum rather than spend hours trawling the WEB.

Many Thanks

Regards

Bobby D

[paul_h]

Ha Ha, you make it and install it and take the big $$, but want some for sucker to do all the leak detecting? If you haven't got the purpose of this thread, it's about how big a pain in the arse leak detecting is!
Seriously, I'm kidding :)
But if you read enough in this thread you'd also know that manufacturers and supermarkets owners pay stuff all. Are you saying you will not be doing any leak detecting on first install?
I don't think anyone would be too interested in picking up the crumbs and inheriting problems unless you are offering good money, and you do the install well and do an initial check. I don't think any large companies have the staff to cope with the rate they are folding in the UK ;)

edit, nice user name. It reminded me of the pub in perth frank posted about in a different thread, where he had the ale in perth which is openly brewed in the basement is bobby dazzlers, and the beer was nail ale. I haven't been there in 3 years since my $750pw mortgage started :(

[australian tech]

what was the outcome chunky,was it leaking evap coils ? is there pressure relief valves on the system , could they be compromised when in defrost. ps.great avitar, looks like my dad..tee he...

[Chunk]

Hi Australian Tech.

Yeah it got sorted eventually,i did put it in one of my posts above.

We had 3 evap coils with fractures that only showed up when coils were warm enough.

Just found out this store is due for a refit shortly so will get rid of all the tat.

Found out recently that when they had their last refit,the cases were second hand and were originally on an r22 system,then modified for r404,i`m pretty sure this is what caused all these problems.

Its been gas tight for 3 weeks so fingers crossed.:)