help fix a catering fridge

[nwb77]

hi forum,
I'm not a fridgie but I want to fix a williams pull out unit type fridge that a mate of mine gave me -cos it has a leak.

I'm experienced in oxy-acet brazing , and many types of copper pipe joinery, I also have and air compressor with an inlet that can pull to 0.05 bar, access to a 13 kg 134a cylinder, and a set of scales accurate to 50grammes, along with all the usual 1/4 inch guages and hoses).
I know from the manufacturer that I need to charge it with 250g of 134a, but what I dont know is how to go about finding the leak!
Last point :- I dont have access to OFN but do have welding argon/co2 cylinders for possible use for purging.
question: what is the best way to tackle this problem?

I thought about cutting both high an low pipes from the compressor (and capping the open pipes with glass putty) the removing the entire circuit which needs a good clean to an open area where i can cover it in foam and pressure test it.

What I dont want to do is cut any capilliary tubes and am concerned that one of them is concentric to the main compressor out line.

hope someone understands this scenario and can help.
thanks adrian.

[bobdaniels]

leave it alone get a fridge engineer you really do not know how dangerous you are !!

[LRAC]

Another wanabe, if you do any repairs top up your life insurance cover.

What a plonker

Lrac

[nwb77]

sorry chaps, I obviously touched a raw nerve there.

Here's the deal. Nice piece of industrial machinery about to get turned into recycled steel because guys like you charge more than it's worth to fix.

Guy like me who has studied chemistry and physics longer than your average mr NVQ sees an opportunity to save some money and put another DIY project under his belt.

If you can't give an explanation of *preciseley* what is 'dangerous' here, you're obviously as clueless as I am when it comes to refrigeration.

o.k. anyone else here seen one of these units and know how the tubing is arranged? thanks in advance.

ad/ :rolleyes:

[Gary]

Can you do it yourself, given sufficient guidance? Yes, but then you are not really doing it yourself, are you? You are simply going through the motions while someone with the requisite knowledge/experience pulls your strings.

A true dedicated DIYer would want to acquire the relevant knowledge before considering the project "under his belt".

I recommend a trip to the library.

[The Viking]

Adrian,

Don't listen to them.
Of course you can do it yourself..

This trade is too short on engineers.

First you find a friendly fridge guy in your neck of the woods, then you ask him if you can start as an apprentice with him.

After a couple of years you should have the knowledge needed to repair your Fridge and after 5 years you might be able to sell your services to other end-users.

Sorry M8, but you really are outside the scope of DIY here.
:cool:

[chillin out]

Last point :- I dont have access to OFN but do have welding argon/co2 cylinders for possible use for purging.

Are you thinking of purging the system with oxygen or argon?

Chillin:) :)

[taz24]

hope someone understands this scenario and can help.
thanks adrian.


Hello Adrian.

The repair you are contemplateing is a normal every day repair for a quallified and experienced engineer.
You on the other hand do not have the right equipment to complete this job correctly.
Your compressor that pumps to o.o5 bar is now running on air and they dont like that.
To pressure test somthing we use OFN because it is inert and DRY.

I personaly think its ok if people play with fridges, AS LONG AS THEY HAVE A REASONABLE UNDERSTANDING OF THEM.
You seem to understand the principles but are not prepared to listen to good advice.
If you want to try repairing this fridge climb down off your high horse and listern to others.

taz.

[nwb77]

Aw come on viking, I'm not not trying to fix a 3 phase vrv aircon unit.

Did you want me to go to technical college for 2 years when I changed the master cylinder on my car braking system or replaced the shock absorbers from the coil springs when the Haynes manual gives clear instructions? (both potentially far more deadly than said tackling of small fridge)

Anyhows I'll break down the reasoning:-
Is welding gas as pure and dry as OFN? instinct says yes it is otherwise weld joints would be compromised, but I'd double check that with the suppliers cos no one here would need to try that if you've all got BOC accounts.

If I fix it with my not quite so perfect Improvised vac pump and end up with a circuit of roughly 95% vacuum and 5% argon, then recharge, will the fridge blow up soon after? One look at the periodic table says no, (Noble gas+ Flourocarbon or Polyalkylene glycol = boring house party).

If I'm over or under by 17% with the recharge due to my +/- 50g accurate scales...will anything rupture or implode? Nope.

Will the combination of the above result in a non optimally performing fridge? possibly, but by the time I have another go at it I'll need a safe handling certificate and at that point you fridgies have got a job.
(in fact you still probably wouldnt want it cos the condenser tray pan thing at the bottom is caked in an inch of grease)

and a bit more respect to us amateurs please, maybe a newbie forum is a good idea so we can be baited fairly and according to set rules.


ad/

[The Viking]

Good Luck.
I hope it will work out for you.


"You can lead a horse to water, but you can not force it to drink"

Or maybe:

"give the benefit of your wisdom, if they do not listen, they will learn through adversity."

[mr cool]

seriously mate dont do it. fridge systems can be so badly damaged by contaminants it is unreal eg the oil in your comp has probably absorbed so much moisture from the air that has got to it it will need a very long vac to make it usable. it is a capillary system too so any particle contaminates will block the capillary line and it just wont work, let alone the rules regarding the handling/ useage of refrigerants. please dont do it. and as for using air/ oxy to press test it is increadably dangerous. an engineer died through decapitation because he press tested using oxy, that was recently and it was oxy in a nitrogen cylinder!! for your own safty i strongly recommend you to leave it be.

[Abe]

Nwb 77

Fridge is a black science.......
Its magic.

Its one of those strange things in life, A Science degree wont help you

Plumbers have tried......
Sparkies have tried.......

Fridgies are born.........not made.

Hence, no disrespect, leave it alone.
Get a guy with the " passion " to sort it.

:)

[taz24]

Anyhows I'll break down the reasoning:-
Is welding gas as pure and dry as OFN? instinct says yes it is otherwise weld joints would be compromised,


Hi Adrian.
I'm one of the sympethetic engineers who gives advice to inexperienced people who want to play with fridges.
Somtimes other posters on this group have complained about the advise given to non experienced.
I tend to judge people individualy and try to advise sensibly to their situation.

I'm starting to worry about you now though.
You have an aragance about you and a disdane to any advice that disagrees with you.

Play with fridges if you wish but please and I do repeat this PLEASE DO NOT PRESSURE TEST WITH OXYGEN.
Their are lots of ways you can hurt yourself in this world and one sure fire way is when you play with compressed oxygen in a contaminated environments.

Climb down of your high horse, stop looking for data to prove your right and listen to a bit of simple advice.

taz.

[ginzo]

Get a qualified fridgie and save some costs you might incur from trial and error. You need to understand refrigeration and fault finding techniques before cutting pipes and breaking into systems (It could be a simple schreader valve leakage). Besides you just cant use any equipment, including gases, just because they are available for your maintenance. Refrigeration is not a DIY trade that you can pick up any part at B&Q and get it over with. I'm just not happy on how you undermine fridgies and I know they can fix it in a minute. But to you with all your physics and chemistry I would kindly suggest you rob a bank....you have a better chance of surviving.

[Gary]

http://www.refrigeration-engineer.com/forums/showthread.php?t=1914

[Brian_UK]

Spot on Gary ;)

[Abe]

Good to see you posting again Gary.
You looking well....

:)

[Gary]

Thanks, Abe... nice to be back.

[fridg]

have a look at this video , this is an engineer , and he got it wrong.

and you want to attempt to do this with very little knowledge.




http://www.youtube.com/watch?v=DjtowzVzl_4

[Andy]

Good to see you posting again Gary.
You looking well....

:)

my very thoughts:) nice to see you Gary:)

Kind Regards Andy:)