Walk-in freezer + multideck problem, please help!

[Johnny Walker]

Hi,

I have a faulty walk-in freezer in a shop, haven't inspected properly yet, I just kind of want to prepare myself for the possibilities.
Symptomps are: About 12.5 bar pressure in both suction and discharge line while compressor is running. No signs of evaporator getting colder or condenser warmer, sight glass is clear, no signs of liquid.
Is it a faulty expansion valve? Or can it be compressor fault? What is the method of fault-finding?

Other issue: 2 Multideck just don't want to go below 8-9 degrees. I suspected that its because of poor ventillation, so we put extra fans behind and more space from the wall. It went down a littlebit but not good.
Suction line pressure is 4.2 bar. What should I check on them? What would be the correct pressure?

Any ideas please?

[chillerman2006]

Problem 1. about 12.5 high and low side probaly nitrogen in system not refrigerant, + no pressure change when running = compressor is not pumping

You need to call an engineer

[Johnny Walker]

Should the pressure change when its filled with nitrogen?

[chillerman2006]

Yes

I could go into detail but I will not apart from confirm the obvious

reasons

1. I'm doing a fellow engineer out of work feeding you info

2. (most importantly) leave it alone before you hurt yourself, if thats nitrogen and that compressor had worked your pipework or part of the system could have burst

Its all well and good helping someone build a coldroom but not to work on a system

[passandscore]

If your suction pressure is about the same as your discharge then you could have a broken
crankshaft, broken valves or a leaking pressure relief valve. The compressor may run smooth if
the crankshaft is broken. A compressor valve check can be done by pumping the compressor
down. If it will not pump down, or pumps down slowly, one or more suction valves may be bad.
If the compressor pumps down and off but the pressure on the suction side rises rapidly, one or
more discharge valves are bad, the pressure relief valve is leaking, or you have a blown gasket

http://www.brainerdcompressor.com/_pdf_files/Why2.PDF

[chillerman2006]

If your suction pressure is about the same as your discharge then you could have a broken
crankshaft, broken valves or a leaking pressure relief valve. The compressor may run smooth if
the crankshaft is broken. A compressor valve check can be done by pumping the compressor
down. If it will not pump down, or pumps down slowly, one or more suction valves may be bad.
If the compressor pumps down and off but the pressure on the suction side rises rapidly, one or
more discharge valves are bad, the pressure relief valve is leaking, or you have a blown gasket

http://www.brainerdcompressor.com/_pdf_files/Why2.PDF

have you read the 12.5bar and fact this fella is not an engineer

[Johnny Walker]

Yeah, you know, I've seen your "fella" working on our refrigeration..
Once:
-Compressor changing, no access valve:
-Cutting off end of the pipe, 1.5 kg of fefrigerant (R404A) goes to the atmosphere... good advice: put gloves on the fire alarm, it might start the system.
Another:
-Regassing a chest freezer, no access valve.
-Fellas solution: cut off pipe ends, 0.8 kg of R134A goes to the atmosphere.
-My question: Isn't it harmful for the health or something?
-Solution: We can pull it out to the air.
I just said leave it, but felt really wrong.

After that, I've done my C&G 2079 in category 1 with 90% passing mark. Since that I have installed a walk-in fridge+freezer and changed a seized compressor. Once I stripped down a huge walk-in and regassed a lot of them successfully. Never ever in my life reliesed more than the allowed level of refrigerant to the air (remaining pressure in an equalised gauge), storing and keeping track of every gramm of refrigerants I have, including rubbish, recycled and new.

By the way, the fella who I was mentioned, working for a huge 100% British firm, covering all London, 20 years in the industry. Don't even want to imagine how much damage did they cause for our planet...They charged £1500 for changing a compressor and min.£200 for regassing, depending on the amount of refrigerant the system needed.

I know that you are trying to keep the secrets what you have learnt in so many years in school, and then practised in the industry, but it doesn't mean that without 4 years of higher education you have no chance to learn it by your own initiative. Considering that I have already have a higher engineering diploma in electrical and mechanical engineering.

I was hoping that you guys can make it easier to learn, and do quality job instead of what I've seen in practice, but all I can see here is huge concrete walls, no real help.

Thanks for reading, if you did. Sorry for my accent, I'm working on it.

Attila

[Johnny Walker]

Sorry, Mr. Mighty Engineer. Thank You.

[chillerman2006]

Sorry, did not mean to offend was just looking out for your safety

we have had the discussion about 2079/J11 many times now and the conclusion is they may as well give them out in xmas crackers

If you could not work out what equalised running pressures are you have NO 2079

[Johnny Walker]

By the way, thank you very much for the information. I will study in the meantime and will try to figure out what happened.
I hope that you don't think that these informations shouldn't be shared with starters like me.

[Johnny Walker]

Ok, I'm sorry as well, I didn't want to offend you.
I was just scared of writing anything because of answers like this.
You know, its pretty hard to learn these things in a foreign language.
I just want to make everything sure.

[chillerman2006]

I have no problem helping any engineer what ever there level

Your original post clearly shows that you chanced running a system that could have caused you harm

Best thing you can do is recover the refrigerant and pressure test with oxygen and check for leaks, when you have done that come back and I'll talk you through all the other not to do's

[Johnny Walker]

I have chanced runnining the compressor, because it was attached together with a fridge, it was live, switching it on was just a touch of a button. If its filled with any other than refrigerant it should be marked and switched off. But now I know I should'nt, you're right. And I won't.

Tomorrow I will evacuate and have a closer look.
Thanks

[Gary]

:(have you read the 12.5bar and fact this fella is not an engineer:(

If we don't know what refrigerant is in the system, then the 12.5 bar is meaningless.

[chillerman2006]

If we don't know what refrigerant is in the system, then the 12.5 bar is meaningless.

It will be either, R22, R404a or a refrigerant of similar pressure

Holding charge of nitrogen is only suspect

[Gary]

Setting aside the possibility of R410A, given R22 or R404a (R507?) the 12.5 bar could conceivably reflect the ambient temp... or even high indoor temp.

[Gary]

Hmmm... maybe it's stuck in electric defrost mode?

[chillerman2006]

Setting aside the possibility of R410A, given R22 or R404a (R507?) the 12.5 bar could conceivably reflect the ambient temp... or even high indoor temp.

I can see what your thinking here mate just you will not find R410a in a counter over here and unfortunatly for us we dont have your glorious Florida weather

The norm here is 22 or 404

[Johnny Walker]

Its 404A. Both the mul;tideck and the walk-in freezer as well.

[Johnny Walker]

Well, actually I was reading back, and I realised that oil coming from the service valve indicates a compressor fault.
This is exactly what happens, a huge amount of oil coming out when I'm connecting or disconnecting the gauge...

[monkey spanners]

A low run current can also point to a compressor thats not pumping,

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

I have two units side by side so am comparing a good one with a bad one, high side gauge is actualy on the suction of the good comp.

Jon :)

[Tayters]

Best thing you can do is recover the refrigerant and pressure test with oxygen and check for leaks, when you have done that come back and I'll talk you through all the other not to do's


Doh!

Or was that a test. :-)

[mad fridgie]

Doh!

Or was that a test. :-)

No, a method of making a bomb!

Blow the coldroom up, no more problems

[mikeref]

No, a method of making a bomb!

Blow the coldroom up, no more problems
Thought my eyes were playing tricks on me but..NO.. there it is in black and white:eek:. Lets NOT use oxygen for pressure testing..Mike.

[chillerman2006]

I think the best thing to do when Joe Public come on here making claims that appear to be false is to contact the regulators and let them deal with it

If we dont start police-ing the industry ourselves, there will never be any improvement

F-Gas Support their number is = 0161 874 3663

[Johnny Walker]

I am happy to show my certificate to anyone who wish to see.
I've done it in Ellis Training, took 1 week.
Actually this reflects to the problem: in 1 week I'm not gonna be a refrigerator engineer, and I don't really want to be. I am maintaining equipments and I want to be able to fix fridges for the company who I work for.

I am able to handle refrigerants in a safe way, and thats important.
And want to learn as well.

[mad fridgie]

I think the best thing to do when Joe Public come on here making claims that appear to be false is to contact the regulators and let them deal with it

If we dont start police-ing the industry ourselves, there will never be any improvement

F-Gas Support their number is = 0161 874 3663

It would seem the JW has got his cert, and good on him, but it shows what a mockery simple courses make of our industry.
There is nothing wrong with learning and everybody has to start somewhere. How much support we give does depend upon how you see each question.
In this case i do think the cart is before the horse, and that JW should perhaps work with others first, instead of jumping in feet first!

[chillerman2006]

.
Actually this reflects to the problem:.

Your quite right it does, it reflects the problem with the new F-Gas Certs

Anyone can get one and as I posted previously they should give them out in Xmas Crackers

From your Original post it clearly shows, you are a danger to yourself and should not be working on equipment unsupervised

This is not a direct dig at you but more so a dig at the state of the industry and the incompetance that is being allowed in

It is absolutely ridiculous that a training course is available that allows individuals to gain a qualification in one week, deeming them competant when they clearly don't have a clue

[chillerman2006]

Atilla

I'll show you mine if show me yours:D joke

I can not be that far from you and if you like,

Send me a private message with a contact number and this Saturday I have nothing better to do, so if your buying lunch I'll come down for the day and guide you through as much as I can

It's only 1 day, but at least its 1 day more than the week you've had and you never know we might both learn something

[Johnny Walker]

Thank you.
I will send you a private message as soon as I have some time to write.

I'm really sorry about the bad introduction, I didn't meant to be rude...

[chillerman2006]

Thank you.
I will send you a private message as soon as I have some time to write.

I'm really sorry about the bad introduction, I didn't meant to be rude...

No problem

You cant get ruder than me once I'm off

Look forward to hearing from you

[Gary]

Your quite right it does, it reflects the problem with the new F-Gas Certs

Anyone can get one and as I posted previously they should give them out in Xmas Crackers

From your Original post it clearly shows, you are a danger to yourself and should not be working on equipment unsupervised

This is not a direct dig at you but more so a dig at the state of the industry and the incompetance that is being allowed in

It is absolutely ridiculous that a training course is available that allows individuals to gain a qualification in one week, deeming them competant when they clearly don't have a clue

As I understand it, this is a material handling certificate and nothing else. It's intent is to qualify people to purchase and transport refrigerant... and nothing else. So... why does it take a weeklong course? During that week, they teach people just enough to be dangerous. They should be teaching people how to transport refrigerant from point A to point B... and nothing else.

I have no problem at all with teaching refrigeration to anyone who wants to learn... but it should not be part of the material handling certification training.

[Gary]

Best thing you can do is recover the refrigerant and pressure test with oxygen and check for leaks, when you have done that come back and I'll talk you through all the other not to do's

Speaking of teaching people just enough to be dangerous...

I understand this is a joke, but someone may take it seriously. We should probably refrain from killing people... not funny.

[Gary]

I am happy to show my certificate to anyone who wish to see.
I've done it in Ellis Training, took 1 week.
Actually this reflects to the problem: in 1 week I'm not gonna be a refrigerator engineer, and I don't really want to be. I am maintaining equipments and I want to be able to fix fridges for the company who I work for.

I am able to handle refrigerants in a safe way, and thats important.
And want to learn as well.

Start here:

http://www.refrigeration-engineer.com/forums/showthread.php?19701-Refrigeration-101

[chillerman2006]

It's intent is to qualify people to purchase and transport refrigerant....

There's alot more to it than that

Incuding

BS EN378 2008
Montreal Protocol
Kyota Protcol
Pressure testing
Strength testing
Charging
Recovering
SCT/SST
Superheat
Subcooling
Brazing
earths atmosphere
Electromagnetic + Ultraviolet radiation
COSHH
Health & Safety at work Regs 1999
Institute of refrigeration - Code of Practice
Leak detection
PPE

[chillerman2006]

Speaking of teaching people just enough to be dangerous...

I understand this is a joke, but someone may take it seriously. We should probably refrain from killing people... not funny.

Joke - of course

From the above list you can see that in order tobe legal in the UK/EU you have to pass and prove compentent to carry out pressure testing

If you can not, you fail and in affect are breaking the law by working on the system...

How's it work your side of the pond ?

[Gary]

Actually this reflects to the problem: in 1 week I'm not gonna be a refrigerator engineer, and I don't really want to be. I am maintaining equipments and I want to be able to fix fridges for the company who I work for.


Make up your mind. Do you want to maintain the equipment or fix it? If you want to maintain it, you should not have a set of gauges. Maintenance is limited to the air side of the system.



While we are on the subject, it is my belief that apprentices should demonstate a very high level of expertise on airflow problems over a long period of time before they are allowed to use gauges. I have seen waaaaaaay too many people put gauges on the machine before checking for airflow problems. I just want to reach out and smack them, while screaming in their ear, [b]"CHECK THE AIRFLOW FIRST, STUPID".

[/end rant]

[Gary]

Joke - of course

From the above list you can see that in order tobe legal in the UK/EU you have to pass and prove compentent to carry out pressure testing

If you can not, you fail and in affect are breaking the law by working on the system...

How's it work your side of the pond ?

About the same. We have our fair share of idiots on this side of the pond, too.

[Emmett]

I have no problem helping any engineer what ever there level

Your original post clearly shows that you chanced running a system that could have caused you harm

Best thing you can do is recover the refrigerant and pressure test with oxygen and check for leaks, when you have done that come back and I'll talk you through all the other not to do's

Please tell me the oxygen comment is a joke!!

[chillerman2006]

Joke - of course

Just to make clear to anyone not qualified

If you attempt to pressure test with OXYGEN YOU PROBALY KILL YOURSELF

[Gary]

There's alot more to it than that

Incuding

BS EN378 2008
Montreal Protocol
Kyota Protcol
Pressure testing
Strength testing
Charging
Recovering
SCT/SST
Superheat
Subcooling
Brazing
earths atmosphere
Electromagnetic + Ultraviolet radiation
COSHH
Health & Safety at work Regs 1999
Institute of refrigeration - Code of Practice
Leak detection
PPE

Clearly, it's all about propaganda... that's fine. Keep it about propaganda and stop teaching people to install gauges.

[coolhibby1875]

this has to be the most pointless thread i have ever read

[chillerman2006]

this has to be the most pointless thread i have ever read

Yet..You choose to join in and keep it going :rolleyes:

[Gary]

this has to be the most pointless thread i have ever read

And your point is... ??????

[Johnny Walker]

Just to finish this thread:
The problem is solved. After measuring the multideck it had a high subcooling and low superheat so it was slightly overcharged. It had only suction valve so we had to remove all the refrigerant (R404A) and recharge it. It works fine.
(And finally I learned how to regass properly and what to look for when taking measures as they don't really explain things on short courses...)

The freezer's compressor is burnt, the oil smells terrible...
A new compressor alone would cost £650 while I received a quote for a brand new system for £1300. They will decide on tuesday if they go for compressor or all system will go.

Extra thanks for Chillerman2006 :)