Evaporator half frosted

[buttonmonn]

Hello guys

I am new to this forum and fairly new to refrigeration so bear with me.

I am an electrician by trade, but I do repair white goods from time to time.
I was asked to have a look at a commercial, display fridge which wasn't cooling.
I did the obvious checks
Power on yes
Thermostat setting was set too high so I turned it 5 degrees celsius
I felt the compressor and it was hot and came on when I turned the thermostat down
Door seals were in good condition
There was no issue with light staying on
The condensor fan was working but the cooling fins were covered in grease and dust and so I gave them a clean.
There is no freezer, no evaporator fan and no frost free system.

I came back the next day to see if cleaning the condensor fins had made any difference and found that the thermometer was showing 10 degrees.
I also noticed that evaporator was only frosted half way along and not particularly cold at the far end. I told them to give the condensor fins a really good clean but that I suspect a lack of pressure in the sealed system; either caused by a problem with the compressor/capacitor, a lack of refrigerant (leak) or a partial blockage in the filter.

Can anyone tell me if I am right and where do I go from here?

Many thanks

Buttonmoon

[r.bartlett]

are you f-gas qualified to work on these systems

[cold.man]

what gas type is it?
what are the pressures? HP and LP
what does the condensor coil feel like inlet and outlet?
what does the drier feel like?
its sound like a small commercial fridge you may have to fit a line tap valve...

[r.bartlett]

what gas type is it?
what are the pressures? HP and LP
what does the condensor coil feel like inlet and outlet?
what does the drier feel like?
its sound like a small commercial fridge you may have to fit a line tap valve...

You moan and moan about FM companies and their situation having to chase each job to the bottom and yet you bend over backwards to help a sparks take our work.... I wonder why our industry is so badly thought of...
I just don't get it...

[buttonmonn]

To be honest I didn't check the gas type but I would say it's going to be R134a. Not old enough to be R12.
I couldn't find a label anywhere to get pressures HP, LP. Looked all over, inside doors, etc.
The condenser coil is hot incoming from the compressor, I didn't feel the drier or the condenser outlet.
What should I be looking for?
I used to work degassing fridges and air conditioning systems about 10 years ago after that I worked as a chef where I was responsible for user maintenance of about 10 fridges/freezers/cold room.
Since then I have worked as an electrician and a building services engineer where I have studied climate control systems including heat pumps.
I have neither the tools nor the inclination to interfere with the sealed system and I do not charge if I fail to fix something.
My intention in this case is to advise the client to call a fridge engineer if that is necessary but I am trying to avoid an expensive call-out if it's just a user maintenance issue/ an old machine issue/ £75 to have the machine condemned.
Also I am just interested and am considering getting specific training in HVAC.
If I am breaking the law please tell me and if it is against the law to work on any part of an AC or refrigeration system is it also against the law to work on a similar system in your own home or business?

Thanks again

Buttonmoon

[cold.man]

fair comment.....but he didnt say he wasnt qualified he said he was new to refrigeration
and i havent moaned about anything just made a point theres a difference....mr bartlett

[cold.man]

buttonmoon you posted your last post whilst i was posting mine, if you are looking on the label for the hp and lp pressures obviously you are not qualified as r bartlett says.
i take that back mr bartlett.....

[buttonmonn]

No I was looking for a make and model number actually

[buttonmonn]

I see you guys are feeling the recession too.
No worries
Thanks for the replies

[jdunc2301]

Evaporator fan issue or SOG

Get a F-Gas qual engineer in to sort it bud

[Rob White]

.

If the condenser has been blocked for some time and if it is on
R134a the chances are the refrigerant will have become thermaly
decomposed (burnt out).

Unfortunately you will not be able to find out if this is the case because
as others have said you have to be qualified to work on the refrigeration
side of the system.

You will have to refer this onto sombody with the correct quals and experiance
to look at the system and diagnose the fault.

All the best

Rob

.

[buttonmonn]

Any of you guys based in London?

[buttonmonn]

Thanks for all the replies

[r.bartlett]

buttonmoon you posted your last post whilst i was posting mine, if you are looking on the label for the hp and lp pressures obviously you are not qualified as r bartlett says.
i take that back mr bartlett.....

No problem. This forum is supposedly for qualified engineers. I would go as far as to say no advice without proof of qualification..

[buttonmonn]

Fair enough. All I want now is a qualified engineer as the law has changed since I last worked with fridges and I have no intention of breaking it or doing a job I'm not qualified for. I have already explained to the customer that I don't own any tools for refrigeration and am not qualified to go any further than the user maintenance. I get asked about AC and fridges on a reasonably frequent basis since working as a spark and up till now I have just shrugged my shoulders and explained that this is not an electricians job. Also having now investigated the prices of F-gas training I doubt that I will be becoming qualified any time soon so it would be good to find a refrigeration/HVAC guy that I could pass work on to.