Any commercial refrigeration people around to help diagnosis

[Mags]

Long shot here, any refrigeration engineers that could help me with a bit of basic diagnosis on a commercial fridge before I have to call a local repair company?
My wife runs a very small florist business from home, last year she bought a large used commercial Electrolux fridge with a CAREL ir33 controller, worked fine for over 18 months and then one morning in Nov we opened it to find it had frozen everything solid and was indicating several degrees below zero.
Whenever we turn it on now it just continues to run the fans/compressor and the temp indicated on the controller is dropping closer to zero.
I've downloaded the controller manual and checked the set point is 7.5 deg and although the display is showing the temp is below this the fridge is running and making it colder still.
A lot of the language on the manual is double dutch to me but given the temp display is correct and the set point is above this I'm assuming whatever senses the temp is fine and I wonder if the controller is no longer able to communicate with the compressor?
Is there anything I can do at home to test/repair or do I just need to call an expert?

The company we bought it from no longer exist so I can't get help there either. When we bough the fridge the guy was super helpful and said he had programmed it to suit the flowers, what that means other than the set point I have no idea!

Thanks
Mark

[richelli]

It will be the controller. If the display temp is getting lower than the set point. If you give it a sharp hard tap with the big rubber end of a screwdriver you may make it work again for a while. The contacts inside will have stuck together from years of the slight arcing you get when they make and break.

You can still get those controllers so it will just be a straight swap. Any fridge company will be able to do it or any electrician who has a basic controller understanding. If you have the manual just write down all the settings and program the new controller with the same settings. The wiring on the back will just be a like for like swap.

Edited by richelli on Wednesday 10th January 19:30

[Mags]

richelli said:

It will be the controller. If the display temp is getting lower than the set point. If you give it a sharp hard tap with the big rubber end of a screwdriver you may make it work again for a while. The contacts inside will have stuck together from years of the slight arcing you get when they make and break.

You can still get those controllers so it will just be a straight swap. Any fridge company will be able to do it or any electrician who has a basic controller understanding. If you have the manual just write down all the settings and program the new controller with the same settings. The wiring on the back will just be a like for like swap.

Edited by richelli on Wednesday 10th January 19:30

Thanks for the reply. I will give this a try and see if I can source another, really appreciate the quick response.

[RJD223]

Agree with richelli.

The contacts on the compressor relay will likely have just welded themselves together.

Just one thing to double check first though - if the Icicle (compressor) icon/light is still showing on the controller (even though the setpoint has been reached) then it's a different issue.

The icon/light should go off once the set point has been reached i.e. when it's cold enough (will only light up when calling for the compressor).

Hope that helps!

[Mags]

Thanks, I don't recall ever seeing that icon/light to be honest even when it was working well.
This weekend I'll pull the controller out, is it feasible I could repair it, I can solder and have swapped PCB components out in the past.
Is there somewhere on the web that covers the repair if I search for the right term?

[richelli]

Don’t waste your time trying to repair it. When you pull it out there will be a sticker on the top with the wiring diagram and the make and model. Just order a new one, swap the wires like for like and input the settings you have copied from the old one. Job done.

[hidetheelephants]

Yep, cheapo controller is £10-15 or a brand name for maybe £80-100 may be better if the fridge looks after expensive stock.

[Mags]

Ok, I will do that, thanks all for the help, much appreciated. It holds anything upwards of £100 of flowers so can't have them getting destroyed again.

[Mags]

Just realised I never replied to this. Thanks for your help, I bought a new controller wrote down and entered all the settings and it works perfectly. Much appreciated.