Evap,suction line and compressor frozen

[Harry Trafford]

Went to a display fridge about 2months ago that had no gas. Found leak and recharge with r134a 2kgs. All seemed good till last week when i got a call saying its not keep the tdmp down. Found the evaporator, suction line and compressor covered in ice.
Checked fans and they are all working.
The lable on the condensor says it can take r404a and r134a
Have i used the wrong refrigerant??


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[Tayters]

Best check if it is defrosting correctly.

You may have used the wrong refrigerant. Label you have is of the compressor, not the system. Look for the data plate or markings on TEV if it has one. This alone wouldn't have caused the coil to ice up if it could initially get the chiller to temp.

Cheers,
Andy.

[martinw58]

have you checked the defrost and temp sensors

[al]

that looks like a counter line which would normally be 404a, as said above pull evap covers and check TXV label, if it's cooled this long then look controls, them yokes are a bugger for icing up, especially if there's a draft on them.

[Harry Trafford]

Ya found today that its got a 404a txv, i also found that some1 previous to me has cut out the evaporator serving the under storage fridge. Could this also result in the condensor flooding the evaporator?

[al]

The condensing unit would most likely now be oversized but with TXV and receiver you should be able to charge it correctly, it'll just hit set point quicker and cycle more, pull out the 134a and start with 0.5kg of 404a and let system run for 15 minutes before adding any more, check stat and fans are ok

[Harry Trafford]

Thanks guys the client has no decided that they dont want to spend anymore on the system because the condensor isnt in great shape and want to price to replace it. The question is now does the smaller evap for the under fridge need a seperate expansion valve to control it?