Need advice!!!

[Northdude]

I had a service call today on a Imperial Pizza Fridge,mod- PS300. Found the cabinet to have lost all its refrigerant, pressure tested it using nitrogen and found lots of major leaks on suction pipe as pipe was completley rotting and was not copper pipe it was metal.Would have replaced the pipe but the suction and capillary go through the bottom of the cabinet to the evaporator and i could not find any access to the evaporator at all so I couldnt find any copper to braise new pipe to so instead i used silver solder on most of the rotten bits which seemed to work although incredibly rough.I pressure teasted it and it held pressure,vacuumed the system and charged it with R134a, ran the sysem,suction pressure was at 1bar and all seemed well, then the suction started to frost back really bad (as if overcharged) and the pressure started to dramatically drop to half a bar and then on to vacuum, i added more gas (should have used scales but werent available) and charged it to around 10psi but then the compressor got really noisy ( as if it was severely overcharged ) and the pressure continued to drop so i switched it off, reclaimed the gas and re-vacuumed it as to make sure all traces of nitrogen were gone incase that was a factor. I then switced it on again and charged it to 1 bar and compressor appeared to be working but discharge was cold but compressor was pumping as when i switched it off the pressure rose and when the compressor kicked in the pressure dropped so im a bit stumped on this one?? I have snagged his compressor but does anyone have any ideas what was happening? And does anyone have any ideas on how I can replace the suction pipe?? And does anyone know where i can pik up a Embraco Aspera Compressor NE11 30Z? All help greatly appreciated.Thanks

[refaircon]

blocked capillary, and or drier. worth checking and or replacing the above. just a thought

[Northdude]

Thanks, just seems strange thoe as before the suction started frosting back, the cabinet was working ok and had dropped 4 degrees in temp. Even if I want to replace the capillery the liquid line sticks out the bottom about 3 inches and the pipe is metal as well so unsure how i can braise on to it, the design is rediculous as theres no access to the evaporator.

[Hopper118]

Try Climate Center or HRP for the compressor.

[ridwan]

dryer blocked, if there is space try and fit danfoss or sporlan 1/4 " dryer vac and charge.remember to charge n liquid phase. hope it works.

[abet_meneses]

moisture in the system seems to be the problem.replace drier and change comp oil and process the system.

regards,

[Gary]

A restriction isn't going to cause the suction line to frost back. Sounds like an evaporator airflow problem to me.

[Northdude]

Ok Thanks, replaced the drier and capillary and replaced the rotten suction with copper using silver solder, vaced and charged but left system running on around 8psi and the suction was sweating and fridge was working ok, but 8psi seems very low as i usually charge them to about 1bar but anymore than 7/8 psi the suction was frosting back?? Still least its working, thanks

[Northdude]

Evap seemed ok, both evap fans were working correctly!

[Andy]

Evap seemed ok, both evap fans were working correctly!

Hello Northdude,

maybe the compressor has been changed in the past and is a bit big, or it is simply over condensing.

Head pressure and liquid temp of the condenser will tell you this.

It's acting like the compressor has gained extra capacity somewhere.

Kind Regards Andy D

[Gary]

Evap seemed ok, both evap fans were working correctly!

Did you check the face of the coil to see if it is dirty?

What are the entering and leaving air temperatures?

[Gary]

Hello Northdude,

maybe the compressor has been changed in the past and is a bit big, or it is simply over condensing.

Head pressure and liquid temp of the condenser will tell you this.

It's acting like the compressor has gained extra capacity somewhere.

Kind Regards Andy D

It's entirely possible that the compressor is oversized for the load, but far more likely that the load is undersized for the compressor (airflow problem)... and as usual we don't have enough information to do a proper evaluation.