Post a reply to the thread: Partially frozen evap, (Thick ice bottom-1/3)
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Time clock? If there isn't one, put one in. If the box is relying on off time from the stat then you can also get ice buildup over time due to inadequate defrost. Start with that first before as well as ensuring a full charge and the fact that the system does cycle off.
A coil that is filled with that greasy lint has decreased airflow, and the defrost doesn't complete itself. After the ice is gone, I usually find a layer of crud.
Originally Posted by HVAC LLC What are some causes for a partially frozen evaporator (besides low charge) on a walk-in evap, 3 fan Larkin food cooler, full charge 404, was running fine, thermostat set on 38, 5 degree differential. Got a call on this, haven't been there yet. Customer defrosted, but may call me back. I know that's not much information, but it's pretty much all I have. I have done all commercial HVAC, not allot of refrigeration, maybe 20%. Thanks. Does the Larkin walk in have a Beacon (1) electronic controller?
Maybe a starved evaporator.
Originally Posted by icemeister Uneven icing of the evaporator coil like that can be due to an improper distributor nozzle. An oversized nozzle can lead to uneven distribution...essentially overfeed some circuits and underfeeding others. More than likely though, your ice buildup is a result of incomplete defrosting. I'm assuming this sytem has no defrost timeclock and relies strictly on the off-cycle time to clear away frost buildup. If ALL of the frost is not cleared off, it will re-freeze and become hard ice. Add a defrost timeclock and set it up for three 30-40 minute defrosts per day. 30, 40 min defrosts per day, now that's funny! Sent from my iPhone using Tapatalk
Originally Posted by HVAC LLC What are some causes for a partially frozen evaporator (besides low charge) on a walk-in evap, 3 fan Larkin food cooler, full charge 404, was running fine, thermostat set on 38, 5 degree differential. Got a call on this, haven't been there yet. Customer defrosted, but may call me back. I know that's not much information, but it's pretty much all I have. I have done all commercial HVAC, not allot of refrigeration, maybe 20%. Thanks. deffective txv
I do residential, so I was just at a gas station I frequent. He asked me to look at his cooler. Complaint was freezing evap. He turned off the unit the night prior. Pan full of water, so I vacuumed out. Coil was icing up immediately. WR defrost with sencing bulb set at +30 whatever that means. Drain mustbe stopped up, but I suspect the defrost Iis not Iinitiating or not running long enough. But what do I know. R-502 frezone. I passed it to a buddy that can do low and med refrigeration. Know when to say nope.
Originally Posted by crackertech Humm.....................I just don't know were to start with this one. Things just went sidewayz
Originally Posted by MPHPS I started working at a restaurant performing services and the owner asked me to look at their Larkin walk in cooler that was only at 50 degrees. Found large section of inside and outside of coils in walk in frozen up, removed all ice, rooftop unit very low on freon, recharged got temp down to 38 degrees, 3 days later all still ok and coils still clear, 1 week later top section inside and outside frozen up, charge ok but temp down to 50 degrees, is this not defrosting and where could I locate the defroster I cannot find it anywhere. Model # is 2 blade low profile Humm.....................I just don't know were to start with this one.
Larkin Walk in cooler freezing up top section only I started working at a restaurant performing services and the owner asked me to look at their Larkin walk in cooler that was only at 50 degrees. Found large section of inside and outside of coils in walk in frozen up, removed all ice, rooftop unit very low on freon, recharged got temp down to 38 degrees, 3 days later all still ok and coils still clear, 1 week later top section inside and outside frozen up, charge ok but temp down to 50 degrees, is this not defrosting and where could I locate the defroster I cannot find it anywhere. Model # is 2 blade low profile
Larkin Walk in cooler freezing up top section only
Originally Posted by 270wsm Since this is on the same subject, i have a similar question. What causes the Txv and distributer tubes to freeze to a ball of ice without the coil freezing up? I run into this alot on walk-in freezers. Moisture in the system.
Originally Posted by jtrefrig if its ice not frost make sure your drain is clear. jbb jtt x2
Originally Posted by 270wsm Since this is on the same subject, i have a similar question. What causes the Txv and distributer tubes to freeze to a ball of ice without the coil freezing up? I run into this alot on walk-in freezers. This could happen with a starved TEV. the Liquid is literally flashing to a vapor inside of the TEV. Or it could be normal and the frost/ice dose not melt in defrost because usually the TEV/distributer tubes are in an enclosed section of the evaporator coil that dose not have heating elements. where as the actual evaporator is in direct contact with the heating elements.
You're really going to need to know the pressures.High pressure the condenser is dirty or the TXV strainer is dirty,Or you're probably low on refrigerant,Or a evap fan is not working,and of course they might of left the door open all weekend or bad seals.......
Since this is on the same subject, i have a similar question. What causes the Txv and distributer tubes to freeze to a ball of ice without the coil freezing up? I run into this alot on walk-in freezers.
X2 check the defrost and the drain line first.
if its ice not frost make sure your drain is clear. jbb
Uneven icing of the evaporator coil like that can be due to an improper distributor nozzle. An oversized nozzle can lead to uneven distribution...essentially overfeed some circuits and underfeeding others. More than likely though, your ice buildup is a result of incomplete defrosting. I'm assuming this sytem has no defrost timeclock and relies strictly on the off-cycle time to clear away frost buildup. If ALL of the frost is not cleared off, it will re-freeze and become hard ice. Add a defrost timeclock and set it up for three 30-40 minute defrosts per day.
Probably not so much fun, but thanks for responding. I will drop by the store and check on it.
TXV probably needs to be adjusted, but if you have never done comm refrig you are in for a fun day of tweeking.
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