I have a hussman open faced cooler that short cycles all the time. I replaced the thermostat thinking it was defective does the same thing dropped charge and weighed in 32 oz 134a still short cycles. the only way i can get this cooler to stop short cycling is i installed a new thermostat instead of mounting it on the coil i ran it to the top of the cooler set it at 40 degrees and it seem to run fine what do you think?
Is it the correct thermostat you are trying to replace it with? Also, if it's sensing coil temp and the valve is not feeding properly it's not going to work right. Fans working correctly? Honeycombs clean?
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Same t-stat this is a fixed orfice so no expansion valve feeding all fans running clean evap clean condenser. i guess my question is why does this thing run on coil temp if there isnt an expansion valve why cant it run off box temp? I never understood that.
Same t-stat this is a fixed orfice so no expansion valve feeding all fans running clean evap clean condenser. i guess my question is why does this thing run on coil temp if there isnt an expansion valve why cant it run off box temp? I never understood that.
Why coil sensing tstat? My guess is because it's an open faced. I take it that's another name for an air curtain cooler. Either way, there's outside air always coming in.
Aside from walk-ins, I usually see R/I coolers (with doors) or sandwich/pizza prep tables coolers. The benefit I see for having a coil sensing tstat is it's nearly impossible to cause a freeze up of the evaporator coil. With a cabinet tstat, if a door is left open, it will remain in a cooling cycle endlessly, causing a freeze up. A frozen evaporator will further perpetuate that since airflow is blocked. The cabinet tstat would never be satisfied.
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"Ma'am, watch that for me while I go turn on the breaker and SCREAM for me if it sparks or pops...."
I have a hussman open faced cooler that short cycles all the time. I replaced the thermostat thinking it was defective does the same thing dropped charge and weighed in 32 oz 134a still short cycles. the only way i can get this cooler to stop short cycling is i installed a new thermostat instead of mounting it on the coil i ran it to the top of the cooler set it at 40 degrees and it seem to run fine what do you think?
You're probably going to have coil icing problems by doing that, but it's difficult to say since you haven't told us exactly what case you have there.
From what you've said I would assume this is a self-contained vertical merchandiser likely similar to the GSVM:
The GSVM-4072 is designed to have a coil sensing temperature control set at 19ºF to 21ºF to maintain between 35ºF and 40ºF average case temperatures.
It the airflow has been compromised by dirty buildup, as was mentioned it may be just a matter of cleaning out the crap. If the original control was actually OK, short cycling would be a typical symptom of reduced airflow with a coil sensing t'stat.
The GSVM-4072 is designed to have a coil sensing temperature control set at 19ºF to 21ºF to maintain between 35ºF and 40ºF average case temperatures.
It the airflow has been compromised by dirty buildup, as was mentioned it may be just a matter of cleaning out the crap. If the original control was actually OK, short cycling would be a typical symptom of reduced airflow with a coil sensing t'stat.
daaam icemeister your a beast in the refrigeration trade. ive read alot of threads and you post alot of good info,
All evaporator fans are running air flow is great I have two other units that are exactly the same in a row next to it and keeping temperature this one runs gets close to 40 degrees then shuts off then 30 seconds later it tries to come back on but it doesnt come on because it just shut off it sounds locked up until it resets after a minute or so start components are working as normal I justed checked on the unit and the thermostat that controls the box works great for now it really does the same thing because the defrost is timed and there isnt an expansion valve
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Originally Posted by HeinzHVACR
"You never know what others don't know."
"Ma'am, watch that for me while I go turn on the breaker and SCREAM for me if it sparks or pops...." 
