What causes the frost on product on the top shelf does it have something to do with defrost, fan delays ?
Frost on Icecream on the top shelf
jaybee
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frost
What model case do you have? Are all the shelves in their proper location? Rack? Selfcontained, or Remote condenser? Had similar problem with a 12' Hussmann frozen cake case! Problem was shelf alignment. There is a diagram showing each shelf's location on the back wall.
Regards,
mckim
What model case do you have? Are all the shelves in their proper location? Rack? Selfcontained, or Remote condenser? Had similar problem with a 12' Hussmann frozen cake case! Problem was shelf alignment. There is a diagram showing each shelf's location on the back wall.
Regards,
mckim
As mentioned check defrost duration and fan delay first.
Also lights and frame heaters should shut off during defrost, if jumpered not to it could add a lot of heat during defrost.
Another thing that one of our techs recently discovered was grossly undersized orifice/nozzles in refurbished cases that had previously ran on R22, now R507. This would create a lengthy pull down time and build a lot of frost on the coil. Check the orifice for stamped nozzle size, don't have the chart here but I beleive it should be a 2 for a 5 door on R507. or equivalent to .56 ton on a 4 door and .7 ton on a 5 door. (check sporlan charts or with your wholesaler).
Also lights and frame heaters should shut off during defrost, if jumpered not to it could add a lot of heat during defrost.
Another thing that one of our techs recently discovered was grossly undersized orifice/nozzles in refurbished cases that had previously ran on R22, now R507. This would create a lengthy pull down time and build a lot of frost on the coil. Check the orifice for stamped nozzle size, don't have the chart here but I beleive it should be a 2 for a 5 door on R507. or equivalent to .56 ton on a 4 door and .7 ton on a 5 door. (check sporlan charts or with your wholesaler).
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Dont forget those air leaks- hae applied foam plenty of times esp. in cases that were installed somewhere else then relocated...not to mention factory air leaks- not calling out names...
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this is a set of glass drs i assume
termination is key here as is fan delay shutting down during defrost, as is time/amount of defrost 1 per day and in the middle of the night without the doors being open for long peroids during defrost like loading or customers standing there with doors open... if you still got a problem i would go to my txv and see what type and its superheat setting, could be dirty or out of adjustment causing long recovery times
termination is key here as is fan delay shutting down during defrost, as is time/amount of defrost 1 per day and in the middle of the night without the doors being open for long peroids during defrost like loading or customers standing there with doors open... if you still got a problem i would go to my txv and see what type and its superheat setting, could be dirty or out of adjustment causing long recovery times
Might be as easy as adjusting the temp
All mentioned above good starting points.
Question 1: is this connected with other cases on a system or standalone?
If connected with others in a system are any other cases experiencing this?
If it is the only one it is likely a defrost problem or air intrusion issue.
Very important-
What is controlling temperature, and what is the temperature?
In a glass door case, if your discharge temp is below -15 you can frost even when your defrost is fine and there is no air intrusion. Many times I have seen cases running between -20 and -30 and after adjusting to -10 the frost dissappeared within 3 days.
All mentioned above good starting points.
Question 1: is this connected with other cases on a system or standalone?
If connected with others in a system are any other cases experiencing this?
If it is the only one it is likely a defrost problem or air intrusion issue.
Very important-
What is controlling temperature, and what is the temperature?
In a glass door case, if your discharge temp is below -15 you can frost even when your defrost is fine and there is no air intrusion. Many times I have seen cases running between -20 and -30 and after adjusting to -10 the frost dissappeared within 3 days.
Yup. Start with the manufacturers specs. and go from there.
Be aware though that failing to reply with the outcome is akin to breaking a chain letter. You will be cursed with numerous complex and mysterious service problems and be mired in perpetual callbacks from repugnant customers and sink to the level of slushie/vending repair guy if you fail to respond.
Be aware though that failing to reply with the outcome is akin to breaking a chain letter. You will be cursed with numerous complex and mysterious service problems and be mired in perpetual callbacks from repugnant customers and sink to the level of slushie/vending repair guy if you fail to respond.
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684 Posts
Is R507 the logical replacement for R-22?
mccool said:
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