Hussman Deli Case Freezing

[HProHVAC]

Hello to everyone, and thanks in advance. I'm an owner of an HVAC service company and deal with some refrigeration for existing customers, mostly small deli equipment and walk-ins.
I have a Hussmann NVGC-120 single duty, gravity deli case that has a problem with freezing. The owner called because it leaks on the floor and makes the it dangerous behind the counter.

I found that the bottom stainless steel pan is covered with ice. The evap coil on top is completely clear of any ice and the case works well otherwise. I noticed that the entire rack below the product is lined with ceramic tiles for appearance purposes. The owner said that they've always been there, but the case was existing when he bought the deli 3 years ago. (the case was manufactured in 2000).

It seems to me that the tiles blocking the air from circulating is the cause due to the pan getting too cold and the condensation not being able to dry off.
I figured I'd run it by someone here since while my experience in HVAC is extensive, lets just say that the refrigeration side is something I don't deal with as often.

Any thoughts would be appreciated.
Rusty

[simon@parker]

Hello to everyone, and thanks in advance. I'm an owner of an HVAC service company and deal with some refrigeration for existing customers, mostly small deli equipment and walk-ins.
I have a Hussmann NVGC-120 single duty, gravity deli case that has a problem with freezing. The owner called because it leaks on the floor and makes the it dangerous behind the counter.

I found that the bottom stainless steel pan is covered with ice. The evap coil on top is completely clear of any ice and the case works well otherwise. I noticed that the entire rack below the product is lined with ceramic tiles for appearance purposes. The owner said that they've always been there, but the case was existing when he bought the deli 3 years ago. (the case was manufactured in 2000).

It seems to me that the tiles blocking the air from circulating is the cause due to the pan getting too cold and the condensation not being able to dry off.
I figured I'd run it by someone here since while my experience in HVAC is extensive, lets just say that the refrigeration side is something I don't deal with as often.

Any thoughts would be appreciated.
Rusty




the tiles are there to hold the product off the base of the cabinet so it doesnt freeze it i would look for a leak in bottom of cabinet when ice is clear would also check cab cut out temp it maybe going too cold also check for airflow into cabinet from outside say air con or draughts from doors or intake extract fans usually a gravity case runs 3 to 5 possibly warmer its a very old design and ineficient (spelt wrong am sure) over here in uk they all forced air design as it maintains a more even temp the gravity ones were phased out over 10yrs ago a few remain for sandwich display but they are fully enclosed and run at 5 Deg C or slightly higher as food guidelines are not so rigerous hope this helps good luck with that :)

[texas64]

Please take some photos. When you say stainless pan, do you mean the condensate pan directly under the coil which hangs inside the case? Or are you referring to the pan that makes the bottom of the display area where products can be placed? The ceramic tiled rack is that a shelf below the evaporator but above the bottom of the display area? Just trying to get a picture in my mind. Also, does this case have a refrigerated portion underneath the glass display area that is designed to hold product? These type of cases have refrigeration lines in the walls that freeze up to chill the product held inside, hence the freezing.