Curtis commercial refrigerator

[sloppyjoe1]

Hi guys. I'm just getting into commercial refrigeration. I have a 3 Curtis refrigerators with evaporator coils iced up. I know that my problem lies with the timer and or pressure switch. Help please

[btglow2894]

Refrigerator evaporators ice up from either bad temp. control, low on gas, or bad evaporator fan motor. Theres a defrost timer on this cooler? Dont see that very often

[primary mech]

Or door gaskets that are bad. I havent seen timers on curtis refrigerators either. I forget the model numbers but are they the units that are half refrigerator half freezer or just cooler? Some more info would help for sure

[herefishy42]

The coil ices up because the compressor doesn't shut off. Coolers are "air defrost". The off time is required for defrosting.

Often a "coil-sensing" temperature control is utilized. This assures positive defrosts. Typically for a 35 degree cooler, the coil will be at 20 degrees when the box is at temp. The control senses this coil temperature and cycles the compressor on the coil temperature regardless of the box temp. then the compressor is disabled until the coil reaches 38 - 39 degrees (when ice cannot exist on the coil). If you are working on old, obsolete, hacked up equipment and cannot get proper control over the defrosting of the coil with an air-sensing temperature control, get a coil-sensing control and stab the coil with the capillary/bulb of the coil-sensing temperature control. Usually takes care of the problem if there are no other concerns - or often works around those other concerns.

[sloppyjoe1]

I have 2 of the Curtis units. One is half freezer and half cooler and the other is a full cooler. The cooler's condensing unit runs continuosly without shutting off so I'll install a coil sensing thermostat. Thanks guys