Metro 9 Series Controlled Humidity Heated Holding & Proofing Cabinets - Manual (Page 14)

12
BASIC TROUBLESHOOTING (continued)
Warning: Only factory approved service agents should attempt
to service, repair or replace electrical components,
wiring or power cord.
8. Humidity too low:
a. Set point is too low. Turn humidity set point up to the desired humidity.
b. Cabinet may be producing the maximum humidity capable at the current temperature setting and food
moisture content. Example: The cabinet might only produce 80% humidity at 200°F (93°C).
c. A door is not closed or sealing properly.
d. If the humidity display is blinking “Fill,” the water reservoir needs to be re-fi lled.
e. If there is more than 1" (25mm) of water in the water reservoir and the display is blinking “Fill”
i. The water in the reservoir is too pure (example — distilled water). Add a tablespoon of baking soda to the water
and stir the water.
ii. The wiring to the water sensor probe may be faulty or disconnected.
iii. The water sensor probe is not pointing vertically down or the plastic bushing is missing from the pr obe.
iv. The water sensor probe may need to be cleaned or de-scaled.
f. Or see step 9.
9. No humidity generation:
a. If humidity indicator light is on but the cabinet does not draw approximately 16 amps:
i. Water heater element may be faulty.
ii. The wiring to the water heater element may be faulty or disconnected.
iii. The controller (water heater relay) may be faulty.
b. If the humidity indicator light does not come on, the controller may be faulty.
10. Displays blink “LO” or “Fill” and Alarm beeps (if “Sound” is on):
a. If the temperature display alternately blinks the current cabinet temperature and then “LO”, refer to steps 5 and 6.
b. If the humidity display alternatively blinks the current cabinet humidity level and “Fill”, refer to steps 8d and 8e.
11. Water level is low but display does not fl ash “Fill.”
a. Accumulation of dirt or scale needs to be cleaned off of water level sensor.
b. Controller may be faulty.
12. Cabinet trips GFCI (ground fault circuit interrupter):
A GFCI receptacle protects against “ground faults” whenever an electrical product is plugged into the GFCI
outlet by constantly monitoring the electricity for any loss of current. If the current fl owing out of the receptacle
differs by a small amount from that returning, the GFCI quickly switches off power to that circuit. The GFCI
interrupts power extremely fast to minimize the possibility of an electric shock.
a. The heater elements may absorb some moisture into their casing and insulation during shipment or during
long periods of not being used (such as during the summer in a closed school kitchen). Plug the cabinet
(without water in the water reservoir) into a non-GFCI outlet, set the temperature to 200°F (93°C) and let it run
for 30-60 minutes to dry out any moisture the elements may have absorbed. (If it trips the standard circuit
breaker call factory approved service agent.) After drying the elements, plug the cabinet into the GFCI outlet;
the cabinet should run without tripping the GFCI.
b. If the cabinet still trips the GFCI, call a factory approved service agent.
Note: The temperature and humidity controls do not require fi eld calibration.
L01-419 Rev. F L&M.indd 12 1/16/12 2:36 PM