Control Thermostat - Bunn GMB-PS Operating & Service Manual

SERVICE (cont.)

CONTROL THERMOSTAT

FIG. 1 CONTROL THERMOSTAT
Location:
The control thermostat is located inside the hood
on the right side.
Test Procedures:
1. Disconnect the brewer from the power source.
2. With a voltmeter, check the voltage across the
blue/black wire on the control thermostat and the
white wire on the power cord for 120 volt model
15 or the white insert on the terminal block for two
wire 120 volt model 20, three wire 120/208 or 120/
240 volt models and the red insert on two wire 200
volt or 240 volt terminal block. Connect the brewer
to the power source. The indication must be:
a) 120 volts ac for two wire 120 volt models, three
wire 120/208 or 120/240 volt models.
b) 200 to 240 volts ac for two wire 200 or 240 volt
models.
3. Disconned the brewer from the power source.
If voltage is present as described, proceed to #4.
If voltage is not present as described, refer to the
Wiring Diagrams and check the wiring harness.
4. Gently remove the capillary bulb and grommet
from the tank.
5. With a voltmeter, check the voltage across the
black wire of the control thermostat and the white
wire on the power cord for 120 volt two wire model
15, the white insert for two wire 120 volt model 20,
three wire 120/208 or 120/240 volt terminal block
and the red insert on the two pole 200 volt or 240
volt terminal block when the control thermostat is
turned "ON" (Fully clockwise). Connect the brewer
All manuals and user guides at all-guides.com
T
A R
S T
O N
F
O F
P2267
Page 14
to the power source. The indication must be:
a) 120 volts ac for two wire 120 volt models, three
wire 120/208 and 120/240 volt models.
b) 200 to 240 volts ac for two wire 200 volt or 240
volt models.
6. Disconnect the brewer from the power source.
If voltage is present as described, reinstall the capillary
tube into the tank to the line 4.5" above the bulb, the
control thermostat is operating properly.
If voltage is not present as described, replace the
thermostat.
Removal and Replacement:
1. Remove wires from control thermostat.
2. Remove the thermostat capillary bulb by firmly
pulling up on the capillary at the tank lid. This will
disengage the grommet from the tank lid.
3. Remove the one #6-32 screw securing the control
thermostat to the mounting bracket in the hood.
4. Slide the grommet to the line 4.5" above the bulb
on the new capillary tube.
5. Insert the capillary bulb through the hole in the
tank lid and press the grommet firmly and evenly
so that the groove in the grommet fits into the tank
lid.
6. Carefully bend the capillary tube so that the tube
and bulb inside the tank are in the vertical position.
NOTE - The capillary tube must be clear of any electri-
cal termination and not kinked.
7. Using one #6-32 screw secure the control thermo-
stat to the mounting bracket inside the hood.
8. Refer to Fig. 3 when reconnecting the wires.
9. Adjust the control thermostat as required.
FIG. 3 CONTROL THERMOSTAT TERMINALS
BLK Lead from
Thermal Fuse
BLU/BLK Lead from
Limit Thermostat
P1171
27479 091596