Control Thermostat - Bunn CWT TWIN Operating & Service Manual

SERVICE (cont.)

CONTROL THERMOSTAT

FIG. 2 CONTROL THERMOSTAT
Location:
The control thermostats are located inside the
trunk on the left side of the component brackets.
Test Procedures:
1. Disconnect the brewer from the power source.
2. With a voltmeter, check the voltage across the blue
wire on the control thermostat and the white in-
sert on three pole 120/240 volt terminal block and
the red insert on two wire 200 volt ,240 volt or the
three wire three phase 230 volt terminal block.
Connect the brewer to the power source. The
indication must be:
a) 120 volts ac for three wire 120/240 volt models.
b) 200 volts ac for two wire 200 volt models.
c) 240 volts ac for two wire 240 volt models.
d) 230 volts ac for three wire, three phase 230 volt
models.
3. Disconnect 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 brewer wiring har-
ness.
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
insert on the three pole 120/240 volt terminal
block and the red insert on the two pole 200
volt,240 volt or the three wire three phase 230 volt
terminal block when the control thermostat is
turned fully clockwise. Connect the brewer to the
power source. The indication must be:
a) 120 volts ac for three wire 120/240 volt models.
b) 200 volts ac for two wire 200 volt volt models.
c) 240 volts ac for two wire 240 volt models.
d) 230 volts ac for three wire three phase 230 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 leads.
2. Remove the thermostat capillary bulb by firmly
P2197
pulling up on the capillary at the tank lid. This will
disengage the grommet from the tank lid.
3. Remove the one #8-32 screw securing the control
thermostat to the component bracket in the trunk.
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 #8-32 screw secure the control thermo-
stat to the component bracket inside the trunk.
8. Refer to Fig. 3 when reconnecting the wires.
9. Adjust the control thermostat as required.
FIG. 3 CONTROL THERMOSTAT LEADS
Page 15
BLU to BLU Lead from
Limit Thermostat
BLK to BLK Lead from Tank Heater
(Brewers W/Out Faucet)
BLK to BLK Fused Lead from Tank
Heater (Brewers with Faucet)
P1129
10737 120800