Bunn FMD-4 - Manual (Page 19)

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CONTROL THERMOSTAT - FMD-4 & FMD-5
FIG. 9 CONTROL THERMOSTAT
P2635
Location
The control thermostat is located at the upper left
rear of the dispenser housing.
Test Procedure
1. Disconnect the dispenser from the power source.
2. Disconnect the black wire of the control thermo-
stat from the black lead from the limit thermostat.
3. Remove bulb from the tank.
4. Check the voltage across black wire on the control
thermostat and the white or red wire on the tank
heater with the tank heater switch in the “ON”
lower position with a voltmeter. Connect the dis-
penser to the power source. The indication must
be:
a) 120 volts ac for two wire 120 volt models.
b) 208 volts ac for three wire 120/208 volt models.
c) 240 volts ac for three wire 120/240 volt models.
5. Disconnect the dispenser from the power source.
If voltage is present as described the control thermo-
stat is operating properly. Reinstall bulb into the tank.
If voltage is not present as described, replace the
thermostat.
SERVICE (cont.)
Removal and Replacement.
1. 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.
2. Loosen the two #6-32 screws securing the ther-
mostat to the front tank mounting bracket.
3. Disconnect the wires from the thermostat.
4. Remove thermostat and remove the screws and
spacers from the thermostat.
5. Discard thermostat.
6. Install two spacers and two #6-32 screws on the
new thermostat.
7. Position the thermostat on the botttom side of the
front tank mounting bracket and tighten the two
#6-32 screws.
8. Slide the grommet to the line 4.5" above the bulb
on the new capillary tube.
9. 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.
10. Carefully bend the capillary tube so that the tube
and bulb inside the tank are in the vertical position
and away from any electrical connections.
11. Refer to Fig. 10 and reconnect the wires.
NOTE - The capillary tube must be clear of any electri-
cal termination and not kinked.
FIG. 10 THERMOSTAT TERMINALS
P1668
BLK from Limit
Thermostat
BLK from Tank
Heater Switch
35135 012103