Control Thermostat - Bunn SRU Operating & Service Manual

SERVICE (cont.)

CONTROL THERMOSTAT

FIG. 6 CONTROL THERMOSTAT
Location:
The control thermostat is mounted on the left front
of the top component bracket.
Test Procedures:
1. Disconnect the brewer from the power source.
2. Locate the thermostat and the voltage check
points.
Check Voltage Across
Model
Black wire on therostat
120/208V &
120/240V - 3- from main
harness to white wire
wire w/ground
in terminal block.
single phase
Red wire on thermo-
230V - 2-wire
stat from main
w/ground single
harness to black wire
phase
in terminal block.
Black wire on thermo-
208V or 240V -
2-wire w/ground stat from main
harness to red wire in
single phase
the terminal block.
4. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #5.
If voltage is not present as described, refer to the wiring
diagrams and check the brewer wiring harness.
5. Disconnect the black or red wires from the control
thermostat.
6. Check for continuity across the terminals on the
control thermostat with the control thermostat in
the "ON" position (fully clockwise), continuity must
not be present when the thermostat is in the "OFF"
position (fully counterclockwise).
If continuity is present as described, the control ther-
mostat is operating properly.
If continuity is not present as described, replace the
control thermostat.
Removal and Replacement:
1. Disconnect the wires from the control thermo-
stat.
2. Remove the thermostat capillary bulb by firmly pull-
ing up on the capillary at the component bracket. This
will disengage the grommet from the component
bracket.
3. Remove the #8-32 screw securing the control
thermostat and mounting bracket to the component
P2113.40
bracket. Remove control thermostat and bracket as
an assembly.
4. Remove knob from control thermostat.
5. Remove the two #6-32 screws securing the control
thermostat to the thermostat mounting bracket.
Remove and discard thermostat.
6. Install new control thermostat on thermostat mount-
ing bracket and secure with two #6-32 screw.
7. Install knob on thermostat.
8. Install thermostat and mounting bracket on the
Voltage
component bracket and secure with one #8-32
120V
screw.
9. Carefully bend the capillary tube so that the tube and
bulb inside the brewer are in the vertical position.
The tube should extend an additional 5.5", above
the bulb into the brewer.
230V
NOTE: The capillary tube must be clear of any electrical
termination and not kinked.
10. Refer to Fig. 7 and reconnect the wires.
11. Adjust the control thermostat as required.
208V or
240V
FIG. 7 CONTROL THERMOSTAT TERMINALS
Page 18
BLK from Main Har-
ness (All Models Ex-
cept 230V CE Models
RED from Main
Harness (230V CE
Models)
BLK to Limit Thermostat
(All Models Except 230V CE
Models
RED to Limit Thermostat
(230V CE Models)
P1730
10067 040100