Tank Heaters - Bunn Dual Operating & Service Manual

SERVICE (cont.)

TANK HEATERS

FIG. 30 TANK HEATERS
Location:
The tank heaters are located on the left and right
side of the tank lid.
Test Procedure:
Electro/Mechanical Models.
1. Disconnect the brewer from the power supply.
2 Check the voltage across the black and the red
wires on 120/208V or 120/240V models on the
tank heaters. With the control thermostat turned to
the "ON" position (fully clockwise), connect the
brewer to the power supply and with a voltmeter,
check the voltage across the wires. The indication
should be:
a.) 208 volts ac for three wire 120/208 volt models
and 240 volts ac for three wire 120/240 volt
models.
b.) 200 to 240 volts ac for two wire 200 or 240 volt
models.
3. Disconnect the brewer from the power supply.
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. Remove the black and red wires from the tank
heaters.
5. Check for continuity across the terminals of the
tank heaters.
If continuity is present as described, reconnect the
wires, the tank heaters are operating properly.
If continuity is not present as described, replace the
l
ga
1 1⁄2
l
1 ga
l
ga
1⁄2
Y
A D
R E
O R
C T
L E
S E
R
M E
A R
/ W
O N
T
A R
S T
l
ga
1 1⁄2
l
1 ga
ga l
1⁄2
T
A R
S T
M E R
A R
/ W
O N
O R
C T
L E
S E
A D Y
R E
P790
tank heater(s).
NOTE - If the tank heater remains unable to heat,
remove and inspect the heater for cracks in the sheath.
Electronic Models:
1. Disconnect the brewer from the power source.
2. Disconnect wires from heater(s).
3. Check for continuity across the tank heater termi-
nals.
If continuity is present as described, the tank heater is
operating properly.
If continuity is not present as described, replace the
tank heater.
NOTE - If the tank heater remains unable to heat,
remove and inspect the heaters for cracks in the
sheath.
Removal and Replacement:
1. Remove wires from tank heater.
2. Remove the four #8-32 nuts securing tank heater
to tank lid.
3. Remove tank heater and gasket.
4. Install new tank heater and gasket with four #8-32
nuts on tank lid.
5. Refer to Fig. 31 when reconnecting the wires.
LEFT & RIGHT
ELECTRO/MECHANICAL
LEFT
FIG. 31 TANK HEATER TERMINALS
Page 38
BLK to Contactor
RED to Contactor
BLU
BLK
BLK to Terminal Block
(Black Insert)
ELECTRONIC RIGHT
BLU Lead from
from Triac Assy.
P803
27040 032201