Lamp Relay - Bunn Ultra-1 Service & Repair Manual

LAMP RELAY

FIG. 51 LAMP RELAY
Location:
The Lamp Relay is located under the upper deck of the
chassis, on the right side.
Test Procedures: (Coil)
1. Disconnect the dispenser from the power source.
2. Connect a voltmeter, across BLU/BLK wire (+) and
the VIO wire (-).
3. Connect the dispenser from the power source.
4. Turn on Power (I/O) Switch. Verify the dispenser
is in the "DAY" mode.
The indication must be:
a) 12 volts dc in the "DAY" mode,
b) 0 volts dc in the "NIGHT" mode.
If voltage is present as described, the Control Board is
operating properly. Replace Relay if it does not energize
when voltage is present.
If voltage is not present as described, refer to the Wiring
Diagrams and check the main wiring harness.
If harness has continuity, replace the Control Board.
SERVICE (continued)
Test Procedures: (Contacts)
1. Disconnect the dispenser from the power source.
2. Disconnect the WHI/VIO and WHI/YEL wires.
Connect an ohmmeter across the two coil
terminals where the wires were just removed.
3. Connect the dispenser from the power source.
4. Turn on Power (I/O) Switch. Verify the dispenser
is in the "DAY" mode.
The indication must be:
a) continuity in the "DAY" mode,
b) open in the "NIGHT" mode.
If continuity is present as described, the Relay is
operating properly.
If continuity is not present as described, replace
the Relay.
Not Used (N/C)
1. (-) 12vdc (VIO) from Control Board J5-7
2. (+) 12vdc (BLU/BLK) to Control Board J5-19
3. 12vac (WHI/VIO) to Lamp Connectors
4. 12vac (WHI/YEL) from Circuit Breaker
47
4 2
3 1
FIG. 52 LAMP RELAY