Left & Right Refrigerant Solenoids - Bunn Ultra NX Service & Repair Manual

Left and Right Refrigerant Solenoids
FIG. 24 R290 REFRIGERANT SOLENOIDS
Location:
The refrigerant solenoids are mounted on a bracket
that is attached in the rear between the auger
motors behind the Auger Motor cover.
WARNING: Before repair and/or removal of any
refrigeration component must be performed by a
trained and licensed R-290 repair technician.
Rear Cover Removal:
1. Remove 4 screws securing rear cover.
2. Grab cover and pull away from machine.
Test Procedures:
NOTE: The "TestRefrigValve" menu will allow the
technician to test the operation of the solenoid coil
and/or output of the main control board.
1. Enter the software program and scroll to main
"Service Tools" menu.
2. Press the "Right Dot" switch to answer "Yes".
3. Press the "Center Dot" switch to advance onto
"Test Outputs" menu.
4. Press the "Right Dot" switch to answer "Yes".
5. Press the "Center Dot" switch to scroll through
the menus until "TestRefrigValve" menu is
displayed.
7. Press the "Right Dot" switch to answer "Yes" to
advance onto "Left RefrigValve" menu.
8. Press the "Left Dot" switch to answer "ON". "Left
RefrigValve" will energize (click sound).
9. Press the "Center Dot" to advance onto "Right
RefrigValve" menu.
10. Press the "Left Dot" switch to answer "ON".
"Right RefrigValve" will energize (click sound).
SERVICE - REAR COVER COMPONENTS
If you hear a click sound or feel the magnetic pull
on top of the solenoid coil, the control board output
is operating correctly. If the cooling drum fails to get
cold and/or weak layer of frost on the cooling drum,
indicates a possible low refrigerant charge or
blockage within the refrigerant solenoid valve.
WARNING: Part Removal and Replacement:
This will require a trained and licensed R-290
technician to make the necessary repair of the
R-290 refrigeration system.
R290 Solenoid Valve Ratings:
Ultra NX 120V Models:
Solenoid Valve: 120VAC/60HZ-110VAC/50HZ
Ultra NX 200-240V Models:
Solenoid Valve: 240VAC/60HZ-220VAC/50HZ
11. Connect a voltmeter across the white wire and
the other wire on the solenoid coil being tested.
Repeat steps 8 thru 10.
NOTE: The voltage output from the control
board must be checked with load (solenoid coil)
connected.
If the control board voltage output is not
present on the refrigerant solenoid valve coil,
replace the main control board.
1 & 2 - Solenoid Valve
Terminals
FIG. 25 R290 REFRIGERANT SOLENOIDS
46
1 2