Bunn JDF Silver Series, Technical Training Manual

Bunn-O-Matic Corporation

15

Connectors and pump speed dials not present on JDF-2 S, CBA  (BUNN P/N: 40177.1001)

• 

J-12

• 

J-13

• 

J-15

Pump Speed Dial 3 and 4

Refrigeration Switch (F)

The refrigeration switch is located behind the splash panel next to the circuit board. This switch 

passes 120VAC power to the water bath pump and compressor K1 relay contact terminal.

Program Switch (G)

The program switch is located near the main control board next to the refrigeration switch. 

The program switch is used to enter timed fill mode, brix test modes and to access the semi-

automatic sanitize mode while the dispense lockout switch is in the ON position.

Step Down Transformer for Lighted Display (H)

This step down transformer is rated for 115 Primary/24 Secondary volts with a 40 VA rating. The 

maximum current on the secondary winding is 1.6 Amps. Transformers are power rated in VA 

(volts x amps) and applies to both the primary and secondary winding. The secondary voltage 

24VAC goes to a rectifier before going to a single or two ballasts located on the inner door panel.

Rectifier (I)

The rectifier receives the 24VAC from the step down transformer and converts the 24VAC over to 

24VDC before going on to the door light ballasts rated at 24VDC.

Door Assembly

The door gasket is mounted and foamed in place to the inner door. Early models with fluorescent lamps may contain 

one or two ballasts mounted on the inner door panel or the latest version being LED lighting. See BUNN service 

bulletin 175 about converting fluorescent lighting to LED lighting. The switch circuit board, which communicates with 

the main CBA, is isolated and mounted to the inner door panel. The portion control switch membranes connect to 

the switch board in logic order from left to right. The user can initiate a portion dispense of product or has the ability 

to set the small, medium and large 

buttons as press and hold during 

setup. When a membrane switch is 

depressed a low input signal is sent to 

the switch circuit board. The input is 

then communicated to the CBA where 

appropriate output voltages are distrib-

uted to the components used during 

dispense.

Note:

 Switch circuit board is not used 

or present on juice machine that use 

mechanical switch buttons in the outer 

door cover.

Dual Ballast Doors

Early Models with Flourescent Bulbs

Door Gasket

Door Latch

LED Lights

Inner 

Door

Door Harness

Slot

LED Circuit

Board

Circuit Board

Label Holder

Bezel

P/C Switch 

Membrane