Bunn JDF Silver Series, Technical Training Manual

Bunn-O-Matic Corporation

17

Pump Assembly Bypass

The bypass holes are used for increased agitation in the water tank which has 

an additional purpose of enhancing the performance and burst capacity of the 

machine. Both pumps are identical in appearance but have two different service 

replacement part numbers. Single hole is used in the JDF-2S and the two hole 

bypass is used in the JDF-4S.

Water Tank Assembly 

The water tank is used for the purpose of containing the non-

potable water in the development of the ice block and the 

process of cooling the potable water in the water coil that will 

be used for the purpose of product dispense. In addition, the 

chilled non-potable water in the tank is used for the method 

of cooling the upper cabinet to keep product at refrigerated 

temperature. The size of the tank and ice block relate to the 

meaning of burst capacity. Burst capacity refers to the number 

of drinks/volume that can be produced without exceeding 41º 

F finished drink temperature within a time frame.

Draining Water Tank

The unit will need to be unplugged or refrigeration switch 

turned off for a period of 48 hours for the ice block to thaw. 

After thaw, remove sight gauge tube from retaining clip and 

lower the tube below tank level and the tank will begin drain-

ing water out of the sight gauge tube.

Water Delivery

When a user depresses a button or membrane on the door an input signal is sent to the CBA. In return the CBA will 

send out the corresponding output to turn on the water inlet valve, dispense motor and dispense valve to begin dis-

pense or portion dispense. The water goes through a strainer and is regulated to 2.0gpm by the flow restrictor in the 

inlet valve. The water flows through the cold water coil that is submerged in the cold water tank and enters the back 

of each dispense valve. 

All dispense valves have a water flow 

rate adjustment to assist in the cali-

bration or ratio set-up of product. Pri-

marily the water is factory set and the 

concentrate is adjusted for ratio set-up 

by pump motor rpm. The concentrate 

and water mixes in the High Intensity 

dispense valve and is being delivered 

out the quick stop nozzle.

The optional cold water dispense is 

only available on the JDF-4S.

Water Return Manifold

Water Coil

Evaporator

Overflow Tube

Cabinet 

Drain Line

Sight Gauge

Fill Tube

Water Inlet Valve

Water Coil

Optional/Cold

Water Valve

Cold Water Nozzle

Dispense Valve