Bunn FMD-4 User Guide

41

FIG. 41 TRANSFORMER

P2635

Location:

 

The transformer is located behind the lower front 

access cover, mounted on the right rear side of the 

component bracket.

Test Procedure:

1.  Disconnect  the  dispenser  from  the  power 

source.

2.  Disconnect  the  four  wires  of  the  main  harness 

from the transformer.

3  Check the voltage across black wire and the white 

wire on the main harness. Connect the dispenser 

to power source. The indication must be:

 

a. 120 volts ac for two wire 120 volt models.

 

b. 120 volts for three wire 120/208 volt models 

and three wire 120/240 volt models.

 

c) 230 volts ac for two wire 230 volt models.

4.  Disconnect  the  dispenser  from  the  power 

source.

If voltage is present as described reconnect the wires 

and proceed to #5.

If voltage is not present as described, refer to the wiring 

diagrams and check the main wiring harness.

5.  Check the voltage between J3-5 and J3-6 on the 

six pin connector at either control board. Connect 

the dispenser to the power source. The indication 

must be 24 volts ac.

If voltage is present as described the transformer is 

operating properly.

If  voltage  is  not  present  as  described,  replace  the 

transformer.

Removal and Replacement:

1.  Loosen the three #8-32 screws securing the com-

ponent bracket to the dispenser housing base.

2.  Pull  component  bracket  out  the  front  of  the 

dispenser far enough so the transformer can be 

disconnected from the main wiring harness.

3  Disconnect the transformer from  the main wiring 

harness.

4.  Remove the two #8-32 screws securing the trans-

former to the rear of the component bracket.

5.  Remove and discard the transformer.

6.  Install new transformer on the rear of the compo-

nent bracket and secure with two #8-32 screws.

7.  Connect the transformer to the main wiring har-

ness (see Fig. 42).

8.   Place  the  component  bracket  into  position  and 

tighten the three #8-32 screws.

FIG. 42  TRANSFORMER TERMINALS

P2640

LIN

E

WHI/GRN from

Main Harness

BLK from

Main Harness

WHI from

Main Harness

WHI/BLK from

Main Harness

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