Bunn FMD-4 Guida Utente

40

FIG. 39 TANK HEATER RELAY

P2635

Location:

 

The tank heater relay is located behind the lower 

front access cover, mounted on the left rear side of the 

component bracket.

Test Procedure:

1.  Disconnect the dispenser from the power source.

2.  Place the tank heater switch in the “OFF” (upper) 

position.

3.  With an ohmmeter, check for continuity between 

normally  closed  (NC-5)  and  common  (COM-3) 

terminals of the relay. The indication must be less 

than 1 ohm.

If continuity is present as described, proceed to step 

4.

If continuity is not present as described, replace the 

relay.

4.  With an ohmmeter, check the resistance across the 

coil terminals (1 & 2) of the relay. The indication 

must be approximately 4,000 ohms (4k

Ω).

If  the  resistance  measures  as  described,  proceed  to 

step 5.

If the resistance does not measure as described, replace 

the relay.

5.  Disconnect the wires from the normally closed (NC-

5) and common (COM-3) terminals of the relay.

FIG. 40 TANK HEATER RELAY TERMINALS

P2639

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 dis-

penser far enough so the tank heater relay can be 

disconnected from the main wiring harness.

3  Disconnect the tank heater relay from the main 

wiring harness.

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

tank  heater  relay  to  the  rear  of  the  component 

bracket.

5.  Remove and discard the tank heater relay.

6.  Install new tank heater relay on the rear of the 

component  bracket  and  secure  with  two  #8-32 

screws.

7.  Connect the tank heater relay to the main wiring 

harness (see Fig. 40).

8.   Place  the  component  bracket  into  position  and 

tighten the three #8-32 screws.

6.  With an ohmmeter, check for continuity between 

the normally closed (NC-5) and common (COM-3) 

terminals of the relay.

7.  Place containers below any three dispense noz-

zles.

8.  Connect the dispenser to the power source.

9.  Simultaneously initiate dispenses at each of the 

selected dispense stations while monitorintg con-

tinuity across the referenced terminals of the tank 

heater relay. The indication must be open circuit.

If continuity is absent as described, the relay is func-

tioning correctly.

If continuity is present, replace the relay.

BLK from

Main Harness

BLK from

Main Harness

BRN/BLK from

Main Harness

WHI from

Main Harness
No Connection

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