Bunn U3 Service Manual

Page 4

CAUTION - The brewer must be disconnected from the power source until specified in Initial Set-Up.

U333 & U3833  requires 3-wire, grounded service 

rated 40  volt  ac, 35 amp or 440 volts ac, 30 amp for 

U333,three phase, 60 Hz or 380 volts ac, 30 amp for 

U3833,  three phase, 50 Hz.  Proceed as follows:

U3 & U38 requires 3-wire, grounded service rated 

10/08 or 10/40 volts ac, U3-30 amp,U38-40 amp, 

single phase, 60 Hz.  Proceed as follows:

NOTE: Electrical source should have a circuit breaker between the brewer and the main supply which breaks all 

poles with a contact separation of at least 3 mm.

CAUTION – Improper electrical installation will damage electronic components.

1.  An electrician must provide electrical service as specified.

.  Using a voltmeter, check the voltage and color coding of each conductor at the electrical source.

3.  Before electrically connecting the brewer, remove the front cupola cover (some models have the thermostat 

knob on the outside of the cover) and rotate the thermostat knob fully counterclockwise to the "OFF" position. 

Keep this knob in the "OFF" position until performing the Initial Setup.

4.  Electrical service is connected at the upper rear of the single service and scrambler brewers using a junc-

tion box. On double service brewers the rear decorative channel must be removed for access to the terminal 

block.

5.  Connect the brewer to the power source and verify the voltage at the terminal block before proceeding.   Re-

place all panels.

GREEN

GREEN

U3A models require -wire, grounded service rated 

30 volts ac, 30 amp, single phase, 50 Hz. Proceed 

as follows:

U3833  requires  4-wire,  grounded  service  rated 

380 volts ac or 440 volts ac, 30 amp, three phase, 50 

Hz. Proceed as follows:

GREEN

GREEN

L1, L, L3, are the 3 phases

V1 = Phase to phase voltage,

 

between any  phases.

V = Phase to neutral voltage,

 

any phase to neutral.

 SYSTEM

VOLTAGE 

 V1 

 V 

  08 

08 

10 

  40 

40 

139 

  380 

380 

0

  440 

440 

54

 

P184

P1844

10060  081106

GREEN

GREEN

P1841

P1843