User's Manual

63
Booster Heater/Wash Tank Heater Interlock Circuit Operation - UH130B, UH230B, UH330B
Booster Heater/Wash Tank Heater Interlock Circuit Operation
For Models UH130B, UH230B The booster heater/wash tank heater interlock circuit removes
power from the wash tank heater whenever the booster heater contactor energizes.
The illustration below shows how the booster heater contactor is wired.
The booster heater contactor is located on the center of the base behind the lower front access
panel.
Interlock Circuit Operation
1. The dishwasher fills with water when the main power switch on the dishwasher is turned on.
The booster heater thermistor calls for heat which energizes the booster heater contactor.
2. The auxiliary contact on the top of the contactor opens and removes power from the
wash tank heater.
3. When the booster heater thermister is satisfied, the booster heater contactor de-energizes
and the auxiliary contacts close applying power to the wash tank heater.
4. This operation is repeated whenever the booster thermistor calls for heat.
To booster
heater contactor
1PH
208-230VAC
To
Auxiliary
Contactor
115VAC
No power when booster
heater is connected for 1 PH
No power when booster
heater is connected for 1 PH
L1 L2 L3 N
Main Terminal Block (MTB)
To wash
tank heater
115VAC
From
main
terminal block
115 VAC
From
main
terminal bloc
k
1 PH
208-230VAC
No power
when booste
r
heater is
connected fo
r
1 PH
No power when booster
heater is connected for 1 PH
L1
L3
L1
N
L2
To booster heater
1 PH 208-230VAC
1H2
1H3
1H1
Auxiliary
Contactor
Booster Heater
Contactor