Controls - Central Control Board - Ccb - A.O. Smith BTH 120 Series Service Handbook

CONTROLS – CENTRAL CONTROL BOARD – CCB
The Central Control Board or CCB is contained in the housing shown below. Access to the board and the
wiring harness plugs can be accomplished by removing two Phillips screws holding the cover.
Remove these
screws to release
cover
The CCB is controlled by the settings given through the desk top menu (UIM). The CCB also monitors all
pressure switches, the hot surface igniter, tank temperatures, the gas control valve, the powered anodes,
and the flame sensor.
The CCB directly controls blower speed on the BTH 199 and 250 models and indirectly controls blower
speed on the BTH 400 and 500 by means of a Variable Frequency Drive (see Page 42).
Note: Improper operation may be the result of a loose connection. Please check all wiring connections and
the power supply to the water heater.
This view shows the cover removed from the CCB.
Servicing should only be performed by a Qualified Service Technician
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