Bosch Therm C1050ES Technical Service Bulletin

Also see for 830ES: Technical service bulletin Technical service bulletin Technical service bulletin Applications manual Installation manual

Technical Service Bulletin:Replacing The Control UnitModels: C1050ES, C950ES, 940ES, 940ESO, 830ESIntroductionTools needed: Phillips head screw driver Small flat head screw driver Needle-nosed pliersNote: Avoid touching printed circuit board (PCB) as static dischargemay damage circuitry.Preparation Push power button to "OFF" and unplug power cord. Loosen two Phillips head screws on bottom rear of front cover.Pull cover bottom outwards then lift cover upwards to remove.Removing control unit Remove three Phillips screws on front of control unit. (Fig. 2,pos. 1) Turn control unit to expose the rear. (Fig. 2, pos. 2). Locate and remove 6 Phillips head screws on back of controlunit (Fig. 2, pos. 3).control unit front33control unit front33Figure 2 Remove rear cover from control unit to expose circuit boardelectrical connections. Slide wire restraints out of control unit.(Fig. 3, pos. 1). Remove two large electrical strip connectors by pulling themaway from board. (Fig. 3, pos. 2). Remove medium sized electrical strip connector by pulling itoutwards. (Fig. 3, pos. 3). Remove small electrical strip connector by pulling it outwards.(Fig. 3, pos. 4). Remove two large ignition wires by pulling them outwards. (Fig.3, pos. 5). Remove yellow/green striped ground wire spade connection bydepressing tab on connector and pulling it gently off the board.(Fig. 3, pos. 6). Loosen two small flat head screws on terminal block for powercord. Pull black and white wires free from terminal block andcontrol unit. (Fig. 3, pos. 7). Loosen Phillips head screw and remove green ground wire con-nection for power cord. (Fig. 3, pos. 8).Figure 311 122 34 5678 Remove control unit from the water heater.Appliance evaluation for PCB jumper locationPlease evaluate the following prior to installation of the replacementPCB:

/ 3

Related manuals for Bosch 830ES