Functional Flow Diagram - Baxi 35/80 IE Installation & Servicing Instructions Manual

Key to Wiring
b - blue
br - brown
bk - black
r - red
g - green
Fig. 28
3. Remove the control box cover securing screws. Disengage the barbs on the control box
from the cover. Remove the cover (Fig. 25).
4. Slacken the cable clamp on the LH side of the boiler chassis (Fig. 26). Insert the cable
through the clamp and route it to the terminal block.
5. Slacken the screws in the terminal block, connect the input cable, and tighten the screws.
6. If an external control is to be connected it can be done at this point. Run the input cable
from the external control through the second cable clamp on the boiler chassis. Refer to the
instructions supplied with the control.
7. To connect external control(s) remove the link between terminals 1 & 2. The switched
output from the external control must be connected to terminal 2 (Fig. 27).
8. Any domestic hot water control should be connected to the DHW relay PCB (Fig. 24) in
most installations. See Section 8.9 for details of suggested system wiring schemes
IMPORTANT: The external control MUST be suitable for 230V switching and
fused 3A maximum
9. Ensure that both mains input and, where fitted, external control input cables have sufficient
slack to allow the control box to drop down. Tighten the cable clamp(s) on the boiler chassis.
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8.9 System Wiring