8.0INSTALLATION
8.8Making The Electrical Connections
To connect the mains input cable proceed as follows:-
1. | Slacken the facia panel securing screws and lift the |
outercase panel so that its securing tabs are clear of | |
the facia. Remove the panel. | |
2. | Completely undo the screws securing the facia |
panel and hinge it down (Fig. 29). | |
3. | Remove the control box cover securing screws. |
Disengage the barbs on the control box from the | |
cover. Remove the cover (Fig. 30). | |
4. | Slacken the cable clamp on the LH side of the |
boiler chassis (Fig. 31). 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 | |
Fig. 30
Control Box Cover
Fig. 29
Fig. 31 | Facia Panel | |
Cable Clamp | ||
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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 230V supply at |
terminal 1 can be connected to the external |
control as shown. The switched output from the |
external control must be connected to terminal 2. |
(Figs. 32). |
NOTE: If the room thermostat being used incorporates an anticipator it MUST be wired as shown in Fig. 32.
| Fuse |
Fused supply 3A | Always fit fast |
230V ~ 50Hz | blow 2A fuse |
Live (brown) 
br
Neutral (blue) 
b
Earth (green/yellow) 
g/y
230V 1 
bk
2 
bk
Terminal Block
Fig. 32
Frost Thermostat |
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L | N | b |
N |
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External Clock |
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| 1 | bk |
| 230 V |
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N | 2 | bk |
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| SL |
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Room Thermostat |
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IMPORTANT: If an integral timer is fitted to the boiler an external frost thermostat wired as shown will not operate correctly. Only external timers may be used in such installations, as in the diagram.
IMPORTANT: The external control MUST be suitable for 230V switching.
Functional Flow Diagram
8.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.
9.If an optional integral timer is to be used it should be fitted at this point. Refer to the instructions supplied with the timer. NOTE: An external frost thermostat cannot be used with the integral timer.
External Controls
L
230 V
br
b
bk
bk
br
Selector /
Reset Switch
b
r
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PCB | bk |
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Flue Thermostat
Safety Overheat Thermostat
NTC Sensor
8.9 | Preliminary Electrical Checks |
| Key to Wiring | |
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| b | - blue |
1. Prior to commissioning the boiler preliminary |
| br - brown | ||
electrical system checks should be carried out. |
| bk - black | ||
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| Fig. 33 | r | - red |
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| g | - green | |
2. These should be performed using a suitable meter, |
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| w | - white | ||
and include checks for Ground Continuity, |
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Resistance to Ground, Short Circuit and Polarity.
bk |
b |
br |
bk |
r |
r |
g |
g |
Gas Valve Modulator
Spark Electrode
Gas Valve
Condensate Trap
Flame Sensing Electrode
Hydraulic Differential Pressure Switch
DHW Flow Priority Microswitch
Publication No. 5111811 | 23 |
