4.
Securely tighten the terminal screws and route the cable(s) through the
re-openable cable clips. Ensure all cables are secured and that the cord grip bush
is tightened to securely grip the main cable at entry to the cabinet. Remove the
factory fitted link wire between the room thermostat terminals on the boiler.
The supply cable(s) must be connected to the main terminals as follows:-
L
- Brown wire (Live) 3A permanent supply
N
- Blue wire (Neutral) for 3A permanent
E
- Yellow/Green Wire (Earth)
SL
- 230V Switched Live - i.e. Room Thermostat
Opentherm
-Optional Keston Chronotherm room compensating
programmable room thermostat. (Part no C.17.4.21.00.0)
Ext. sens.
-Optional outside temperature sensor for weather
compensation. (Sensor part no C.10C.0.09.00.0)
Ensure connection is made such that if the cable slips in its anchorage the current
carrying conductors become taut before the earthing conductor.
4.9
EXCHANGING A BOILER
Before removing an existing boiler add Fernox Supafloc , or equivalent cleaning agent, in
accordance with the manufacturers instructions. Open all radiator valves and fire the
boiler. When the system is fully heated, shut off the gas supply and drain down the central
heating system.
Important
The C36 Combi and C36P Combi comb
ination condensing boilers contain components which could be damaged or blocked by grease,
dirt or solder etc. It is essential that sludge or scale is removed from an existing system
before fitting the boiler.
The guarantee provided with the Keston C36 Combi and C36P Combi does not cover
damage caused by system debris or sludge.
Connect the new boiler as instructed in this manual and fit in accordance with Sections
4.1 to 4.8
Fill to a pressure of about 2.5 bar. Check the complete system for water soundness. If
leaks need to be rectified using flux or solder the system must be flushed cold again
before proceeding.
Reduce the pressure to the Initial System Design Pressure. Vent the system.
Gas Supply
The complete gas installation up to the boiler gas control valve must be checked for
soundness. BS 6891.
Electrical Installation
Carry out preliminary electrical safety checks, i.e. Earth continuity, Polarity, Resistance to
Earth, Short Circuit and earth loop impedance using a suitable test meter.
Initial Firing
The gas pressure setting is factory adjusted to within the required range and does
not need readjustment. If the reading is incorrect then check such factors as soundness
of the air and flue pipe joints, pressure sensible joints and the gas inlet pressure
(minimum 18 mbar required for Natural Gas and 31 mbar required for LP gas). If all joints
are sound and the gas inlet pressure is satisfactory set the gas pressure check the gas
input. Full details of this procedure are given in Section 5.9 Timing The Gas Meter.
Combustion Testing
It is advisable on all installations that the combustion quality is checked by measuring the
carbon dioxide (CO
2
), or oxygen (O
2
), level. This procedure is detailed in Section 5.7
Combustion Testing. Badly tuned combustion will lead to reduce the life of the boiler and
invalidate the warranty.
WD388/0/2004 Chapter 4 : Installation
The Keston C36 Combi & C36P Combi Boilers
Installation & Servicing Instructions
Page : 21
