Exchanging A Boiler - Keston C90 Installation And Servicing Instrucnion

WD352/0/2003
1. The electrical supply must be as specified in Chapter 2 - Section 2.4 Electrical.
WARNING :
2. All external controls and wiring must be suitable for mains voltage. Supply wiring
should be in PVC insulated cable not less than 1.0mm
(material code H05VV-F).
3. The permanent live supply connection may be via a 5 amp fused double pole
switch, serving only the boiler. (Refer to Chapter 2 - Section 2.4 Electrical Supply).
4. Securely tighten the terminal screws and route the cable 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.
The supply cable(s) must be connected to the main terminals as follows:-
Terminal N
Terminal L
Terminal E
Terminal SL1 -
Terminal SL2 -
Terminals 1,2,3,4
Ensure connection is made such that if the cable slips in its anchorage the current
carrying conductors become taut before the earthing conductor.
3.10

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 Keston condensing boiler contains 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.
The guarantee provided with the Keston 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
3.1 to 3.9
For sealed systems, fill to a pressure of about 2.7 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 for sealed systems, if
applicable. Vent the system.
Gas Supply
The complete gas installation up to the boiler service cock 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 using a suitable test meter.
Initial Firing
The gas pressure setting is factory adjusted to within the required range and
should not normally need re-adjustment. If the reading is incorrect then check such
Installation & Servicing Instructions
Chapter 3 : Installation
THIS APPLIANCE MUST BE EARTHED
- Blue wire (Neutral) for 5A permanent supply
- Brown wire (Live) 5A permanent supply
- Yellow/Green Wire (Earth)
230V Demand Signal from main zone
230C Demand Signal from DHW/Zone 2
Optional Keston C90/C110 Outside Temperature
Sensor. This will activate weather compensated flow
setpoint when responding to a demand signal on
SL1
The Keston C90 & C110
2
to BS 6500 Table 16
Page : 18