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WD51/2/1997 Chapter 3 : Installation
3.9
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 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.
As a safety precaution it is advisable to fit an 'in line' strainer before the boiler.
The guarantee provided with the Keston 170 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 3.8
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
such factors as soundness of the
air and flue pipe joints, pressure
sensible joints and the gas inlet
pressure (20 mbar required). If
all joints are sound and the gas
inlet pressure is satisfactory set
the gas pressure to the required
pressure. Full details of this
procedure are given in Section
4.7. This will ensure that
combustion is good enough to
allow combustion fine tuning to
take place.
Combustion Fine Tuning
It is advisable on all installations that the combustion quality is checked by measuring the
carbon dioxide (CO
Combustion Fine Tuning. Badly tuned combustion will lead to reduce the life of the boiler
and invalidate the warranty.
Installation & Servicing Instructions
Burner pressure
Adjustment
Burner pressure
test nipple.
), or oxygen (O
), level. This procedure is detailed in Section 4.9
2
2
The Keston 170 Condensing Boiler
GAS VALVE
check
Page : 20
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