the flueway and is drained at the base of the flue connection to the heat exchanger or
drain points within the flue.
Fig. 1.2 - Boiler Layout
The condensate is very slightly acidic (about the same acidity as vinegar) and should be
piped in a plastic pipe. It is not harmful to the waste disposal system and may be disposed
of as normal waste water.
The flue gases are piped in a 50 mm muPVC (BS5255 and/or BSEN1566-1 and
BSEN1329) plastic or, alternatively, 75mm composite plastic pipe to the outside. The
temperature of the flue gases are usually around 5
o
C to 10
o
C above the temperature of
the return water. The flue pipe should be terminated outside the building from where they
cannot re-enter the building or any other adjacent building.
The heating level may be controlled by room thermostats, hot water calorifier thermostats,
programmer time clocks and energy management systems. A Keston room controller can
be connected which will provide enhance controls such as room compensation and
optimum start to further increase efficiency and comfort levels.
The C45, C40P and C55(P) feature an integral frost protection function which will operate
the pump, regardless of the external controls, should the boiler temperature fall below
7
o
C. In the event the boiler temperature falls below 3
o
C the boiler will also fire. This is to
avoid damage to the boiler through freezing of boiler water. The boiler will turn off when
the flow temperature exceeds 10
o
C.
The C45, C40P and C55(P) feature an integral pump exercise function which will run the
pump, without firing the boiler, for 10 seconds in the event the boiler is on standby for in
excess of 24 hours without firing. This is to help prevent seizing of the pump due to long
periods of inactivity.
1.3
RELATED DOCUMENTS
The Keston C45, C40P and C55(P) Condensing Boiler must be installed in accordance
with the current issue of the Gas Safety (Installation and Use) Regulations 1996, current
IEE Wiring Regulations, Building Regulations, Building Standards (Scotland)
Consolidation, and the Bye Laws of the local Water Undertaking.
WD536
Chapter 1 : General Instruction
The Keston C45, C40P, C55 and C55P
Installation & Servicing Instructions
Page : 2