controlling the speed of
the fan. The optimum
pump speed is also
detected
and
automatically selected
by the boiler.
When the return water
temperature is below
55
o
C, part of the water
vapour
in
the
combustion
products
will condense inside
the heat exchanger,
thus
increasing
the
boiler efficiency further
by releasing the latent
heat of condensation.
This condensate falls
to the bottom of the
heat exchanger where
it is separated from the
flue gases and exits from the boiler through the condensate drain. Any condensate
formed in the flue runs back down the flueway and is drained at the base of the flue
connection to the heat exchanger or drain points within the flue.
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 Keston
composite plastic pipe to
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,
programmer
time clocks and compatible
energy
management
systems.
An
optional
Keston room controller can
WD500 Chapter 2 : General Instruction
The Keston Q37 & Q37P Boilers
Installation & Servicing Instructions
Page : 5
