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 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. It should also be terminated such that flue
products cannot be drawn into the boiler air intake terminal.
The heating level may be controlled by room thermostats, programmer time clocks and
compatible energy management systems. An optional Keston room controller can be
connected which will provide enhanced controls such as room compensation to further
increase efficiency and comfort levels. However, this is only recommended for heating
only applications. Once the controls are set the boiler operates automatically. Further, a
Keston outside sensor can be connected to the boiler which will automatically invoke
weather compensated heating which further boosts user comfort and boiler efficiency.
In the event of the
boiler overheating the
safety
devices
will
cause
a
safety
shutdown. A safety
discharge valve and
discharge pipe is fitted
to the boiler.
The
Qudos
28s
features an integral
frost
protection
function
which
will
operate
the
pump,
regardless
of
the
external
controls,
should
the
boiler
temperature fall below
10
o
C. In the event the
boiler
temperature
falls below 5
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
15
o
C.
The
Qudos
28s
features an integral
pump
exercise
function which will run
the
pump,
without
WD420/3/2007 Chapter 2 : General Instruction
The Keston Qudos 28s & Qudos 28sP Boilers
Installation & Servicing Instructions
Page : 6
