© Baxi Heating UK Ltd 2008
10
3.6
Condensate Disposal
This boiler incorporates a 75 mm trap.
Ensure the disposal of condensate complies with
any national or local regulations in force.
Failure to install the condensate disposal pipework
correctly will affect the reliable operation of the
boiler.
The pipe must always slope continually downward
away from the boiler by at least 50 mm in every
metre (approx. 2.5°). No air breaks are required in
the pipe.
1. The pipe should be run in a proprietary drain pipe
material e.g. PVC, PVC-U, ABS, PVC-C or PP. Metal
pipework is NOT suitable for use in condensate
disposal systems.
2. The pipe should be a minimum of 21.5 mm diameter
and must be supported using suitably spaced clips
to prevent sagging.
3. To reduce the risk of condensate being trapped, as
few bends and fittings as possible should be used.
4. When disposing condensate into a soil stack or
waste pipe the effects of existing plumbing must be
considered. If soil pipes or waste pipes are subjected
to internal pressure fluctuations when WC's are
flushed or sinks emptied then back-pressure may
force water out of the boiler trap and could affect the
operation of the boiler.
5. Any condensate pipework external to the building (or
in an unheated part of it e.g. garage) should not
exceed 3 metres in length and when in an exposed
position, waterproof insulation is recommended. It is
also recommended that the pipe diameter is
increased to 32 mm.
If the boiler is fitted in an unheated location the entire
condensate pipe should be treated as an external
run.
Examples are shown of the following methods of
termination in order of preference:-
i) via an internal discharge branch
(e.g. sink waste) - Fig. 4.
ii) to an internal soil & vent pipe - Fig. 5.
iii) to a drain or gully - Fig. 6.
iv) to a purpose made soakaway - Fig. 7.
BS 6798 & Part H1 of the Building Regulations
give further guidance.
Boiler
50 mm per metre (2.5°)
Minimum fall
Termination to an internal soil
and vent pipe
450mm min
Boiler
Termination via internal discharge
branch e.g sink waste - downstream
Sink
Pipe must terminate
above water level but
below surrounding
surface
Boiler
Pipe must terminate
above water level but
below surrounding
surface
Termination to a drain or
gully
Boiler
500mm min
Termination to a purpose made
soak-away
Holes in the soak-away
must face away from the
building
Fig. 4
Fig. 5
Fig. 6
Fig. 7
