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6 Condensate Disposal
6.1 General Requirements
When in condensing mode the Grant
VORTEX Eco boilers produce
condensate from the water vapour
in the flue gases. This condensate is
slightly acidic with a ph value of around
3 (similar to vinegar). Provision must be
made for the safe and effective disposal
of this condensate.
Condensate can be disposed of
using one of the following methods of
connection:
Internal connection (preferred
option):
• into an internal domestic
wastesystem (from kitchen sink,
washing machine, etc.)
• directly into the soil stack
External connection:
• into an external soil stack
• into an external drain or gulley
• into a rainwater hopper (that is
part of a combined system where
sewer carries both rainwater and
foul water)
• purpose made soakaway
All condensate disposal pipes must
be fitted with a trap - whether they are
connected internally or externally to a
domestic waste system/soil stack or run
externally to a gully, hopper or
soakaway.
6.2 Connections
Connections into a rainwater hopper,
external drain or gulley should be
terminated inside the hopper/drain/
gulley below the grid level but above
the water level.
Condensate disposal pipes should not
be connected directly into rainwater
downpipes or to waste/soil systems
connected to septic tanks.
Condensate should not be discharged
into ‘grey water’ systems that re-use
water used in the home (not including
water from toilets).
It should be noted that connection of a
condensate pipe to the drain may
be subject to local Building Control
requirements.
6.3 Pipework
Condensate disposal pipework must be
plastic (plastic waste or overflow pipe is
suitable).
6.5 Condensate Soakaway
To keep external pipework to a
minimum, locate the soakaway as close
as possible to the boiler but ensure
it is at least 500 mm from building
foundations and away from other
services, e.g. gas, electricity, etc.
The condensate pipe may be run above
or below ground level and can enter
either the top or side of the soakaway
tube. Refer to Figure 6-1.
Ensure that the drainage holes in the
soakaway tube face away from the
building.
Backfill both the soakaway tube,
and the hole around it, with 10 mm
limestone chippings.
Only use a soakaway where the soil is
porous and drains easily. Do not use
in clay soils or where the soil is poorly
drained.
Condensate disposal pipes should
have a minimum ‘nominal’ diameter
of 22 mm (¾”) - e.g. use 21.5 mm OD
polypropylene overflow pipe.
Condensate disposal pipes must be
fitted with a fall (away from the boiler) of
at least 2.5° (~45 mm fall per metre
run).
Condensate disposal pipes should
be kept as short as possible and the
number of bends kept to a minimum.
Pipes should be adequately fixed to
prevent sagging, i.e. at no more than
0.5 metre intervals.
6.4 External Pipework
Ideally, external pipework, or pipework
in unheated areas, should be avoided. If
unavoidable, external pipework should
be kept as short as possible (less than
3 metres) and 32 mm waste pipe used
to minimise the risk of ice blocking the
pipe in freezing conditions.
The number of bends, fittings and joints
on external pipes should be kept to a
minimum to reduce the risk of trapping
condensate.
!
NOTE
IMPORTANT: Copper or steel pipe is
NOT suitable and MUST NOT be used.
!
NOTE
Where it is not possible for the
pipe to fall towards the point of
discharge - either internally into
a waste system or externally to a
gulley (e.g. for boilers installed in
a basement), it will be necessary to
use a condensate pump.
Figure 6-1: Purpose made condensate soakaway
!
NOTE
For boiler installed in an unheated
area such as an outhouse or
garage, all condensate pipework
should be considered as an
‘external’.
!
CAUTION
Any damage due to condensate
backing up into the boiler due to a
high water table, in the case of a
soakaway, or flooded drains when
the condensate disposal is via a
gulley or soil stack, is not covered
by the Grant product guarantee.
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