Technical data

PRE-INSTALLATION
6 720 648 547 (2012/06)12
3.4.2 EXTERNAL CONNECTIONS
If no other discharge method is possible then the use of an externally run
condensate drainage pipe terminating at a suitable foul water discharge
point, or purpose-designed soak away, may be considered. If this
method is chosen then the following measures should be adopted:
▶ The external run be kept as short as possible and not exceed three
metres.
▶ The pipe should be run internally as far as possible before going
externally and the pipe diameter should be increased to 32mm before
it passes through the wall to the exterior. The pipe should be insulated
using suitable waterproof and weather resistant insulation.
▶ The external pipe should take the shortest and least exposed route to
the discharge point, and should "fall" as steeply as possible away from
the boiler, with no horizontal runs in which condensate might stand.
▶ The use of fittings, elbows etc. should be kept to a minimum and any
internal “burrs” on cut pipe work should be removed so that the
internal pipe section is as smooth as possible.
FITTING AN EXTERNAL AIR BREAK
• Refer to figure 13 when a rain water down pipe is used to dispose of
condensate.
• An air break must be installed in the 43mm pipe work, between the
boiler condensate outlet and the drainpipe, outside the property, to
avoid flooding during adverse weather conditions.
Fig. 13 Disposal into a rainwater down pipe
Where the pipe terminates over an open drain or gully, the pipe should
terminate below the grating level, but above water level, in order to
minimise “wind chill” at the open end.
The use of a drain cover (such as those used to prevent blockage by
leaves) may offer further protection from wind chill.
Pipe drainage will be improved if the end is cut at 45° as opposed to a
straight cut.
Fig. 14 External disposal
CONDENSATE SOAK AWAY
• The condensate drainage pipe may be run above or below the ground
to the soak away. The examples shown on this page run above ground.
• The soak away must use a 100mm Ø plastic tube with two rows of
three 12mm holes on 25mm centres and 50mm from the bottom of
the tube. The holes must face away from the house.
• The tube must be surrounded by at least 100mm of limestone
chippings to a depth of 400mm.
NOTICE: Freezing conditions
▶ Pipe work length should be kept to a minimum and the
route as vertical as possible.
▶ Weather proof insulation must be used.
NOTICE: Condensate waste
▶ Care should be taken when siting a soak-away to avoid
obstructing existing services.
Continued - Key to condensate illustrations
8 PVCu strap on fitting
9 100mm Ø minimum plastic pipe
10 Drainage holes
11 Limestone chippings
12 Bottom of sealed tube
13 Insulate and increase pipe size
14 Pipe work transition
15 External air break
16 Air gap
17 External rain water pipe into foul water
18 43mm 90° male/female bend
* Condensate trap of 75mm already incorporated into the boiler
Condensate drainage pipe can be run above or below
ground.
18 8
13
14
17
15
16
1
6720644744-09.2Wo
*
25mm min.
14
13
1
6720644744-10.2Wo
*