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Dealing with Condensate
Five suitable drainage points
1. Internal drain stack pipe
2. Waste water pipe *
3. External drain or gully *
4. Rainwater hoppers that carry both rain water and foul water *
5. Purpose-made soakaways
* Care should be taken not to contaminate any “Grey Water Systems”
Pipework
Condensate pipework should be plastic, same as used for standard wastewater plumbing.
Similarly the drainage system where the condensate discharges to should also be resistant to the acidic conden-
sate.
Connection to the internal trap in the boiler can be achieved by using a 20mm solvent weld socket.
Pipework should be kept as short as possible.
External runs should be avoided, but when necessary be a minimum of 3 meters in 32mm diameter pipework and
lagged to avoid freezing, this also applies to pipe runs in unheated areas such as garages.
To reduce the possibility of condensate being trapped in the pipe, the number of bends should be kept to a minimum.
Pipework must be angled down from the boiler with a fall of at least 2.5.
The pipework must be supported at a distance of 0.5m for inclined runs and 1.0m for vertical runs.
Condensate traps
Where the condensate drain is not sealed to the discharge connection a trap will be required. The water seal should
be 38mm or more for external discharge and 75mm or more for internal discharge. When connecting to a exter-
nal stack the trap should be located within the building.
Stack Pipes
Condensate connections should be at least 450mm above any bend at the bottom of a stack pipe in a single or multi-
story dwelling up to 3 storeys.
There are specific requirements when connecting to a stack pipe serving
multi-storey buildings greater than 3 storeys.
All connections to stack pipes should avoid across flow between other Branch pipes.
Soakaways
Any soakaways have to be purpose-made and located as close to the boiler as possible, but clear of the buildings
foundations and any buried services. The best option is to purchase a soakaway from a drainage manufacturer and
install it to the manufacturers recommendation.
