IDEAL INDEPENDENT COMBI 24, Installation And Servicing

28

Installation and Servicing

SECTION 2 - INSTALLATION

2.15 CONDENSATE DRAIN

137

47

149

Condensate

Drain

T

his appliance is fitted with a siphonic 75mm condensate trap 

system that requires filling before operating the appliance for the 

1st time or after maintenance.
All condensate pipework should conform to the following:

a.  Where a new or replacement boiler is being installed, access to 

an internal ‘gravity discharge’ termination should be one of the 

main factors considered in determining boiler location.

b.  Plastic with push fit or solvent connections.

c.  Internal plastic pipe work a minimum of 19mm ID (typically 

22mm OD)

d.  External plastic pipe must be a minimum of 30mm ID (typically 

32 OD) before it passes through the sleeved wall.

e.  All horizontal pipe runs, must fall a minimum of 45mm per metre 

away from the Boiler.

f.  External & unheated pipe work should be kept to a minimum 

and insulated with Class “O” waterproof pipe insulation.

g.  All installations must be carried out in accordance to the 

relevant connection methods as shown in the “Condensate 

installation diagrams” & BS6798:2009

h.  Pipe work must be installed so that it does not allow spillage 

into the dwelling in the event of a blockage (through freezing)

i.  All internal burrs should be removed from the pipe work and any 

fittings.

In order to minimise the risk of freezing during prolonged very cold 

spells, one of the following methods of terminating condensate 

drainage pipe should be adopted.

Internal Drain Connections

Wherever possible, the condensate drainage pipe should be routed 

to drain by gravity to a suitable internal foul water discharge point 

such as an internal soil and vent stack or kitchen or bathroom 

waste pipe etc.  See Figs 1 and 2.

Condensate Pump

Where gravity discharge to an internal termination is not physically 

possible or where very long internal pipe runs would be required 

to reach a suitable discharge point, a condensate pump of a 

specification recommended by the boiler or pump manufacturer 

should be used terminating into a suitable internal foul water 

discharge point such as an internal soil and vent stack or internal 

kitchen or bathroom waste pipe etc. (fig 3).

External Drain Connections

The use of an externally run condensate drainage pipe should 

only be considered after exhausting all internal termination options 

as described previously.  An external system must terminate at a 

suitable foul water discharge point or purpose designed soak away.  

If an external system is chosen then the following measures must 

be adopted:
The external pipe run should be kept to a minimum using the most 

direct and “most vertical” route possible to the discharge point, with 

no horizontal sections in which condensate might collect.

-  For connections to an external soil/vent stack see Fig 4.  

Insulation measures as described should be used.

-  When a rainwater downpipe is used, an air break must be 

installed between the condensate drainage pipe and the 

downpipe to avoid reverse flow of rainwater into the boiler 

should the downpipe become flooded or frozen, see Fig 5.

-  Where the condensate drain pipe terminates over an open 

foul drain or gully, the pipe should terminate below the grating 

level, but above water level, to minimise “wind chill” at the open 

end.  The use of a drain cover (as used to prevent blockage by 

leaves) may offer further prevention from wind chill.  See Fig 6.

-  Where the condensate drain pipe terminates in a purpose 

designed soak away (see BS 6798) any above ground 

condensate drain pipe sections should be run and insulated as 

described above.  See Fig 7

Unheated Internal Areas

Internal condensate drain pipes run in unheated areas, e.g. lofts 

basements and garages, should be treated as external pipe.

Ensure the customer is aware of the effects created by a frozen 

condensate and is shown where this information can be found in 

the user manual.

Boiler

with 75mm 

sealed 

condensate 

trap

Min Ø 19mm 

Internal pipe

Minimum 

connection 

height up to 3 

storeys

Soil & vent stack

≥ 450

75

Boilers without 75mm sealed 

condensate trap must be fitted with 

a 75mm trap and visible air break

Sink/basin/

bath or

shower

Boiler

with 75mm 

sealed 

condensate 

trap

Min Ø 19mm 

Internal pipe

Internal soil & vent stack

Boilers without 75mm sealed 

condensate trap must be fitted with 

a 75mm trap and visible air break

75

≥ 100

≥ 100

Figure 1

 - Connection of Condensate Drainage Pipe to 

Internal Soil & Vent Stack

Figure 2

 - Connection of a Condensate Drainage Pipe 

Downstream of a Sink, Basin, Bath or Shower Water Trap to 

Internal Soil Vent Stack

continued . . . . . 

INST

ALLA

TION