Installing the System Piping 37
Routing of Pipework
The condensate pipework must fall at least 50mm per metre
away from the boiler, taking the shortest practical route to the
termination point.
Support the pipe at least every 50 cm for near horizontal
sections and 1 metre for vertical sections.
Wherever possible, the condensate pipework should be routed
internally to prevent freezing. 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 Pipework
Wherever possible, the condensate drainage pipe should be
terminated at a suitable internal foul water discharge point such
as (a) an internal soil and vent stack or (b) an internal kitchen
or bathroom waste pipe, washing machine waste pipe etc. A
suitable permanent connection to the foul waste pipe should be
used.
The possibility of waste pipes freezing downstream of the
connection point should be considered when determining a
suitable connection point - e.g. a slightly longer pipe run to an
internal soil stack may be preferable to a shorter run connecting
into a kitchen waste pipe discharging directly through the wall
to an external drain.
Where “gravity discharge” to an internal termination is not
physically possible (e.g. the discharge point is above the
appliance location, or access is obstructed by a doorway), or
where very long internal pipe runs would be required to reach
a suitable discharge point, the following measures may be
adopted.
Use of a Condensate Pump
Condensate can be removed using a condensate pump, of a
specification recommended by the pump manufacturer.
The pump outlet should discharge to a suitable internal foul
water discharge point, such as (a) an internal soil and vent stack
or (b) an internal kitchen or bathroom waste pipe, washing
machine waste pipe etc.
A suitable permanent connection to the foul waste pipe should
be used and the manufacturer’s detailed installation instructions
for the pump should be followed.
If you are using a condensate pump, ensure that the pump
allows for up to 3.78 LPH of drainage for each boiler in the
system.
4.5 Connecting the Condensate Drain
Line
The Navien NCB700 boiler creates condensation when it
operates. This condensation has an acidic pH of 3-5. Follow all
local codes and regulations when disposing of condensate from
the boiler (BS 6798).
CAUTION
●
Do not cap or plug the integrated condensate line. If
prevented from draining, condensate can damage the
boiler.
●
The condensate line must have a continuous fall
downwards to drain correctly.
The drain line can be connected to the condensate trap using
a condensate trap hose. The hose connection must be secured
with a hose clip.
Note
This hose is supplied along with the boiler.
Before putting the boiler into operation water must be poured
into the exhaust connection to fill the condensate trap.
Condensate Pipework
For correct condensate pipework installation, the tube must
have a minimum diameter 19 mm ID (Typically 22 mm OD).
The condensate pipework must be made of a material that can
withstand corrosion, e.g. PVC, PVC-U, ABS, PVC-C or PP. It must
not be made of metal.
For safety reasons, the end of the condensate pipework must be
as close as possible to the draining point.
