Technical data
Hydraulic installation
Installation and maintenance instructions ecoTEC plus 0020116700_06  23
6
6.5  Low loss header 
A low loss header disconnects the boiler from the heating 
system. The system is no longer dependent on the remain-
ing feed head of the boiler. In conjunction with the boiler 
circulation pump, the low loss header ensures that a suffi-
ciently high minimum quantity of water is always circulating 
through the boiler. No electrical accessories are required in 
order to use a low loss header.
6.6  Connecting the condensate discharge 
pipework
a
 Danger!
Risk of death from flue gases!
Due to an empty or insufficiently filled con-
densate trap, flue gases may escape into 
the room air.
 > Make sure that the condensate water 
siphon is filled with water when switching 
on the boiler.
The ecoTEC plus boilers are equipped with a condensate 
siphon. (The filling height is 145mm). The siphon collects 
the condensate that has formed in a vessel with a capacity 
of approx. 200 ml, and intermittently deposits the contents 
to the discharge pipe. This minimises the risk of the dis-
charge pipe freezing up. 
7 
d 
Soakaway 
c 
6 
5 
Gulley 
a 
Internal 
stackpipe 
3 
4 
3 
b 
Internal 
discharge system 
11
2
3
6.4  Condensate discharge pipework
 > Connect the condensate discharge (1) of the boiler to a 
condensate discharge pipework (3) which has a minimum 
internal diameter of 19mm (22mm outside diameter for 
all external pipes) and is made from an acid-resistant 
material (e.g. plastic overflow pipe).
i
  The condensate discharge pipework must have a 
continuous fall (45mm per metre) and should 
whenever possible terminate at a suitable dis-
charge point within the heated envelope of the 
building that will remain frost free under long 
periods of low external temperatures. 
 > During installation remove all burs from inside of cut 
pipe work and avoid excessive adhesive which may trap 
small pockets of water close to the pipe wall which can 
freeze and build into a larger ice plug. 
 > As with other pipe work insulate the condensate dis-
charge pipe to minimise any risk of freezing and beware 
when crossing cavities that the fall is maintained and the 
pipe sleeved.
 > The condensate discharge pipework must terminate in a 
suitable location.
Further information can be obtained from "BS 6798 Specifi-
cation for installation of gas–fired boilers of rated input not 
exceeding 70 kW net". The condensate siphon (2) must be 
filled with water as described in the relevant section before 
the boiler is commissioned.
6.7  Connecting the discharge pipe to the 
expansion relief valve on the boiler
The expansion relief valve for the heating installation is 
integrated in the boiler.
 > Install the discharge pipe for the expansion relief valve 
so that it does not interfere with the removal and fitting 
of the condensate trap.
i
  We recommend not to shorten the discharge 
pipe supplied.
 > Leave an installation space of at least 180mm beneath 
the condensate siphon.
min.
180
1
2
3
6.5 Fitting the discharge pipe to the expansion relief valve 
(example: VUW boiler)










