Technical information

19
iii) Discharges at high level; I.e. into a metal hopper and metal down
pipe with the end of the discharge pipe clearly visible (tundish visible or
not).
O
r onto a roof capable of withstanding high temperature discharges of
water 3m from any plastic guttering systems that would take such a
discharge (tundish visible).
iv) Where a single pipe serves a number of discharges, such as in
blocks of flats, the number served should be limited to not more than 6
systems so that any installation can be traced reasonably easily.
500 mm Max.
3
00 mm
Min.
Temperature & pressure
r
elief valve
Metal discharge pipe (D1) from
t
emperature & pressure relief valve.
to tundish.
Metal discharge pipe (D2) from tundish
w
ith continuous fall. See Table 2 and worked
example.
Tundish
F
ixed grating
Trapped gulley
Discharge below
f
ixed grating.
(see page 6 for
a
lternative points
of discharge).
Fig.10.4
The single common discharge pipe should be at least one pipe size large
than the largest individual discharge pipe to be connected.
If unvented hot water storage systems are installed where discharges
from safety devices may not be apparent I.e. in dwellings occupied by
the blind, infirm or disabled people, consideration should be given to
the installation of an electronically operated device to warn when
discharge takes place.
Note: The discharge will consist of scalding water and steam. Asphalt,
roofing felt and non-metallic rainwater goods may be damaged by such
discharges.
Warning
The outlet from the temperature & pressure relief valve must not be
used for any other purpose.
The temperature & pressure relief valve must not be removed in any
circumstances. Any of the above will totally invalidate the warranty.
Note
The discharge from the central heating and domestic hot water systems
may be joined together after the tundish.
Air Release Points:
These must be fitted at all high points where air naturally collects
and must be sited to facilitate complete filling of the system.
The appliance has an integral sealed expansion vessel to
accommodate the increase of water value when the system is
heated.