19
6.2.6
Termination of Discharge Pipe
Download discharge at low level, i.e. up to 100 mm above external surfaces such as car parks, hard standings,
grassed areas etc, are acceptable providing that where children may play or otherwise come into contact with
discharges, a wire cage or similar guard is positioned to prevent contact, whilst maintaining visibility.
Discharge at high level, i.e. into a metal hopper and metal down pipe with end of the discharge pipe clearly visible
(tundish visible or not) or onto a roof capable of withstanding high temperature discharges of water and 3 m from any
plastic guttering system that would collect such discharges (tundish visible). 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 discharging can be traced reasonably easily. The single common discharge pipe should be at least one
pipe size larger than the largest individual discharge pipe to be connected. For further information contact your
Building Control Office or The British Board of Agreement.
Metal discharge pipe (D1)
from temperature
relief valve to tundish
Discharge below
fixed grating
(3.61 gives alternative
points of discharge)
Fixed grating
Trapped gulley
600 mm
maximum
300 mm
minimum
Discharge pipe (D2) from
tundish with continuous fall.
See 3.56, Table 1
and worked example
Safety device
(e.g. temperature
relief valve)
Tundish
Table 1
Product code
Max. design
pressure
Operating pressure
CW feed & coil
Pressure drop
Primary heater
Temp./pressure
Relief valve
Safety valve
Pressure/conn.
Exp. Vessel
pre charge
WH-TD20E3E5-UK
8bar
CW in 2bar, coil 2bar
0.09bar
90 - 95°C/10bar
8bar/15mm-1/2"
3.5bar
WH-TD30E3E5-UK
8bar
CW in 2bar, coil 2bar
0.11bar
90 - 95°C/10bar
8bar/15mm-1/2"
3.5bar
Table 2
Product code
Actual
capacity
Heat-up (min)
coil
Rating (kW)
coil
Heat loss
kWh / 24h
Primary
Flow rate
Hot Water
Capacity
WH-TD20E3E5-UK
198 l.
21
26.9
1.9
(15 l/min, - 80°C)
179 l.
WH-TD30E3E5-UK
287 l.
32
22.8
2.3
(15 l/min, - 80°C)
237 l.