Ecodan 150 Standard Installation And Servicing Instructions page 21

Table 5 - Sizing of copper discharge pipe (D2) for common temperature relief valve outlet sizes
VALVE OUTLET SIZE
G 1/2
G 3/4
G1
NOTE: The above table is based on copper tube. Plastic pipes may be of different bore and resistance. Sizes and maximum
lengths of plastic should be calculated using data prepared for the type of pipe being used.
Fig. 8: Typical discharge pipe arrangement (extract from Building Regulation G3 Guidance section 3.5)
Safety device
(e.g. Temperature
relief valve)
600mm maximum
Discharge pipe (D2 from tundish,
with continuous fall. See Building
Regulation G3 section 3.56,
Table 4 and worked example)
MINIMUM SIZE OF MINIMUM SIZE OF
DISCHARGE PIPE DISCHARGE PIPE
D1 D2 FROM TUNDISH
15mm
22mm
28mm
Metal discharge pipe (D1) from
Temperature relief valve to tundish
Tundish
300mm
minimum
MAXIMUM
RESISTANCE
ALLOWED,
EXPRESSED AS
A LENGTH OF
STRAIGHT PIPE (i.e.
NO ELBOWS OR
BENDS)
22mm UP TO 9m
28mm UP TO 18m
35mm UP TO 27m
28mm UP TO 9m
35mm UP TO 18m
42mm UP TO 27m
35mm UP TO 9m
42mm UP TO 18m
54mm UP TO 27m
RESISTANCE
CREATED BY EACH
ELBOW OR BEND
0.8m
1.0m
1.4m
1.0m
1.4m
1.7m
1.4m
1.7m
2.3m
Discharge below
xed grating
(Building Regulation
G3 section 3.61 gives
alternative points
of discharge)
Fixed grating
Trapped
gully
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