Installation manual

Installation and servicing instructions strictly reserved for qualified gas installers
23
Valve outlet size Minimum size
of discharge
to tundish D1
Minimum size of
discharge pipe
D2 from tundish
Maximum resistance
allowed expressed as
a length of straight pipe
i.e. no elbows or bends
Resistance
created by
each elbow
or bend
G 1/2” 15 mm 22 mm
28 mm
35 mm
up to 9 m
up to 18 m
up to 27 m
0.8 m
1.0 m
1.4 m
G 3/4” 22 mm 28 mm
35 mm
42 mm
1.0 m
1.4 m
1.7 m
G 1” 28 mm 35 mm
42 mm
54 mm
1.4 m
1.7 m
2.3 m
500 mm
max.
300 mm max.
1
3
2
4
Legend
1 Safety device eg. temperature relief
valve
2 Tundish (supplied)
3 Trapped gully
4 Fixed grating
Discharge pipe D1: from temperature relief
valve to tundish.
Discharge pipe D2: from tundish with
continuous fall.
See table above for size examples. •
2
1
D2
D1
Legend
1 Tundish (supplied)
2 Gully
D1 Discharge pipe
D2 Discharge pipe
Discharge pipe D1: from heating safety
valve on jig.
Discharge pipe D2: from domestic hot
water safety valve.