17
5.9 Annual inspection of safety valves
MAINTENANCE INSTRUCTIONS
!
Maintenance should be carried out by persons over 18 years of age, with sufficient
understanding.
!
Annual inspection of safety valves:
- Open valve for 1 min. by turning the knob (K) approx. 90 degrees to the open position.
- Visually check that the water is flowing freely to the drain.
- YES = OK. Close the valve by turning the knob (90) a further 90 degrees to the
closed position.
- NO = NOT OK. Disconnect power supply / shut off water supply. Contact installer.
K
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 hop-
per and metal down pipe with the 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 plastics guttering system that would
collect such discharges (tundish visible).
Where a single common discharge pipe serves
more than one system, it should be at least one
pipe size larger than the largest individual dis-
charge pipe (D2) to be connected.
For further information contact your Building
Control Office.
Valve Outlet size
Minimum size
of discharge
pipe D1
Minimum size of
discharge pipe D2
from tundish
Maximum resistance allowed
expressed as a length of straight
pipe (i.e. no elbown 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
Safety device
(e.g. temperature
relief valve)
Metal discharge pipe (D1) from
temperature relief valve to tundish
600 mm.
maximum
Tundish
300 mm.
minimum
Discharge pipe (D2) from tundish,
with continous fall. See table and
worked example.
Discharge below
fixed grating
(see text for alternative
points of discharge)
Fixed grating
Trapped gulley
