A
XES SC MANUAL
IOM-58
28 of 30
June 14 R5
OUTDOOR AIR INTAKES, MIXING SECTIONS AND DAMPERS
Outdoor air intakes, screens, and adjacent areas shall be checked semi-annually for cleanliness, integrity
and proper operation. Adjust dampers where required.
SAFETY SHUTOFF VALVE LEAK TEST:
Safety shutoff valves require a qualified technician to perform a leak (bubble) test to determine tightness
of closure on a least an annual basis. A very small amount of leakage is normal. Valve leakage rates
exceeding those noted in the table below require repair or valve replacement. For more detailed valve
leak test instructions, refer to the valve manufacturer’s instructions.
1.
De-energize the control system.
2.
Close the upstream manual gas valve.
3.
Connect a ¼” (6mm) tube to the outlet
pressure tap on the safety shutoff valve.
4.
Immerse the opposite end of the ¼” (6mm)
tube (cut to a 45° angle) vertically ½”
(13mm) into a clear container of water.
5.
Count the number of bubbles appearing
during a 10 second period.
6.
If the bubble rate is greater than that noted
in the table repair or replace the valve.
7.
If bubble rate is less than noted in the table,
remove the ¼” (6mm) tube, reconnect the
outlet pressure tap plug.
8.
Energize the control system and open
upstream manual gas valve.
9.
After testing check all piping connections
and plugs for external leakage.
The maximum leakage rate (bubbles/10sec.) is 6.
1/2 (13mm)
CUT AT
45 DEGREE
ANGLE
JAR OR GLASS WITH WATER
1/4 IN (6MM) ALUMINUM OR
COPPER PILOT TUBING
1/4 (6MM) FLEXIBLE TUBING
GAS SUPPLY
UPSTREAM
MANUAL
GAS COCK
PVR
SSOV
MANUAL
GAS COCK
DOWNSTREAM
TEST
TAP
LEAK
A
B
C
E
D
1
CAN ALSO BE A PERMANENT PETCOCK.
PRV = PRESSURE REGULATING VALVE.
2
USE ONLY ONE OF THE DOWNSTREAM TAPS ON THE SSOV.
SSOV = SAFETY SHUTOFF VALVE.
4
3
Fig. 5 Valve Leak Test.
2
3
4
DOWNSTREAM
GAS COCK
MANUAL
1
F
