TABLE 9 : SYSTEM ALARM/FAULT INDICATION WITH A SERVICEABLE GAS
Possible cause
Remarks/rectification action
1. Electrical power failure
Check POWER ON indication is
illuminated and other indications are
normal
2. Gas service pressure .
Independently check gas service
incorrect
pressure in area being monitored
3. Pressure switch stuck in fail
Check resistance of interconnecting
position
wiring, line monitor module and
pressure switch.
(180 +/- 5% ohms with contacts closed)
(690 +/- 5% ohms with contacts open)
If value is incorrect check continuity
exists through pressure switch. Check
pressure switch adjustment and
replace switch as necessary, complete
with line contact module
4. Wiring defect between panel With a serviceable pressure switch
and pressure switch
fitted, check resistance of
interconnecting wiring and line
monitor module (<10 ohms indicates
a short circuit or > 5K ohms indicates
an open circuit). Locate wiring defect,
repair as necessary or replace
line monitor module.
5. Main ribbon connector faulty
Check main ribbon connector on
power supply pcb. Replace power
supply pcb as necessary (Para 4.9)
6. Main ribbon damaged
Check main ribbon cable. If damaged
replace light display pcb (Para 4.8)
7. Power supply pcb faulty
Replace power supply pcb (Para 4.9)
8. Light display pcb faulty
If all other checks have failed to rectify
the fault, replace the light display
pcb (Para 4.8)
5. FAULT DIAGNOSIS
continued
