8.2 - FAILURE TO DEPRESSURISE (cont)
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VISUAL
INDICATION
Neon indicator
light off
Failure to change
All gauges
showing pressure.
Failure to exhaust
POSSIBLE CAUSE
Incoming supply
failure.
All gauges showing
line pressure.
Air leaking from
exhaust port on
changeover valve
All gauges showing
line pressure
Air leak from ’NOT’
logic
CHECK
Sticking valve stems due to
desiccant dust.
Weak signal to operate
inlet valves. Damaged
O-ring on spool in
changeover valve,
damaged seal on inlet
cylinder
No signal to open exhaust
cylinders, cam timer not
rotating.
Faulty seals on cylinder
Faulty ’NOT’ logic
REMEDY
Check power supply
Clean and renew where
necessary. Check desiccant
condition.
Check for air leaks on valve
fittings, Replace if
necessary. Replace
changeover valve. Check
and renew cylinder seals
where necessary.
Check electrical supply.
Check fuses. Check cam
timer is turning.
Check, and renew where
necessary.