8.3 - FAILURE TO REPRESSURISE
Page 32 of 34
VISUAL
INDICATION
Column not
achieving line
pressure before
changeover.
Depressurisation
Dryer fails to
pressurise
Audible noise loss
of gauge pressure.
No system air
pressure inlet air
only
POSSIBLE
CAUSE
Slow
repressurisation
No air from exhaust
when dryer
depressurised.
Loss of line pressure
exessive.
Depressurisation
after switching.
Dryer pressurised on
one side only
Air leaks
Inlet pressure gauge
reading line
pressure, column
gauge reading zero
Dryer locked off
CHECK
Q.R. valve not opening
(SAR only)
Purge valve closed or
blocked
Damaged valve disc
Sticking valve stem
Damaged guide bush
Broken or damaged exhaust
valve disc. Exhaust valve
unable to close.
Cam timer rotation
Electrical supply
Damaged seals/ ’o’ rings
gasket failure, Damaged
pipe/tube connections
Both inlet valves closed
REMEDY
Check control signal from
logic element (black control
pipe)
If OK change valve.
If no signal change logic
Check and adjust where
necessary.
Check and renew where
necessary.
Check and renew where
necessary.
Change cam timer.
Change fuse.
Change ’o’ rings and
gaskets if necessary.
Replace faulty fittings /
seals and logic elements
where necessary.
Check control pipework to
cylinders have not been
removed and giving wrong
signal. Remove inlet
flexipipe and manually
move back inlet cylinders.
slowly reintroduce system
air into dryer.
