Pressure control/
hold time/vent cycle
Pump with internal pressure
switch only
Internal pressure switch closes at
psi
(240 bar)
and opens at
psi
(179 bar)
.
After pump starts a lubrication cycle,
motor stops when pressure at pump reaches
preset pressure of psi
(240 bar)
.
Pumpgoes through two holding periods:
H
and
H
.
Holding time (H)
• Internal pressure switch must stay closed
for consecutive seconds before going to
H
. If internal pressure switch opens dur-
ing the seconds, pump restarts and
runs until internal pressure switch closes.
Holding time (H) – will last for
seconds
• At end of seconds, if internal pressure
switch is closed, pump begins vent cycle.
• If at end of seconds internal pressure
switch is open, pump restarts and runs
until internal pressure switch closes.
When it closes, vent cycle takes place.
• If at end of seconds internal pressure
switch is closed, but during
H
hold time
internal pressure switch did open, pump
restarts and pumps for seconds before
vent cycle begins.
Possible faults
•
E
Fault – failure to build pressure at
pump within allotted minutes of
pumping time.
•
E
Fault – failure to vent at pump.
Internal pressure switch has seconds
to open when motor reverses to locate
vent position.
Pump with internal and
external pressure switch
Internal pressure switch closes at
psi
(240 bar)
and opens at
psi
(179 bar)
. External pressure switch
closes at psi
(172 bar)
and opens at
psi
(131 bar)
.
After pump starts lubrication cycle, motor
stops when pressure at pump reaches preset
pressure of psi
(240 bar)
. Pump can
go through three holding periods:
H
,
H
and
H
.
Holding time (H)
• Internal pressure switch must stay closed
for consecutive seconds before going
to
H
. If internal pressure switch opens
during seconds, pump restarts and
runs until internal pressure switch closes.
Holding time (H) – lasts for
seconds
• At end of
H
, if internal pressure switch
is closed and external pressure switch is
closed, pump begins vent cycle.
• At end of
H
, if internal pressure switch
is open or both internal and external
pressure switches are open,
H
appears
on display. Pump turns on again and
pumps until internal pressure switch is
closed. When both internal and external
pressure switches are closed, vent cycle
takes place.
• If at end of
H
internal pressure switch is
closed but external pressure switch is
open, pump turns on for seconds and
then stops and waits until external
pressure switch closes.
H
appears on
display. When both internal and external
pressure switches are closed, vent cycle
takes place.
Holding time (H)
• Holding time
H
remains until both
internal and external pressure switches
are closed and then vent cycle takes place.
If both pressure switches do not close
within allotted pumping time of min-
utes, alarm occurs. If internal pressure
switch opens during
H
, it repumps until
internal pressure switch closes.
Possible faults
•
E
Fault – failure to build pressure at
pump within allotted minutes of
pumping time.
•
E
Fault – failure to build pressure at end
of supply line.
•
E
Fault – failure to vent at pump.
Internal pressure switch has seconds to
open when motor reverses to locate
vent position.
•
E
Fault – failure to vent at end of supply
line. External pressure switch must be
open before next lube cycle takes place.