Steris SYSTEM 1E, Maintenance Manual

Page: 43 / 179

3-5
764333-675
The stabilization phase starts immediately after
pressure is reached in the filter housing. A 3-minute
timer is started and the air compressor is controlled
to maintain filter housing pressure between 51.73
and 58.75 psig. This phase pushes any water out of
the filter and housing. If the air compressor cannot
maintain air pressure between this range, the test is
aborted.
• Monitoring
At the beginning of the monitoring phase, solenoid
8 is closed, sealing off the housing of the MaxPure
Filter, and the air compressor is turned off. After
15 seconds, the pressure is recorded and a 2-minute
timer is started. At the end of the 2 minutes, the
pressure is recorded and matched against the
starting pressure. If the pressure drop is greater than
4.4 psig, the filter flows more than the allowed rate
and the test is aborted.
3.3.3 Air Manifold Description
Air from air compressor (COMP1) enters air manifold
at fitting.
NOTE: Air compressor (COMP1) maintains 31 to
43 psi in the air system.
SOL1 is de-energized when the compressor is turned
off to vent the compressor output line to atmosphere.
This prevents the compressor from starting while
under load. SOL1 is also energized when the
compressor is turned on. Air manifold check valve
(CK5) prevents loss of system air pressure.
Compressor control switch (LS5) controls air
compressor operation. It opens at 40 + 3 psi, turning
the compressor off; and closes when pressure drops by
5 + 1 psi, turning the compressor on.
Inflatable seal is inflated through air manifold check
valve (CK7) and air pressure regulator, which limits
air pressure in seal to 40 psig until SOL2 is energized
open, venting the seal to atmosphere.
LS2 prevents water flow related components from
energizing until seal pressure reaches 30 + 3 psi, at
which pressure the switch closes. Should the seal
pressure drop below 24.5 + 4.5 psi during operation,
LS2 opens, and the cycle ends (aborts). The drain
sequence is initiated following an abort.
Air-water solenoid valve (SOL8) is used only during
the membrane test for the MaxPure Filter.
Air pressure to operate the drain and circulation pinch
valves is supplied through fittings. These pinch valves
are operated by the circulation pinch valve and the
drain pinch valve solenoid (SOL3 and SOL4).
The pinch valves are used for holding water in the unit
and diverting water to drain.
A list of the components used in the unit is shown in
Table 3-1 .
3.4 PRINCIPLES OF
OPERATION – LIQUID CHEMICAL
STERILIZATION PROCESSING
CYCLE DESCRIPTION
Event 0
– This is an out-of-cycle condition with power
supplied to the unit. All solenoid valves are OFF at
this point.
Event 1 – Cycle Start: The operator must press START
button. Control checks lid switch (LS4) for a latched
lid. If lid is latched, control progresses to
Event 2 .
If at any time during the cycle LS4 is detected open,
an alarm occurs and the cycle aborts. (Alarm:
"CHAMBER OPEN".
)
A. The control begins monitoring TC1 and TC2, if
either exceeds 60°C, the cycle aborts. The control
monitors the temperature for the duration of the
cycle.
B. The control checks the UV intensity when the
cycle start button is pressed. If the intensity is less
than 6.0 mA, the control does not start the cycle.
Once the UV intensity is above the 6.0 mA
setpoint, the control starts the cycle.
C. The control verifies the MaxPure Filter life and
will not start the cycle if the filters has been in use
for more than 90 days.
D. When HTR1 is on, if TC1 and TC2 reach >7
degrees difference an abort is called. (ALARM:
"HEATER PROBLEM" .)
Event 2 – Compressor Operation : The control enables
output to air compressor (COMP1) and SOL1,
inflating the seal. LS5 controls COMP1 output
pressure. Note that LS2 is activated by compressed
air and allows electrical power to be supplied to
various components. Control also prints header on
cycle tape. While header is printing, control
progresses to
Event 3 .
Event 3 – Seal Inflation : Control allows 10 seconds for
seal inflation. After 10 seconds, control progresses to
Event 4 .
Event 4 – HP Pump OFF Test: H.P. pump monitor
(pressure switch)(LS6) checked for open condition.
Since the P2 H.P. Pump is not running at this point,
LS6 should not be activated. This step verifies the
switch has not failed in the closed condition. If LS6
is open, control energizes drain pinch valve solenoid
(SOL4) and SOL5. Control progresses to
Event 5 . If,
however, LS6 is sensed closed, an alarm occurs and
the cycle aborts. (Alarm:
"HP PUMP FAILURE:
PUMP OFF". )