Sechrist Millennium Technical Bulletin 001

Sechrist Millennium Technical Bulletin 001
Sechrist Millennium Technical Bulletin 001
Cannot Reset“A01: Low / Loss of Inlet Gas Pres” Alarm
“hysteresis” pressure range is typically 8 ~ 18
PSIG (0.56 ~ 1.27 kg/cm2, 55.2 ~ 124.1 kPa).
Understanding A01 Alarm
Example 2:
The “A01: Low / Loss of Inlet Gas Pres” alarm can be
activated if either or both of the following conditions do
not meet:
1. The air or oxygen inlet supply pressure must be
above 30 PSIG threshold (2.11 kg/cm2, 206.8
kPa);
2. The differential pressure between air and oxygen
inlet supplies must be less than 20 PSI (1.41
kg/cm2, 137.9 kPa).
When the alarm is activated, the “A01: Low / Loss of
Inlet Gas Pres” alarm message is displayed on the LCD
display panel. The red visual indicator and the audible
alarm are also activated. You cannot reset the alarm if it
is still active. If the alarm condition is corrected, both the
alarm message and the red visual indicator remain, but
the audible alarm is turned off automatically. The user
can press the Alarm Reset button to clear both the alarm
message and the red visual indicator.
NOTE: An exclamation mark (!) after the alarm
message indicates that the alarm is still active
and cannot be reset using the Alarm Reset
button.
NOTE: An exclamation mark with dots (.!.) after the
alarm message indicates that there are more
than one alarms occurring at the time.
If both air and oxygen inlet supplies are initially set at 40
PSIG (2.81 kg/cm2, 275.8 kPa), and if the oxygen inlet
supply drops below its low threshold of 30 PSIG
threshold (2.11 kg/cm2, 206.8 kPa), the A01 alarm is
activated. No gas “bypassing” or “cross-over” function
from the air-oxygen mixer will take place because the
differential pressure is less than 20 PSI (1.41 kg/cm2,
137.9 kPa). If the oxygen inlet supply pressure is
restored above 31 PSIG (2.18 kg/cm2, 213.7 kPa) with a
relatively small “hysteresis” pressure, the audible alarm
is reset automatically. The visual indicator and A01
alarm message remain until user presses the Alarm Rest
button.
A01 Alarm Can Be Caused By:
a)
b)
c)
d)
e)
Low or loss of air inlet supply
Low or loss of oxygen inlet supply
Clogged inlet filter
Hospital gas supply regulator malfunction
Excessive pressure drop between hospital gas
supply source and the ventilator gas inlets
f) Unbalancing of air-oxygen mixer, i.e. differential
pressure between air & oxygen is greater than 20
PSI (1.41 kg/cm2, 137.9 kPa)
g) Air-oxygen mixer malfunction
h) Inlet air pressure transducer malfunction
i) Inlet oxygen pressure transducer malfunction
Example 1:
If both air and oxygen inlet supplies are initially set at 60
PSIG (4.22 kg/cm2, 413.7 kPa), and if the air inlet supply
drops below 40 PSIG (2.81 kg/cm2, 275.8 kPa), i.e. the
differential pressure is greater than 20 PSI (1.41 kg/cm2,
137.9 kPa), the A01 alarm is activated. At the same
time, the gas “bypassing” or “cross-over” function from
the air-oxygen mixer will start to replace the lost air with
oxygen to continue balancing the mixer. If the air inlet
supply rises above 50 PSIG (3.52 kg/cm2, 344.7 kPa)
with a pneumatic “hysteresis” of approximately 10 PSIG
(0.70 kg/cm2, 68.9 kPa), the gas “bypassing” or “crossover” function ceases, and the A01 alarm can then be
reset.
Inlet Gas Supply Requirements
a) Air:
30 to 60 PSIG
Medical Grade
2.11 to 4.22 kg/cm2
206.8 to 413.69 kPa
b) Air Fitting:
No. 1160A (Male), CGA-DISS with
Filter & Water-trap
c) Oxygen:
30 to 60 PSIG
Medical Grade
2.11 to 4.22 kg/cm2
206.8 to 413.69 kPa
d) Oxygen Fitting: No. 1240 (Female), CGA-DISS
NOTE: The higher the gas inlet pressure, the higher the
pneumatic “hysteresis” pressure is to be
overcome to reset A01 alarm. The pneumatic
Page 1
Verify If Air-Oxygen Mixer / Cross-Over Assembly
Malfunctions
Verify If Air Or Oxygen Pressure Transducer
Malfunctions
a) Open the Millennium back cover to expose the airoxygen mixer.
b) Set both air and oxygen inlet supplies to 50 PSIG.
c) If A01 alarm is activated and cannot be reset…
d) Crimp off the 1/16” tubing immediately from output
port of the cross-over assembly residing below the
air-oxygen mixer (see figure below).
e) If audible alarm is reset automatically, press Alarm
Reset button.
f) If visual indicator and A01 alarm message is
cleared,
then
Air-Oxygen
Mixer/Cross-Over
assembly is malfunctioned and should be serviced
by authorized personnel.
a) Setup the test system as shown in figure below.
b) Adjust both regulators to 0 PSIG.
c) Connect the Test Fixture directly to the DC Power
input.
d) Hold down the Calibration button (CAL) on the Test
Fixture and turn the Power (I/O) toggle switch to ON.
e) Millennium will enter pressure transducer calibration
mode.
f) Verify that both air & oxygen pressure transducers
@ 0 PSIG are between 6 and 95 raw counts (51
nominal).
g) Adjust air inlet regulator to 30 PSIG (2.11 kg/cm2,
206.8 kPa), verify that the raw counts are between
98 and 250 (181 nominal).
h) Adjust oxygen inlet regulator to 30 PSIG (2.11
kg/cm2, 206.8 kPa), verify that the raw counts are
between 98 and 250 (181 nominal).
i) If both air and oxygen pressure transducers are
within specifications, then the transducers are
functioning normally.
j) Otherwise, the failed transducer should be replaced
by Sechrist service technician.
AIR /
OXYGEN
MIXER
AIR
OXY
IMPORTANT: The above procedure is for
verification only. DO NOT PRESS ANY FRONT
PANEL PUSH-BUTTONS (As it might change the
calibration settings). Once verification of air or
oxygen is completed, make sure to turn the Power
(I/O) toggle switch of the Test Fixture to OFF to
exit the pressure transducer calibration mode.
CROSSOVER
ASSY
CRIMP HERE
MILLENNIUM
0-100 PSI
AIR
OXY
OXYGEN INLET
SUPPLY
PRESSURE
REGULATOR
0-100 PSI
AIR INLET
SUPPLY
TEST FIXTURE
P/N 80251
PRESSURE
REGULATOR
AC SUPPLY
AC ADAPTER
Millennium Technical Bulletin 001
Rev. B, 02/05
Page 2
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