Precision Medical Air-Oxygen Blender - Manual (Page 29)

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Air-Oxygen Blender
SECTION 4: TROUBLESHOOTING
Test #’s Problem Probable Cause Remedy
1
Pressure drop greater
than 2 psi in two
minutes
Leakage from manifold caused by cut or
missing o-ring or due to particulates.
Check ALL manifold connections (inlets, outlets,
plugs, proportioning valve, alarm poppet, etc.) with
oxygen leak detector to find source of leakage; if leak
is found, remove appropriate parts and clean seal
area and o-rings and/or replace appropriate o-ring.
Aluminum Blocks ONLY
Leakage from diaphragm housing
caused by damaged diaphragm or
particulates.
Check diaphragm housings with oxygen leak
detector. If leak is found, replace with new
Engineered Composite Diaphragm Blocks.
Aluminum Blocks ONLY
Leakage from check valve/diaphragm
housing seal caused by cut or missing
o-ring or due to particulates.
Check check-valve/diaphragm housing seal with
oxygen leak detector. If leak is found, replace with new
Engineered Composite Diaphragm Blocks.
Ball not sealing in the alarm bypass. Replace spring and ball in alarm bypass; ensure
seal surface is clean.
Auxiliary bleed is open. Close auxiliary bleed by turning and pulling knurled
collar away from cover until bleed is closed.
Leakage from one of the outlets. Replace outlet.
2 and 3 Back flow leak Faulty inlet. Replace duckbill valve or entire inlet assembly.
4 thru 8
Measured F IO
2
values
do not meet target
values
Outlet flow is less than 3 lpm. Adjust flowmeter to 3 lpm ( Note: flow must be
adjusted after each change in F IO
2
setting).
Proportioning valve endpoints are not
set correctly.
Set proportioning valve endpoints (See setup
procedure in Section E) .
Diaphragm blocks not balancing
properly.
Replace with new Engineered Composite
Diaphragm Blocks.
Internal leakage in proportion valve. Remove proportioning valve; clean seal areas and/
or replace the two rear o-rings. If necessary, replace
proportioning valve assembly.
9 thru 11
Measured F IO
2
values
do not meet target
values
Bleed not open. Open bleed by turning and pushing the knurled
collar until it contacts the cover.
Blockage in bleed holes. Replace auxiliary outlet.
Internal leak in proportioning valve. Remove proportioning valve; clean seal areas and/
or replace the two rear o-rings. If necessary, replace
proportioning valve assembly.
Flow not set to 1 lpm. Adjust flow to 1 lpm.
Diaphragm blocks not balancing properly. Replace diaphragm block.
12 and 14 Alarm not audible and
gas is not exiting the
alarm vent
Pressure differential not sufficient to
trigger alarm.
Ensure supply pressures are set properly to achieve
differential ( Low Flow: 18 to 22; High Flow: 13 to 25).
Alarm not audible and gas
is exiting the alarm vent
Faulty alarm. Replace alarm. (See Figure C & M)
13 and 15
Alarm does not turn off
after balancing supply
pressures
Faulty alarm assembly. Replace alarm assembly. (See Figure D & K)
Ball not sealing in the alarm bypass. Replace spring and ball in alarm bypass; ensure
seal surface is clean.
16 thru 19
Measured flow values
do not meet minimum
target values
Gas inlets are restricted. Check appropriate gas inlet(s) for restriction in
gas pathway; replace duckbill or entire inlet as
necessary.
High flow model only: low flow inlets
installed in place of high-flow inlets.
Confirm that high-flow inlets are installed; replace
as necessary.
Alarm bypass is threaded too far into manifold
block (only applicable to tests 17 and 18).
Replace ball and spring (see Figure I for proper
assembly method).
High flow models only: wrong ball in
alarm bypass block (only applicable to
tests 17 and 18).
Confirm that correct ball is installed in alarm
bypass; replace as necessary.