HELiOS Portables Technical Service Manual • PN 20562190 Rev E
47
HELiOS P
or
tables
Troubleshooting & Repair Procedures
XI
RP19 – Demand Flow Control Valve Test
1. Make sure the unit has been leak tested (RP2).
2. Fill the H300 or H850 from a properly saturated source of
liquid oxygen.
3. Allow the unit to sit undisturbed for approximately 30 min-
utes to allow it to stabilize at its primary relief valve pres-
sure.
4. Attach a calibrated flow meter to the top cannula barb on the
H300 or H850 using a length of 3/16 in (0.48 cm) diameter
tubing (B-778214-00) if necessary.
5. Set the flow control valve to its lowest demand setting (1 on
the H300, D1.5 on the H850).
6. Verify that there is no oxygen flow from the unit and the
flow meter reads “0”.
7. Disconnect the calibrated flow meter.
8. Connect the Jet Venturi assembly (B-778210-00) to the bot-
tom cannula barb on the front of the H300 or H850.
9. Connect the DISS nut and tailpiece of the Jet Venturi assem-
bly to a 0-6.90 bar (0-100 psi) source of gaseous oxygen.
10. Slowly increase the pressure of the gaseous oxygen source
until a continuous flow comes from the top cannula barb.
11. Reconnect a calibrated flow meter as described in step 4.
12. Check the demand inspiration tailflow at each demand flow
setting. Verify that they are within the ranges listed in Table
7 (H300) or Table 8 (H850).
13. Disconnect the Jet Venturi assembly from the unit.
14. Set the flow control knob to the lowest continuous flow set-
ting (0.12 for the H300, C1 for the H850)
15. Check the continuous flow at each flow setting. Verify that
they are within the ranges listed in Table 6 (H300) or Table
7 (H850).
16. Disconnect the test flow meter.
17. Attached a dual lumen cannula to the H300 or H850.
18. Adjust the cannula to your face and breathe normally.
19. At all demand flow settings, verify that oxygen flow cycles
on and off in response to your inhalation and exhalation.
Verify that you sense a brief “puff” of oxygen at the begin-
ning of each inhalation.
20. Disconnect the cannula.
NOTE: Do not block the open “bleeds” on the Jet Venturi
assembly. This can cause damage to the flow control valve.
Figure 46:
Jet Venturi Assembly Attachment
NOTE: If continuous flow does not occur at these flow settings,
reset the demand valve by blowing across (not into) the bottom
cannula barb or by attaching a dual lumen cannula to the bottom
cannula barb and breathing in once or twice.
Flow
Setting
Measured Flow
Specification
(LPM)
Acceptable
Range (LPM)
0
None
0.00
0.00
0.12
Continuous
0.12
0.02 - 0.22
0.25
Continuous
0.25
0.10 - 0.40
0.5
Continuous
0.50
0.35 - 0.65
0.75
Continuous
0.75
0.60 - 0.90
1
Tail Flow
0.50
0.35 - 0.65
1.5
Tail Flow
0.65
0.50 - 0.80
2
Tail Flow
0.75
0.60 - 0.90
2.5
Tail Flow
1.00
0.85 - 1.15
3
Tail Flow
1.50
1.30 - 1.70
3.5
Tail Flow
1.75
1.40 - 1.90
4
Tail Flow
2.00
1.70 - 2.30
Table 7:
H300 Flow Tolerance
