3. Compare the measured value with the checking values in the table.
Tab.49 Checking/setting values for O
2
/CO
2
at low load for G20 (H
gas)
Values at low load for G20 (H gas)
O
2
CO
2
(%)
Gas 320 Ace 285
4.8
Gas 320 Ace 355
4.8
Gas 320 Ace 430
4.8
Gas 320 Ace 500
4.8
Gas 320 Ace 575
4.8
Gas 320 Ace 650
4.8
Gas 620 Ace 570
4.8
Gas 620 Ace 710
4.8
Gas 620 Ace 860
4.8
Gas 620 Ace 1000
4.8
Gas 620 Ace 1150
4.8
Gas 620 Ace 1300
4.8
(1) Nominal value
(2) Nominal value
4. If the measured value is outside of the values given in the table,
correct the gas/air ratio.
5. Use the adjustment screw B to set the percentage of O
2
/CO
2
for the
gas type being used to the nominal value.
Increasing the gas flow, will decrease O
2
and increase CO
2
. The
direction in which the adjusting screw must be turned to increase or
decrease the gas flow is indicated on the gas control valve. The 5- to
9-section boilers are supplied with a different gas control valve from
the 10-section boiler. See drawing for the position of adjusting screw
B for low load.
6. Check the flame through the inspection glass. The flame must not
blow off.
7. Repeat the full load test and the low load test as often as necessary
until the correct values are obtained.
8. Set the boiler back to the normal operating status.
7.3
Final instructions
1. Remove the measuring equipment.
2. Screw the cap on to the flue gas measuring point.
3. Seal the gas valve unit.
4. Put the front casing back.
5. Heat up the central heating system to approximately 70°C.
6. Switch the boiler off.
7. Vent the central heating system after approx. 10 minutes.
8. Turn on the boiler.
Fig.78
Adjusting screw B
AD-0000493-01
B
3
B
2.5
7 Commissioning
50
7734324 - v.03 - 29092020
