HAMWORTHY HEATING LTD
25
MILBORNE
500001130/J
8. The gas valve throttle setting can now be
regulated.
This is a based on the flue gas combustion analysis
rather than a fixed pressure. Check the CO
2
values
in accordance with table 7.1. If the CO
2
values are
incorrect then adjustment must be made by
adjusting the gas valve throttle screw. Turning the
throttle screw anticlockwise increases the CO
2
value. Turning the throttle clockwise decreases the
CO
2
value. See fig 7.4.8.
Note: To increase the gas flow turn the throttle
screw anti clockwise, to decrease the gas flow
turn the throttle screw clockwise.
12. Ensure that the combustion settings are still
correct at maximum output and if necessary repeat
steps 7 to 12 until the settings are correct.
Fig 7.4.8 - Throttle Adjustment
9. Allow the boiler to stabilise at maximum power
and if necessary readjust the gas flow rate.
10. Reduce the boiler power to minimum by
pressing switch S5 on the control panel.
The first digit of the display will indicate the fan
speed. L = minimum speed.
11. The minimum gas rate can now be set. This
again is based on the flue gas analysis rather than a
fixed pressure. Check the CO
2
values in accordance
with table 7.1. If the CO
2
values are incorrect then
adjustment must be made by adjusting the gas
valve offset adjustment screw. See figure 7.4.11.
Turning the offset screw anticlockwise decreases
the gas flow and decreases the CO
2
value. Turning
the offset clockwise increases the gas flow and
increases the CO
2
value. See fig 7.4.11.
Note: To increase the gas flow turn the offset
screw clockwise, to decrease the gas flow turn
the offset screw anti-clockwise.
Fig 7.4.11 - Gas Valve Offset Adjustment
Gas Maximum
Minimum
Natural Gas
(model 381 & 501)
CO
2
9.2 - 9.4%
CO - (80 - 100ppm)
CO
2
8.3 - 8.5%
L.P.G.
(model 501)
CO
2
10.2 - 10.4%
CO - (80 - 100ppm)
CO
2
8.6 - 8.9%
L.P.G.
(model 381)
CO
2
10.5 - 11.0%
CO - (80 - 100ppm)
CO
2
9.0 - 9.5%
Table 7.1: Flue Gas Analysis
CO
2
Readings
13. The individual boiler module is now
commissioned. If there are further modules to be
commissioned then switch the commissioned
module off using the external thermostatic controls
or time clock to ensure correct shutdown. Further
modules may now be commissioned individually by
following procedure detailed and used for the first
module.
14. Once all modules have been commissioned
switch all modules to the ‘on’ position and take a
dynamic gas inlet pressure test reading to ensure
that the gas supply is sufficient for full operating load
conditions. This should be taken at all boiler
modules to ensure the supply is satisfactory at all
boilers.
