dunphy TD - Combustion Analysis and Adjustment

Operating Instructions For TD/TAD4 Dual Fuel Burner
June 13 71 of 165 TD/TAD4 Manual Rev 4
7.4.5 Firing the burner
 Ensure that the heat demand will allow an extended run, otherwise the burner may not
continue to fire throughout the time required for throughput measurement or commissioning
procedure.
 Unscrew or loosen the outlet gas pressure test point on the gas valve and connect a
manometer.
 Open the manual gas isolation valve.
 Switch on the mains electrical supply and, if the control box is locked out (indicated by the
reset button being illuminated) press the lockout reset button. For electrical modulation
systems, please consult relevant manual.
 Provided all control devices, thermostats etc are in the `on` position the burner control box
will start the operating sequence. For information relating to sequence of operation please
refer to section 5.
 If the control sequence fails to start, check for correct setting of the gas pressure proving
switch.
 The amount of gas flowing through the valve can be adjusted by using the ‘ ’ and
‘ ’ and is proportional to the amount of combustion air set by the air damper
motor. Cam setting for the air damper have been described in section 4.1.
 ‘ ’ is used to set the Low Fire rate and ‘ ’ is used to adjust the high fire
rate. A combination of the two settings will define an operating line between high fire and
low fire and the valve will maintain the air/gas ratio across this range. Full information on
the gas multiblock may be found in section 4.
 Adjustment of ‘ ’ will have an effect on the setting of ‘ ’ and vice-
versa. It may take 3 or 4 fine adjustments at both high fire and low fire to ensure good
combustion at both ends.
ALWAYS CHECK THE COMBUSTION READINGS AFTER MAKING ADJUSTMENTS.
7.4.6 Combustion values and results
All combustion readings must be taken with an approved and correctly calibrated test kit.
The following combustion values should be reached:-
Low Fire
CO content 0 - 20 ppm
CO
2
content 9 - 11 %
O
2
content 5.4 - 2%
High Fire
CO content 0 - 20 ppm
CO
2
content 10 - 11%
O
2
content 3.6 - 2%
In all cases the CO figure should not exceed 100mg/m
3
maximum.
The nett flue gas exit temperatures should be taken throughout the process of setting the
combustion.
The figures will vary according to the type of appliance but for shell and sectional boilers will be in
the range of 180 - 250C gross.
Always keep the exhaust flue gas temperatures within the manufacturers recommended
range and ensure that the appliance is not over or under fired. Warm up the boiler, or raise
steam in accordance with appliance manufacturer’s instructions.