ACTIVATION
Before gas is admitted to the burner, at least two faultless ‘dry runs’ must have taken place. No interlock may
be by-passed during these runs.
Dry Run
1. By means of pressure test nipples and with both manual isolating valves closed, using air or inert gas, test
the burner valvetrains for leaks, and the safety shut-off valves for pressure tightness.
2. Start the main duct fan.
3. Adjust the pressure switch to 1.9 mbar (0.7in wg).
4. Make electricity available to the system.
5. Check by manipulation of the control instrument that the modulating motor and butterfly valve operate
correctly. Remove the link between motor and valve, and close the valve by hand.
6. Operate the ‘Burner Run’ button. The combustion air fan (if fitted) should start, and following the purge
period a spark should appear at the burner. About 10 seconds after the spark is initiated the spark should
stop, and because no gas is available the control should go to ‘lockout’.
If the spark fails to appear:-
a. Check the spark gap. It should be 2-3 mm.
b. Check the electrical circuit.
c. Check the settings of the pressure switches.
d. Check all interlocks.
Repeat the test.
Live Run
7. Make certain the ball valve between the motorised butterfly valve and the burner is closed.
Adjust the valve train governor to give the minimum possible gas pressure.
Open the ball valve at the inlet to the valve train.
8. Operate the ‘Burner Start’ button, the pilot should light. If it does not light after three attempts:
a. Check that the pilot gas valve is operating.
b. Adjust the adjustable port pilot cock as follows, starting with the cock two turns open:
Remove the top hexagon screw cap c/w washer. The slotted head adjusting screw now exposed is
turned clockwise for less gas and counter-clockwise for more gas.
For flame rod system the proper amount of pilot gas is the minimum that will reliably ignite each time
the spark electrode is energised. A scanner system will require a slightly larger pilot than a flame rod
system.
Repeat the test.
9. Run the motor to its lowest position and try to start the burner. if a stable low flame is not obtained, or if the
flame is too large, it may be necessary to adjust the butterfly valve slightly against the clutch. When this
has been done, screw in the ‘bottom’ adjusting screw until it just touches the stop, and tighten the locknut.
10. If any adjustment has subsequently to be made to the high fire rate, it must be done by adjusting the gas
pressure and not by adjusting the butterfly valve. If the high fire rate is altered it may be necessary to
adjust the low fire rate by following the above procedure from 1. above. If this method is not followed the
control characteristics of the valve and motor will be spoilt.
MAINTENANCE
To ensure the continuing fault-free operation of the burner, the following operations should be undertaken every
six months:
1.
Clean the working faces of the burner with a stiff brush.
2.
Clean the fan impeller (a dirty impeller will cause a dirty flame).
3.
Check all safety circuits.
4.
Check pressure, etc, against the values recorded when the burner was commissioned.
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