BURNER OPERATING SEQUENCE
The MDFL burner operating sequence (refer to the controller sequence table below) begins with a
pre-purge period on full air. When gas is selected, the fuel is then supplied to the burner at start rate
and ignition initiated. Start gas flame proving is followed by establishment of the main flame.
When oil is selected, on completion of the pre-purge period the appropriate oil valve or valves open,
ignition is initiated and the flame is established.
In both cases, the burner controller will then continue to its normal operating position and the
operation of the burner will be controlled by the pressure and/or temperature requirements of the
appliance.
Time
(seconds)
LFL 1.333
Description
T1 40
Pre-purge
T2 6
Pre-ignition
T3
3
Safety lockout time
T4
Not applicable to two-stage
or fully modulating operation
Delay start rate to main flame – single stage
T5
12
Delay start rate to main flame – multi-stage
T6 12
Delay between main flame low & main flame high (two-
stage burners)
T7 18
Post-purge
T8
12
Air pressure switch interlock
T9
91
Total start time
T total
106
Total controller cycle time
Note: The pre-purge times shown refer to the control box only. The time taken for the air damper to
move to the appropriate position will extend the total purge time up to a maximum of 157 seconds,
depending on the firing rate and air requirements of the appliance.
MDFL 3300 & MDFL 4000 Issue 2 08/08
Page 22
Summary of Contents for MDFL 3300
Page 16: ...MDFL 3300 MDFL 4000 Issue 2 08 08 Page 15 VALVE PROVING SYSTEM LDU 11 Standard fitting...
Page 30: ...MDFL 3300 MDFL 4000 Issue 2 08 08 Page 29 MODULATING CAM BOX...
Page 43: ...Electrode Setting Details MDFL 3300 MDFL 4000 Issue 2 08 08 Page 42 All dimensions in mm...
Page 48: ...NOTES MDFL 3300 MDFL 4000 Issue 2 08 08 Page 47...
