Commissioning; Combustion Adjustment - andrews OFS25 Installation Manual, Operation And Service Manual

SECTION 4
COMBUSTION
ADJUSTMENT
20

COMMISSIONING

IMPORTANT:
These oil fired water heaters must be commissioned by a competent engineer.
CAUTION / IMPORTANT: PRESSURE WITHIN COMBUSTION CHAMBER SHOULD READ
BETWEEN -0.2 MBAR AND -0.5 MBAR, ADJUST THE DRAUGHT STABILIZER TO ENSURE
A READING OF -0.1" TO -0.4" IS ACHIEVED TO ENSURE SAFE AND CORRECT OPERATION.
CAUTION: DO NOT OPERATE THE WATER HEATER UNTIL THE STORAGE VESSEL IS
COMPLETELY FILLED WITH WATER. WITH WATER RUNNING FROM ALL HOT TAPS.
CAUTION: ENSURE THE CORRECT NOZZLE IS FITTED TO SUIT THE FUEL TYPE BEING
USED. SEE TECHNICAL DATA SECTION 2 OR PAGE 21.
A. To light the burner
1) Turn on the fuel supply to heater.
2) Switch on power supply to burner.
3) Rotate the thermostat adjustment knob to the desired water temperature at
which the burner will begin its prepurge. At about 15 secs. the burner will light.
The thermostat should be set at a temperature to suit the system it controls.
4) The two control thermostats should be set to the same temperatures . (OFS108
& OFS 163 only)
B. To shut off the burner
1) Rotate the thermostat adjustment knob to the off position.
2) For long periods only, eg. holidays or periods of 7 days switch the burner power
supply 'OFF', and turn off the fuel service cock. For shorter periods eg. less than
7 days, leave the heater under control of the thermostat.
C. Burner Adjustment
The burner comes factory pre-set. The correct burner head settings are shown below.
Refer to the table if the nozzle or electrodes are replaced.
B
C
A
The burner is factory pre-set to an average value that must then be adjusted to the water
heater in question. To adjust the combustion device, start by increasing the air volume.
When the burner starts it is burning with excess air and smoke number 0. Reduce the air
volume until soot occurs and increase again to reach a combustion free of soot. By this
procedure an optimum adjustment is obtained. See Below.
Loosen the fixing screw '6' and bring the air damper into the position thought to be
necessary as a midway point for fuel to be burnt. Turn the main switch to ON to power
the burner and ignite it. Correct, if necessary, combustion air delivery by adjusting the
intake damper and the position of the deflector disk (adjustable via screw 2). The burner
is, in fact, fitted with a special screw to adjust the position of the deflector disk; this
device allows for optimisation of combustion by reducing or increasing the air flow
between deflector disk and head. It is normally necessary to reduce (undo screw 2) the
air flow between deflector disk and head when there is reduced fuel delivery: this
passage must be proportionately more open (screw in screw 2) when the burner is
working with a higher fuel delivery rate. After modifying the position of the deflector
disk, it is, usually, necessary to correct the air damper positions and afterwards check for
proper ignition. See diagrams on page 21.
D
MOD.
BTL 4
BTL 6/10/20
A B C D
3 0 6 2,5
3 2 6 3