Unigas RG91 Manual Of Installation - Use - Maintenance page 17

Light oil burners, double stage

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13 the 3rd cam drives the opening of the 2nd stage solenoid valve (EVG2) and must be set between the other two cams, however

near to ST1;

The cycle goes on and il the thermostat TAB is connected, the control box drives the burner to high flame. If there is not theTAB

thermostat, place a bridge between terminals 6 and 7 on the MA terminal block (see picture above).

15 By means of ST2 cam, adjust the air flow rate in high flame stage;

16 to increase the high flame position (and consequently to increase the degrees), move the cam to a higher position: the actuator will

move to the new ST2 position;

to decrease the high flame position, move the cam to a lower position, remove the bridge between 6 and 7 terminals only for a

while, then replace it: the actuator will shift just few degrees towards the low flame position and then will move to the new high

flame position.

18 Once the adjustmet is performed, check again that the combustion parameters are in the set limits.

19 Replace the actuator cover.

Adjusting the combustion head

To let the burner operate at a lower output, turn clockwise the VRT screw and move progressively the combustion head back towards

the MIN position.

Note: loosen VB screw to free the VRT screw; adjust the head and then remember to fasten VB again.

Attention! if it is necessary to change the head position, repeat the air and gas adjustments described above.

Calibration of air pressure switch (when provided)

To calibrate the air pressure switch, proceed as follows:

Remove the transparent plastic cap.



Once air and gas setting have been accomplished, startup the burner.

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During the pre-purge phase o the operation, turn slowly the adjusting ring nut VR in the clockwise direction until the burner lockout,

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then read the value on the pressure switch scale and set it to a value reduced by 15%.

Repeat the ignition cycle of the burner and check it runs properly.



Refit the transparent plastic cover on the pressure switch.

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PART II: INSTALLATION

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