Unigas LX60, Manual Of Installation - Use - Maintenance

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PART III: OPERATION
31
Adjusting the combustion head
The burner is factory-set with the head in its "all-ahead" position, as for the minimum output. To operate at a higher power,slightly move
the combustion head backwards, turning clockwise the screw
VRT . .
Fully-modulating burners
.To adjust the fully-modulating burners, use the CMF switch on the burner control panel (see next picture), instead of the TAB thermo-
stat as described on the previous paragraphs about the progressive burners. Go on adjusting the burner as described before, paying
attention to use the CMF switch intead of
TAB .
The CMF position sets the oprating stages: to drive the burner to the high-flame stage, set CMF=1; to drive it to the low-flame stage, set
CMF=2.
Setting air and gas pressure switches
The air pressure switch locks the control box if the air pressure is not the one requested. If it
happens, unlock the burner by means of the control box unlock pushbutton, placed on the bur-
ner control panel.
The
gas pressure switches check the pressure to avoid the burner operate when the pressure
value is not in the requested pressure range.
Adjusting the maximum gas pressure switch (when provided)
To calibrate the maximum pressure switch, proceed as follows according to its mounting position:
1
remove the pressure switch plastic cover;
2 if the maximum pressure switch is mounted upstreaam the gas valves: measure the gas pressure in the network, when flame is off;
by means of the adjusting ring nut
VR , set the value read, increased by the 30%.
3 if the maximum pressure switch is mounted downstream the “gas governor-gas valves” group and upstream the butterfly valve:
light the burner, adjust it according to the procedure in the previous paragrph. Then, measure the gas pressure at the operating
flow rate, downstream the “gas governor-gas valves” group and upstream the butterfly valve; by means of the adjusting ring nut
VR , set the value read on step 2, increased by the 30%;
4 replace the plastic cover.
Calibration of air pressure switch
To calibrate the air pressure switch, proceed as follows:
z
Remove the transparent plastic cap.
z
Once air and fuel setting have been accomplished, startup the burner.
z
During the pre-purge phase o the operation, turn slowly the adjusting ring nut VR in the clockwise direction (to increase the adju-
sting pressure) until the burner lockout, then read the value on the pressure switch scale and set it to a value reduced by 15%.
z
Repeat the ignition cycle of the burner and check it runs properly.
z
Refit the transparent plastic cover on the pressure switch.
CAUTION: perform these adjustments once the burner is turned off and cooled.
CMF = 0 stop at the current position
CMF = 1 high flame operation
CMF = 2 low flame operation
CMF = 3 automatic operation
VRT
“all-ahead” position
“all-backwards” head position
CMF
VR