Unigas HR512A, Manual Of Installation, Use And Maintenance

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PART III: OPERATION
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tion.
Turn the burner off; then start it up again. If the adjustment is not correct, repeat the previous steps.
8.2 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.
8.3 Maximum oil pressure switch
The oil pressure switch on the return line, checks that the pressure does not exceed a default
value. This value must not be higher than the maximum acceptable pressure on the return line
(this value is reported on the specification table). A pressure change on the return line could
affect the combustion parameters: for this reason, the pressure switch must be set, say, at 20%
over the pressure recorded during the combustion adjustment.
It is recommended to verify that the combustion parameters are within the range of acceptable
values even against a pressure variation that gets close to the limit of the pressure switch
This check should be carried out along the whole range of the burner output.
In case of inacceptable values, reduce from 20% to 15% the overpressure; later on, repeat the
adjustments described above.
CMF = 0 stop at the current position
CMF = 1 high flame operation
CMF = 2 low flame operation
CMF = 3 automatic operation
CMF