Unigas HTLX 1025.1 Installation Manual page 26

PART I: INSTALLATION MANUAL
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. The factory setting is 4 bar.
It is recommended to verify that the combustion parameters are within the range of acceptable values even against a pressure varia-
tion 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.
Minimum oil pressure switch (when provided)
The minimum oil pressure switch on the inlet line, checks that the pressure does not drop below a default value. The pressure switch
must be set, say, at 10% under the pressure at the nozzle.
Oil pressure switch adjustment
Follow the below instruction, according to the pressure switch installed.
Trafag Picostat 9B4..
ADJUSTMENTS FOR GAS OPERATION
Adjustments - brief description
The air and fuel rates adjustments must be performed at the maximum ouptput first ("high flame"): see the LMV5.. related manual..
Check that the combustion parameters are in the suggested limits.

Check the flow rate measuring it on the counter or, if it was not possible, verifying the combustion head pressure by means of a dif-

ferential pressure gauge, as described on par. "Measuring the gas pressure in the combustion head".
Then, adjust the combustion values by setting the "gas/air" ratio" curvepoints (see the LMV5.. related manual).

Set, now, the low flame output, in order to avoid the low flame output increasing too much or that the flues temperature gets too low

to cause condensation in the chimney.
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