CIB UNIGAS - M039168CC
27
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.
Calibration of minimum gas pressure switch
As for the gas pressure switch calibration, proceed as follows:
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Be sure that the filter is clean.
z
Remove the transparent plastic cap.
z
While the burner is operating at the maximum output, test the gas pressure on the pressure port of the minimum gas pressure
switch.
z
Slowly close the manual cutoff valve (placed upstream the pressure switch, see gas train installation diagram), until the detected
pressure is reduced by 50%. Pay attention that the CO value in the flue gas does not increase: if the CO values are higher than the
limits laid down by law, slowly open the cutoff valve as to get values lower than these limits.
z
Check that the burner is operating correctly.
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Clockwise turn the pressure switch adjusting ring nut (as to increase the pressure value) until the burner stops.
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Slowly fully open the manual cutoff valve.
z
Refit the transparent plastic cover on the pressure switch.
Adjusting the high gas pressure switch (when provided)
To calibrate the high pressure switch, proceed as follows:
z
remove the plastic cover;
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measure the gas pressure in the network, when flame is off;
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by means of the adjusting ring nut
VR
, set the value read on step 2, increased by the 30%;
z
replace the plastic cover.
PGCP Gas leakage pressure switch (witn Siemens LDU/Siemens LMV burner control)
z
remove the pressure switch plastic cover;
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adjust the PGCP pressure switch to the same value set for the minimum gas pressure switch;
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replace the plastic cover.;
Fig. 15
VR
