Unigas HP60, Manual Of Installation - Use - Maintenance

C.I.B. UNIGAS - M03957CI

32

Calibration of air and gas pressure switches

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 low gas pressure switch

As for the gas pressure switch calibration, proceed as follows:

z

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.

z

Clockwise turn the pressure switch adjusting ring nut (as to increase the pressure value) until the burner stops.

z

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 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.

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.

To move the adjusting cam set CMF=1 or 2 and then CMF=0.

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 burner 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.

VR

CMF

CMF = 0   stop at the current position
CMF = 1   high flame operation
CMF = 2   low flame operation
CMF = 3   automatic operation