De Dietrich MS 24 MI FF - Инструкция по эксплуатации - Страница 83

82

71.03982.03 - EN

INSTALLATION INSTRUCTIONS

19. GAS CONVERSION

The authorised Technical Assistance Service can convert this boiler to natural gas (

G. 20

) or liquid gas (

G.31

). 

Carry out the following operations:

A)  replace the nozzles of the main burner and the gas diaphragm (if itted); 
B)  new max. and min. calibration of the pressure regulator.

A) Replace the burner nozzles

•   carefully pull the main burner off its seat;
•   replace the main burner nozzles making sure to fully tighten them to prevent gas leaks. Nozzle diameters are speciied 

in table 2.

B) Calibrate the pressure regulator

•   connect  the  positive  pressure  test  point  of  a  differential  pressure  gauge  (possibly  water-operated)  to  the  gas  valve 

pressure test point (

Pb

) (Figure 10). Only for models with sealed chambers, connect the negative pressure test point of 

the manometer to a “T” itting in order to join the boiler adjustment outlet, the gas valve adjusting outlet (Pc) and the 
pressure gauge. (The same measurement can be made by connecting the pressure gauge to the pressure test point 
(

Pb

) after removing the front panel of the sealed chamber);

  Measuring burner pressure using methods other than those described could lead to incorrect results as the low pressure 

created by the fan in the sealed chamber would not be taken into account.

B1) Adjustment to nominal heat output:

•   open the gas tap and switch the boiler to the Winter mode;
•   open  a  hot  water  tap  that  can  provide  a  low  rate  of  at  least  10  litres  a  minute  or  make  sure  there  is  maximum  heat 

demand;

•   remove the modulator cover;
•   adjust the tube brass screw (a) until the pressure values shown in table 1 are obtained;

make sure that the dynamic inlet pressure of the boiler, measured at the gas valve pressure test point (Pa) (Figure 10) is 
correct (37 mbar for propane or 20 mbar for natural gas).

B2) Adjustment to reduced heat output:

•   disconnect  the  modulator  power  cable  and  unscrew  the  screw  (b)  until  a  pressure  value  corresponding  to  reduced  heat 

output is achieved (see tab. 1);

•   reconnect the cable;
•   mount the modulator cover and seal.

B3) Final checks

•   attach the additional plate supplied with the transformer, specifying the type of gas and the calibration performed.

Figure 10

gas valve 

mod. SIGMA 845

b

a

0605_1502