Riello 3789310, Installation, Use And Maintenance Instructions

Page: 9 / 76

5
GAS PRESSURE
The adjacent tables show minimum pressure
losses along the gas supply line depending on
the maximum burner output operation.
Column 1
Pressure loss at combustion head.
Gas pressure measured at test point 1)(B), with:
combustion chamber at 0 mbar.
Column 2
Pressure loss at gas butterfly valve 2)(B) with
maximum opening: 90°.
Column 3
Pressure loss of gas train 3)(B) includes: adjust-
ment valve VR, safety valve VS (both fully
open), pressure governor R, filter F.
The values shown in the various tables refer to:
natural gas G 20 PCI 9.45 kWh/Sm
3
(8.2 Mcal/
Sm
3
)
With:
natural gas G 25 PCI 8.13 kWh/Sm
3
(7.0 Mcal/
Sm
3
)
multiply tabulated values:
- column 1 - 2: by 1.5
- column 3:by 1.35
Calculate the approximate maximum output of
the burner thus:
- subtract the combustion chamber pressure
from the gas pressure measured at test point
1)(B).
- Find the nearest pressure value to your result
in column 1 of the table for the burner.
- Read off the corresponding output on the left.
Example:
• Maximum output operation
• Natural gas G 20 PCI 9.45 kWh/Sm
3
• Gas pressure at test point 1)(B) =6.7 mbar
• Pressure in combustion chamber = 3 mbar
6.7 - 3 =3.7 mbar
A maximum output of 500 kW shown in Table
RS 64 MZ corresponds to 5 mbar pressure, col-
umn 1.
This value serves as a rough guide, the effective
delivery must be measured at the gas meter.
To calculate the required gas pressure at test
point 1)(B), set the maximim output required
from the burner operation:
- find the nearest output value in the table for
the burner in question.
- Read off the pressure at test point 1)(B) on
the right in column 1.
- Add this value to the estimated pressure in
the combustion chamber.
Example:
• Required burner maximum output operation:
500 kW
• Natural gas G 20 PCI 9.45 kWh/Sm
3
• Gas pressure at burner output of 500 kW, taken
from table RS 64 MZ, column 1 = 3.7 mbar
• Pressure in combustion chamber = 3 mbar
3.7 + 3= 6.7 mbar
pressure required at test point 1)(B).
INSTALLATION
THE BURNER MUST BE INSTALLED IN CON-
FORMITY WITH LEGISLATION AND LOCAL
STANDARDS.
WORKING POSITION (C)
The burner is designed to work only in the posi-
tions
1 , 2 , 3 and 4 .
Installation 1 is preferable, as it is the only one
that allows the maintenance operations as de-
scribed in this manual. Installations
2 , 3 and 4
allow the working, but make the operations of
maintenance and checking of the combustion
head more difficult page 14.
Any other position could compromise the correct
working of the appliance.
Installation
5 is forbidden, for safety reasons.
Data of head thermal power and
gas pressure refer to operation
with gas butterfly valve fully open
(90°).
(A)
2
VS
VR R
3
1
F
RS 64 MZ

p (mbar)
kW 1 2
3
3970144
3970197 3970180
3970198 3970181
3970182 3970221
3970225
400 2.0 0.3 14.1 7.4 5.2 3.8
450 2.8 0.4 17.0 8.8 6.1 4.0
475 3.3 0.5 18.4 9.4 6.6 4.1
500 3.7 0.5 19.9 10.1 7.0 4.2
550 4.5 0.6 23.2 11.6 8.2 4.4
600 5.4 0.7 26.7 13.2 9.5 4.6
625 5.8 0.8 28.5 13.9 10.1 4.7
650 6.3 0.9 30.3 14.7 10.8 4.9
700 7.4 1.0 34.0 16.4 12.1 5.1
750 8.5 1.2 37.7 18.0 13.4 5.4
800 9.6 1.3 41.5 19.9 14.8 5.8
850 10.7 1.5 45.3 21.8 16.3 6.2
(B)
D3790
2 3 4 5 1
D3928
(C)