Unigas HRX92R-FGR, Manual Of Installation - Use - Maintenance, Page: 33 / 132

PART III: OPERATION
33
VERSION WITH FGR <50 mg / kwh AIR DAMPER
Adding fumes reduces the flame temperature and produces less NOx nitrogen oxides.
Adjustments - brief description
The air and fuel flow rates are set at maximum power ("high flame") first: consult the attached LMV manual.
When adjusting the burner air / gas curves with AZL (see attached instructions LMV2x) for the various points that are set on the LMV2x
/ 3x, it is possible to adjust the opening of the Fume Recirculation Butterfly
(E) .
The air and fuel flow rates are set at maximum power ("high flame") first: consult the attached LMV manual.
During the calibration of the maximum point P9 of the LMV, it is possible through the slotted cam
(D) to lock the maximum opening of
the butterfly. Recirculating Fumi FGR (E) .
Adjust the air / fuel ratio by acting on the AZL display and commanding the position of the servo controls dedicated to air damper and
gas throttle.
Through the variable sector (C) :- By screwing the screw (V) in correspondence with the guide bearings (F) , the opening of the Fumes
Recirculation Butterfly- Increases and consequently the percentage of the recirculation fumes increases.
- Unscrewing the screw
(V) in correspondence with the guide bearings (F) decreases the opening of the Flue Recirculation Butterfly
and consequently decreases the percentage of the recirculation fumes.Check that the combustion parameters are within the
recommended limits.
Check the flow rate by measuring it at the meter or, if this is not possible, by checking the pressure in the combustion head with a
differential pressure gauge, as described in the paragraph "Gas pressure curves in the combustion head according to the flow rate".
Then, adjust the combustion by defining the points of the "gas / air ratio" curve (see the attached LMV manual). Finally, adjust the
power of the low flame (following the instructions in the attached documentation for Siemens LMV) in order to avoid that the power in
low flame is too high or that the temperature of the fumes is too low to cause condensation in the chimney.
.
MPORTANT: During the adjustment procedure always check that the combustion parameters are in the suggested
limits
E
A
C
D
F
B
V
A
C
D
F
E
B
V
Increases
butterfly
opening
Decreases
butterfly
opening
The air servocontrol (A) controls the air damper (B) and the recirculation flue gas inlet (E) through the variable sector (C) and the
slotted cam (D) . The variable sector (C) regulates the intermediate steps. To increase or decrease the flow rate of the fumes, act
on the variable sector (C) by screwing or unscrewing the screws (V) point by point. (D) Further separate adjustment with the slotted
cam to determine the maximum throttle opening (E) at maximum burner output. (E) FGR butterfly valve.
Decreases
butterfly
opening
Increases
butterfly
opening
Low noise air intake (R) Aluminum air intake (P)