Unigas K990A, Installation Manual

Page: 26 / 112

PART III: OPERATION
26
AIR FLOW AND FUEL ADJUSTMENT
Adjustments - brief description
The air and fuel rates adjustments must be performed at the maximum ouptput first (“high flame”): see the LMV5.. related manual..

Check that the combustion parameters are in the suggested limits.

Check the flow rate measuring it on the counter or, if it was not possible, verifying the combustion head pressure by means of a dif-
ferential pressure gauge, as described on par. “Measuring the gas pressure in the combustion head”.

Then, adjust the combustion values by setting the “gas/air” ratio” curvepoints (see the LMV5.. related manual).

Set, now, the low flame output, in order to avoid the low flame output increasing too much or that the flues temperature gets too low
to cause condensation in the chimney.
Start-up procedure
1 Turn the burner on.
2 the LMV control box starts the system test cycle: the AZL display shows the System Test message; at the end of the test, it shows
the main page and the system stops (the safety chain is open) waiting for the startup enabling signal (standby - Program phase no.
12)
Main page
3 check the fan motor rotation (see related paragraph).
4 make the safety chain enabling the system to start up
5 the combustion cycle starts: the system will show the operating stages
- Prepurging (program phase no.30)
- Driving to ignition position (program phase no.36)
- Ignition position (program phase no.38)
- Fuel (the fuel solenoid valves open)
- Flame (the flame lights up)
- Driving to low flame (the actuator drives to low flame).
NOTE: the C and A , on the .
Once the ignition cycle ends, the main page is shown:
Main page
Set point: temperature set-point
WARNING! During commissioning operations, do not let the burner operate with insufficient air flow (danger of
formation of carbon monoxide); if this should happen, make the fuel decrease slowly until the normal combustion
values are achieved.
WARNING! the combustion air excess must be adjusted according to the values in the following chart.
Recommended combustion parameters
CO
2
(%) O
2
(%)
Fuel
Recommended (%) CO
2
Recommended (%) O
2
Natural gas 9 ÷ 10 4,8 ÷ 3
LPG 11 ÷ 12 4,3 ÷ 2,8
Setpoint 80°C
Act.value 78°C
Fuel GAS
Standby 12
Setpoint 80°C
Act.value 78°C
Load 24%
Flame 60%