5.5 BURNER START-UP
TL
TR
Motor
{
2
Air damper motor
1
0
Ignition transformer
Valve
High fire
Low fire
5.6 MIN. AIR PRESSURE SWITCH
Adjust the air pressure switch after having performed all other burner adjustments with the air pressure switch set
to the start of the scale. With the burner operating at the minimum power, slowly turn knob clockwise until burner
locks out. Then turn the knob anti-clockwise by about 20% of the set point and subsequently check to see if
burner has started correctly. If the burner locks out again, turn the knob anti-clockwise a little bit more.
5.7 MAX. AIR PRESSURE SWITCH
The over pressure switch must be set after all other adjustments have been made. Its purpose is to cause the
burner to shut down if the combustion chamber pressure increases above normal operational values.
Begin with the switch at the highest setting, with the burner working at the maximum output, adjust the dial
anti-clockwise, decreasing its value until the burner shuts down. Now increase the value by one set point and
re-start the burner. If the burner shuts down due to the pressure surge in the combustion chamber caused by
the ignition gas, check that the start gas rate is less than 25% of the main gas rate. If it is, increase the value
on the over pressure switch by a further half a set point and repeat the test.
NOTE:
To comply with the Appliance Standard Pr EN 1020, the CO value must not exceed 0.1% under normal oper-
ational conditions.
:
Attention
As a rule, the air pressure switch must prevent the air pressure from lowering below 80% of the adjustment value
as well as preventing the CO in the fumes from exceeding 1% (10,000 ppm).
To check this, insert a combustion analyser into the chimney, slowly close the fan suction inlet (for example with
cardboard) and check that the burner locks out, before the CO in the fumes exceeds 1%.
6.
MAINTENANCE
The burner requires periodic maintenance carried out by a qualified and authorised technician in conformity
with legislation and local standards.
Maintenance is essential for the reliability of the burner, avoiding the excessive consumption of fuel and con-
sequent pollution.
Before carrying out any cleaning or control always first switch off the electrical supply to the burn-
er acting on the main switch of the system.
THE BASIC CHECKS ARE:
Leave the burner working without interruptions for 10 min. and set rightly all the components stated in this
manual. Then carry out a combustion check verifying:
Content of CO
(%)
2
30s
2.5s
Content of CO (ppm)
20s
25s
Flue gas temperature (°C).
11
GB
11s
3s
3s max.
5s
D6222
20067072