Lamtec ETAMATIC OEM - Automatic Function Monitoring During Operation; Test During Burner Start; O 2 Monitoring Band

42
7 O
2
Trim
7.5 Automatic Function Monitoring During Operation
7.5.1 Test During Burner Start
The actual O
2
value is checked to ensure that during pre-purge it corresponds to the air value
(equal to or greater than 18 vol.% O
2
and less than 24 vol.% O
2
).
After ignition, the actual O
2
value must reach a value equal to or below 14% within 45 seconds.
Reaching the threshold value is monitored. If one of the two parameters is not met, O
2
trim is
deactivated. The control unit outputs the value “Base value without control”.
7.5.2 O
2
Monitoring Band
During burner operation, the actual O
2
value is continuously monitored for one maximum and
two minimum permissible values. These ranges are located around the O
2
setpoint as a func-
tion of firing rate. If the actual values stay outside these bands for a defined period, the control
system is deactivated and a “Fault” warning is output.
Thereafter, the control unit’s output (correction input) corresponds to “Base value without con-
trol” or “Base value with air deficiency”.