● flame detector
● differential pressure switch
● gas pressure switches
● gas shut-off valves
● servomotors
● O
2
/CO trim control (if equipped)
● boiler safety devices
Flame detector
Test method
Outcome
Step 1
1. Prevent any light from reaching the detector and
start the burner.
The burner must shut down and lockout at the end
of safety time. Error code 25 and the text
No flame
at end of safety time.
Step 2
1. Start the burner.
2. Activate the flame detector with a light source
during pre-purge.
The burner must shut down and lockout at pre-
purge program phase. Error code 23 appears on the
display.
Step 3
1. Start the burner. Wait until the start-up
sequence is finished.
2. Remove the flame detector from the burner, and
prevent any light from reaching the detector.
The burner shuts down. Error code 26 and the text
Loss of Flame
appear on the display.
Differential pressure switch
For the physical location of the ports and for adjusting the switch, see section
Adjusting
combustion differential air pressure switch
.
Test method
Outcome
Step 1
1. Disconnect the high pressure hose (+) from the switch.
2. Start the burner.
After testing, reconnect the high pressure hose.
Boiler pre-purging begins. The burner
must shut down before the pre-purge
cycle is completed.
Error code 28 and a text
Air pressure off
appear on the display.
Step 2
1. Disconnect the low pressure hose (-) from the switch.
2. Start the burner.
After testing, reconnect the low pressure hose.
Boiler pre-purging begins. The burner
must shut down before the pre-purge
cycle is completed.
Error code 28 and a text
Air pressure off
appear on the display.
Step 3
1. Start the burner. Wait until the start-up sequence is
finished.
2. After the start-up is completed, rotate the setting wheel on
the switch towards the maximum setting.
After testing, return the setting wheel to its original position.
The burner should shut down before the
maximum setting.
Error code 28 and text
Air pressure off
appear on the display.
Step 4
1. Start the burner. Wait until the start-up sequence is
finished.
2. After the start-up is completed, disconnect both pressure
hoses from the switch.
After testing, reconnect both hoses to the original positions.
The burner should shut down
immediately after hoses are
disconnected.
The burner will shut down immediately.
Error code 28 and text
Air pressure off
appear on the display.
Gas pressure switches
For instructions on adjusting the switches, see section
Adjusting gas pressure
switches
.
Gas pressure, minimum
106 (114)
M4248 2316EN
