Servomotors adjust the position of the air damper or gas valve during load changes. If a servomotor does not follow the command correctly, the air-gas ratio may be disrupted, causing instability or a trip.
Does not move at all
Check the power supply, command signal, limit switches, and mechanical connection to the damper or valve.
Moves but not to the correct position
Possible causes include a loose linkage, gear wear, or incorrect position feedback.
Command and feedback deviation
In systems with feedback, comparing the requested and actual position is very useful. A large deviation can trigger an interlock.
Combustion symptoms
Black smoke, high O₂, low O₂, unstable flame, or trips during load changes may be related to an incorrect servomotor position.
After maintenance
If a linkage has been disconnected or a servomotor replaced, the correct position matching with the combustion curve must be verified before the installation returns to full load.
