65
®
Modulation Problem
PROBLEM
POSSIBLE CAUSE
SUGGESTED ACTION
Sensor or modulation rate
inaccurate.
V/I input setting incorrect. 5/24V supply set-
ting incorrect.
Check option parameter 05.5. Check SENSOR IN and
SUPPLY links.
Intermittent positioning
faults.
Lead drive setting incorrect.
Profile not suitable.
Profile too close to micro-switch.
Poor Earth or screening.
Feedback potentiometer faulty.
Change lead drive (option param. 05.1/05.2).
Increase servo-motor range (by adjusting linkages).
Move end points further away from high/low.
Check wiring.
Move servo-motor across range and check f/back.
Modulation rate sticks at a
profile setpoint.
Lead drive position similar or same as adja-
cent setpoint.
Enter commission ratio mode and change the lead drive
setpoints or change lead drive.
Unit stuck at low fire.
Meas. value exceeds setpoint.
Low fire hold time not expired.
Warming limit active (EK16 =1).
Unit in manual.
External low fire hold.
Sequencing low fire hold.
No fault.
Wait for low fire hold time to expire.
Wait for boiler to warm up.
Press the AUTO key to change to auto mode
Check auxiliary input functions (Option Parameter
10.0 -10.9)
Increase the mod. rate in manual mode.
Unit stuck at mod. rate.
Serial communications.
Unit in commission mode.
Disable or change mod. slider in ComFire.
Press RUN then ENTER to enter run mode.
