37
Installation and operation manual
–
DTHR-V9-2020
An error message is displayed in a red window when an alarm is active.
The following table shows the different alarms configured in the PLC. Each alarm will be displayed
on a red window with the description and an alarm number on the left corner.
ALARM
DESCRIPTION
POSSIBLE CAUSES
Gas feedback lost
The gas valve actuator feedback is missing during:
#10: Pre-purge step (3)
#11: Burner ignition step (4)
#12: Modulation step (6)
#13: Low fire step (7)
•
Broken feedback wire from gas
valve actuator.
•
Bad wiring connection.
•
Gas valve actuator defective.
•
PLC expansion TM3 defect
Burner low air
pressure
Burner air proving switch in alarm during:
#20: Safety verification 1 step (2)
#21: Safety verification 2 step (2)
#22: Pre-purge step (3)
#23: Pre-purge End step (3)
#24: Burner ignition step (4)
#25: Flame stabilization step (5)
#26: Modulation step (6)
#27: Low fire step (7)
•
Air blower defect.
•
Pressure switch tubing broke.
•
Too much air pressure leakage.
•
Burner box leakage.
•
Too low minimum combustion fan
adjustment.
•
Pressure switch defective.
Burner flame
control
Flame safeguard in alarm or missing signal during:
#30: Burner ignition step (4)
#31: Flame stabilization step (5)
#32: Modulation step (6)
#33: Low fire step (7)
•
No signal sent to the flame
safeguard from the PLC.
•
No power on the flame safeguard.
•
Flame safeguard in alarm (see
next section).
Fan feedback lost
Combustion air fan feedback signal is missing during:
#40: Burner ignition step (4)
#41: Flame stabilization step (5)
#42: Modulation step (6)
#43: Low fire step (7)
•
Broken feedback wire from
blower fan.
•
Blower fan defective.
•
No power on the blower fan.
•
Resistor (RE1) defective.
Flue vent back
pressure limit
Too much back pressure in the flue vent or exchanger:
#50: Burner ignition step (4)
#51: Flame stabilization step (5)
#52: Modulation step (6)
#53: Low fire step (7)
•
Blocked flue vent.
•
Too much restriction in flue vent.
•
Blocked exchanger or drain.
•
Pressure switch defective.
Air intake
restriction limit
Too much restriction in the combustion air intake:
#60: Burner ignition step (4)
#61: Flame stabilization step (5)
#62: Modulation step (6)
#63: Low fire step (7)
•
Blocked combustion air intake.
•
Too much restriction in the air
intake or ducting.
•
Pressure switch defective.
Gas feedback
deviation
Too much gap between the gas command and gas
feedback during:
#70: Modulation step (6)
#71: Low fire step (7)
•
Damaged feedback wire.
•
Blocked gas valve.
•
Defective gas valve actuator.
Fan feedback
deviation
Too much gap between the fan command and fan
feedback during:
#80: Modulation step (6)
#81: Low fire step (7)
•
Damaged feedback wire.
•
Bad blower calibration (see
Start-
up
section)
•
Defective blower fan.
Note:
If an alarm is active on the PLC, a manual reset on the touch screen panel is required before the alarm
can be cleared and the unit restarted.
PLC alarms
