Dunkirk DMG-240 Installation, Operation & Maintenance Manual page 72

Shut-
down Description
Code
Su:20 Identification running
(1)
Communication error with
Su:21
SU PCB
No flame during
Su:22 operation
Internal error on the SU-
Su:25
(1)
PCb
tFG sensor above
Su:29
(2)
maximum setpoint
No tFG sensor connected
Su:30 /shorted Boiler stop
(2)
After 5 times tF>tF Max:
Su:33
controlled stop
After 5 times tFG>tfmax:
Su:34
(2)
controlled stop
Insufficient gradient on
Su:35 T1(supply) or T2(return)
after burner starts
These lock-outs are not stored in fault memory
(1)
tFG : flue gas sensor
(2)
13 - TROUBLE SHOOTING
Shutdown Code Table
Probable Causes
---
Bad connection
No ionization current
---
Non-existent or insufficient
water circulation / sensor
error
Flue high limit disconnected /
Sensor error
Non-existent or insufficient
circulation / sensor error
Non-existent or insufficient
circulation / sensor error
Non-existent or insufficient
circulation / sensor error
72
Checking/Solution
No action required
Check whether SU PCB has been correctly fitted in the
connector on SU PCB
Purge gas supply to remove air
Check gas valve is fully opened
Check supply pressure
Check operation and setting of gas valve
Check air inlet and exhaust are not blocked
Check there is no recirculation of combustion gases
Replace the SU PCB
Replace flue high limit.
Check circulation (direction, pump,valves)
Check water pressure
Check sensors are operating correctly
Check sensor has been correctly fitted
Check cleanliness of heat exchanger
Replace flue high limit.
Replace supply sensor.
Check circulation (direction, pump,valves)
Check water pressure
Check sensors are operating correctly
Check sensor has been correctly fitted
Check cleanliness of heat exchanger
Replace flue high limit.
Check circulation (direction, pump,valves)
Check water pressure
Check sensors are operating correctly
Check sensor has been correctly fitted
Check cleanliness of heat exchanger
Check circulation (direction, pump,valves)
Check water pressure
Check sensors are operating correctly
Check sensor has been correctly fitted
Check cleanliness of heat exchanger
P/N 240011656, Rev. E [07/30/2018]