Technical data

5 Troubleshooting Thermo 230 / 231 / 300 / 301 / 350
506
5.3.2.4 Fault Symptom "Foreign Light Detection
during Run-up or Run-down"
5.3.2.5 Fault Symptom "Flame Sensor Defective"
5.3.2.6 Fault Symptom "Temperature Sensor
Defective"
Has heater been in long time operation
shortly before ?
YES
NO
Flame sensor defective, replace.
Control unit defective, replace.
Allow heater to cool down and restart (approx. 2 min.).
Does same symptom show again?
Clean combustion tube.
Remove coke deposits.
Control unit defective, replace.
Flame in run-down.
Replace solenoid valve.
Flame sensor defective, replace.
YES
NO
If replacement of flame sensor does not cure
the problem, replace control unit.
Are electrical lines and contacts to and on
temperature sensor o.k.?
YES
NO
Temperature sensor defective, replace.
WARNING: Water may escape!
If replacement of temperature sensor does not cure
the problem, replace control unit.
Make contacts or replace component.
WARNING: loss of water!