Troubleshooter - Maxitrol

Check cross lighting of main burner to 2nd thermocouple system.

Measure the voltage of the 2nd thermocouple

Check the voltage in Mv 22 Seconds after the servomotor starts to run, c.q. just before the fire goes out. 

- The glass window has to be mounted. 
- Measure between the black wire and earth point on the gas control.
- Requirement: The voltage should be > 5 mV after rectification.

Voltage 0 mV

The 2nd thermocouple is defective. 
Cross lightning the main burner very slowly. Take the action 'Cross lightning too slow' (see below), before taking any further action. 

Voltage <1,8 mV

- The cross lighting main burner is too slow. Take actions 'Cross lighting too slow' (See below), before taking any further actions!
- The 2nd thermocouple is barred. Check:
          - Is the 2nd thermocouple free of vermiculite, chips or pebbles. 
          - The position of the logs or pebbles. 
          - Are the burner holes under the couple open. 
- The 2nd thermocouple is defective. (Cross lighting is okay, but voltage creeps up too slowly)
- The flames are instanble. See ... before any other actions are taken!!
- The burner pressure is too high or too low. 
- The 2nd thermocouple is not positioned correctly in the flame, bend it into the correct position. (See the manual)
- The 2nd thermocouple is positioned correctly (See the manual) bend it into the flame. (Only if cross lighting and flame picture are ok!! Check here.)

Voltage > 1.8 Mv

The receiver is defective. Replace it. 
 

Cross lighting of main burner to slow

Measure the time in seconds from the moment the servomotor starts running until the flame reaches the 2nd couple. 
Requirement: The flame must be in position at the 2nd thermocouple <10 seconds. If not, check:

- Is the 2nd thermocouplefree from vermiculite, chips, or pebbles?
- The position of the logs or pebbles.
- If the burner holes are (locally) blocked. Remove vermiculite dust. 
- Is vermiculite missing or not evenly distributed across the burner.
- Are chips on the burner?
- Lack of combustion air. Check 2.20? 
- Cross lighting in low setting. (Possible when the thermostat function is used)