Hello, I have a TRUMA s2200 in my 120GT Puck, I have only used the heater once when we bought it to check it was working and it was fine (6 months ago).
Today I went to test it again and there was a good spark etc BUT I had left the vent covers on and obviously filled it with gas, after taking them off I started again and it had a blow back ( I probably only left it for a minute or so) .
Now I don’t get any spark for ignition, my question is have I killed my heater off and damaged it beyond redemption or is there a fault finding scale of doom anyone has to eliminate my stupidity ? I have tried a search on the Forum but cant find anything that matches ,Thank you

It could be something as simple as the battery connection in the electronic ignition module has been disturbed by the explosion.

Or that the ignition of the excess gas has deformed the burner unit causing the igniter spark probe to short circuit against the metalwork. You can test for this event by removing the spark electrode connection from the electronic ignition module to check if you can hear it clicking (sparking) - it will be quite faint compared to the sound you should hear with it connected.

In any event the heater should be removed and inspected for damage.

Thank you for the quick reply I will get in and have a good look