Truman Combi C400 gas only

[James power]

I ran low on gas my boiler would not heat water. I changed the gas and it still won't work. Fault E122H is showing up. I look up on YouTube trying to reset no joy. I tried to now I went back today to try again and there are only 2 icons on Pannell clock and spanner. I'm in Ireland south and can't get in to any of the service to have it repaired. Please help I'm new to all of this only started motor home use last year.

 

[GeoffnDee]

Is gas getting to the cooker ok ? if so , you may have to try restarting the boiler a few times to clear any air that may be in the supply pipe.