Atwood heater problem

[charlie m]

Hi all
I have a 2015 Grand Design 303 rls.
I have a problem with the heater. We live in fl.
So we use it very little. Now that we are retired we
use it a little more. The problem is that is starts and
lights, runs for a few seconds and flame goes out.
The whole process starts over and will do this till you
turn it off. I replaced the igniter but no better.
Here comes the good part. If you stick a 3/4 wrench
in the exhaust it works like a million bucks. Anyone have
any ideas how I can get this to work without the wrench.
Thanks for any help.
Charlie....

[Rutrue]

my rv works on utube has some good videos on how to repair heaters and just about anything on your rv. also az expert has good info videos! look them up.

[Chap1021]

If it is igniting that's good. Fire requires fuel, air and heat. If dirtdobbers get into the mixing tube for the gas and air it restricts the air flow. Check the metal tube for dirtdobber deposits, they like the smell of propane for some reason. Take it apart and clean the tube or replace it, then when you do get it to work put the screens on the intake and exhaust to prevent. I just helped my neighbor take apart his hot water heater that had dirtdobber deposits and was not working. Works as good as new once deposits are removed.