no flames for hot water?

You say you are in a mobile home, are you using LPG (Propane) if so, the problem may be caused by the main injector. LPG is 4x more powerful than natural gas so the injector is 4x smaller. Take out the main burner so you can see the gas injector, the actual hole will almost be invisible so a replacement is recommended. As a stop-gap a fine wire can be used to clear the aperture. One of those sewing needle threaders is about the sme size and sturdy enough.

Townteck
August 2009