Water heater replacement for 1982 Airstream Limited

[Rocket1]

Only lukewarm water, so replaced the gas control valve and the pressure release valve, gas comes on for 15 minutes with a healthy flame.
Then turning water on after 15 minutes only gives a brief 2 cups of hot water, the rest of the water is then lukewarm.
Any suggestions, maybe sediment in the tank?

If a new heater is required what is the brand and where to buy?

[Bev1940]

I'm wondering if anyone has replaced the furnace in a 1978 31' AS with a portable propane-fueled heater or even a small gas fireplace?

[Bill M.]

I replaced my 88 model Atwood 6 gallon with a new Atwood 6 gallon bought from one of the online rv stores. I put in a gas-electric combination unit. I would not do that again. I just use the gas and the combo was just slightly larger than the old unit causing some minor problems in installation ease.

Have not replaced a furnace yet but when I do I will get another furnace installed. I like it being installed where it is and out of the way. Plus it works well with the ducted outlets to the bath and bed areas and it protects the plumbing from freezing when cold weather camping. So I would not like your choice of alternatives