odor from hot water heater

[Thunderman]

Have a new 2955RL, 03 that was still on the lot. First time out no problem, second time out noticed an odor that eventually went away. Checked it yesterday (no use of trailer since last week-end) and a definite odor coming from the hot water heater. Would appreciate your comments, thanks.

Weldon and Carolyn
2001 F-250 PSD, CC
2003 2955RL Montana