The aux heater burns diesel so it will smell a bit! how much smoke is it produceing? lots? if it is? what colour smoke? the most common failure on these units are the glow plugs oiling up and causing an incomplete burn! hence the smoke and unburt fuel smell
if for any reason it fails to ignite FIVE times it will shut down till the fault codes are cleared and the fault fixed, so keep an eye on it as without it working your heater will suck
and wont blow that hot