I would route the exhaust out the other side of the heater so there was no chance of it getting sucked into the fan and entering the camper. Your heater is obviously tuned correctly for your elevation but if you use it at high elevation it'll burn rich and CO will increase. Also any restriction to combustion air intake or exhaust will increase CO. Could be something as simple as a spider building a web in the intake tube.

Good video,just installed one in my garage,and bought a house carbon monoxide alarm and it's always at the back of your mind, cheers Ian 🇬🇧

I am very wary of carbon monoxide output on these heaters , you clearly havent tuned your diesel heater properly and you should not have any carbon monoxide emissions from your diesel heater, check the seal on the top of the glow plug as sometimes it doesnt seal properly and alows carbon monoxide to escape from the burn chamber into the hot air stream. from the glow plug breathe hole, yes the tiny little breathe hole, you wouldnt believe it was true. next you need to get into the special settings menu on the blue lcd screen enter either 1866 or 9009 on the four dashes accessed by pressing the top left button on the lcd screen to enter the menu and adjust the heater at the lowest top fan setting and Hz setting that allows the two red bars to show on the display, adjustments to the top fan speed, you can turn the heater down with the lcd remote in the mnual setting using the remote to see what the lowest setting is that allows the two red bars to light up on the lcd screen.. this will allow it to burn very lean using only 1 to 2 litres of diesel in a 12 hour period. we run ours all night in a caravan at 1.7 hz we have carbon monoxide alarms set up to activate if it is being produced at all. our top fan speed is 4500 and our top temperasture setting is 5.1 Hz (or pump speed if you will) this may differ on yours. we first took delivery of the same unit as yours it was producing 33 parts per million of carbon monoxide, now it is tuned through the special settings it produces zero carbon monoxide emissions, its no good telling you my settings as every diesel heater has a slightly different combustion output even though they all appear to be the same design. try turning the rubber mount for the pump upside down so that the pump rests on the rubber mount rather than hanging from it ours is a little quieter now.