Tech: installing a diesel heater on its side.

We often recommend mounting the heater on it's side with the gloplug up OR mounting it vertically.

We have a VEVOR heater which had a bad MB which we changed. It ran fine for @ 20 minutes at 3000rpm. When we slowed it down to 1800rpm it began to pulse or surge.

We changed the low fuel from 1.5Hz in steps to up to 2.2Hz which did not eliminate the surge, just made it worse at the higher settings.

From 3000rpm to 4500rpm, there was no surge. We suspected the soft green line might be the problem as the surge was in time to the pump pulses. So we changed to the hard 2mm *5mm line. No difference.

We set the fuel to 1.5Hz @ 1800 and 4.5Hz at 4500rpm. It still pulsed up to 2500rpm and gave black puffs of smoke. We had also tried running with out intake/exhaust pipes and with exhaust only.

We took the intake grille off altogether. No change. We stood the heater vertically and the pulsing immediately stopped.

We then set the heater back down in the most common attitude with intake and exhaust facing down. No pulse.

We change the fuel back to factory settings of 1.8Hz, 1800 and 5Hz 4500. No pulse.

So, although the manual clearly shows the heater can be mounted with the exhaust/intake horizontal (as long as the gloplug is facing up) wall mounting this heater in this configuration would not be acceptable.