Aeroheat Diesel heater problem

[SY Amalie]

I have a diesel heater from 2015 that has worked more or less flawless. The odd red light after shutdown but easily sorted by unplugging and plugging the four-lead connector from the very basic control panel.

This time, however, when I tried to start it after a four month wait it decided to do nothing.
No sound from the fan or the dieselpump, and after a few seconds of silence the red light comes on. If I try to press start again, the red light comes off and it all looks good but if I try to start again it does the same.
I pulled it apart and had a look at the mainboard, but with limited skills all I could do was look for obvious/visible damage or corrosion, it all looked good. There was no obstructions inside, the fan turned smoothly and it all looked good.
Does anybody know if it does a self-check first? So if the fan or the dieselpump is seized or the glowplug is shorted out it would just give a red light?
There was no current draw on the battery monitor.
It is getting on a bit, but I would be grateful for some pointers as it worked perfectly fine when I left the boat, and it looks like a well made heater.
I have tried to look online, but there seems to be very little information on these heaters.
It is a Aeroheat D-4 and it is labeled KOMP as well.

 

[fredrussell]

The general advice given on here is to just bung a “Chinaspacher” in there. They’re so cheap and you can use the existing ducting and exhaust from your dead heater. I don’t know the make “Aeroheat” but I’m assuming the D4 bit means it’s a similar heater to an Eberspacher Airtronic D4, which is the heater that, ahem, ‘inspired’ the cheap Chinese models.