pertol heater?

[DEVO]

Hi guys,i have a 1980 t25 with a 1.6 Aircooled ct engine.i was under it last week and i dropped down a large metal guard so i could change the fuel filter.the guard was covering a large metal canister that had a fuel line going to it,tee,d off the line going to the engine.its also fitted with a coil similar to one fitted to a motorbike.it also has ducting that connects to the heat exchangers.i guess its a heater for the cab but i havent a clue how to get it working,there doesnt seem to be any controls in the cab for it.the van itself is ex-german military but had been converted to RHD a couple of years ago so maybe the dash that its using now hasnt the controls.any info would be appreciated.CHEERS,. DEVO