I have a Rapido 7095DF with a Truma Combi E heater. The controls are the two knobs rather than the electronic panel. Before the winter I drained the water and boiler and left the auto frost valve open. Also left all the taps and shower open. Today I tried to put the heater on, on gas to warm the van up (without filling the water) but I get a red, constant light after a few seconds. Checked battery voltage, no problems. Tested with 230 V attached but same thing happens. Then i tried to warm up the van with electric instead, but same thing happend; red, constant light... what can be the issue?
Regards
Regards