Truma ultraheat 230v no green light

[Jamesworld47]

No green light on 2004 truma ultraheat, not working on 230v, fine on gas.
Test sequence?
Thanks Jim

 

[toad a caravan]

I hope these may be of use

 

[toad a caravan]

And welcome

 

[IanB1485]

Main cause is the transformer on the pcb has popped. The pcb is located at the rear of the appliance below the circulation fan assembly , loosen the three fan screw s( do not remove) and rotate the assembly anticlockwise to release and move out of way the pcb is under the cover. A blown transformer is easy to spot , it looks like the attached photo( the brown object with the black burn stain on it)You can get the transformer (with relays) as a kit off ebay or the complete pcb for an eye watering price of £160 from Prima Leisure or just the transformer from Farnell electronic components (part code 3967044 or 4209748). also some will offer to repair the pcb for you look up 'truma ultraheat pcb'

 

[toad a caravan]

Ian,is there no heat sink fitted,the case also doesn't look over ventilated, I'll keep trundling along with my obsolete and antiquated carver 3000😄

 

[IanB1485]

Toad , nope no heatsink and no ventilation . The 'blue transformers from Farnell are thermally protected, so shouldn't suffer the same fate as the original.
Way back when, I designed a piece of electronics and the pcb manufacturer selected a similar ( as the original ones in the Truma ) transformer on the PCB . Over the next two years we suffered >300 failures , which meant our service engineers had to go out to site and replace them FOC (very embarrassing as the designer)and I then specified the Farnell transformer on the newer pcbs and suffered no further failures. Lesson learned:- buy cheap , buy twice. Also I've seen and repaired several Caravan PSUs/chargers with a similar transformer (used to initially supply 12V to the control circuitry) , fortunately the little transformers hadn't died on these PCB's