Hi folks Im a new member to the forum but know there are some knowledgeable folk out their and I need help with the common problem of an Ultraheat not working on mains. bought van (pastiche 2000 520/4) end of last year(private sale) had it out for Easter and discovered its a bitza!!.Wires(2) at rear of fire not connected no green light on controls igniter the wrong one for 3002 a mess.Ive solved gas issues but mains not working .Ifound Gary's full explanation on how to check things and clarify continuity on an old UK link but lost it so I would be grateful for help to check out the wiring.There is a master switch on the wall behind the fire which feeds into the pcb unit is this the fused spur? Cheers folks Stuart
Is there 240v arriving at the ultraheats control board? faulty isolation switches and or 3 pin in-line cable connections can prevent power getting to control board.
If you have power at the board and no green light on switch, then usual problem is blown 10v transformer on control board. This is the grey block and biggest thing on the board, quick check is the top should be utterly flat, if it's domed upward at all then is blown.
Some don't show this, so there are four pin connections underneath, check resistance between wide pair on input side reads give or take 2000 ohms resistance, if blown it will be open circuit so no reading.
Isolate mains before doing above resistance checks
Well I've no idea, I'm fairly certain they should be 12v from the battery and as either has no white in the colours, both will be positive wires.
Generally the only thing on the Truma heating that uses 12v is the fan on 1/4" spade connections but that needs an earth wire of course.
BUT, I've just noticed the age of this thing, Truma heating kicked off in the UK in 2001, least 99% anyway and they all work as I've described above.
However, Truma already had their original Ultraheat which is different in design. Essentially and obviously, this one has the elements in front of the gas fires heat exchanger and a separate control box with loads of wiring?
I don't know a deal about this early one as it's rarely seen in the UK
The elements on this truma are behind the gas fire and damn hard to get at without removing whole assembly The controlbox is located on bottom of fire below elements and the fan(Ive already removed that).If this is older type will that explain why there is a 240v master switch between caravan mcb and heater controlbox or is this the fused spur as it shows in caravan wiring diagram which by the way is as much good as an ashtray on a motorbike for this problem.Could it be more of a bitza than I thought?!!!
Well there is no point in wondering anymore out it comes and Ill reinstall checking as I go .To quote my old man Ive"BOUGHT A PIG IN A POKE" Thanks for help so far Ive no doubt that Iwill be back in touch probably for a box.
Gary thought Id up date you .Fused masterswitch on spur had a 13amp fuse in it and burnt out across neg turminals inside switch.Fuse OK Checked PCB and cannot see any trace of the blown effect on the top of large grey item actually looks fairly new pcb .the other worrying thing was a 240v cable leading across van either to fridge or 3 pin socket(havnt checked yet) SCOTCHLOCKED ONTO HARNESS BELOW MAIN MCD. Do you think this Is this standard coachman wiring?
All ok now Gary Thanks for help .You were right about up grade of heater Coachman confirmed the Ultraheat was offered at this time but was installed as an extra which explains the extra wiring.The scotchlocked extra 240v spur was not their doing as exterior 240v socket was not an option so was obviously fitted by a -----.....! Thanks again