Truma water heater issues!

[BarrieLow]

Hi I require your expertise. I have a 1998 Abbey vogue 416 gts. Our truma water heater only appears to work on gas but lately it has just stopped heating. When you turn the control dial the little green light no longer comes on (neither does the red light) and the boiler doesn’t fire up. We have done the obvious, made sure the gas is on, the valves are open, the fuses are intact and the flue cover is off. Have checked the manual and it’s not much help. It’s worked all year until now and we haven’t changed anything. I don’t even know where to start looking, please help

 

[otherclive]

Do your other gas appliances work satisfactorily in parallel operation? If not it may be a regulator issue. Are you using butane or propane as butane looses its ability to function well as temperatures reduce towards zero.

 

[IanB1485]

The gas control on the Truma Ultrastore is a pcb located on the RH side of the unit(see photo) under the grey plastic cover with the terminals facing upwards. On it is a small 20mm glass fuse see second photo with black arrow pointing to it.Given you have checked there's 12V power to the PCB it sounds like the fuse may have popped. IF you don't feel confident then the you could contact a mobile engineer (See www.mobilecaravanengineers.co.uk a click on Find an engineer) The PCB can also be repaired see A & R electronics who advertise a repair service on ebay (https://www.ebay.co.uk/itm/156612222014)

 

[BarrieLow]

Do your other gas appliances work satisfactorily in parallel operation? If not it may be a regulator issue. Are you using butane or propane as butane looses its ability to function well as temperatures reduce towards zero.

Hi mate, thanks for the reply. Our heater, fridge and cooker all still work on the same gas supply and we’re using propane

 

[IanB1485]

@otherclive The OP has posted that neither the green or red LED light up indicating a lack of 12V ( the green lead would light initially and you hear a small 'clunk' as the gas valve opens , then if no gas the valve shuts and the red LED comes on to indicate a flame failure )

 

[BarrieLow]

@otherclive The OP has posted that neither the green or red LED light up indicating a lack of 12V ( the green lead would light initially and you hear a small 'clunk' as the gas valve opens , then if no gas the valve shuts and the red LED comes on to indicate a flame failure )

So if it’s a lack of 12v power, where do I start looking? Checked all of the fuses that I could find and they’re all good and the ‘water heater’ switch in the cupboard is on and lit up. What do I check next?

 

[BarrieLow]

The gas control on the Truma Ultrastore is a pcb located on the RH side of the unit(see photo) under the grey plastic cover with the terminals facing upwards. On it is a small 20mm glass fuse see second photo with black arrow pointing to it.Given you have checked there's 12V power to the PCB it sounds like the fuse may have popped. IF you don't feel confident then the you could contact a mobile engineer (See www.mobilecaravanengineers.co.uk a click on Find an engineer) The PCB can also be repaired see A & R electronics who advertise a repair service on ebay (https://www.ebay.co.uk/itm/156612222014)

Hi mate, yeah checked that fuse too and they’re filament appears to be intact

 

[IanB1485]

power to the pcb , the water heater is usually under the front RH seat take of the grey cover and look for the 12V supply cable which leads to 4 way connector (at the bottom of the my second attached photo) if you have 12V going to it the pcb needs repairing/replacing and the options are as my earlier post.If you don't have 12V at the connector then you need to check the cabling at the pcb , back to the caravans wiring harness until you find a 12V and 0V , also check the other two cables are firmly seated into the PCB's edge connector.

 

[ProfJohnL]

Hi Barrielow,

You have told us the glass fuse's filament seems intact, but that doesn't actually tell you the fuse is OK. obviously if the filament isn't there that is a virtual certainty the fuse has blown, but you can't assume the apparent presence of a filament means the fuse is OK. Considering the age of the caravan (and I assume the water heater) sometimes under normal use a fuse can weaken and fracture over time and still leave the filament apparently there. So if you are competent with electrics it's worth testing the continuity of the fuse with a multimeter or refering the diagnosis to a professional.

If the fuse has operated and left the filament visible, its likely to be just age/use related, and there shouldn't be a problem with simply replacing fuse with one of the correct value. But if a fuse has ruptured and the filament has clearly either melted, disappeared or the the inside of the glass tube has darkened, these tell-tales indicate the fuse has carried too much current, and that usually means something else has caused excess current to flow, so the circuit needs to be repaired or replaced, again that is a job for someone who is genuinely competent with electrics and electronics.

As you probably know fuses are usually specified by the their current rating in A (Amps) or mA (milliamps) and the value is usually marked on the fuse body or stamped into an end cap. The rating on glass fuses is also usually by a capital letter which indicates the sensitivity of the fuse :-

• FF: Very Fast Acting (Flink Flink)
• F: Fast Acting (Flink)
• M: Medium Acting (Mitteltrage)
• T: Slow Acting/Time Delay (Trage)
• TT: Very Slow Acting (Trage Trage)

Breaking Capacity (Interrupting Rating): This marking indicates the maximum fault current the fuse can safely interrupt.

• L: Low breaking capacity
• H: High breaking capacity

It's important for your safety to replace a fuse with the correct rating and type.