Truma 6e - heating imbalance!

Fantail19.......... wrote: Does the fan merely "blow" air across the heater or does it also contribute to the heating of water within the tank? I'm a bit confused as we have tried increasing the spped of the fan - but it merely seems to contribute to the problem?...

Thanks for replying.

The truma has two fans. One sucks fresh air from outside, into the boiler guts where it mixes with the gas and burns a flame inside the heat exchanger. Then the burnt gas is blown out of the exhaust flue to the outside air.
The other fan blows ambient air, from inside the MH around the outside of the heat exchanger, gets hot and travels along the cardboard tubes to the warm air outlets. Then round and round inside the van and eventually back into the heater to get warmed again.
Heating the hot water is a natural product of the fact that some water is stored in the heat exchanger and as this gets hot when the heating is on, the water gets hot as well. I don't worry how hot it is, I just use the mixer facility on all the taps to get the desired water temperature. You can have hot water, cold water, or just warm water from any of the taps or shower.

If you select hot water only, just the outside air is sucked in, mixed with gas, burnt, and blown through the flue to the outside air. Only the burner fan is used.
If you select heater only, both fans run, one is used to burn the gas, the other is used to blow the warm air around inside the van.
If you select hot water and room heater, both fans run, and as cold water is drawn into the heat exchanger the computerisation boosts the amount of gas and the speed of the burner fan to shove lots and lots of energy into the heat exchanger so it can heat up cold water and cold air both at once.

. . . .  .and if you think that an all-electric campervan is a good idea, just try it and see. You need lots and lots and lots and lots and lots of batteries to replace one bottle of LPG. Or a dirty great fat cable running to the nearest 13 A socket - which I have yet to see on a camp site. (But then I don't like camp sites - or at least not the UK ones, they charge too much)

The balanced flue fan runs on EL1 or EL2 when no gas is being supplied or burnt which undermines the Combi's efficiency credentials.  Wasted EHU heat is felt at the flue.

It may not be an issue with the Truma boiler although possibly.
The error you describe isin't an error, but rather a warning, hence the W in front of the code.
It means the boiler is too hot and this is why the fan to distribute the air heating increases in speed to push out heat into the campervan and cool the boiler. This normally occurs when the boiler has been first put on HW only, the boiler becomes very hot to heat the water and then air heating is put on e.g.with a low thermostat temp, so the boiler is too hot for the air temp selected and attempts to distribute the heat quickly in order to reach the selected temp. I suggest you therefore don't need to turn the Truma heater off as this is normal (has happened to me) and within a few mins the fan speed returns to normal.

However, in light of that if you are not heating the water first, then this shouldn't be happening specifically at the temps of 11-13C you specify. It maybe a possibility that you have a fault with the thermostat rather than truma heater? I have also seen this where a spec of dust gets into the thermostat (next to the Truma CP) and I've seen the temp on my Truma CP register 30C!, when in fact the air temp is nowhere near that. Blowing hard into the thermostat has removed the offending dust and the temp then registers correctly. Perhaps try that before a trip to Truma?

williamsp2578 wrote:It may not be an issue with the Truma boiler although possibly.
The error you describe isin't an error, but rather a warning, hence the W in front of the code.
It means the boiler is too hot and this is why the fan to distribute the air heating increases in speed to push out heat into the campervan and cool the boiler. This normally occurs when the boiler has been first put on HW only, the boiler becomes very hot to heat the water and then air heating is put on e.g.with a low thermostat temp, so the boiler is too hot for the air temp selected and attempts to distribute the heat quickly in order to reach the selected temp. I suggest you therefore don't need to turn the Truma heater off as this is normal (has happened to me) and within a few mins the fan speed returns to normal.

However, in light of that if you are not heating the water first, then this shouldn't be happening specifically at the temps of 11-13C you specify. It maybe a possibility that you have a fault with the thermostat rather than truma heater? I have also seen this where a spec of dust gets into the thermostat (next to the Truma CP) and I've seen the temp on my Truma CP register 30C!, when in fact the air temp is nowhere near that. Blowing hard into the thermostat has removed the offending dust and the temp then registers correctly. Perhaps try that before a trip to Truma?

Thanks for your input - sorry i didn't reply sooner. I will certainly check the thermostat for dust! No, we definitely had not heated the water first.... and after some investigating, by our dealer and conversations with both Truma and AS and trying to recreate the situation - our boiler is confirmed as at fault and now sits on a bench.... awaiting replacement. Thanks again to all folks who contributed thinking and experience to this issue - which I have noted we were not the only ones to experience a similar experience in the last few months!