Truma Ultrastore intermittently cuts out on gas

[Christhecaravanner84]

Following on from my thread about pigtails…. On my current trip I’ve had the the water heater stop working every so often. The first I know about it is lukewarm water then I discover the thermostat which usually has a green light also has a red light. I turn it off and on again and it fires right back up and heats another tank of hot water. Does anyone know what is going on here?

 

[Christhecaravanner84]

Ah its quite breezy here today and a lot of wind around the flue. I can hear the ignition going and smell gas around the flue but it gives up. When it does light successfully, you can hear the flame blowing about a lot. I think some kind of windbreak is needed.

 

[Christhecaravanner84]

Problem solved with a quick trip to the local GoOutdoors…. Mind you, it might have to come down at night if its still windy. Flapping likely to drive me mad when trying to sleep!

 

[ProfJohnL]

The Truma Ultrastore is a product that has been around since the 1980's and its air intake and exhaust has only had mild alterations over that time. It is a a truly balanced flue design, and it should not be unduly affected by windage. Consequently I do wonder if the appliance needs to be serviced to check the condition of the burner.

 

[otherclive]

I have never encountered a problem with a Ultrastore over many years of use in some quite inclement weather. Wonder if this one is due a service?

 

[Christhecaravanner84]

Quite possibly . I shall get it looked at soon. Just a bit reluctant paying a load of money to “professionals” when they failed to correctly diagnose the faulty switch on my fridge, but i haven’t really got any choice.

Confuses me trying to understand how a flue of any kind can be completely impervious to wind, but I never have any issues with the boiler at home in windy weather. So obviously the science is sound.

 

[ProfJohnL]

...
Confuses me trying to understand how a flue of any kind can be completely impervious to wind, but I never have any issues with the boiler at home in windy weather. So obviously the science is sound.

Balanced flues combine the flue outlet and the air intake in a small area which means the wind can't produce much pressure differential between the flue and the air intake. This enables the thermal drive created by the flame on the burner to maintain a more consistent flow through burner system in much wider range of wind conditions.

Yout domestic boiler may also have a balanced flue arrangement, but becasue it has to cope with much greater quantities of flue products from its much bigger burner capacity it almost certainly has a fan assisted combustion system to ensure the flue gases continue move in the right direction.

 

[Christhecaravanner84]

Balanced flues combine the flue outlet and the air intake in a small area which means the wind can't produce much pressure differential between the flue and the air intake. This enables the thermal drive created by the flame on the burner to maintain a more consistent flow through burner system in much wider range of wind conditions.

Yout domestic boiler may also have a balanced flue arrangement, but becasue it has to cope with much greater quantities of flue products from its much bigger burner capacity it almost certainly has a fan assisted combustion system to ensure the flue gases continue move in the right direction.

Thanks for this explanation John.

 

[Joshyb]

After having the same issue, it turned out it was exhaust gasses flowing back into the unit and snuffing the flame out. The workaround was to drill a 50mm hole in the exhaust vent and the issue has dissapeared. This works in the wind no issues at it should as its a balanced flue. Always be sure to make sure you have a carbon monoxide alarm to ensure no gas is coming back into the van.

 

[Dustydog]

I wonder why Truma never thought of that😜.
In all my years of caravanning the one thing that needs respect is the gas system. I suspect there maybe something seriously wrong in your system. Carbon monoxide is the silent killer..Sorry not a modification I can support.

 

[Joshyb]

I wonder why Truma never thought of that😜.
In all my years of caravanning the one thing that needs respect is the gas system. I suspect there maybe something seriously wrong in your system. Carbon monoxide is the silent killer..Sorry not a modification I can support.

you are right, i can see the issue. When we installed the cowel extension it was installed upside down. we have checked and no carbon monoxide is leaking into the van. you can see where the exhaust gas is leaking into the air intake at the bottom of the circle we cut out. We are going to reinstall correctly. I will edit this to say its a short term workaround but not a fix