Truma heating without power on (1 Viewer)

Nov 19, 2022
114
63
Funster No
92,538
MH
swift edge 494
Silly question maybe , but I don’t know if anyone can clarify , I assumed my Truma heating wouldn’t work without a power supply , however , noticed this morning when I turned power off the fans around home continued to blow hot air ??

Is this normal because common sense tells me power is required to power the fans that blow the heat?

I’m not on EHU , and the power is turned off , but heating still blowing hot on 20 degrees

Can anyone clarify

Thanks
 
Feb 9, 2008
4,107
5,945
SW Scotland
Funster No
1,453
MH
LP Coachbuilt
Exp
Since 2008 after caravanning for 20 years
The Truma uses 12v power except for the heating elements which are 230/240v.
 
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Dec 17, 2016
979
1,006
Malvern
Funster No
46,488
MH
Hymer B525 2006 A cl
Exp
2012
The fan will continue to blow until the air from the heater drops below the thermostat temp - often it powers up more for a minute or so and then stops. The fan and controls as willH said are running on 12v
 
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steveswift
Nov 19, 2022
114
63
Funster No
92,538
MH
swift edge 494
The fan will continue to blow until the air from the heater drops below the thermostat temp - often it powers up more for a minute or so and then stops. The fan and controls as willH said are running on 12v
Yes i understand that , however , power is off , so how is 12v powering the fans ?
 
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steveswift
Nov 19, 2022
114
63
Funster No
92,538
MH
swift edge 494
The Truma uses 12v power except for the heating elements which are 230/240v.
But there is no power on , power is switched off at unit , heating still blowing , 30 mins since switching off

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Apr 27, 2008
11,863
14,130
Eastbourne East Sussex
Funster No
2,327
MH
Hymer low profile
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Since 1972
Power isn't off. Usually turning off 12v at the panel does not turn off supply to the heater fridge electric step and often one of the lights. It is still using your leisure battery.
 
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steveswift
Nov 19, 2022
114
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Funster No
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swift edge 494
Obviously what youve turned off doesnt turn of the heater
My understanding is when this is set to off . All power is off ?

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steveswift
Nov 19, 2022
114
63
Funster No
92,538
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swift edge 494
Power isn't off. Usually turning off 12v at the panel does not turn off supply to the heater fridge electric step and often one of the lights.
Oh great to know many thanks , for sure though if power is off my lights don’t work . Other things I haven’t checked but thanks
 
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Jan 17, 2014
1,272
2,413
Wellington, Telford, Shropshire
Funster No
29,731
MH
Van Conversion
Exp
Since 1977
I would assume that the heater has a permanent supply regardless of switches to ensure that it always shut down in a safe and orderly manner. This would be to make sure that the burner area was cooled to a safe temperature and all combustibles were completely burnt and gasses cleared from the system.

Eberspacher / Webasto blown air heaters work that way for safety so I don't see why a Truma would not be the same.
 
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Dec 17, 2016
979
1,006
Malvern
Funster No
46,488
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Hymer B525 2006 A cl
Exp
2012
My understanding is when this is set to off . All power is off ?
Not everything - the electric step and the boiler low temperature dump valve and various other bits will still have a 12v power supply

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Hoovie

Free Member
May 16, 2021
1,249
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MH
Autotrail
The fan will continue to blow until the air from the heater drops below the thermostat temp - often it powers up more for a minute or so and then stops. The fan and controls as willH said are running on 12v
just an FYI.... Depending on the model of Truma Heater, you have two options:
1) Set the fan to Auto and it will run between off and the maximum you set on the speed dial depending on the temperature
2) Set the fan to On and it will run constantly at the setting you select on the speed dial

Option 2 is very useful as you can use it without the heater being on to provide blown air ventilation in the summer.
 
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Hoovie

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May 16, 2021
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Autotrail
But they run at full pelt drain 5-6 amps and hardly do anything to cool the van.
It is not an air conditioner so no reason why they should provide a cooling feature - but they add circulation and with an extraction fan running it is handy.

And it IS still an available option
 
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Oct 10, 2018
2,028
1,155
Bracklesham Bay, West Sussex
Funster No
56,646
MH
PVC
Exp
Since 2005
steveswift You need to turn the heating off using the separate Truma control as later Motorhomes have Truma heating that can be used en-route and has its own power supply not involving the Motorhome control panel being on or off ( it may still run a short time for its cooling sequence and then stop)

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Feb 14, 2021
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8,135
Milton Keynes, UK
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79,219
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Burstner Lyseo 727G
Exp
19 month year 18000 miles UK, Ireland, France, Spain, Germany, Italy. Campsites and off Grid.
Oh great to know many thanks , for sure though if power is off my lights don’t work . Other things I haven’t checked but thanks

On mine some of the internal lights work with power off - others don't.
 
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