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trumatic C3400 termostat does not work


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I hawe a problem with trumatic C3400, actually 2 problems.


The termostate does not work, the heeter just continue to vaarm ewen if its warm enough, i added an exstra termostate that switch on and of the heeter, it worked for a while but now there is the problem that the heeter will not start.


I tries to start but then the red led is lighted. Its possible to start the heeter but it starts only after some times retrying.


What can be the reason for the trumatic C3400 not stopping heating.


What can bee the reason for trumatic C3400 not starting ewerytime and lighting the red led.




If you hawe had the same problem it would bee really nice to hear from you.

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Welcome to the Out&AboutLive forums, thor.


Is your Truma heater actually a C-3400, because that would mean it was made between 16 and 19 years ago?


Operating/Installation instructions for C-Series heaters can be downloaded from here:




Possible reasons given for the heater going into 'failure mode' (when the control-switch's red warning light will be continuously lit) are insufficient gas pressure, insufficient combustion air, or fuse failure. If the red light flashes, the operating voltage is too low. Air getting into the gas pipework will result in the need to make several (sometimes many) attempts at starting the heater before it will run continuously.


These are things that the user may be able to do something about, but failure for the heater to operate may be because the gas solenoid valve is not opening or is blocked, the gas-igniters aren't working (as happened with my C-3402) the printed-circuit board has developed a fault, the combustion-fan has failed, etc.


There's little point in guessing at the reasons for your problems. If you look for obvious causes (like there being no gas in the gas-bottle) and cannot find anything, you will need to have the heater checked by a professional.

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