# Truma Combi 4 E heater noise



## Rodav (Jul 21, 2012)

Hi, I am a caravanner seriously thinking of the move to a motorhome , with all the experience out there on MHF can someone help?
We have just been looking at an Autocruise Starburst which seemed ideal for our requirements but as the better half is very anti fan noise we asked the dealer to fire up the heating system "Truma Combi 4 E" initially it was silent for a couple of minutes then the fan started up and increased to full speed and made a very loud noise, it stayed at this speed until I turned down the thermostat then fan stopped completely! is this normal does the fan only have two speeds? Can any owners of these Truma heaters comment :?:


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## Pudsey_Bear (Sep 25, 2008)

Hi and welcome, We had the same heating system and noisy it shouldn't be at all, you should be able to hear it if you listen, but not very loud, I'm a light sleeper, but the heater would never wake me on a winters night.

Make sure everything works, not just turns on check the water gets hot, that all the taps work, that the tanks will drain, and of course all the electrics and do a damp check, older caravans always seemed damp to me, motorhomes should never smell or be damp.

If the dealer uses the phrase "Oh they're all like that" walk away, they're not all like that, but some are from day one.


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## Spacerunner (Mar 18, 2006)

The fan speed is related to the temperature required and the heat available from the Truma.
So, if you switch on the heating on a chilly day the boiler requires some time to make sufficient heat available, this is when the fan will run slowly and almost silently. As more heat becomes available the fan will increase in speed and noise in an attempt to attain the required temperature that you set on the thermostat.
Once the required temperature is reached the boiler and fan will close down.
Now the boiler has a good reserve of heat stored the fan will only come on, at a slow speed, to keep to the required temperature setting.
Noise levels are almost unnoticeable during normal usage.


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## spykal (May 9, 2005)

Hi

Spacerunners description is spot on but I think I know why you are worried. The Truma Combi when it is first put on using Gas as the energy source will make quite a lot of noise ... akin to a small jet engine whining away under the bed , the noise is from both the blown air fan and the fan that circulates the burnt gas exhaust gasses through the flue. As soon as the heater itself is up to temperature and it has reached or got near to the required room temperature set on the thermostat the noise will reduce to barely audible. Once this has happened it is so quiet that I often have to put my hand near an outlet to make sure that it is still operating. 

On a hook up and set to just use electricity the Combi is much quieter in the early stage as there will be no flue gasses to get rid of... and it is really quiet when ticking over to maintain the temperature set on the thermostat.

As with all thermostats we do find that there are occasions where we start to feel cold but the theremostat has not realised this :roll: I am sure that this is to do with the on/off margin of the thermostat and its position in the van ( quite near to the cooker) ... so sometimes I have to just move it up a bit to trigger the heat on.... then, of course, a few minutes later it get " its getting too hot in here " :lol: 

I think I have only ever once set the Combi to use both Gas and Electricity together and that was when the van was on the drive at home and I did it just to see how fast it could heat up the van... it was very fast , less than 15 minutes to get the van up to a toasty temp on a very cold day... the fan noise was considerable until it reached the temp I wanted.

Best idea is to go back and ask if you can give it another test.... which in this warm weather could be difficult but the Truma on gas should behave as we have described... lots of noise from the flue fan in the warm up stage then hardly any fan noise once it gets going.


Mike


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## Rodav (Jul 21, 2012)

Hi Spykal, 
Spot on with the "small jet engine noise". Does this same noise come on each time heat is called for by the thermostat or is it just a once off when first switching heat on ? Also is Hot water on gas as noisy? Sorry to be a pain but its a long return trip to revisit.

BR 
Dave


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## philoaks (Sep 2, 2008)

Rodav said:


> Hi Spykal,
> Spot on with the "small jet engine noise". Does this same noise come on each time heat is called for by the thermostat or is it just a once off when first switching heat on ? Also is Hot water on gas as noisy? Sorry to be a pain but its a long return trip to revisit.
> 
> BR
> Dave


Hi Dave,

I have the same heater in my Bolero. The only time the "jet engine" is apparent is when the space heater is first warming things up. The crucial word here is "space". If you have just put the system on to heat the water then it is almost silent in operation both on gas, electric or both together.

As previously mentioned there is a small fan to clear exhaust gases that operates whenever the heater is on (water and space). This fan is hardly noticable. The main fan, to provide the blown air heating is the noisy one but only in the beginning.

Phil


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## spykal (May 9, 2005)

Hi

On hot water alone and fueled by gas our Combi is only slightly noisy at the start up ... The flue fan gets going first and is quite noisy, then the gas lights up and a you can hear the burner/flame roar ... then after a minute or so the fan slows and the noise level is very low.... it is there in the background but not a problem for us. Noise is a difficult thing to be specific about ....certainly if the Truma continued to roar all the time it would be unacceptable but for us the heat up noisy period when on blown air is not a problem and assuming that the Truma Combi in the van you have looked at is functioning as it should then it should also be OK . Lots of us have Combi heaters so if it was a major problem I am sure that there would be lots more threads about it.

Mike

P.S.
There is one very little problem with the Truma Combi in the Starburst ..it is sited under the foot of the longest single bed .... which is nice in the winter, it keeps my feet warm but in the summer we make sure it is turned off before bedtime.


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