Truma Combi not heating on Electric Only

[MichaelT]

Going away tomorrow so have van on EHU to get it warmed up. On the ELEC 2 setting the water has got hot but the heating is struggling, the fan is not cutting in to circulate the air. I moved it to Mix 2 and that seemed to kick it into action so back to ELEC 2 and fan cut out straight away, then a few moments later cut in again then off. Will probably leave it overnight to see what happens, currently on 20 degrees so it should cut in as its freezing out. No errors on CP panel all looks normal.
Any ideas?

 

[KUSKUS]

Have you got the hot water on boost, on ours if you do it cuts out the electric heating for about 40 minutes and then the heating cuts back in.

 

[Campervan_man]

Just put it on heating only not heating and hot water ?

 

[MichaelT]

Have you got the hot water on boost, on ours if you do it cuts out the electric heating for about 40 minutes and then the heating cuts back in.

No it is just on hot

 

[MichaelT]

Just put it on heating only not heating and hot water ?

But it should work on both plus once the water is hot it will only be powering the heating (not sure if the heating works off the hot water jacket anyway)

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[Campervan_man]

Put some pics on of the display/ controls ?

 

[MichaelT]

Put some pics on of the display/ controls ?

No errors, just says water is hot and the MH sign is flashing cos its only 14 degrees inside and I have it set on 20.
Just had another look some gentle heat coming out but only luke warm, turned fan to high, that made the air stream a lot faster but still only warm hot hot air. Normally we run it on Mix 2 and on eco the fan cuts in till it gets to temperature (quite quickly) then it cuts in and out as required, never had it on just ELEC before so wonder if it is working as it should or maybe one element has gone but no errors on CP.
Will leave it now on 16 degrees overnight and see if it gets heated up to that.

 

[PeteH]

pdf;-

 

[MichaelT]

pdf;-

thanks I already got the english version.

 

[Hetti]

We never find that on electric only it gets up to required temp. We always find we have to put it on electric and gas get it up to required temp then put onto electric and it then seems to hold temp.

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[KUSKUS]

ON ELEC2 its only 1800 watt so I suppose we shouldn't expect too much .

 

[MichaelT]

We never find that on electric only it gets up to required temp. We always find we have to put it on electric and gas get it up to required temp then put onto electric and it then seems to hold temp.

That's what I was thinking

 

[MichaelT]

Left on overnight and set at 16 degrees, only got to 15 so looks like the ELEC settings are not powerful enough to heat van. Going for 1st check at the dealers in April so will ask them to check it out though based on past performance not overly confident they would know what they are doing. Will just use Mix setting like we do normally for now.

 

[MichaelT]

Update: I contacted Truma and this is their reply, will check the dealer when I take it in.

Thank you for your enquiry. The electric function of the Combi Heaters (Combi 4E/6E) are an 1800w supplementary heat source to the gas operation of the heater.

The gas functions will operate at 6kw so will get the van up to temperature quicker than using the electric function which may is only a third of the gas power of your system. If you feel that the operation of the electric is not performing as well as it has in the past then you can ask your dealer to check the electric elements in the heater as these can occasionally fail without registering a fault code at the control panel.

If you require any further assistance do not hesitate to contact us.

 

[WillH]

As Truma state, it's really a gas heater with supplementary electric function though it is worth checking the elements. You should get a reading of 59 ohms on a single element using a digital multimeter.

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[MichaelT]

As Truma state, it's really a gas heater with supplementary electric function though it is worth checking the elements. You should get a reading of 59 ohms on a single element using a digital multimeter.

will leave that to the dealer.

 

[Pausim]

In cold weather I do not expect the electric heating to cope in my 7m motorhome and yours is bigger. I get it up to temperature on gas and then see if the electric heating can keep it there.

 

[two]

Use gas whenever you are paying for electricity. It's cheaper. Well, it's a while since I did the calculation and, if you're using Calor it might not be that significant now but, it's definitely cheaper if you have refillable. If you use MIX, you will get much better performance and the 'leccy is used as priority so, when only a little heat is needed it'll only use electricity (but only use MIX if the EHU is at no additional cost. The fan only comes on when the chamber is hot enough, so that's why you had the 'intermittent' effect. They are gas boilers. The electric element was added as an afterthought to appease the Brits using CAMC sites.

 

[WillH]

As a rule of thumb with our 7m van, if the outside temperature is 5° or less, the electric elements will not cope and we supplement with gas. Especially if it's windy. in the summer, if on EHU we use the electric for hot water.

 

[Jenben]

As a rule of thumb with our 7m van, if the outside temperature is 5° or less, the electric elements will not cope and we supplement with gas

I’m surprised. Our 6.75 m van coped fine (20c) using just the Truma electric heating when staying at ski resorts with temps down to -20c outside. Maybe the installation and insulation make a difference?

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[peterc10]

Most Truma heating systems sold for motorhomes do not have any electric heating elements in them. That is because it is largely the UK market that wants electrics. Most European motorhomers do not specify electric heating.