Truma D6 E puzzle

[CRD]

We have a Truma D6E in our new Carthago Malibu. it works fine, but on EHU using the 2KW selection, when both water and heating were switched off, it still turned on occasionally making a deep rumbling sound and then after about 10 minutes turned itself off.

It doesn’t do this when using diesel, so has anybody any ideas how to stop this rumbling sound, or is it working normally in electric power mode? I can’t find anything in the manual about it.

BTW, I published this by mistake, hence the edited message,

Thanks
Chris

 

[RubyOptics]

Is the puzzle to complete the above sentence??!!

 

[Landy Andy]

I have know knowledge of this boiler. But I can tell you that an immersion heater element in a domestic hot water cylinder can be quiet noisy, and that maybe what you are hearing is normal, then ceases as immersion cools.

 

[CRD]

Thanks, Landy Andy. I understand that the immersion heater element could be noisy in the Truma hot water cyclinder, but it makes this noise when the water and heating system is turned off at the control panel!

This is why I find it puzzling, but the real issue with the rumbling noise, is that the boiler is situated under the fixed beds and wakes me up at night, which is why I turn it off at night.

Chris

 

[Landy Andy]

Oh. Reread it and you are saying that on EHU that it comes back on, as too boost the water. Can’t understand why it would do that whilst off, unless it has a frost setting.

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[CRD]

Yep. Even though it is turned off at the control panel, the boiler still occasionally rumbles as though it’s doing something (I don’t know what!). This only happens when powered by the EHU, and not when being powered by diesel.

It might be an incorrect frost setting, but this was happening two days ago in Somerset.

Thanks for your help.

Chris

 

[Jonno1103]

These units are a partnership between Truma & Eberspacher and are only fitted in some mainland European built motorhomes. There have been complaints about them regarding noise since day one although they tend to be directed more towards a noisy diesel fuel pump. They're not a marriage made in heaven and quite a few owners have had them replaced at great cost with the more usual Combi 6E. Many coachbuilders & converters won't touch them with a barge pole.

Truma recommend filling and turning on the boiler for 10 minutes every month to a temp of 60c even when the van is not in use to maintain performance, problem there is that they don't tend to highlight that in the operating manual and it's not a requirement in the gas/electric Combi 4 or 6.

I'd have the water pressure tested first of all as a common fault is 'kettling' due to water passing over the heat exchanger too slowly - they need a higher pressure than the more common Combi's. A pressure problem would also cause your pump to turn on irregularly. If your pump is fitted close to your boiler it could be this rather than the D6E rumbling.

 

[CRD]

Hmmmm… Doesn’t sound like good news. It’s quiet when using diesel so we could use that instead.

A pressure problem would also cause your pump to turn on irregularly. If your pump is fitted close to your boiler it could be this rather than the D6E rumbling.

It could be the pump rumbling. I’ll have to see where it is. I’ll also ask the dealer to check the water pressure.

Thank you for this information Jonno1103