De-scaling Truma Combi heaters.

[Brian Kirby]

Have any of you well informed and clever types come across this?

I recently read an article in a French magazine recommending that the above activity should be carried out at least annually, and ideally more often than that.

The method described was (briefly) disconnect the feed hoses from the heater, fill the heater with vinegar, turn on the water heating and, when the vinegar fumes issued from the outlet spigot, turn off.  Then flush thoroughly.

This sounded a bit drastic and, as I couldn't find anything to that effect in my Truma manual, I contacted Truma.  Oh yes, they said, use 2 litres of wine vinegar to 10 litres of water, fill the heater and leave for 4-5 hours to work, empty and flush.  Have you a factsheet on this I asked.  No said they, it's all in the operating manual.  So, I searched again and lo, it said fill the heater with wine vinegar (12 litres?!), leave to stand, and then flush out.  There's actually a few more words than that, but not much more guidance!  No mention of the dilution, for how long to leave it or how often to do this.  Then I looked at the French instructions and it says much the same, omitting the flavour of the vinegar but adding formic acid as an alternative.  Still no guidance on strength of solution, dwell time or frequency.

At the moment I've just e-mailed Truma back with a request they review their maintenance advice and at least describe what is actually to be done, with what strength of de-scaler, at what frequency, and be whom.

However, I thought it would be interesting to know if anyone among you has ever done this, and with what results?  Also, has anyone suffered from a drastic fall of in water heater performance attributable to limescale?  Or should we just add Calgon to the drinking water :-)?

Regards

[Derek Uzzell]

I read the same French magazine article as you and had a good chuckle to myself. Most Truma Combi owners haven't a clue about the technical aspects of these appliances and, even if they were fortunate enough that the heater's installation allowed them to gain access to the water-hose connections and get acid inside the water-jacket, wouldn't dream of carrying out the recommended process themselves. And as for it being carried out by a motorhome dealer as part of a 'habitation service'.... Frankly, given the design of a Combi's water-jacket, I think you'd need a huge amount of lime-scale to make a significant difference to water-heating performance. One thing's certain, I'm not following Truma's advice over this. (By the way, does your Combi require the 'safety modification' Truma has issued notices about?)

[Brian Kirby]

Derek

Re Truma's advice, such as it is, nor am/have I! 

I'd never heard of anything quite so bizarre in connection with these heaters.  However, I thought I'd ask, just in case everyone else popped up and said "oooh, have'nt you done that yet, you really should" or words to that effect!

If the inside of our kettle is anything to go by, there must be some scale in the water heater.  But how on earth could you ever tell its extent, or the degree of success achieved? 

I do wonder how much the sales of Truma Combis/boilers will increase in France as a consequence of the LMCC advice, assuming anyone is nuts enough to follow it!  I await the letters page of the next issue with interest!

To answer your question, no.  Mine was built before whatever it was, was changed.

[colin]

Slightly puzled by your posts, are you deriding using vinager as descaler or descaling truma? I ask as next van may have truma

[Brian Kirby]

No Colin, just deriding Truma's de-scaling guidance. 

Don't worry, the actual heater is very effective.  If you get a Combi, make sure you order the electric water heating element though (unless you're one of those who never go to campsites, of course).

Regards