Mileo 294 shower problem - help

as far as I am aware the boost option on the truma system is nothing to do with the shower per say.  It heats the hot water to a higher temperature than normal so when mixed with cold you have hot water for longer.

Does the kitchen tap still produce hot water once the shower has stopped, if so I would say the mixer valve is faulty on the shower.  If all the hot water has gone i.e. none from any tap and you ahve had it on boost and the boost icon has stopped flashing to indicate its up to temperature then the problem is with the Truma water heater.

Does the boost icon stop flashing at all?

Are you using just electric, if so try it on gas to see if that makes a difference, if so it may be one of the elements has gone U/S.

Hi.. Thank you for reply... we have tried using the boost with electric and gas mix setting and the boost indicator stays flashing... all the hot water goes from the sink and shower and you do not hear the boiler heating during using the shower... I would have expected the boiler to be heating once the cold water starts going into the boiler but this doesn't happen.Do you know how long you would expect a shower to last when the boost is up to temperature and mixing with cold water?

We would normally get 2 quickish showers or 1.5 longish ones i.e. Mrs T has a long shower and I get a short one   .  Just try it on gas only it as you say should start to reheat once the water is started to be used and using only gas will determine if its the element that is not working.

As a footnote ours is a Truma 6 so not sure of the difference, others may help there but the principal is the same just the KW difference I think but once water is up to temp its the same.

From what you have said in your OP  I think you have the ‘Truma  Combi 4e’

 See: https://www.truma.com/uk/en/heating/combi-4-e.php  this has a total water capacity of 10 Litres with an 1800w electric element that takes about 20mins to raise the temperature of the water from 15c to 60c. So if you take two showers, one immediately after the other in theory you can have 5 litres at 60c each.  However 60c is far too hot for the human body and cold will need to be mixed with it, thereby giving a quantity greater than the 5 litres mentioned above.

Now in practice as the hot water is being drawn off it is being replaced in the boiler by cold water and some mixing takes place, thereby constantly reducing the temp of the water  available. Even if the element is working from the moment the hot is being drawn off, 1800w will be insufficient to keep up. (theoretically only 1 litre per 2mins).

You say that you only get hot water for 2-3mins.Have you tried measuring the amount of hot supplied at one go as you may actually be drawing off all of the boiler capacity during that time.  Although I have no experience of this particular system, 2-3mins does seem a very short time to me.

agree with pretty much all of the above replies...

like Michael, we get two showers (one straight after the other) from one heated tank of water....heat 10 ltr to 60 deg, mixed with cold gives about 13 ltr of hot enough water...

i get say 5 ltr, OH will have about 8 ltr...

aswell as heating the water to a slightly higher temp, the other thing it does is to turn off any heating to focus on the water...

the only difference in the combi 4 and 6 is the power available on gas (4 or 6 kw) and mixed (3.8 or  5.8 kw) power sources.

on electric only, either can heat with 900 or 1800 watts.

either can heat to 40 or 60 deg, the chosen power source will determine the rate of heating.

while its true to say that hot water is being replenished with cold, the cold comes in at the bottom and the hot goes out at the top, so it doesnt drag the temp down 'too' quickly....

two showers should be easily doable from one heating....

..."the only difference in the combi 4 and 6 is the power available on gas (4 or 6 kw) and mixed (3.8 or  5.8 kw) power sources.on electric only, either can heat with 900 or 1800 watts"...

I am a little puzzeled as to why the Combined  power output is actualy less than that of the Gas alone. and can you heat the van its-self using Electricity only?

PS. I seem to be having some trouble getting this to post tonight

I am not sure of the logic of the power either I thought on dual fuel it gave the higher output, but yes you can heat the van on electric only but as BB says if you have the water on boost it will prioritise that over heating. On a cold day to warm the van faster put it on dual fuel and it will heat faster. 

when on mixed mode, the full 1800w of the electric side is used (if selected....its possible to have mixed mode with 900w electric...for use on a low amp site?)

the gas side only uses 2kw (on the combi 4) or 4kw (on the combi 6). dont understand the logic but these are the figures AFAIK.

i think the ALDE units use full gas and electric outputs to give their 'mixed mode' totals....again AFAIK.

i have a combi 6E.

as Michael says, heating the van is perfectly possible on electric only (900/1800w) as is water heating.

with the latest control panel, its possible to manually control the fan speed....by ramping this up to 'high' even the lowish electric output can be boosted around the van in a far better way than the older system, where the fan speed was determined by heat output.....so, low heat (electric) meant low fan.....which in turn usually meant van not warm enough...

the change in the fan speed has really made a huge difference.

Apologies to OP for going a little off topic but, as a non-caravanning relative of mine is about to join the fraternity, I am being asked questions about heating. Surely if the heat output on Gas alone is greater than the Dual output, although the difference is small, the van would heat up quicker on the Gas setting, so do you find this not to be the case?

BoleroBoy. You say that the 4 E only uses 2kw on gas yet Truma in their Technical Details:  Rated thermal output claim 2000/40000w, yet quote at: Rated thermal output in mixed operation 3800w. All of which is a little confusing.  

I am wondering if theses appliances have the potential for localised internal over-heating issues, due to their design constraints, when dual output is used.