Chauffe'au Questions - Again

[UlsterRugby1999]

I'm sorry to visit this old chestnut again BUT - I need to ask a few questions of you wise owls.

Last year (2009) we had a thread discussing solar water heating. It was a great thread and loads of very useful information came out of it. It is something that I will be opting for at some point in the future but not just now. Funds and all that.

During the discussions, I had indicated that our electricity consumption was very high and I suggested that our hot water use might be seriously contributing to the high consumption. Some of you guys had looked at this with me and suggested various routes to follow and tests etc. I have been trying a wee test this week to see how things might work out.

Using the HC charging rate for electricity (21:45 through to 5:45) only to heat our chauffe'au (plus 1 hour during the day time) we have been able to reduce our weekly Kw consumption by an average of 105 Kw. I know this figure cannot be simply multiplied by 52 weeks to give a reasonable annual saving but lets assume that we do so and use only 80% of the total. This would give us an annual reduction in consumption of 4368Kw. At a cost of 0.0839 (HT) this would save us circa 438.1€ (TTC) per annum. No mean sum.

Here's the BUT - we never get to the end of a day without running out of hot water. During the test, no dishes were washed except one dishwasher load which uses cold water anyway as is the case for the washing machine. The usual mode of a half full sink of hot water to wash a few knives and mugs etc didn’t happen. Showers were kept to the shortest time possible and so on. Our tank is 250 litres and the unit is heated (I believe) by a 3Kw heater. My 84 year old mother-in-law has twice tried to run a bath and the water has been tepid at best. Now I'm not quite flavour of the month. [:(]

So, with the best intentions in the world (and of my pocket too) I have to revert to leaving the Chauffe'au on 24 hours a day.

Even with the solar systems that we see advertised which generally use a 300 litre tank, would I still end up with a tank of hot water for her bath each night. I understand that they have an electrical element too to augment any additional requirements but could this be taken up with charging/heating times during the HC hours? You see what I mean.

What are your thoughts folks? All advice, as always, gratefully appreciated.

[AnOther]

What temperature is the chauffe'au

thermostat set to, the hotter it is the longer it's going to last. Is

the baloon new or old, newer ones will be far better insulated, a key

factor in retaining your expensive heat.

[quote user="UlsterRugby1999"]This would give us an annual reduction in

consumption of 4368Kw. At a cost of 0.0839 (HT) this would save us

circa 438.1€ (TTC) per annum. No mean sum.[/quote]

All savings are to the good of course but I'd say roughly €1/day is a very small price to pay to keep a MIL in hot water [6]

[suein56]

[quote user="UlsterRugby1999"]What are your thoughts folks? All advice, as always, gratefully appreciated.[/quote]

How old is your CE? Do you think, perhaps, it is time to replace it? Or are your chauffe eau elements clogged up with limescale or something?

Our CE is 14.5 years old and still works well ... but we have been in our rented house for 4.5 years now and I have noticed a deterioration in its functionality in that it takes a lot longer to heat up the same amount of water nowadays than it did before. We can still cope with 3 visitors* all having showers every day, lots of washing up in the sink BUT the water heater then works continuously throughout the off peak periods - we have 2** - to heat the water. Whereas before the water heated quickly in a much shorter time.

*and we 2 of course.

** 02h00 till 07h15 and 14h20 till 17h05

[Poolguy]

[quote user="UlsterRugby1999"]

I'm sorry to visit this old chestnut again BUT - I need to ask a few questions of you wise owls.

Last year (2009) we had a thread discussing solar water heating. It was a great thread and loads of very useful information came out of it. It is something that I will be opting for at some point in the future but not just now. Funds and all that.

During the discussions, I had indicated that our electricity consumption was very high and I suggested that our hot water use might be seriously contributing to the high consumption. Some of you guys had looked at this with me and suggested various routes to follow and tests etc. I have been trying a wee test this week to see how things might work out.

Using the HC charging rate for electricity (21:45 through to 5:45) only to heat our chauffe'au (plus 1 hour during the day time) we have been able to reduce our weekly Kw consumption by an average of 105 Kw. I know this figure cannot be simply multiplied by 52 weeks to give a reasonable annual saving but lets assume that we do so and use only 80% of the total. This would give us an annual reduction in consumption of 4368Kw. At a cost of 0.0839 (HT) this would save us circa 438.1€ (TTC) per annum. No mean sum.

Here's the BUT - we never get to the end of a day without running out of hot water. During the test, no dishes were washed except one dishwasher load which uses cold water anyway as is the case for the washing machine. The usual mode of a half full sink of hot water to wash a few knives and mugs etc didn’t happen. Showers were kept to the shortest time possible and so on. Our tank is 250 litres and the unit is heated (I believe) by a 3Kw heater. My 84 year old mother-in-law has twice tried to run a bath and the water has been tepid at best. Now I'm not quite flavour of the month. [:(]

So, with the best intentions in the world (and of my pocket too) I have to revert to leaving the Chauffe'au on 24 hours a day.

Even with the solar systems that we see advertised which generally use a 300 litre tank, would I still end up with a tank of hot water for her bath each night. I understand that they have an electrical element too to augment any additional requirements but could this be taken up with charging/heating times during the HC hours? You see what I mean.

What are your thoughts folks? All advice, as always, gratefully appreciated.

[/quote]

So you've arrived at the point of enlightenment. Bravo that man. (No disrespect intended but I want to make a very serious point.)

It should not need a concerted effort on your part to analyse the consumption of your existing electric hot water system, in order to come to the realisation that you should be doing all you can do with the energy which is available to you for free. It should be a faite completé or a 'no brainer' in the modern vernacular.  The economics of installing solar hotwater heating do not need to be proven, that has been done and redone so many times that it should part of common consciousness now I would have thought.

By the way, solar thermal (heating your domestic water) is by far the most economical and most successful of the renewable energy measure available to a private individual with modest needs and modest means. Can you imagine a world where you have no choice .... I mean that it is obligatory to install a solar panel on the roof to provide for this need - hot water. Well, you may not believe me but I think that that is a reality in the not to distant future. If that is true ( or even if it isn't) I cannot quite understand the reluctance for most people to adopt such measures, simple as it is, tired countless times, proven countless times, what is the hold up. What's the agonising decision, why procrastinate? (and NO its NOT TOO expensive.)

This idea though modest, is probably to single most available and most effective thing that any of us can do to contribute to the now urgent effort to reduce carbon emissions - (oh dear did I say a dirty word). Sorry for that but it does need to be said and no matter whether you agree with the whole Copenhagen Summit thing or not, it will not go away and soon the choice will be taken from your hands. I notice that this subject is glaringly omitted from this forum. No one is really talking about it, not in terms of installations anyway - why could that be.

Equally, those people on the previous thread who were agonising over the search for fuel oil - well take comfort, that problem too will be solved for you very soon – soon there will not be any!

If you need information on how the integration of a solar system is achieved to your specific system, there is a lot available, more than 250 brands, and thousands upon thousands of willing installers waiting, pipe wrench at the ready to dash round and 'do the business'. So I suggest, have a go, believe just a little bit more, see what is happening around you, Solar panels can help you, other people are doing it and they will certainly help to assure our future - this is the bit that you CAN do.

By the way, if you get a heating engineer to design your system then there is no reason that you should run out of hot water, no matter that MIL (84) wants a bath - its doable. So for goodness sakes ...... just ask.

Andrew

 

 

 

[UlsterRugby1999]

[quote user="AnOther"]What temperature is the chauffe'au thermostat set to, the hotter it is the longer it's going to last. Is the baloon new or old, newer ones will be far better insulated, a key factor in retaining your expensive heat.

[quote user="UlsterRugby1999"]This would give us an annual reduction in consumption of 4368Kw. At a cost of 0.0839 (HT) this would save us circa 438.1€ (TTC) per annum. No mean sum.[/quote]

All savings are to the good of course but I'd say roughly €1/day is a very small price to pay to keep a MIL in hot water [6]

[/quote]

The temp of the CE was reduced from max to approx 67 degrees C. This was done following suggestions from the previous thread I mentioned. The tank is circa 4 years old but there is every likelihood that our very hard water has caused some lime scale clogging. We now have a water filter system in place but there may well have been some lime scale clogging before this was installed.

[quote user="suein56"]Our CE is 14.5 years old and still works well ... but we have been in our rented house for 4.5 years now and I have noticed a deterioration in its functionality in that it takes a lot longer to heat up the same amount of water nowadays than it did before. We can still cope with 3 visitors* all having showers every day, lots of washing up in the sink BUT the water heater then works continuously throughout the off peak periods - we have 2** - to heat the water. Whereas before the water heated quickly in a much shorter time.
*and we 2 of course.
** 02h00 till 07h15 and 14h20 till 17h05
[/quote]

Sue, I got a wee bit lost with the *'s but I take it that you have HC between the two sets of times you mentioned. Despite this, do you keep your CE running all the time or is it only using HC hours.

Andrew, I have spent many hours reading up on solar and other heating arrangements and this was discussed at length in the previous thread. You mention the lack of expense but you must understand that while I can buy a new solar water heating system for (2500€ - 4500€ plus installation costs using Leroy Merlin as an example for supplier) I can buy a new ballon for 249€ or 6-10% of the cost of the solar set up. Expensive is relevant to the individual and for some of us, while reducing carbon footprints (a newer buzz word) is the right option financially it isn’t the top option at the moment.

The reality is that while most of us know what is the right thing to do, the costs of so doing are prohibitive. It’s as simple as that.

[AnOther]

[quote user="Poolguy"]Equally, those people on the previous thread who were agonising over the search for fuel oil - well take comfort, that problem too will be solved for you very soon – soon there will not be any!

[/quote]Why go and spoil an otherwise excellent post with such alarmist drivel. Of course oil will run out - eventually - but it won't be in the lifetime of any one here.

Might I direct you to THIS authoritative treatise and specifically the conclusion that:

At current consumption rates, oil reserve life will be measured

in centuries

Solar heating may be a 'no brainer' but if you simply haven't got the resources to pay for it, as a great many on meager fixed incomes won't, it's an irrelevence.

If governments were really serious about promoting alternative energy systems instead of just paying lip service then they would run schemes whereby it could say, be installed for free against a lien on a property when sold or an estate after death. Even in today's straightened times if there were the genuine will the money could be found. Think how many properties could be insulated and upgraded for the billions being disgustingly and irresponsibly squandered on the 2012 Olympics for instance or the near 2 billion in overseas aid gifted since 2003 to a country which is nuclear developed and armed, militarily resurgent, and has a moon landing programme, I'm talking about India !

[cooperlola]

Ulster Rugby this does certainly seem a bit rum!  We run our chauffe-eau on HC as you do and it gives us at least one bath a day plus keeps my cleaner (paid for by thelorry driver who caused my accident btw, I am not rolling in money) happy enough and she can't walk past anything without wiping it.   We do wash clothes and dishwash from cold during the night but have never found the ballon to be inadequate except if we have visitors.

Like you, solar,heat pumps and the lord knows what would be delightful but the capital to do it ain't always there for those trying to save tens of euros on utility bills, is it?

Happy to have a chat about carbon emissions any day, anywhere, any time, Andrew!  I don't know if I'm a believer or not but even if human beings aren't the cause of climate change it does not give us an excuse to be profligate with the earth's resources imo.  But it's tough to expect those who are already struggling financially to make capital investments to make up for the sins of others - many of whom are rich corporations, not poor hard-working individuals or retirees who have already done their bit.  I'll shut up now.[:D]

[UlsterRugby1999]

[quote user="cooperlola"]Ulster Rugby this does certainly seem a bit rum!  We run our chauffe-eau on HC as you do and it gives us at least one bath a day plus keeps my cleaner (paid for by thelorry driver who caused my accident btw, I am not rolling in money) happy enough and she can't walk past anything without wiping it.   We do wash clothes and dishwash from cold during the night but have never found the ballon to be inadequate except if we have visitors.

Like you, solar,heat pumps and the lord knows what would be delightful but the capital to do it ain't always there for those trying to save tens of euros on utility bills, is it?

Happy to have a chat about carbon emissions any day, anywhere, any time, Andrew!  I don't know if I'm a believer or not but even if human beings aren't the cause of climate change it does not give us an excuse to be profligate with the earth's resources imo.  But it's tough to expect those who are already struggling financially to make capital investments to make up for the sins of others - many of whom are rich corporations, not poor hard-working individuals or retirees who have already done their bit.  I'll shut up now.[:D]
[/quote]

Thanks cooperlola - how big is your ballon? What Kw is the heater? We have myself and my wife, my MIL, a 16 year old lad and an 11 year old girl. This equates to 4 showers, 1 bath (sometimes [;-)] ) 1-2 small dish washes and the usual hand washes etc after the loo. Normal enough I'd guess and the blurb when we were buying the CE stated that 250lts was about right for a family of 5.

Maybe its, in part, down to the calc on the element not heating it up as quickly and as efficiently as it should. I dont know.

As an aside, our power consumption is such that (without having completed the final end of year stats yet) we'll have consumed in the region of 2800 - 3000€ worth of electricity from both HP and HC units, hence my attempts to reduce not only my carbon boot print (in my case) but the burden on my wee pocket.

[AnOther]

[quote user="UlsterRugby1999"]

we'll have consumed in the region of 2800 - 3000€ worth of electricity from both HP and HC units

[/quote]

Are you all electric ?

Our whole fuel bill for a year is about 1/2 that, that's oil for CH, leccie, and bottled gas for the kitchen hob. OK there are only the 2 of us but we're not particularly thrifty.

HP & HC units ?

[suein56]

[quote user="UlsterRugby1999"]

Sue, I got a wee bit lost with the *'s but I take it that you have HC between the two sets of times you mentioned. Despite this, do you keep your CE running all the time or is it only using HC hours.[/quote]

Sorry to be so confusing, looking back at my post now I think I was more tired than I realised!.

Our CE heats up only during off-peak hours ie for us 2am till 7.15am and 2.20pm till 5.05pm. And that provides enough hot water for 5 people, all having daily showers, and including washing up.

[quote user="UlsterRugby1999"]how big is your ballon? What Kw is the heater? [/quote]

200 ltrs and 2.2 Kw

[UlsterRugby1999]

[quote user="AnOther"][quote user="UlsterRugby1999"]

we'll have consumed in the region of 2800 - 3000€ worth of electricity from both HP and HC units

[/quote]

Are you all electric ?

Our whole fuel bill for a year is about 1/2 that, that's oil for CH, leccie, and bottled gas for the kitchen hob. OK there are only the 2 of us but we're not particularly thrifty.

HP & HC units ?[/quote]

No to the all electric question AnOther. We burn wood and I've recently installed reversible air-con units but thats it. During my test over the past few weeks, nothing changed in terms of normal usage of electricity. The ONLY thing that was altered was the times that the CE was connected and this was only during the 8 hours of the HC plus approx 1 hour during the HP times. This reduced our consumption by 105Kws on a weekly basis. I would continue the test but MIL is starting to smell a tad and MOH is about to kill me. [;-)][:D] 105 Kw per week equates to 5460 units per annum and while I'm not suggesting that this would be a truely representative figure of the potential saving, it would still amount to a considerable saving - and - all of it would have come from the amount of time the CE was NOT connected to the power supply. So, either we use/waste an incredible amount of water or my CE is knackered or calc'd up or both.

Try this thread - its the original one that was discussed last year. 

http://www.completefrance.com/cs/forums/1/1843644/ShowPost.aspx#1843644

THis is why I asked, originally, about the BricoDepot (sorry guys) system which seemed to be within my range financially.

[UlsterRugby1999]

[quote user="suein56"][quote user="UlsterRugby1999"]

Sue, I got a wee bit lost with the *'s but I take it that you have HC between the two sets of times you mentioned. Despite this, do you keep your CE running all the time or is it only using HC hours.[/quote]

Sorry to be so confusing, looking back at my post now I think I was more tired than I realised!.

Our CE heats up only during off-peak hours ie for us 2am till 7.15am and 2.20pm till 5.05pm. And that provides enough hot water for 5 people, all having daily showers, and including washing up.

[quote user="UlsterRugby1999"]how big is your ballon? What Kw is the heater? [/quote]

200 ltrs and 2.2 Kw[/quote]

Brilliant Sue. many thanks for the response. Tired - I understand tired. [:D]

[Chancer]

I have never quite understood the mechanics of a calced up heating element, I can see that it would be slower to impart the heat but where else can the heat go to ?

Ballons are so well insulated and using an infra-red heat gun on mine shows no measurable heat loss coming out of the bottom where the element fixing flange is.

When one has a calced up electric kettle element we can visually see that the water is initially slower to boil but the converse is also true, when the boil sensor cuts the electricity supply the calced up element continues to impart its residual heat for longer than an uncalced one, clearly this is wastefull as you are just overboiling the kettle and heating the room but in the case of the chauff-eau all the heat is contained within the insulated casing.

My theory is, and I would like to hear the opinions or experience of others on this, that the volume of water is significantly reduced in a calced up chauff eau, having disc cut in two an old one (that had already been removed from service) in order to get it out of my cellar I found that almost the entire volume was stuffed full of calc. A neighbour has also told me that he removed the element from a lady friends one and removed several buckets of calc, she then had much more hot water available.

I would suggest to the OP that before deciding to replace the chauff eau or got to solar powered (which could in fact take decades to amortise, certainly not within the lifetime of the unit in a hard water area) he removes his element (and the shield if blindé) and removes the loose calc from the cylinder. 

If you have the full volume of 250 litres available it should be more than sufficient for your needs as with the blending effect of the incoming cold supply you actually get 30 to 40% more volume of hot water than the cylinders capacity, for this reason the temp of the stat is usually set much higher than the temp of the water tha comes out of the cylinder.

good luck to you!

[UlsterRugby1999]

Thanks Chancer - and while I dont understand the science behind a lot of all of this, I do understand your logic. This coming weekend has already been set aside for the tank work as you have suggested so that'll be an interesting exercise.

250 litres simply isnt lasting. Yesterday, for example, with the ballon having been on during the entire 8 hourse of HC time, there were 3 medium length showers, a few hand washes, NO dish washes from the tap and 1 or 2 small sinks of water used. In the evening when my MIL ran the hot water for her bath, there was literally no hot (even warm) water. Surely we didnt use 250 litres plus as described.

[Dave&Olive]

hi ok

              we have a 250 ltr tank it`s only on for a few hours a night , it even serves the Gite with no problem, It can also be heated by the wood/oil fired boiler but even though I only pay €3  a stere for wood I find it less expensive to run it on leccy.

              Might I suggest your group de security is leaking  to drain  ???

                                   Dave

[AnOther]

You are ignoring the fact that once the heater is switched off any hot water drawn is replaced by cold which in turn cools the remainder. 3 early morning showers could easily consume 1/2of your 250lt so you would need to reheat the whole ballon afterwards to have any hope of it lasting the day or providing a bath in the evening.

Of course there is no point whatsoever in having a ballon on overnight, after all it's only required to heat the water once which is just before it's needed so why have it cycling for 8 hours or so ?

I think a more efficient regime would be to have it come on in the morning for as long as it takes to reach full temperature immediately before it is required and stay on untill the morning demand is over, and then long enough to reach full temperature again. The will leave you with a full tank for the day and then, with a final cycle in the evening, before MIL's bath, she will have all she needs.

You wil likely find that the actual kWh cost of this might work out comparable or lower and provide a more consistent supply of hot water to boot.

In our first property many years ago we had no CH but had an open fire with a back boiler and an immersion heater. I made a 'one shot' timer for the immersion whereby you pressed a button which switched the heater on and when it reached the temperature for the thermostat to open it switched it off completely until you pressed the button again or manually overrode the whole thing.

I can't remember now exactly how often we used to press the button but I don't think it was ever more than say 2 or 3 times a day and with between 4 and 6 in the house we always had plenty of hot water.

[suein56]

[quote user="AnOther"]

Of course there is no point whatsoever in having a ballon on overnight, after all it's only required to heat the water once which is just before it's needed so why have it cycling for 8 hours or so ?[/quote]

Because that is the way HC - heures creuses - off peak - works. Our HC is on an old abonnement from 1995 so we get 2 periods, one of 5+ hours overnight and one of <3 hours in the afternoon. Which I am sure helps us spread the water heating in the way you describe.

[quote user="AnOther"]

I think a more efficient regime would be to have it come on in the morning for as long as it takes to reach full temperature immediately before it is required and stay on untill the morning demand is over, and then long enough to reach full temperature again. The will leave you with a full tank for the day and then, with a final cycle in the evening, before MIL's bath, she will have all she needs.

You wil likely find that the actual kWh cost of this might work out comparable or lower and provide a more consistent supply of hot water to boot.

[/quote]

Sounds good, but I am not sure how this would tie in with HC though it might be possible with a secondary timer and the OP switching from HC/HP to an ordinary option thereby saving on the inceased standing charges that go with HC/HP but then having to pay at the full rate for all his electric usage.

[Chancer]

[quote user="AnOther"]
Of course there is no point whatsoever in having a ballon on overnight, after all it's only required to heat the water once which is just before it's needed so why have it cycling for 8 hours or so ?
[/quote]

Because the HC (Heures Creuse ) electricity is 40% cheaper.

There seems to be some thermo-clime effect in a ballon whereby the water is hotter at the top (where it is drawn from) than the bottom, certainly if you use half the hot water volume for one bath and then run a second one the water does not come out at half the temperature.

If you have ever sat in a bath while it is filling and felt when the hot water runs out it is fairly dramatic and goes from very hot to warm to cold in less than a minute.

I suspect that having a ballon saturated with calc removes this effect and your cold water dilution hypothesis comes into play.

P.S. most ballons with the exception of the 300l ones have the element rated to heat the water in around 5 hours, they are so well insulated that no cycling occurs during the remaining 3 hours unless hot water is drawn. I know this to be true on my own set up as my 6kw abonnement does not allow me to use my washing machine (1800watt) whilstthe storage heaters and ballon are heating, I use a timer to run the machine after the ballon is heated, if it cycled after that I would have had a early morning trip before now.

P.P.S. Using a monostable timer as you describe would require the button to be pressed 5 hours before you wanted your bath! One can do this quite simply by puttiing the chauff eau contactor in the march forcé position

[AnOther]

Yes, obviously, but what is the point of it coming on a say midnight or whenever it is and cycling even once or twice when all you need is for it to be on for long enough before you need the hot water in the morning ?

[UlsterRugby1999]

Mmmmm - Dave - thanks for that. Makes it look worse I guess. Can you explain your last comment in more simple English. [8-)][8-)] Cheers. If you mean the security valve at the base of the ballon, I'm certain that it has little or no water coming from it.

[Chancer]

[quote user="AnOther"]Yes, obviously, but what is the point of it coming on a say midnight or whenever it is and cycling even once or twice when all you need is for it to be on for long enough before you need the hot water in the morning ?

[/quote]

The fact that the electricity costs 40% less during les heures creuse.

[Clair]

[quote user="AnOther"]Yes, obviously, but what is the point of it coming on a say midnight or whenever it is and cycling even once or twice when all you need is for it to be on for long enough before you need the hot water in the morning ?[/quote]

The CE comes on and off automatically through the contacteur HC (twice a day in our case, 2 to 7 am and 2 to 5 pm).

[AnOther]

[quote user="Chancer"][quote user="AnOther"]Yes, obviously, but what is

the point of it coming on a say midnight or whenever it is and cycling

even once or twice when all you need is for it to be on for long enough

before you need the hot water in the morning ?

[/quote]The fact that the electricity costs 40% less during les heures creuse.[/quote]Am I really being so unclear ?

Yes, of course I know HC electricity is cheaper at night, a little credit please, and I'm not saying don't use it, only use it intelligently.

I

honestly don't know how long the average ballon takes to reach full

temperature we don't have one, nor HC, 5 hours seems a rather long time to me

but I'll go with it anyway.

Assuming 5 hours then, and that you

want your showers at say 8am, then what possible advantage is there in

having it come on at midnight or at any time before 3am.

However well insulated it is there has to be some loss of stored heat

so it's probably going to cycle at least once or twice between 5am and 8 am

which will be nothing more than a complete waste of electricity. Even

if it only drops a handful of degrees, and less than the hyteresis in

the thermostat so it never cycles at all, all that means is that the water will

not be as hot as it could have been at 8am.

If on the other hand you put a simple timer on your HC supply, set for the ballon to

come on from 3am to 8am, it will have just heated up to it's maximum and be

ready for use with absolutely zero power wastage.

My simple point is that there is no point in it being on for any longer than the time it takes to fully heat up - and not a minute more.

[Dave&Olive]

hi ok

                Will have a go ...  a case of why does my toilet only overflow at night ...     it is just  a pressure relief valve.. here is a pic

 http://www.bricodepot.fr/bordeaux/node/479346  note they have a teflon one for hard water .

     Water heats up expands blows out this valve system tops it self up with cold water     and we start again .. if you do not have one of these fitted to the inlet  http://www.bricodepot.fr/bordeaux/node/479345  and the water pressure goes up at night same thing happens

         Why not leave the heater on all day and just keep putting your hand on the outlet see if it`s passing. ( drain will get hot )

  The only other thing I could suggest is the STACK pipe in the tank has come off / got a hole in it

                   hope this make sense

                        Dave

[UlsterRugby1999]

Good man yourself Dave. Even a thicko like me can understand that explanation. Thanks for making it easy to follow. AS for the stack pipe, how can I tell. This weekend coming I intend to empty the tank (my MIL will really love me know) and take out the element and check for calc etc. Will I be able to see the pipe from there and is it repairable?

AnOther - sorry if I have sounded thicker than normal, I understood your point but on our HC system nothing happens to change over from HP to HC it simply carries on and our facture shows us what we have consumed via each type of charging unit. There is no switch over or anything like that and all electrical appliances which were running prior to 21:45 automatically consume HC units from 21:46 until 05:45. To set the CE as you rightly suggest I would need to include a timer, presumably in the Cons Unit on the buzz bar, and set it to come on at, as you say, 3:00 and go off at 8:00 or whatever.

My problem at the moment is that I do not know how long it takes for the ballon to be completely filled with water heated to the set temperature. During the testing period, I simply flicked on the disjoncteur at 21:50 and flicked it off at 6:30 when we got up. Not rocket science but close enough. Either way, we were not getting a full days hot water supply from the tank so either it was losing it as Dave suggests (which may prove to be the reason) or the element and or ballon are so clogged up that it wasnt heating a full 250 litres. I guess I'll find out at the weekend.