My oil fired Central Heating boiler works in tandem with an electric water pump, which I believe is the norm.
The boiler ‘fires up’ when its internal thermostat tells it too. The electric water pump remains on regardless of whether the boiler is heating or not. So it wastes electricity and reduces its operating life and reliability.
I believe I just have to buy an electronic thermostat that is either wired in or otherwise communicates with the boiler and water pump that switches both on to maintain the desired room temperature?
I can’t economically justify an alternative central heating system just now given it otherwise works fine, (albeit environmentally unfriendly).
Mine was the same when we moved last year. I asked the engineer when he serviced the boiler and apparently its just the way its been wired up. My programmer failed earlier this year so as a temporary measure we just used a plug with a 24 hr timer, so the pump comes on when the boiler is switched on. I didn’t notice and significant change in electricity usage, but there must have been some.
Thanks for that reminder Mark and your prompt response.
That’s what I have done in the past and that works fine.
I suppose if the timer is only programmed to turn on for say 2 hours in the morning and say 4 hours in the evening that would at least cut down on the time the water pump is in constant use. The rest of the day I have portable oil column heaters and wood fire for those rooms occupied .
From memory, my pump circulator uses about 13watts, not a great deal of electricty. It just seems to hark back to when using stuff didnt matter. I think its to use the latent heat built up in those huge boilers so could carry on keeping you warm a bit longer, the thermostat sounds a good idea. BIL’s has 3 thermostats 2 are safety ones from what I can see. Have you any you could utilse already?
Thats about the times we use for the boiler, supplemented with the wood burner. I wasn’t particularly worried about the electricity cost when the boiler was used daily, but the pump stayed on when the boiler was switched off so was more concerned about wear and tear.
AFAIAA the circulation pump will only run if the/a central heating boiler is in it’s on cycle. It’s there to pass the hot water around the radiators; when the return flow to the boiler cools off sufficiently (as the heat has been transferred into your living spaces) the boiler will kick in heat the water again.
IMO if you switch off the circulation pump the moment the boiler is no longer firing you are possibly wasting heat, although your system may well thermosyphon a bit.
Not circulating the hot water may mean that you have too large a hysteresis between the heated areas being comfortable or too cool, which might lead to turning up the thermostat/s & wasting even more energy.
I would think the thermostat would be close by the boiler so as it off the pipework would cool to say 30c and then turn the pump off. It wouldnt overide the roomstat, but likewise must turn the pump back on when the water heats, so maybe not quite as simple as first thought. I use a fan connected to a thermostat on a radiator to force the convection around the room so this idea is working the other way around.
Our oil fired system has a 3 speed Salmson circulating pump with power consumptions of 18, 31, and 48 watts according to whether one sets it to slow , medium, or fast, and the pump receives its electrical power directly from the boiler itself. The pump only runs when heat is being demanded by the room thermostat, and runs all the time that such is the case whether the boiler is actually fired up and burning oil or not.
The boiler has its own internal thermostat to regulate the outflow temperature, so that is what prevents the burner from running all the time that the system is active.
The whole system is governed by a simple time clock that controls the electrical supply to the boiler. For the boiler to fire up, it needs the time clock to be in its ‘On’ time-slot, AND for there to be demand from the room thermostat.
When we first bought the house, someone had fitted a direct connection (shunt) across the room thermostat terminals so that the boiler ran all the time that it was switched on. There was no timer back then and so it was necessary to make a trip to the cellar every time one wanted to turn the boiler on or off. This was most inconvenient, inefficient, and very expensive, so the room thermostat and the time clock were fitted rapidly.
What we now have is an automated system that works very well, and doesn’t use anything like the amount of fuel that was previously the case.
By the way, a simple plug-in timer is hugely cheaper than a fancy programmer box, although the latter would no doubt be needed if you want to control the heating remotely from your smartphone.
My ballon has given up and a new one that is connected o my boiler will, apparently, be quite expensive to replace. Would it be possible to just have a new ballon which isn;t connected to the boiler - these stand alone balloons are far more affordable and to operate it on a timer set to off-peak hours? Not certain that I am going to be able to afford much, if any, oil for the boiler this year anyway -may be relying on wood fires - but need to get hot water up and running again?
Tia for guidance - I have a plumber coming on Tuesday so would like to be ‘genned up’ in advance of that, if possible.
The answer to your question about the Ballon is ‘Yes’. Certainly you could have an independent Ballon and run it on the cheaper night rate electric.
There will be a need to alter some of the pipework, and also possibly some electrical work to be done to provide an adequate supply, though if there is a reasonably adjacent 3 pin (earthed) power socket it shouldn’t be too much of a problem.
I think your best bet is to ask your plumber to provide two separate ‘Devis’ estimates, one for repairing the system as it is now, and the other for changing to an independent electric Ballon. That way you will be able to compare costs and then decide what to do.
One advantage of having a Ballon that is separate from the heating boiler is that if one system breaks down, or cannot be used for other reasons, then the other system will still be functioning.
Additionally, the electric bill can also be paid on averaged monthly payments throughout the year instead of having to find a large sum all in one go for an oil delivery.
Please don’t say that. Water heaters should be wired via their own separate circuit, & hard wired - no plugs/sockets involved. NF C 15-100 applies.
In order to use cheap rate power (Heures Creuses) @Jan61 will need to be signed up to either the HC/HP dual tarif, or Tempo.
Ideally the water heater will run via a special contacteur in the electrical tableau, which is controlled via a pair of wires back to the meter - this means it will only heat up during the cheap eight hours of HC, but it can be overidden if required. If that is not possible then a decent DIN rail mounted timer can be used, ideally a digital one that doesn’t lose track of time due to power cuts, summer/winter time etc.
Thank you so much for your very helpful and informative response - the idea. of two Devis is excellent. I was always able to run the previous Ballon independently of the c/h boiler - for instance, in the summer months when I didn’t use the c/h for two or three months and there was a timer switch fitted to the fuse box. The fuse box is rather ancient and needs replacing but I am assuming that it could continue to contain a timer switch for the Ballon whether independent of the c/h, or not.
Thank you, again, for your time and advice - most kind.
Atvb Jan
No reason why a new ballon can’t do the same, no new plumbing needed.
On your old ballon, it could well be that its the element (is your main disjoncteur tripping out?) or thermostat thats failed. These can be relatively easily and cheaply changed.
Hi Jane, welcome!
Ask your plumber to test the resistance (heating element) and thermostat. If one is faulty I’d have both changed at the same time, also ask the plumber to empty the tank and descale / clean any sediment. There’s not much can go wrong with a hot water tank.
Edit and change the groupe de securité
Yes, I was hoping it would just be the element that needed changing but the marque is no longer made and so, I think, a spare part such as the element would not be available - I don’t know if they are universally replaceable. The 300L ballon was in place when I bought the property over 30 years ago so I can’t really complain if it does indeed need replacing. However, I will ask the plumber whether the element could be the only problem and if it could be replaced - would save a lot of expense and hassle - I suspect I will receive a gallic shrug in response…
Hello Wozza
Wow! What a fantastically helpful site this is… thank you, I’m copying all these ideas and tips and will make some notes in French - I’m beginning to feel quite sorry for my unsuspecting plumber - I did use him for something quite a few years ago and he is lovely - he is going to be faced with a wealth of options and ideas. Looking forward to getting it sorted soon and will update you all if I may as to progress.
Atvb
Jan