Managing multifuel stove running central heating - how?

elljay

I asked for hints and tips on managing this system on a different discussion and  received some very useful advice - have also googled like mad, it all adds to the sum of information. 

I have moved into a house which has a multifuel stove in the sitting room which also does the central heating and hot water.  There is also an immersion heater which I leave on all the time.  I'm trying to work out the best ways of managing the system, it seems to be a few steps forward and a few back.  Does anyone else have the same set up and can advise me please?

Another contributor suggested that by having the pump on when the water in the wrap-around boiler was cold all I was doing was circulating cold water (of course!).  So once I've lit the fire I've tried waiting till I can physically feel that the boiler water (by touching the stove at the sides) is hot and the outflow pipe heating up and then turn on the pump.  Yes!!!!  This gets warm water to the radiators.  However the whole lot quickly cools down and so I turn off the pump, wait for the boiler to heat up and off we go again, warm rads for an hour or so.  I'm thinking that the pump might be set too fast, I need to work out how to slow it down.  Or??

The next thing is the stove controls, I can't work out the best combination of primary and secondary to keep it burning hot.  I'm trying different fuels, some wood (very dry softwood from a furniture factory), some heat logs and some smokeless coal.  The heatlogs are great but burn away quickly, the coal lasts but doesn't seem to heat the boiler any quicker and not much flame to look at on a damp afternoon.  And the thermostat in the hall is showing 15 now with the fire having been lit since 9 am..  

And finally......really sorry about war and peace...the water gets very hot, much too hot to hold your hand under for even a split second, when the fire is on.  Next morning the water is luke warm, and I have to press the reset button on the thermostat on the hot water tank.  So where has all that  hot water gone and why has the immersion heater switched itself off?

Someone is coming round next week to look at a problem with the chimney and 2 others have exchanged the thermostat in the hall and something else to do with the stove but none seem able to talk me through the whole anatomy of the system so I can work out how to manage it.  At the moment I'm an absolute slave to it - I daren't go out though it's probably warmer out there.  I've downloaded the manual which is mostly about the actual stove not the whole heating system in its totality.

Help please for a cold granny!  Thank you

EJ

FreeBear

Some pumps will have a dial on the back with three positions - If you have one, try setting it to 1 - That will be the slowest setting.

To avoid having to get up and turn the pump on manually, a thermostat could be attached to the "hot" pipe coming out of the boiler. Linked to the hallway thermostat, you would have simple (all be it crude) control system.

How well insulated is the property ?

If you don't have much insulation, it is worth seeing if you can get some installed under the ECO Scheme - Low income households & pensioners should qualify for free insulation and possibly other improvements..

elljay

Ah thank you.  Good advice.  Will go and dig around in the depths of the airing cupboard for the pump and its settings.  Logic tells me that should help.  I think the house has reasonable insulation though a large fully glazed outside door is single glazed and I have been draughtproofing everything I can, that seems to have made a difference but insulation assumes there's heat to keep in - sometimes I reckon it's warmer out than in!  I've also made door curtains.

The thermostat idea is good, someone else suggested that - so what temp does it need to be set at?  Also if I have to get up from under the warm cat to look at it, I might as well get up and touch the stove.  You mentioned linking it to the hall thermostat?  How would that work?

Thanks - really appreciate your help - as I said, every little bit adds to my understanding.  EJ

gamston

do you know how your system works ?
 have you motorised valves on the pipework to divert water from CH to hot water cylinder ?
as freebear says you could fit a pipe thermostat to start/stop the pump automatic
is your multi fuel stove big enough for the radiators you have ?
if the stove is the only form of heating is it on most of the time now ? i would think about a timer for the electric immersion heater as you shouldn't need it on when you running the stove (maybe in the summer you want the immersion on in the mornings save you lighting the stove)
stove control wise its a try it and see as everyone situation is different, yes you can get the basic's from the book, but you will need to play with it
if it was me I'd get someone to look at your system and tell you how it works then you can see how you can make it better for you, doesn't need to be plumber/heating engineer, a diy could tell you what you have on your system
was the stove put in by a company or diyer ?

elljay

Thank you..  The stove was put in by a company.  It's their people who have been back (and are coming back this week to check smoking) Each only seems to know his bit of it rather than how it all works together.  One of them explained the heating timer in great detail - pointless if the stove isn't on, which I pointed out.  He said oh yes hadn't thought of that.

Lots of questions gamston, I have no idea about motorised valves, how the pipe thermostat would speak to the pump, immersion timer and all that.  But I'm jolly well going to find out.  Thank you.

I have electric fan/convector/infrared heaters all over the place (rarely used) but am usually warm in the mornings after a hot shower/brew. I try to go out in the mornings then put the fire on mid day ish.  40 yrs ago I had an open fire which heated water and rads and that was straightforward.  It prioritised hot water then when the water was hot enough (whether from the fire or the immersion) it would switch to radiators.  Didn't kill the immersion.  Great, simple, understandable.  Not sure why this isn't the same.

Off to research some more.  Thank you again.

EJ

Mickey666

Sounds like the OP could use a flue thermostat on their boiler stove.  I also have a multi-fuel boiler stove and I use a flue thermostat to switch on the pump that circulates the water to my heat store (glorified hot water tank).  This means that when the boiler stove is lit, water is not circulated until the flue reaches a certain temperature, meaning that cold water cannot be circulated through the stove and so it heats up faster.
This is not the same as mine but the principle is the same:
 https://www.stovesonline.co.uk/wood_burning_stoves/Flue-thermostats.html

gamston

wonder if you could use wireless controls for your system, not cheap but you do not have to run cables to/from control unit and thermostat's, motorised valves etc
i would hope the company that put the system in (even if did it put the system in to fit a price) they would setup up to be econmical to run using simple controls (thermostats/motorised valves
the company that put the system in must have "design plan" of the system, see if you can find that or get it from them, at least with that we could see what you have

gamston

i have an oil boiler as well multi fuel boiler stove both hooked up the CH & hot water tank, so my system will be slightly different to yours.
i've had 2 multi fuel stoves, the first was a 9kw with that one if i run it with mrs at the shops when she got home she could hably get in front door as heat in house would knock her over, with this one 14-16kw there is nowhere near the same heat outputted to the rooms

coffeehound

elljay said:

...the water gets very hot, much too hot to hold your hand under for even a split second, when the fire is on.  Next morning the water is luke warm, and I have to press the reset button on the thermostat on the hot water tank.  So where has all that  hot water gone and why has the immersion heater switched itself off?

It sounds like there should be motorised valve(s) which divert the boiler water to the radiators and away from the hot water tank once the tank has reached temperature.  If such motorised valves are fitted, it sounds like it/they are stuck open.  This would also let the hot water then circulate back through the cold boiler letting it cool down overnight.  The fact that the immersion heater safety trip is operating shows that the water is being heated to over 90ºC which is bad for a range of reasons!  Does the hot water tank have a thermostat strapped to its side?  If so, what is it set to?  Should be no higher than 70.