In your last thread you have already had a lot of first class advice ref your obviously too small hot water tank - for a start it is in no way a TS! But just to add my voice to the others: the tank is too small and needs to be about 300%+ bigger! I have a 40kW wood burner and a 1500 ltr TS - the tank is adequate but on the small side. The number of people living in a house is the last thing considered when sizing a TS as it is almost irrelevant!

Your problems must surely stem from your poorly designed system and you must choose to treat the symptoms or cure the illness. In this respect, sorry but I can only offer advice on the proper cure; I suspect addressing your symptoms will require some sophisticated expertise from someone with a good understanding of your system - not impossible.....

Mine is just a WB. But yours must put loads of heat to the water system, rather than the room - invariably they are designed to heavily favour the wet side otherwise your one room would overheat. But the issue is how much heat your house needs relative to the amount of heat 'stored' in your battery. You can do the sums easily enough if you know your house's heating requirement. Even if you don't, take a figure say 8kW, take your tank's stored heat say 40 deg to 80 deg times 210 ltrs - now how many hours (minutes) will your tank last. Also do it the other way around - take the rated output of your boiler to the wet side - what is it 8 - 10 kW? How long does it take a 10kW supply to raise your tank's temp to its maximum from the lowest DHW temp of 40 deg?

I'm no pro with this stuff, worked it out once for my system, and it is late but I seem to remember 1kWh will raise 100 ltrs of water 8.6 deg so isn't that 10kWh will raise 210 litres by 40 degs (approx) ie the 'space' in your tank 80-40 (temp diff). So for a 10kW output from fully cold (ie any less and you don't have hot water) to fully hot is less than 1 hour. Probably made a fool of myself but this seems about right. And the same for your house heating, what is it not less than a 5kW requirement for sure - so call it 10kW and your 'store' can only store enough heat for 60 minutes heating of your house..........

Anyway, it doesn't matter how many times you ask the question, 'too small' is the only answer you will get - the people who told you so in your last post know their stuff. 00:21 hrs bed time..

What do you mean by "I have had a problem with getting the _stove_ up to temperature"? Do you mean the fire isn't burning properly? If so I don't see how increasing the size of the TS would make any difference with that specific issue. For example when starting with a stone cold thermal store both a large one and a small one would both deliver cold water to the stove. It must be a pump speed issue. What water flow temperatures are you seeing out of the stove?

Once the stove is performing ok then yes the size of the TS will effect how long it can heat the house with the stove OFF.

The other condition that must be met is the energy balance...The average energy put into the store must match that being taken out. In other words the average put in by the stove (for example over 24 hours) must match that taken out to heat the house over the same period.

Water will be FLOWing from the stove to the store in one pipe and RETURNing back again in another. When the stove has been running for awhile (say half an hour) measure the temperature of the flow and return pipes about half way between the store and stove.

If the fire isn't burning well AND the reason is because the stove is being chilled then I was going to suggest turning the pump speed down rather than up.

I would at least try different wood. We have two stoves (neither have boilers) but one has problems burning poor wood. The other seems to burn allmost anything well. Don't buy a whole load specially just rummage the garage for off cuts or something.

Hi Nicki
Just reading your thread to see if anyone had suggested a loading valve yet when I got to your last post. A loading valve ensures the water is heated in the boiler (stove) to a pre set temp say 60 degrees. Only at that point does it allow a small amount of cooler return water to enter the boiler and mix with the hot water. At the same time the hot water will flow to the TS. It keeps this up so that the temperature of the stove/boiler stays hot which is what you want. Examples are the well known laddomatt and the Thermomatic K I think its is called. Fitting a loading valve (while not cheap) will reduce the cooling effect of the boiler water on the stove's combustion, keeping it burning hotter and cleaner. I would be interested to know why such a valve wasn't built into the system.

I can't give you any help, apart from my experience. We have just had a wood burner with back boiler fitted. We have a valve with electronic sensor that turns the pump on and off.
We light the fire, it heats the water jacket around the fire up to 50' and then the pump turns on. If the TS is very cold the temp will soon drop and as soon as it hits 48' the pump turns off. Fire warms jacket up to 50' and pump goes back on and this repeats until the temp of the TS is such that the water in the jacket doesn't drop below 50' and the pump remains on continually.
Out TS is 900 litres and has enough water in it to heat our house the next day wihtout having to light the fire in these temps until the evening. We work from home so have heating on all day, but only lowish. When it was colder we were having to light the fire during the day to boost temps.

If you have an electronic valve, maybe you need to turn it up, so the fire heats up more before it starts pumping water?

HI skier-hughes and evan - many thanks for your suggestions - I will discuss both with my installer. Ironically, today it seems to be burning a little better - no idea why - and the shower system has been rigged up so I won't be so heavy on the hot water which will make life much easier also the TS only seemed to drop a couple of degrees after a quick shower - great !

Hi skier-hughes - yes my flue is insulated as well - however today it is not burning so hot - I presume that direction (and amount) of wind can affect burning? It is quite windy at the moment (in the south).

Nicky, told you I wasn't a pro - sune clearly is and has hit the nail on your head - so forget the term TS and stick with DHW tank. I am sure he is right about the draw too, I have seen exactly this situation before - now he mentions it. Good luck.