Wood Burning Stove with Back Boiler - Help!!

[Frenchie Cullen]

Hello,

This is my first post so please be patient with me if I am in the wrong category for my questions!

I have moved into a house with a wood burning stove with boiler bit attached to it that fuels the heating and hot water system for the 3 bedroom cottage… the maximum temp for the stove is 500* but we NEVER get the temperature that high.. We have gone through 3 x 0.80 cube bags of hard wood within 4 weeks.. We cannot get the fire to last through the night and the house is FREEZING every morning.. Do I close the top vent? keep it open? open the bottom vents? keep them closed? half open half closed? I just have no idea!!

In addition to the struggles above, once the hot water tank is fully heated, the pumps turn off and the pipes stat banging and clanking which is worrying.. we therefore have to run the hot tap for a while when this starts so that the pumps turn back on and start all over again..

This is the first time I have ever had a fire…. never mind using it to heat the house..

Is the stove big enough?

How do we control the hot water, or can we?

Are we wasting money on wood as we are going through it so quickly? Is there a better way? I have been home for 3 hours and already used a basket of wood (hard wood not soft).

Is there a way to keep the fire going for longer so that the house is warmer during the night?

I would really appreciate some help from you all

 

[begreen]

The boiler section is going to scavenge quite a bit of heat. It's hard to give advice without knowing the make and model of the stove. That and a picture would help.

 

[brazilbl]

I'm glad the expert chimed in as I was typing. I learned so much from two sources: 1). The informational videos on basic wood stove operation from either the manufacturer or web videos.
2). The unbelievably friendly folks out here that are willing to help.
Basically - the more information you give them, the better they can help you. Knowing what brand of wood stove/insert it is will go a long way toward solving the problem.

 

[Rearscreen]

Hi Frenchie, first let me say if you ever want to do a temporary house swap between Vermont USA and Scotland let me know. Heating is one thing, hydronics is another. I installed my own oil fired boiler and hydronic radiant heating based on one tiny book. Pumping Away by Dan Holihan. His web page is Heatinghelp.com
Oddly, in America, most hydronic heating systems are installed backwards and injects air into systems leading to all kinds of knocking problems. The hystory of why this happened is in his book. This is based on pressure exerted at wrong parts of the loop through the circulator creating expansion of air. In simple terms if your circulator is pumping water into the heat source heating the water there is a problem right off. Placement of expansion tank within the loop and air bleed is important also. My house that I bought 3 years ago was installed backwards with the circulators pumping into the boiler.

 

[Frenchie Cullen]

Thank you all for your responses..

I have a Hunter Herald 8 Multi-Fuel stove with back boiler. A picture has been attached, I have also attached a photo of the output tag that came with the stove which is only 1 year old.

I hope this helps

 

[Frenchie Cullen]

Hi Frenchie, first let me say if you ever want to do a temporary house swap between Vermont USA and Scotland let me know. Heating is one thing, hydronics is another. I installed my own oil fired boiler and hydronic radiant heating based on one tiny book. Pumping Away by Dan Holihan. His web page is Heatinghelp.com
Oddly, in America, most hydronic heating systems are installed backwards and injects air into systems leading to all kinds of knocking problems. The hystory of why this happened is in his book. This is based on pressure exerted at wrong parts of the loop through the circulator creating expansion of air. In simple terms if your circulator is pumping water into the heat source heating the water there is a problem right off. Placement of expansion tank within the loop and air bleed is important also. My house that I bought 3 years ago was installed backwards with the circulators pumping into the boiler.

I will keep that in mind.. the cottage in Scotland comes with a french bulldog who snores though...

 

[begreen]

As you can see from the label, most of the heat output goes to the water. 75% to the hot water and 25% to room heat.

Do you have the manual? It's available here under Hunter Herald 8 (wet)
http://www.woodburnerwarehouse.co.uk/hunter-documentation

I would recommend reading it cover to cover with a focus on the operation of the stove. Make sure that the Multifuel grate lever is in the up position if burning wood. That will allow an ashbed to accumulate and will stop air from feeding below the fire.

I do see that this stove appears to go through wood quickly. From the manual:
With a full load of wood, the stove will need to be refueled approximately once every 1.5 hours

 

[electrathon]

As to the hydronics, you SHOULD NOT be stopping the pump once the water is up to temp. The banging you are hearing is flash boiling of the water turning to steam and back to water. Hoping that you have proper expansion tank sizing for your system, this is a big safety issue. A much better control system would be a solar controller. The pump should run whenever the coil becomes hotter than the storage water, usually there is a temp differential of about 15 degrees to prevent short cycling of the pump. If you have too much hot water you divert the heat at the return line to a baseboard radiator system. This heat can be diverted to a back room on the house that tends to run cold. An automatic temperature controlled valve can do this automatically.

 

[Frenchie Cullen]

Thank you so much for your help!!

I have looked over the instruction manual and have sorted out the vents etc which has been so valuable.. Still going through sooo much wood though..

I have also spoken to my brother (who is a plumber) to see if he has any ideas on how to best sort out the hot water situation..

Could I maybe ask for one more piece of advice? What type of wood does everyone think is best for burning? for heat and for longevity? for example oak?

FInally, what would your advice be for buying a new stove? anyone in particular have great reviews? We have looked at a Stovax Stockton 11? Bearing in mind that we need the boiler..

Thanks in advance

 

[electrathon]

Look for a controller like this one: (broken link removed to https://www.ebay.com/itm/Steca-0301-U-SunEarth-SETR-0301U-Solar-Hot-Water-Control-w-2-Sensors-Cord/191138745667?hash=item2c80c1cd43:g:imIAAMXQuCdTh3QE)
It will make your pump run whenever the stove water is hotter than your storage tank water. If your water is getting to hot, have your brother put in baseboard heaters in the loop.

 

[jetsam]

Those hydronic baseboards aren't just a safety measure... they will put a lot of heat back in the house.

You could also consider adding the baseboards and an outdoor boiler, and putting a regular woodstove where the stove is now. That would give you all kinds of wood-powered heat- you mightnot even use the stove much. My neighbor has an outdoor boiler as his only heat, and he seems to really like it.

 

[begreen]

Not sure if this is a house on acreage or a town house, nor the size of the house, but I suspect the area being heated is smaller than US norms. Remember this is Scotland. Frenchie, how large is the house? Are there alternative fuels that could be used for hot water heating that would allow you to switch to a heating only stove? Electric, gas, wood pellet??