Small things matter

[Moxi]

"Never really thought about giving it a name but perhaps Fanny will do. "

Is that because she blows a lot of hot air ? right I am off before my wife reads this over my shoulder !

Moxi

[Joeboy]

Had a nice couple of hours working away on the floor this morning getting rid of worst of multiple year dropped ember burn marks. Used the new oscillating multitool in sand mode.

Cut the plum wood inset piece and wedged it in. A 1/2 hearted attempt at worst bits for blackening and I'm liking the look today.

Definitely something umami about woodstoves. Not just the imparted flavour to food either.

[Joeboy]

Well, that's my Christmas present to myself arrived and he fired up within seconds of placing on stove.

He is whisper quiet (name's Steve) and is defo making a difference. Feeling that I walk.into a wall of heat further away than before. Even a magnetic thermometer with it. What a time!

I think he may also have a partial cloak of invisibility.

Steve looks a lot like my Lidl bargain and I've noticed a big difference in the heat being pushed into the room.

I noticed a change today. Felt it first then confirmed on the gauges. The extra twin impeller.fan is shoving significant heat from the 3 linked rooms out into the rest of the house. We all know our own homes and with both doors open from the 3 linked rooms the whole house is getting the benefit of the wbs. Normally about 0.75 deg difference between wbs rooms and hallway. That has dropped to 0.1 deg 30 minutes ago and is now equal. I did not expect this, much .

The wbs room isn't ramping up as fast either. Could regulate flow with either door but right now it's just right.

In addition, our fit cheque arrived today covering the cost of the fan and a beer or 3.

[Moxi]

JB,

Shouldn't your magnetic thermometer be located on the flue to tell you if you are condensing creosote etc in the chimney ?

Moxi

[Joeboy]

JB,

Shouldn't your magnetic thermometer be located on the flue to tell you if you are condensing creosote etc in the chimney ?

Moxi

Twinwall, doesn't read internal temp accurately. That spot it's on gives an accurate firebox temp. TBH, I know the stove well and burn only dried, seasoned wood. The gauge is for show as it was a freebie with the fan.

You are right though, should be on a single skin flue to monitor effectiveness of burn.

[Moxi]

Thanks, I was asking as much to check my own understanding that my thermometer was in the right spot, it’s always good to check with my peers as I am often wrong ………. Welll according to SWMBO I’m never right.

Moxi

[Joeboy]

Thanks, I was asking as much to check my own understanding that my thermometer was in the right spot, it’s always good to check with my peers as I am often wrong ………. Welll according to SWMBO I’m never right.

Moxi

No worries, my swmbo is from the same tribe. Maybe it's a Welsh thing? I run the firebox at about 250 degs, opening up to about 300 if we get into higher minus air temp figures outdoors. Clean it once per year in Spring, only got a handful out last year during clean. Moisture count in the logs makes a massive difference to re firebox temps and condensate happy molecules. I try to airdry for a minimum of 9 months. Some goes a year and a half. How long do you airdry for Moxi?

[openspaceman]

I run the firebox at about 250 degs, opening up to about 300 if we get into higher minus air temp figures outdoors.

I note you are measuring your firebox temperature outside case.

To cleanly burn wood all the products of combustion should reach a minimum of 850C for about 1.5 seconds. This is why modern stoves have insulating refractory brick lining. A 1kg piece of wood at 20% moisture content has about 4kWh of heat energy which has to heat up all the massflow of combustion products, stoichiometric oxygen, excess oxygen and all the nitrogen from the air having a free ride through the system to this temperature, increase the moisture content and it struggles to get there.

The heat of the combustion products is then transferred to the heat exchange surfaces of the stove such that, ideally, the exhaust exits the top of the chimney above 100C. We had industrial wood boilers that, given wood below 30% mc would have flu exit temperature of down to 115 C so got most of the heat from the wood into the circulating water. A domestic stove probably needs to have a flue gas temperature above 150C in order to allow for heat losses in the chimney. I run mine hotter as I have a concrete lined brick chimney which acts as a retained heat store.

[Joeboy]

I run the firebox at about 250 degs, opening up to about 300 if we get into higher minus air temp figures outdoors.

I note you are measuring your firebox temperature outside case.

To cleanly burn wood all the products of combustion should reach a minimum of 850C for about 1.5 seconds. This is why modern stoves have insulating refractory brick lining. A 1kg piece of wood at 20% moisture content has about 4kWh of heat energy which has to heat up all the massflow of combustion products, stoichiometric oxygen, excess oxygen and all the nitrogen from the air having a free ride through the system to this temperature, increase the moisture content and it struggles to get there.

The heat of the combustion products is then transferred to the heat exchange surfaces of the stove such that, ideally, the exhaust exits the top of the chimney above 100C. We had industrial wood boilers that, given wood below 30% mc would have flu exit temperature of down to 115 C so got most of the heat from the wood into the circulating water. A domestic stove probably needs to have a flue gas temperature above 150C in order to allow for heat losses in the chimney. I run mine hotter as I have a concrete lined brick chimney which acts as a retained heat store.

I'd be interested to.know how an average homeowner would obtain the 850 deg C reading? For me an efficient vigorous burn is obtained at a consistent 250 degs exterior top point of stove face. If it hits 300 I will throttle back the air a little. I assume I'm hitting the 850 internal but i really dont know? As you have said, there are so many variables in build material and design. The first year I ran the WBS then cleaned at year end there was a decent amount of flue combustion debris.

I put it down to damp logs and not being (me) dialed in to a constantly changing process. Running a clean (as you can wbs) isn't complicated but knowing what you are looking at and adjusting as the season changes is critical.

I'll be honest, it is my fave RE thing. I miss it when I shutdown for Summer. Good point on the hotwater robbing X amount of energy from the gas lift through the flue.

'A 1kg piece of wood at 20% moisture content has about 4kWh of heat energy'. That is interesting, would that be a hardwood? Most of my available is soft or soft/hard. About the only legit hardwood I have is cherry and that is limited. Cheers!

P.S, the Woodstock I have is mostly cedar, pine, ash, fir & larch and a bit of beech. All legit harvested and processed under solar powered conditions.

[Joeboy]

One of the things I immediately like about the stove gauge is that at a distance the needle at tdc is the 250 deg sweetspot. I had the digital thermometer out to check and its all very much the same readings on both at 250 or 300. If I went much beyond the 300 I'd hear the stove creak and be running the risk ongoing at higher temps of damaging the glass.

For a zero cost and unexpected bonus, its a handy wee thing.



I've damned myself of course by taking a photo at 225 degs when the fire was waning.