Why am I getting higher temps with less AIR ??? Old VC

[kwikrp]

I have an Old VC Defiant late 70's model. So I have been having this dilemma that I was having trouble getting temp up past 450. Was told bad wood . Got good wood still problem exists. Told air problem not enough somewhere there was a restriction or blockage. Vac and cleaned back and every other suggestion, but still same results. Every time I attempted to burn in horizontal mode the heat would dramatically fall and not come back. By accident I turned the primary air way down, was trying to put the fire out by choking it cutting off the air supply. I noticed that the stove soared to 500 then 600. WOW !! I thought it was a fluke so I repeated this many times since. Then I got temp up to 535 and went into horizontal by closing damper and lowered the primary to almost the closed position and the stove hung there and then the heat rose to 550 and stayed there for some time. Not exactly sure how long but I know my oil burner did not turn on last night till 5:30 Am and last night was cold here coldest in maybe 15 years? When I looked at the stove at 5:30 am it was still around 400 and had some very hot almost white in color coals.
I thought that more air created faster hotter burns ? This seems the opposite ! If you were wondering I did check that I was closing the primary air supply not opening it!! Can someone explain this to me?

 

[jeff6443]

think of a cutting tourch to much air yellow smokey flame cut it back blue hot flame . gotta play with these things

 

[JustWood]

Less heat going up chimney.

 

[Todd]

Once the stove gets hot enough the secondary combustion kicks in and eats all those gases and smoke, if the air is set too high the draft will suck those gases up the chimney before they have time to ignite.

 

[LeonMSPT]

Got an old VC insert... 0046 model. I can burn the glass clean in it wide open, but if I really want it HOT I close the bypass damper and cut the airflow into the insert to almost closed... watch out... burns the glass clean and drives you into a pair of shorts and a t-shirt fast.

Last two nights... 28 and 23 below zero... 80 to 85 in the living room and the bedroom 45 ft away is 65 to 75 degrees... just get up every five hours or so and throw a couple more logs on. Wait a few for them to light, then close the bypass damper. It's bright until it comes up to temperature and then the air shuts itself down and idles at 550 to 600 for five more hours.

 

[webbie]

Wood goes through various phases when it burns. Turning the air down on a fire which is well underway - in the coal stage (lots of red embers) will increase the heat for two reasons.....one is that less air (which is cold) causes less dilution, the second is that less air means less heat going up the chimney!

Turning down an older stove early in the burn, though, is not the same as a modern stove. Often this will end up smoldering the wood and causing a dirty, low temp burn and lots of smoke. The key is getting the feel of exactly how your stove, wood and chimney work in combination with the weather and your heating needs. Learn about how to burn and then apply those lessons. We have some tutorials on starting and tending fires in our Main info section.

 

[LLigetfa]

think of a cutting tourch to much air yellow smokey flame cut it back blue hot flame . gotta play with these things

Your fingers are on the wrong knob. Smokey flame is too much acetylene/not enough oxygen. Too much oxygen and it goes POP.

Primary air is cold and can cause incomplete combustion. More primary air may steal from the supply and/or the draft and mean less secondary air. Secondary air is superheated and promotes further combustion.

 

[Valhalla]

Kwiprp,

Check that the small round air port at the back is open and clear. Vacuum it out when you do your cold stove cleaning