For reading interest....I modified my PE spectrum............

.......16 or more years ago a few months after I purchased it soley to extend the burn cycle.
OK, I considered the ramifications of voided warranty , insurance, and never gave safety a thought either and to be honest I never had any regrets. I have always felt that EPA requirements at least partially forced the industry priority to satisfy test requirements . Anything else was a bonus.
The problem I had with the original configuration/design of the removeable baffle (secondary air plenum) directly above the fire was that it shot long flames out of the downward facing holes resulting in prematurely burning the top of the fresh re-load of wood , significantly decreasing the length of burn and producing more heat than necessary. I also think this same situation/reason might have contributed to complaints that the air supply control could not be lowered enough and led to some user modifications of that air control .
Ok , what I did was to bolt on a length of 1/4" X 1-1/2" flat stock with approx 3/8 " space between it and the row of downward facing holes (front to back) which effected/diverted the secondary air to enter the firebox from both sides of the flat stock vs straight downward. It worked like a charm and still does to this day.
The secondary burn above the fire is still colorful but the wood no longer burns from the top down prematurely.

Comments welcome.

wxman said:

I have been contemplating a similar design with my Pacific Insert, did you use stainless and just space it with some washers? Bolt it to existing holes in the manifold or drill new ones?

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I drilled 3 holes and tapped 5/16" hex head bolts into the manifold and steel washers or nuts for spacers. I`m pretty sure I used steel flat stock. SS might even be better but after 16+ years it has not warped.

I sold the stove off to a friend of mine 8-9 yrs ago and he uses it in his new a chalet styled open floor plan house with a 18 ft peaked ceiling above the stove. It heats his entire house nicely. I get to see and check out the stove on occasion so I know it`s current condition and how well it works. He is more than happy with it`s operation and capability.
It was just way too much of a heater for my basement (700-800 sq ft) finished area. I couldn`t take the 80* + heat any more down there.
Here`a link to the diagram

http://www.pbase.com/johnd1/image/110643380

Oh! I just remembered on one occasion with this stove I had enough coals to restart a fire after 21 hours. Yeah, it could have been a one time fluke or a super quality load of hardwood but I was amazed. Obviously it might not have given off a whole lot of heat for many of those 21 hrs but it sure could hold hot coals for a long time. Overnight burns were never even close to a problem.

CZARCAR said:

sounds like u bought 2 big a stove in the first place & by blocking secodary may have compromised its efficiency
ideally i think overhead burn should 99 out of 100 holes flaming & 1 unflaming hole assuring there is ample O2 & minimal excess of pyrogas for combustion. if all holes are flaming u dont know if theres enough O2 for full combustion & only a CO analysis of exhaust would tell the story.
kicker is incomplete combustion of wood-CO = 1 energy unit
combustion of CO-CO2=2.5 energy units as effected by stochiometric combustion=ideal burn

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Read it again Pook, maybe slower this time. No secondary burn air holes are blocked. There`s a space to divert the secondary air supply 90 degrees out each side. I don`t think diverting the air supply caused any restriction. I can tell you this, when secondary combustion begins to take place in that stove the air getting sucked in appears to be damned strong and maybe audible (don`t recall) judging by the length of those flames that shot out the airholes in the manifold . No. I don`t believe for a minute that was an issue to consider . The secondary burn remains a nice colorful sight to behold but not any more the straight down flames torching the top of my loaded firebox and prematurely and significantly reducing the freshly loaded firebox.
As far as I`m able to ascertain without any test equipment , my simple mod worked very well and pretty much the same in two different houses . It immediately solved my complaint and with no negative changes whatsoever in the stove`s operation or heat output .
If I thought otherwise I would have removed the flat stock and screwed the bolts back in the holes.

CZARCAR said:

Gio said:

CZARCAR said:

sounds like u bought 2 big a stove in the first place & by blocking secodary may have compromised its efficiency
ideally i think overhead burn should 99 out of 100 holes flaming & 1 unflaming hole assuring there is ample O2 & minimal excess of pyrogas for combustion. if all holes are flaming u dont know if theres enough O2 for full combustion & only a CO analysis of exhaust would tell the story.
kicker is incomplete combustion of wood-CO = 1 energy unit
combustion of CO-CO2=2.5 energy units as effected by stochiometric combustion=ideal burn

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Read it again Pook, maybe slower this time. No secondary burn air holes are blocked. There`s a space to divert the secondary air supply 90 degrees out each side. I don`t think diverting the air supply caused any restriction. I can tell you this, when secondary combustion begins to take place in that stove the air getting sucked in appears to be damned strong and maybe audible (don`t recall) judging by the length of those flames that shot out the airholes in the manifold . No. I don`t believe for a minute that was an issue to consider . The secondary burn remains a nice colorful sight to behold but not any more the straight down flames torching the top of my loaded firebox and prematurely and significantly reducing the freshly loaded firebox.
As far as I`m able to ascertain without any test equipment , my simple mod worked very well and pretty much the same in two different houses . It immediately solved my complaint and with no negative changes whatsoever in the stove`s operation or heat output .
If I thought otherwise I would have removed the flat stock and screwed the bolts back in the holes.

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seems the diversion might have effected a restriction & u got superheated secondary air from alteration? maybe good if front/unblocked secondaries were fully flaming so to add air to possible inadequate O2 for stochiometric combustion & like i said 99/100 overhead flamers assure enough O2 & if not , CO in exhaust tells the invisible story of inefficiency.
it is also possible that the non burning log tops were simply outgassing without ignition which results in excessive pyrogas for available combustion air from secondaries.
this i htink i know=if tubes are burning no O2 is available for pile underneath, if tubehole aint burning the air is cooler & dives down per density & feeds the pile underneath. i still think u bought too big a stove in the first place

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Hey Pook,
Theoretically, you could have a point or two , but unless you are an expert in this field , neither of us will know. The technical end is a bit over my head since there`s no quick and easy way for most folks to test/measure the efficiency of a field installed stove but I think stochiometric efficiency numbers don`t always equate to how well a stove operates. As said before , meeting EPA specs might be the priority of at least some manufacturers and this can effect the efficiency of overall stove operation itself.
As I said before with my simple non invasive modification the fire lasts longer, puts out the same amount of heat , the same wild colorful secondary burn as always, no smoke exiting the chimney, never any creosote deposits anywhere in flue or chimney.

The fact that I bought a stove larger than what I needed is not a factor in my post. The point is that the manifold downward facing holes torch the top of the wood load during a secondary burn resulting in too fast of a burn. This is going to happen wherever the stove is placed.

CZARCAR said:

changed my prior post above. just playing devils advocate & actually appreciate creativity

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Pook,
I really appreciate your replies. Good discussions require participation and you have introduced some interesting points to consider. The devil`s advocate role is always helpful. I tend to look at things from a practical common sense only POV and too often ignore the tech side , probably due to my limited education.

BeGreen said:

Gio, I've noticed when there are big thick slabs of splits, loaded E/W in the stove than they get a perfect V cut into them by the secondary flames. It's interesting that you found such a dramatic change in burn times by spreading the secondary air. How were the stove top temps? Did they drop after the mod?

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I never loaded the PE spectrum EW since I had tried and returned a Regency that loaded that way (awkward) and I was very dissapointed in it`s burn time. It required re-loading more than 3 times a day. The Spectrum was a revelation to me with it`s NS loading and plenty of red hot coals after an 8 hr burn. I never worried about leaving the Spectrum go longer than 8 hrs as it always had enough coals for a quick and easy relight but 3 times a day was my normal regimen.

To be honest I don`t recall a significant change in stove top temps but the truth is there could have been . I probably didn`t accurately monitor stove / pipe temps before the mod and I hesitate to use the word dramatic trying not to exaggerate the extended burn time to be anything but a noticeable overall improvement in that regard and as I think equally important , a better controlled burn.

With the extended burn times after the mod it seems fair for me to conclude that I must have changed the heat output curve . The pre mod initial high burn which to me was almost out of control and short lived was now leveled off and better controlled.