Outdoor Wood Furnace Info
Outdoor Furnaces - Manufacturers with NON EPA-Certified Models Only => Shaver Furnace => Topic started by: gas-on on January 14, 2012, 08:21:46 AM
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I have a Shaver 165 that we have used for 3 years now. I have had the same problem every year. When it gets below 25* outside it just can't keep up with my House and Shop. The house is forced air and the shop is radiant heat. In the past I have spoken to Shaver and the floor heat people and they blame each other for the system not working. The floor is directly plumbed with a secondary loop from the stove. The stove just can't recover fast enough to keep up. The burn times on a full load of wood are less than 8 hous because the blower never shuts off. Does anyone have any ideas to help make this work better?
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Welcome to the site! Have you tried adding extra insulation to the furnace?
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165 is only putting out at max 150kbtu s, so I'd say your under sized especially since you have had 3 years to adjust and learn the system.
To confirm, isolate the shop and see what kind of burn times you get with just the house.
Ed
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I would say you need a bigger furnace.
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I told the people at Shaver how much space I was going to heat and they recommended this stove. I thought that if I did not let the floor water return directly to the stove that it would help with this problem.
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I told the people at Shaver how much space I was going to heat and they recommended this stove. I thought that if I did not let the floor water return directly to the stove that it would help with this problem.
where would you direct it to?
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if you have had this problem 3 years as stated then i would agree that you have had time to learn how to perate your stove. so the next question is the blaming each other thing...did you tell the OWB salesman how many square feet your were planning on heating (if yes he should have slod you a large enough unit)
did the floor heat installer actually install the floor properly (with at least 2 inches of blue foam (or equivelent) under your slab and up the edges to the top of the concrete?
also are your underground pipes well insulated (is there snow melting above them or is the ground unfroze when ground elsewhere is froze)
is your home and shop well insulated.
you can make a general assumption for your home that you require about 40 btu per square foot of living space and if your shop is 8 foot ceilings and well insulated then you can guess about the same amount of btu
a 2000 square foot home would need (easy figuring as your insulation value and not knowing your heat loss) about 80,000 btu per hour on those cold cold nights use the same kind of figuring for your shop and add the two together. it is my personal opinion that the manufacture rate their stoves quite high as when the test them they have everything about as perfect as you can have it, and i think that a stoves real rating is much lower than what they say. I am nto sure how they test them or rate them but i would make a guess they are likley only about 80 to 85 percent of what they claim
as for your infloor heat i would ask the same question, if you are not going to return the water to the stove directly where are you going to send it. you should be sending water into your floor loop only about 110 or less degrees and if it is properly designed it should be returning about 10 or 12 degrees less
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I have a Shaver 165 that we have used for 3 years now. I have had the same problem every year. When it gets below 25* outside it just can't keep up with my House and Shop. The house is forced air and the shop is radiant heat. In the past I have spoken to Shaver and the floor heat people and they blame each other for the system not working. The floor is directly plumbed with a secondary loop from the stove. The stove just can't recover fast enough to keep up. The burn times on a full load of wood are less than 8 hours because the blower never shuts off. Does anyone have any ideas to help make this work better?
I would like to add my $0.03.5 here. I'm not seeing where you mention how many square feet you have to heat...I had originally ordered up a 165 Shaver for my house/shop...but after discussing the sq. footage with several people around here, they all talked me into going with the next furnace size up. So I chase to pay the extra $900 and bought the Pro Series 250 Shaver. My house is about 3600 sq. ft and the shop is a moot point because money was tight and I don't have it heated by the OWB.
We too have in floor "liquid" heat in the office here at home and we have "nice" heat all the time. however unlike your situation, our in floor heating came "before" the OWB...by about 5 years. You mention the blower operating WOT all the time...there's another problem....you might want to consider getting an auto damper along with either a Honeywell Aqua-stat or a Ranco T-stat. With either of these t-stats, you can set the differential for when the damper opens and or closes. I have the Ranco and it WILL be in operation tomorrow morning. When I got the Shaver 250, the company "forgot" to install the larger blower motor with the auto damper and I was continually burning wood just like you.
But be this as it is...it surely sounds to me like you have too small a furnace. When You bought this OWB, did you go through a sales rep in your neck of the woods or did you talk directly with Shaver? Or was the fellow's name Ben?
By the way, welcome to the forum. Good luck with your situation, and I can tell you that you have come to the right website to solve your problems...lot so f knowledge available here and it's all free.
Lugnut
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I called shaver direct and they gave me another number to call, and yes it was Ben. I have work very hard to make this work. We put alot of time in the floor making sure it was properly installed using 2" blue board, solar guard and plastic below that. My house is 7 years old and is 2400sqft the shop is 1200sqft.
As where I would direct the water diffrently... What if I used a water heater as a tank and a heat exchager to seperate the direct flow of water back to the stove. Whenthe floor is running I only lose 6-8* through the floor but when it sits idle and when it first comes on the water temp could be 40-50* colder than the stove.
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does your pump run on demand or 24/7?
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I called shaver direct and they gave me another number to call, and yes it was Ben. I have work very hard to make this work. We put alot of time in the floor making sure it was properly installed using 2" blue board, solar guard and plastic below that. My house is 7 years old and is 2400sqft the shop is 1200sqft.
your home and shop using an average of 40 btu per foot per hour equals 144,000 btu per hour on those cold nights. your stove (i read here) is only rated at 150,00 and i believe they are over rated by at least 15 percent (no proof just gut feeling)
you need more btu to deliver
the eat load is onnly an average guess...yours could be more or less
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I do not know what you have your 165's water temp set at, but I also have a new 165 (with the auto damper) and I was experiencing the same issue during very cold temps outside. I had my temp set above 160 on the OWB. I tried setting it even higher but that did not work. I set the temp to around 140 and that seems to have helped the situation.
I was thinking that having the blower running all the time you keep injecting cold outside air into the fire box. Which made me think about running a tube from the blower intake to the smoke stake before it goes through roof of the enclosure (above the water tank) which could either be wrapped around the smoke stake to heat the air inside or maybe the tube could be placed near the stake so the the air it is sucking in and sending to the fire box is heated. Does anyone think the heated combustion idea would work?
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I have thought of doing the same thing myself. Bending up a box under the roof around the stack and pulling heat from around the stack before it is sent in under the grates. I would think that when it is bitterly cold out that the air being sent in could have a cooling effect on the bottom side of the firebox. Taking what heat you can off of the stack would be an efficient place to pre-heat it that's for sure.
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powerstroke i have an 8 inch schedule 40 chimney, i have fabricated a 3 foot section of 8 inch with a 6 inch inside it, i plan on istalling this in my chimney next summer and pumping water from my stove around the chimney and back into the boiler. i am hoping to recover a lot of heat this way as when the furnace runs i know the stack gets quite hot. i am hoping ot increase my efficiency by at least 10 percent? if i put this right at the bottom of the chimney i dont think it will create too much of a problem with creosete. And this is R&D si uf ut fails i will jsut let teh water out and be doen with it..lol
:o
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That's why I love this site Willie........everybody is always thinkin! :)
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powerstroke i have an 8 inch schedule 40 chimney, i have fabricated a 3 foot section of 8 inch with a 6 inch inside it, i plan on istalling this in my chimney next summer and pumping water from my stove around the chimney and back into the boiler. i am hoping to recover a lot of heat this way as when the furnace runs i know the stack gets quite hot. i am hoping ot increase my efficiency by at least 10 percent? if i put this right at the bottom of the chimney i dont think it will create too much of a problem with creosete. And this is R&D si uf ut fails i will jsut let teh water out and be doen with it..lol
:o
I have been waiting to post this until I was confident in what I was seeing but, for what it is worth I got a really good deal on a aqua stack a couple of weeks ago. My furnace is a hawken with a force air draft. For 4.5 years I have watched the heat waves come out of the stack when the blower was on. I have a cap on my chimney and with a ir gun the inside of the cap would hit 500 degrees plus. So a couple of weeks ago I said to myself, "what the heck I will give it a try"(aquastack). My chimney cap now runs between 350-400 degrees at full burn and there is a NOTICABLE DECREASE in wood consumption. Now that temps have cooled down to more January like I think a 15% reduction would be conservative. I am very pleased to say the least. I was terribly sceptical and concered for creosolt but so far it seems to be no problem. I did have to adjust the air restricter plate to allow for a little more cfm's, as I was getting a little more smoke than I liked, but it now burns smoke free after start up.
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woodman what does that thing look like??
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It is a very simple design. Basicly 2 long rectangles roughly 20" long linked at the bottom by a 2" port. There is a tab on either side that allows it to drop into the chimey from the top. Each side has a 1" female pipe thread port at the top. I plumbed it so the return water goes to the stack first then back to the owb. Note: it is designed for a 8" chimney.
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powerstroke i have an 8 inch schedule 40 chimney, i have fabricated a 3 foot section of 8 inch with a 6 inch inside it, i plan on istalling this in my chimney next summer and pumping water from my stove around the chimney and back into the boiler. i am hoping to recover a lot of heat this way as when the furnace runs i know the stack gets quite hot. i am hoping ot increase my efficiency by at least 10 percent? if i put this right at the bottom of the chimney i dont think it will create too much of a problem with creosete. And this is R&D si uf ut fails i will jsut let teh water out and be doen with it..lol
:o
Have you thought about making it a drain back design? Having it setup so when the boiler is running it pumps water up into it and then drains back out when it is idling. Doing that should keep from losing some heat off it while the boiler is idling. It would also allow turning it off to allow the chimney to run hotter to burn it out every now and then.
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I called shaver direct and they gave me another number to call, and yes it was Ben. I have work very hard to make this work. We put alot of time in the floor making sure it was properly installed using 2" blue board, solar guard and plastic below that. My house is 7 years old and is 2400sqft the shop is 1200sqft.
As where I would direct the water diffrently... What if I used a water heater as a tank and a heat exchager to seperate the direct flow of water back to the stove. Whenthe floor is running I only lose 6-8* through the floor but when it sits idle and when it first comes on the water temp could be 40-50* colder than the stove.
i can't see where a bigger stove will cure this problem? dumping that amount of cold water back to the stove will drop your water temp big time and slow the recovery.
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i can't see where a bigger stove will cure this problem? dumping that amount of cold water back to the stove will drop your water temp big time and slow the recovery.
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in the radint floor if 1/2 pex was used there would be about (actually a little less) 1 gallon per 100 feet of pex. a 1200 squate foot shop would likley have about the equivelent of about 1200 feet of pipe that qould equal about 12 gallons of water i can't see where sending 12 gallons of cool water back to the boiler would cause your boiler not to be able to recover quickly?
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Whenthe floor is running I only lose 6-8* through the floor but when it sits idle and when it first comes on the water temp could be 40-50* colder than the stove.
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the water temp coming out of the radiant floor should be 40 to 50 degrees cooler than your boiler when it is running..the temp of your water entering the floor loop should be less than110 degrees and likely your OWB is running 50 degrees above that
the 6 to 8 degree loss in your floor loop is perfect and i am guessing your house is losing about 20 degrees between in and out temps when the house is calling for heat...i really believe you are maxing out your stove in cold weather. lets go back to your underground pipe..does it melt the snow on the ground above it? what type of underground pipe do you have?
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My stove is set at 140 *.
The snow when I have any this year stays right on top of the ground. I made my own lines. I wraped the lines in solor guard then pulled them thru black corragated pipe.
I have temp guages on the incoming and out going lines. This way I can tell where I am losing heat. The house loop only loses 4-6* when it is nor calling for heat. When heat is on I lose 8-10*. The shop loop loses 6-8* when no heat is needed.
The floor is computer controlled and has a mixing valve that uses return water from the floor to control the ingoing water temp. It just seems when the floor turns on the massive drop in water temp causes the stove temp to drop to 80*. It then takes forever for the stove to catch up.
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again i caution you taht your house and shed on those very cold nights may be drawing over 140,000 btu per hour and i read here your stove is estimated at 150,000. i think (only my assumption) that your stove may deliver that amount of heat for an hour,maybe 2. remember an oil or gas furnace can deliver its set rating continuously as the fuel never runs out but wood on the other hand burns down and give of less btu's as it does. this means you will be delivering less (likely less than you need) aprt way through a fill. if you are taxing your stove to the max then you will require to fill more often to keep enough fire in teh box to deliver those high btu.
it is still my belief your stove is too small
another thing i dont see clearly is if your floor is properly installed how does the water in the lines cool 50 degrees between cycles of the floor loop?
if you are introducing water into the floor at 100 degrees and you say it is leaving the floor 50 degrees cooler by the next time your floor loop cycles then your insulation under the slab sends of a red flag to me as that would be ground tempature?
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you also say yor shop loses 6 to 8 degrees when the floor loop is not running. i take it you have a by pass and the water from the house to the stove is circulating always? if that is the case and you are losing 6 to 8 degrees in this loop it may be nothing or it may be something, that depends on where this heat is going and how fast your water is traveling. again what about the floor loops temp. if your room is 70 at about chest hight (likley where your thermostat is) and by the time this area cools down 3 or 4 degrees (likley where your thermostat would call for heat again) you say your floor loop has cooled to 50 .if your floor loop water is 100 then you say it cools to 50..that is cooling rather quickly don't you think? if your room cools 4 or 5 degrees between when the thermostat shuts off and turns on and your floor has cooled 50 degrees don't you think that is a little extreme
if your floor loop cools off to a temp less than your room between calls for heat i would guess your floor is not insulated properly and your floor is actually drawing heat from your room?
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I have two pumps running. One for the house and the other for the shop and yes I have a bipass loop installed for the shop.
The thermostat is set at 60* that controls the floor. I have a temostat on the other side of the room It always reads 65*. I work in the shop during the winter mostly on weekends. The floor only turns on every couple of hours. I have never checked on how often it turns on and off.
I thought that if the water did not return to the stove that it would keep the stove temp higher and not have such sudden drops. Would some kind of heat exchanger help or would it not be worth even trying?
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how hot is the water going into your floor loop
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The water from the stove is 140* it enters the shop at 138-136* it then can bi pass and return to the stove or when the floor pump turns on it goes in the floor at 100* after the mixing valve does it thing.
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just for a try i would up the stove to 155 or so on and 165 or 170 off and then turn the floor heat in temp down to 90
i am not sure this will help but hey, you can try this for free
it is my belief that if you feed hotter water to the floor loop on delivery and turn down the floor loop it will do two things
1 use more of the return water to cool the loop and use less of the hot water being delivered
2 it will cause the floor loop to run longer to reach the desired temp so the floor will not cool down as often and dump that colder water back to the boiler
if you notice that this makes an improvement you might try lowering the floor loop temp a little more (i have heard of guys running at 85 in a shop) but you must keep the delivered btu rate above what your building is losing in order to heat it.
as i said this is just something you can try with no cost and may help .......good luck
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gas-on,,,,what modifications have you done to your shaver?
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i had a shave for 3-years also and when its below 30 degrees i would fill it every 6 hours, shaver told me also to go withe the 165, i sold mine and got a accemefurance 320, twice the size and love it,