EKO 40 is on its way and I still don't have a plan

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jedclamoit

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Apr 16, 2012
18
I've been lurking in the shadows on this forum for years, not able to play because I wasn't burning wood, but hopefully next winter will be a different story. I'd like to do this install myself as many have done on this site, all I have are the schematics from Tarm's site which appear detailed enough, but where do I get these components online? If I go with local supply houses they might go "huh?" This is a hush hush system in WA, I'm sure the PacNW will be the final holdout against wood fired central heating. Anyway I don't have any wood boiler brilliant minds to pick around here, its all clandestine.

I'm looking at a two boiler system as I'm adding the EKO onto my existing electric boiler system. We have 3400 sf of 4" radiant slab that I would like to use as the thermal storage allowing the boiler to run full on with all zones open until the burn is over, so I need controls and components to override the existing Tstats to open all zone valves whenever the wood boiler is running, then revert back to the existing electric boiler until another fire is lit in the EKO. This would no doubt cause temperature oscillations, but I think I could deal with that in lieu of water storage for now (if that makes sense?) Would someone be willing to share their wisdom and a good reliable parts list to add this boiler onto my existing system? Thanks for anything!



Here are the components listed on woodboilers.com (tarm) the design I've been looking at is a .pdf on the same site "two boiler Primary Secondary Design No thermal storage" http://www.woodboilers.com/admin/uploads/public/WoodBoilerPlumbingSchematic0111Web.pdf

Termovar Loading Unit - Integrates the Termovar Tempering Valve, a balancing valve, 3 thermometers, and a Grundfos 15-58 3 speed circulator in a compact solution. Includes ball valve isolation unions.

Termovar Tempering Valve - Automatic, thermally operated valve that ensures a minimum return water temperature to the boiler, which increases efficiency, prevents tarring, reduces thermal shock, and increases the life of the boiler. Includes ball valve isolation unions.

Automag Zone Valve - Normally closed 24 VAC 1” zone valve designed for continuous power supply. This valve is used to provide the code required heat dumping zone during loss of power situations.

Honeywell AT72D Transformer - 40 VA Multi-mount transformer. Plate, foot, or knock out mounting. Primary 120VAC 50/60 Hz nine inch leads. Secondary 24 Vac secondary uses two screw terminals. Provides a power source for Automag zone valve.

BLT Control - A tidy UL approved control with simple instructions that makes integrating a wood boiler and heat storage tank with an existing boiler a snap. The control includes an on/off switch and a three position switch that includes wood only operation, back up only operation, or wood with automatic back up operation. Integral diagnostic indicator lights simplify trouble shooting.

Honeywell L4008A 1015 Aquastat - Breaks on rise 100-240F w/5-30F adjustable differential. 66 inch capillary. Tank mounted, this aquastat is the switch that begins the automatic back up function when your tank is below your useable water temperature.

Honeywell L4006A 1009 Aquastat w/ ¾” Well - Makes on fall 100-240F. Used to sense wood boiler supply temperatures by mounting in the supply pipe. Starts the backup burner when the wood boiler temperature drops (auto backup function for add-on wood boiler used without heat storage).
 
Welcome to the boiler room and congrats on yuor EKO 40. I am running a 25 with pressurized storage. I installed my system, took about 4 months, it was frustrating, time consuming, I learned a lot and pretty satisfying when it all came together. Been running it for 2 1/2 years now.

I am far from an expert, there are guy's who are way smart then me, but I question your design of using your slab for storage. The only way to use the slab would be to insult the hell out of the top and bottom other wise all those BTU's you put into the slab are just going to radiate into the living space. Radiant is intended to use low temp water to heat the living space not +180* water straight from the boiler. The only way to store BTU's is with an insulated tank and that can be an open non-pressurized system or a closed tank pressurized system. BTU's are stored, when there is a call for heat BTU's are taken from storage and delivered to the zone requiring them.

As of for getting your components, I got some from my local plumbing supply house, Home Depot and PEXSUPPLY.COM. With the exception of the Tremovar and Automag these are standard HVAC components. My heating supply house carried the automag and the guy's were somewhat familiar with the basics of wood boilers but not the use of storage.

Try to locate a member in you area so that you can see how there system is set up. I was foggy on how to do this until I went to the house of the person I bought my EKO from. He gave me a blue print of the setup, I took a bunch of pictures and it made sense and was pretty straight forward from there.

Good luck
 
I would not just "dump" the heat into the slab. You might consider two t-stats, one for the wood and the other for the backup. Set the wood t-stat for something like 75F and the backup for 68F. It takes a LOT of BTUs to raise a 4" slab from 68 to 75. Don't worry about idling, you'll only do that for a couple of seasons until you add storage and figure out you can get your domestic hot water from the wood boiler too! Be careful though, when the other half (if there is one), gets used to the warmer wood heat you'll be lighting fires all the time.
 
I'm looking at a two boiler system as I'm adding the EKO onto my existing electric boiler system. We have 3400 sf of 4" radiant slab that I would like to use as the thermal storage allowing the boiler to run full on with all zones open until the burn is over, so I need controls and components to override the existing Tstats to open all zone valves whenever the wood boiler is running, then revert back to the existing electric boiler until another fire is lit in the EKO. This would no doubt cause temperature oscillations, but I think I could deal with that in lieu of water storage for now (if that makes sense?) Would someone be willing to share their wisdom and a good reliable parts list to add this boiler onto my existing system? Thanks for anything!

When buying your components, like timberr gave you a couple of good ones, especially PEX supply, I found some other items that I couldn't find anywhere else in the following places: eComfortUSA, Pexuniverse, Perfect Pay Supply, Houseneeds, and blueridge supply. You can probably save some serious money if you purchase a separate pump, thermometers, and valves from PEX supply to substitute for the Termovar Loading unit. PEX supply's price for the Danfoss tempering valve in 1 1/4" is about $140. I don't know how much the Termovar valve is. Also, you can buy a NO Honeywell 3/4" valve instead of the automag for about $73. The only reason I'm mentioning that is availability and common use. Also, I have a small 100 gallon tank for some heat storage (and DHW) and I notice now in the shoulder season my pellet boiler doesn't just go to idle often, it shuts off for hours on end and lets the buffer tank heat the house when needed. I've got the control board set for a min temp of 140 and so that 100 gallons of 185 degree buffer water can store a fair amount of heat. You might consider some form and size of storage for your EKO.
 
Thanks for the online resources! So how much of a temperature occilation should I expect dumping a full burn into the slab? Would the heat get exchanged fast enough to allow the boiler to run full tilt? I guess I need to figure what 130,000 btu does to a 4" slab, water would get mixed right away so perhaps this idea wouldn't allow the boiler to run full on anyway. There is some math that is certainly escaping me at the moment, I need to see if this would allow the boiler to run efficiently and what the temperature swings would be. As for storage in the future, that's looking like a hot tub with some coils in it :)
 
I have an EKO 40 and been running it for 4 years. I had no problem installing mine in Washington State. The county inspectors thought it looked real nice. I know outside wood boilers are illegal in Washington, but there is one running on Hwy. 395 South of Colville that has been running since I moved here in 2004. I live 100 miles north of Spokane. If you are near, you could take a look at my setup.
 
Here is a link I found to calculate your slab thermal capacity: http://www.ehow.com/how_6127389_calculate-heat-capacity-concrete.html

Based on your figures, you can store about 30K BTU/deg F. So one hour or burning at 120 KBTU/h would raise you slab temperature (theoretically) 4F. Based on this, I don't think using your slab for storage will be a good idea, your temperature swings will be very large.
 
Bulldog, I'm in Whatcom County the birth place of everything environmental it seems, don't get me wrong I like helping the planet but here's a case where they are preventing people from using a pretty responsible product. The local building depts. create so many hoops for us to jump through, just to build a house. Even with a UL sticker these things would be hard to get through either building dept. here. So we waited to close out the permit and now I can play. Thanks for the offer of showing me your install, I would love to see it if I get over to Spokane area!

Hunderliggur, thanks for that formula, how many total btu s does the eko 40 put out off a full load of wood roughly? Looks like I shouldve saved some coin and bought the smaller model 25 to do what I thought I was going to do? Anyway I'm sure over time I can use the full capacity of the 40--it was the recommended size for our square footage, plus we have vaulted cielings and a lot of glass. I'll have to start looking at the water storage. Has anyone on this board mapped out a better schematic than what I found on the Tarm site?

Thanks again everyone for reading and contributing, this has been good. I guess I'll be figuring out how much water I need to store to let this unit burn full on after my slab goes up 4 degrees or so.
 
While using your slab for storage is far from ideal, it is possible with some temp swing. You will probably only want to burn 1/4 to 1/2 load at a time If your going to do it that way. Don't burn half a load and then a hour later when the house is not warm burn more. you will cook yourself out of the house 15 hours later. You would be better off to get some storage if you can.
 
Has anyone on this board mapped out a better schematic than what I found on the Tarm site?

Look at the "stickies" on this forum. The simplified pressurized system design might do you very well.
 
so design heat loss is better than I thought 88,165 BTU/hour at my design temp of 15 F. I do plan to heat storage at some point and supplement the DHW, I believe I'd still want the EKO 40?
 
Well let's not forget that you can run your boiler as a "normal boiler" without storage and without dumping all of it's output into your slab. If you setup your floor thermostats properly and let the EKO do the thinking for you, you can have a very comfortable home with the only downside really being a bit of idling on your EKO.

EKO's can and will run perfectly fine without storage. There are all kinds of users around here that do it. Your 40 may be substantially oversized for use without storage but that really will only result in additional idling and reduced effciency. If this is a short term situation - just do it. Make sure you clean out your smoke pipe with some regularity and save your nickles for 1,000 gallons of storage as soon as it make sense.

I think running the boiler "normally" will be substantially better than trying to use your slab as a buffer. Nobody in your house is going to be happy if room temps swing from 55 degrees to 95 degres every day. No way...
 
so design heat loss is better than I thought 88,165 BTU/hour at my design temp of 15 F. I do plan to heat storage at some point and supplement the DHW, I believe I'd still want the EKO 40?

I guess I didn't see this post! 88,000 btu/hr is a very high heat loss for a home your size. How did you come up with this number? Is your slab properly insulated?

For reference I heat 3,200 square feet with loads of windows, vaulted ceilings, etc and so on and my average heat load is 20-30k btu/hr with peak loads of closer to 50k btu/hr with below zero temps outside, 70 inside.
 
Well let's not forget that you can run your boiler as a "normal boiler" without storage and without dumping all of it's output into your slab. If you setup your floor thermostats properly and let the EKO do the thinking for you, you can have a very comfortable home with the only downside really being a bit of idling on your EKO.

EKO's can and will run perfectly fine without storage. There are all kinds of users around here that do it. Your 40 may be substantially oversized for use without storage but that really will only result in additional idling and reduced effciency. If this is a short term situation - just do it. Make sure you clean out your smoke pipe with some regularity and save your nickles for 1,000 gallons of storage as soon as it make sense.

I think running the boiler "normally" will be substantially better than trying to use your slab as a buffer. Nobody in your house is going to be happy if room temps swing from 55 degrees to 95 degres every day. No way...

I've been heating my shop by running the circulator once a day. Havn't had over a 5 degree swing in temps in 24 hours. From 55 to 95 is overexagerating to say the least.
 
I've been heating my shop by running the circulator once a day. Havn't had over a 5 degree swing in temps in 24 hours. From 55 to 95 is overexagerating to say the least.

Indeed...I was trying to be a bit sarcastic.
 
well I calculated 3448 sf of exterior wall area and 1516 sf of windows and doors (double pane low e), single story slab on grade with r10 beneath slab, however, slab isn't well insulated from footing stem walls, couldn't figure out a great way to isolate the slab from the stem walls-- not wanting rigid insulation as part of my flooring detail (we just polished the concrete for the final finish). Ya it's my first heat loss calc, I could have missed something but my wall, ceiling and window areas are pretty accurate, 34000 cubic feet of area within the home. I guess you're right, our house is god awful in the winter! We currently have an 80,000 btu electric boiler based on the heating contractors calcs (which I never saw).

So if my design heat loss was 88K btu that means I need 88K plus whatever I may need to draw for the DHW on the coldest days of winter? Well the eko 40 is pretty much a done deal but I probably could've gotten away with the 25 plus storage. If I get storage the most I can really fit is 500 gallons without taking over the garage with my central heating system.

Thanks again guys for the input!
 
Do you have a handle on what your electric costs are running the electric boiler for a heating season? Or a month? And what are your electricity rates?

EDIT: And, if it helps, storage doesn't have to be all in one tank all in one place. If you've got places to stick 100 gallon tanks around, they can be tied together to increase storage. Added plumbing & more awkward insulating will be a bit of a pain, but if it gains needed storage it would be worth some thinking about.
 
we used 178 Kwh/day for central heat through the peak winter months, so that's 607361.21 btu/day, but we didn't heat zones of the house and had tstats set below where we were truly comfortable (about 2 or 3 degrees lower than we'd really want).
 
we used 178 Kwh/day for central heat through the peak winter months, so that's 607361.21 btu/day, but we didn't heat zones of the house and had tstats set below where we were truly comfortable (about 2 or 3 degrees lower than we'd really want).

Holy crap - that's $30/day here at our rates. Pushing $1000/month. Wouldn't take long to recover cost on a new gassifier at those numbers.
 
well I calculated 3448 sf of exterior wall area and 1516 sf of windows and doors (double pane low e), single story slab on grade with r10 beneath slab, however, slab isn't well insulated from footing stem walls, couldn't figure out a great way to isolate the slab from the stem walls-- not wanting rigid insulation as part of my flooring detail (we just polished the concrete for the final finish). Ya it's my first heat loss calc, I could have missed something but my wall, ceiling and window areas are pretty accurate, 34000 cubic feet of area within the home. I guess you're right, our house is god awful in the winter! We currently have an 80,000 btu electric boiler based on the heating contractors calcs (which I never saw).

So if my design heat loss was 88K btu that means I need 88K plus whatever I may need to draw for the DHW on the coldest days of winter? Well the eko 40 is pretty much a done deal but I probably could've gotten away with the 25 plus storage. If I get storage the most I can really fit is 500 gallons without taking over the garage with my central heating system.

Thanks again guys for the input!

Wow that is a huge heatloss . Is your house 2/4 or 2/6 construction. What r value is in your ceiling .
 
2/6, again lots of big windows. ceiling is where we dumped a lot of money actually, 2" of closed cell poly urethane foam sprayed on, then r38 batts = r 52. i'll rerun the numbers tonight perhaps, but the energy bill doesn't lie we were at 178 kwh/day for a month or so, nasty cold temps don't last too long here in NW WA.
 
2/6, again lots of big windows. ceiling is where we dumped a lot of money actually, 2" of closed cell poly urethane foam sprayed on, then r38 batts = r 52. i'll rerun the numbers tonight perhaps, but the energy bill doesn't lie we were at 178 kwh/day for a month or so, nasty cold temps don't last too long here in NW WA.

I heat roughly 35000 cubic feet of space between 2 dwellings I think at the coldest of the season here I was using close to 40 thousand btu's per day. Must be a lot colder there . Do you have a smart metre on your house if so I know that a lot of them that were installed here are giving very inaccurate readings.

Huff
 
Huff dog, I do live close to border near bellingham, and i must have a smart meter because I've never seen anyone come to the house.
 
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