Noob to post...... Attack???

[BoilerMan]

Hello all!! I've been reading this forum for, wait for it............ 3 years now. Well I thought i should finally register and post.

Against my better judgment I bought a New Yorker WC130 a couple of years ago, I know smoke dragon, and it is the sole heat for my 3,200 ft2 house/ garage. It was a money thing at the time, and there were no used boilers to be found....... Anyhow, looking to unload the dragon and upgrade to a gasser. I've searched and there only seem to be a couple of members on here with the Attack DP or DPX. The reason I ask about the Attack is I've sourced a used one at a reasonable price. It is located 7 hours away so I can't just take a look at it. It is a 60hz model and it is a DP45 series. I have storage in a 2,200 ft2 8" thick slab with the tubing about 6" deep (on purpose), and a 115 gal. indirect water heater so I can go for several days w/o a fire. My house is super insulated built by me, so BTUs are not much of a consideration. I"m open to any other choices as well. Thanks for the great site and true real world expierence and re-engeneering when recessary!
Taylor

 

[woodsmaster]

I dont Know Know much about the attack. I do Know that to use your slab as storage you will have a little swing in temperature. I've been heating my shop like that. I run the circulator for an hour or so while the boiler is running without mixing the temp down much. I do that once a day in the winter. I have maybe a 5 degree swing at the most.
I think you about have to run stuff manually for it to work well. A little less if it's going to warm up some A little more if it's going to be colder. Most my slab is 6 " with the tubing in the middle.

 

[Fred61]

Don't know much about the boiler but your means of storage caught my attention. While that many tons of concrete may have the capacity to hold many BTUs of heat, control becomes an issue. Your slab will not absorb nor release the heat quickly enough to keep up with demands both on input and output. If the slab envelopes the total area to be heated, you will probably get more heat from stratification than from the tubing whithin but it won't release when you want it to. On cold days it will not release at a rate quickly enough to make up for demand and on warm days, perhaps when the sun is shining in, you will more than likely overheat. Anyhow, if you do pump heat into the slab,be sure it is high and dry and well insulated from the earth. Remember it has the same number of square feet of surface on the bottom too!

 

[Sawyer]

I use a Tekmar 509 Thermostat which uses the slab sensor on a 8"+ slab (had to re-pour the slab after building settled) with the tubing in the lower 2" above 2" foam board. This controls the temperature swings. I set max/min temps at 1 degree difference. Prior to the group recommending this control the room temperatures swung drastically and the loads on the boiler were extremely unpredictable as in cold showers in the morning.

 

[Tennman]

Always suspicious when someone is selling a modern boiler. Ask a bunch of questions. Been a few of Attack posters here over the years, not many, but one guy quite consistently and he seemed pleased. When I went to New Horizons I looked at the EKO, Attack, something else, and the BioMass. Attack quality appeared fine. Far smaller user base, but I don't recall Attack owners having a negative impression. It actually had some design features I preferred over the EKO and it was less expensive. But bells go off when someone is selling a gassification boiler. But could simply be they're not up to the wood processing lifestyle. Not a big market for used boilers so you have very strong negotiating leverage.

 

[Armaton]

Taylor,

Eliot Dudley has an Attack, search the site, he has a thread on it. Works for him.

 

[BoilerMan]

Taylor,

Eliot Dudley has an Attack, search the site, he has a thread on it. Works for him.

I've read his threads, EW seems to be the only one on here with one.

I visited a friend who heats several apartment buildings with Econoburns, first time I've seen a gasser in operation, not on youtube.

When I say storage in the slab I meant I just use it as a radiant slab it takes so long to heat up and it releases the heat well. Of course as mentioned it's a bear if we leave for more than three days in the winter, Quadrafire stove in the living room is the means for heat as I throw piece after piece in the boiler. But normally I see only 2 degree swings in room temp. Build one fire a day and reload once or twice depending on the outside temp. It has worked well for two years, after the learning curve.

The claim is "selling for health reasons" I've emailed several questions about Hz. etc.

 

[woodsmaster]

I've read his threads, EW seems to be the only one on here with one.

I visited a friend who heats several apartment buildings with Econoburns, first time I've seen a gasser in operation, not on youtube.

When I say storage in the slab I meant I just use it as a radiant slab it takes so long to heat up and it releases the heat well. Of course as mentioned it's a bear if we leave for more than three days in the winter, Quadrafire stove in the living room is the means for heat as I throw piece after piece in the boiler. But normally I see only 2 degree swings in room temp. Build one fire a day and reload once or twice depending on the outside temp. It has worked well for two years, after the learning curve.

The claim is "selling for health reasons" I've emailed several questions about Hz. etc.

Just charge your floor a little extra before you leave and should be fine when you home in three days. With that much mass it should hold the heat a long time.

 

[ewdudley]

Just to review (DP 45):

Pros:

Dealer was first-rate, price was right. Doors, seals, hinges, loading bypass, primary/secondary air adjusters all solid and durable. Easy to clean, no fire tubes, no turbulators.​

​

Cons:

No fire tubes, no turbulators, so therefore lacking in heat exchanger surface. I was aware of this going in and choose to operate the unit at a 20 kW (70,000 btu per hour) net heat delivery rate by throttling the air intake, which reduces flue temperature and increases efficiency. So not really a disadvantage if reduced firing rate is sufficient.​

​

I felt it lacked exterior insulation and added an inch of rock wool panels.​

​

Air controls and RK20001 controller are designed to control supply temperature, which makes no sense to me for heating storage, but not a problem peculiar to the Attack boiler. ​

​

And no end-of-burn draft fan shutdown, again not a problem specific to Attack.​

Controls were replaced with custom and conventional boiler controls cheaply and easily enough, but it all takes time. All in all I'm very pleased, but I'm the kind of guy that likes his Focus just as much as his A6, just for different reasons.

If buying used sight unseen then no matter what brand of unit it would be critical to have some guarantee that the unit was never operated without return temperature control.

 

[BoilerMan]

Thanks EWD,
I would throttle it down as well, I have no problem useing conventional aquastats for control either. I like the idea of dry contacts opening and cutting power to everything, no drivers, little transformers, or LCD screens to be struck by lightning (I am an Industrial control electrician). I assume I only get 70-90K BTU out of my existing setup anyhow. The price is right, and a road trip to pick it up. I just need to unload my current setup. Are the exterior panels simply steel which screw/rivit to each other? Is there room to use 1-2" of Roxul or is space between boiler jacket and plate steel limited to 1/2" so some added sheet metal is needed? What do your stack temps stay at in full gassification with it throttled, and before? Their site says 428F for their efficiency speck of 86% which seems high for a stack temp over 400.

This info is great I can't say enough good things about this site for we wood burning nerds! It's like money in the bank with oil as high as it is.

 

[ewdudley]

I would throttle it down as well, I have no problem useing conventional aquastats for control either. I like the idea of dry contacts opening and cutting power to everything, no drivers, little transformers, or LCD screens to be struck by lightning (I am an Industrial control electrician).

My RK2001 behaved erratically for a few weeks and finally died altogether, which motivated me to take it out of the control scheme. If you end up with one that runs reliably it can be set up to do what you need, so no need to toss it from the get go. But adding end-of-burn draft fan shutdown would be a good thing to plan on doing.

Are the exterior panels simply steel which screw/rivit to each other? Is there room to use 1-2" of Roxul or is space between boiler jacket and plate steel limited to 1/2" so some added sheet metal is needed?

The side panels hang on ears that can be bent out further, which would make room for more and higher quality insulation. Also there's no insulation on the bottom. I found some very light gauge aluminum channels at a big box and used them to frame an outer jacket.

https://www.hearth.com/talk/threads/50hz-boilers-specifically-attack-atmos.65486/

What do your stack temps stay at in full gassification with it throttled, and before? Their site says 428F for their efficiency speck of 86% which seems high for a stack temp over 400.

I built a closed-loop control and run stack temperature according to setpoint. At 340 degF I seem to get good output. It's only supposed to be 1% for each 30 degF stack temperature reduction, so no big deal going from 428 degF to 340 degF, but can't hurt. 425 degF to 450 degF sounds about right when running without draft inlet restriction. I've always assumed their 86% number was some kind of nonsense.

 

[BoilerMan]

EWD,
I've been searching on the web for how to clean the heat exchanger, and what the surface looks like. If possible can you post pics, I've found lots on the DPX with the fire tubes cleaned from the top. Does the DP have the same cleaning door on the top, just lacking in the fire tubes? Do you have to brush it out or scrape it from the top. The DPX looks to be on par with most of the other boilers I've seen. Not as much info on the DP as far as cut-aways go. I wish I were closer to one or a dealer to I could have a look myself. Thanks geltlemen for your time!
Taylor

 

[BoilerMan]

Also a big question, is the flue connection on top only or can it be mounted so it's rear/ horizontal exit. All the pics I can find look as though the DPX can be switched, but can the DP as well?
So close to buying this boiler.......

Taylor

 

[jimbom]

Taylor, After you make your boiler decision, I would really appreciate some information on your slab storage. By my math you have storage of about 35,000 Btu/. I was wondering what your heat load at design condition might be. And the temperature band you operate the floor within. Also, the insulation value on the non emitting sides of the slab and the value on the emitting side. Based on your posts, it seems like your boiler could raise your slab about 2/hour if the room surfaces were equal to the floor surface temperature.

I have a 5" insulated basement slab that I want to couple with an equal size 1.5" slab on the first floor. Real world experience would really help me with some of my estimates. Slab storage will work well for me if I can hit the sweet spot on insulation on the top of the basement slab. I have run the numbers, but nothing beats actual experience.

Good luck with the boiler decision.

Thanks, Jim

 

[jimbom]

Don't know much about the boiler but your means of storage caught my attention. While that many tons of concrete may have the capacity to hold many BTUs of heat, control becomes an issue. Your slab will not absorb nor release the heat quickly enough to keep up with demands both on input and output. If the slab envelopes the total area to be heated, you will probably get more heat from stratification than from the tubing whithin but it won't release when you want it to. On cold days it will not release at a rate quickly enough to make up for demand and on warm days, perhaps when the sun is shining in, you will more than likely overheat. Anyhow, if you do pump heat into the slab,be sure it is high and dry and well insulated from the earth. Remember it has the same number of square feet of surface on the bottom too!

I have been cogitatn this myself. Seems on warm days, the conditioned space interior surfaces will be at or greater than the slab surface. Therefore, little transfer of energy. On days when the conditioned space interior surfaces are cooler than the slab surface, heat transfer will increase due to the T.

 

[ewdudley]

EWD,
I've been searching on the web for how to clean the heat exchanger, and what the surface looks like. If possible can you post pics,

DP has a typical primary chamber on top with a nozzle feeding down to a refractory table in the lower chamber. The refractory table forms a channel from the front of the lower chamber to an exit port at the back. The walls of the two chambers and the floor of the lower chamber are the most significant heat exchange surfaces.

Flue gases leaving the lower chamber go straight up through the fan and out the horizontal flue neck. There's some ribs on the back of the water jacket protruding into the rear vertical chamber that act as heat sink fins, but no tubes. Much of the rear vertical chamber is jacketed with incoming combustion air channels.

There's a horizontal cover at the top of the vertical rear chamber and a vertical cover down at the bottom for cleaning the rear vertical chamber. I feel the rear vertical chamber is unimportant so I only clean it once a year, even though it's easy enough to do. Cleaning the lower chamber makes a measurable difference in heat output as a function of flue temperature, but the rear chamber not so much.

Pictures of the DP 45 show vertical flue necks, but mine is horizontal. However in my case at least the flue was not what determined the distance from the wall.

Don't know from DPX, looks like any other downdraft vertical firetube unit.

 

[BoilerMan]

Thank You EWD! I think I'm going to make the purchase.
Jimbom, I do not want to brag, but I do not have a typical house. I built it 100% myself in 2009 with heat loss at the top of every decision made. It has 200sq ft of triple pane galzing, 70% of which is on the south and east. R70 in the attic, and R32 in the walls. Fiberglass in conventional construction, with 1.5" Dow Truff-R on the interior of all walls and ceiling, all taped and spray foamed at any gaps, then strapping and wall/ ceiling material. The house is as air tight as convertional construction can be. I am not able to light a fire if the dryer is going, it will pull the draft down the chimney. There is outside air supplying all combustion appliances, and I monitor indoor air quality.

Anyhow, my design load is under 20,000 BTU/hr. I dump water in the slab (1/2" PEX 12" O.C.) @114 for the duration of a fire ( about 3 hours) and use my indirect DWH as a dump zone when the boiler reaches 190 . There is 2" Blueboard under the slab and 4" BB vertically around the perimeter. It is a monolithic pour with the edges 12" thick. The surface is covered with porcelain tile with the remainder not covered in the boiler room.

I reload the boiler and adjust the slab supply to 118 if it's below zero for more than 10 hours or so. I maintain 68 with a 2-4 degree swing. Wood is my only heat source accept for the 1500 watt electric heater my wife uses in the bathroom if she's cold. Last winter, which was very mild I burned 3.5 cord yellow birch/ hard maple.
In this weather, and the temp around 35 for about a week I build a fire in the boiler every other day with a 4 degree temp swing, and burn about 40 pounds of wood in each fireing. I hope to cut that wood down more, but more importantly, have it so my wife who stays home be able to load it and forget it, with my current setup I babysit and monitor stack temps closely at 350 and watch the smoke roll out the chimney
I hope this answers some of your questions. I need to go to bed.........
Taylor

 

[jimbom]

Taylor, Thanks very much for the information. When you get a chance, just two more questions:
What is the slab surface temperature after a three hour 114 charge?
How thick is the slab away from the thickened edge?
Thanks again for your information, Jim

PS
Sounds like we think alike. My house is 50 x 42 with actual heat load at design temp of 23,000 Btu/hour. Majority of my glass is on the south and east also. I have been heating for 20 years with a 40 gallon gas hot water heater except for this season. Between the basement and first floor, I have a combined 6.5" thick concrete slab for potential storage. Just now completing the heating season 100% on a wood stove. Did circulate the hydronic to even out floor temperatures from the south/stove space to the north spaces. Did not add energy, just moved the water through the system. It had minimal effect since temps were fairly close throughout the house anyway. Not sure if I will do that next year.

 

[BoilerMan]

Jim,
the slab is 7-8" thick with the tubing 2" from the bottom (6" of concrete above the PEX). The surface temp never gets over 75 because of the short duration of boiler operation/ huge mass above tubing. Usually I see 85-90 returning water from the slab at the end of a boiler fireing. It's all relivant, the longer heat is circulated the cooler the water would need to be to maintain the slab temp. I know of people that heat with oil and the water feeding the slab is only a few degrees above room temp on a moderatly cold day, and only a 5 drop from the water returning from the slab, but that's how a constant circulation system with properly tuned outdoor reset is supposed to work.

PS I think of it like a big Russian fireplace, only my fire is coupled to the "mass" with water, and not heating it directly.

Taylor

 

[jimbom]

Jim,
the slab is 7-8" thick with the tubing 2" from the bottom (6" of concrete above the PEX). The surface temp never gets over 75 because of the short duration of boiler operation/ huge mass above tubing. Usually I see 85-90 returning water from the slab at the end of a boiler fireing. It's all relivant, the longer heat is circulated the cooler the water would need to be to maintain the slab temp. I know of people that heat with oil and the water feeding the slab is only a few degrees above room temp on a moderatly cold day, and only a 5 drop from the water returning from the slab, but that's how a constant circulation system with properly tuned outdoor reset is supposed to work.

PS I think of it like a big Russian fireplace, only my fire is coupled to the "mass" with water, and not heating it directly.

Taylor

Taylor, Excellent. Thanks for the information. My 1.5" slab is constant flow outdoor reset. Twenty years ago I set it up to compare slab supply water temperature to outdoor temperature. Today I might add a room air temperature limit to take advantage of the passive solar contribution. Instead, I just let indoor temperature float up on sunny winter days. The extra mass keeps it from getting too warm. Thanks again for sharing your system. Jim

 

[BoilerMan]

Bringing this post back from the dead, I built my first fire today in the DPX! All went well, but I don't have a way to tell if it's in full gasification or not. It's a negitive pressure boiler (exhaust fan, not forced draft) so when I open the lower door there is no secondary flame. It does seem hot, but there is still some black on the door and the fron of the refractory. Should it self clean? I thought it should. I opened up the secondary air, but I don't know what to look for. Some light smoke, but it's dark now so I can't tell. Any help, would be great! Thanks guys.

TS

 

[flyingcow]

Kinda the same thing with the Innova, neg draft. got a peek a boo piece of glass ( not always clear) to look thru. Kinds hit and miss, got no smoke out the chimney. My stack temp was about 400-ish. Used my stack temp as a a guide as much as i have as using a visual thru the glass.

 

[flyingcow]

BYW-got black on the door and some creosote on the upper chamber. No biggie. SOP.

 

[BoilerMan]

I've started a new post on this so we can let this thread go to the grave!

TS