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[LittleJohn]

I was wondering if anyone here uses heat from their OWB to purposely melt snow from sidewalks, aprons or patios. 

Reason I ask is that I recently built a house heated by CB e-Classic 2400 and I was thinking about running pipe in the concrete before sidewalks and aprons are poured??  I was just wondeirng how hard it is on the boiler and how often do you have to refill fire box??  Will definately seperate snowmelt from boiler with a HX and mixing valve, so I can run glycol and not shock OWB. 

[willieG]

it can be done, it uses lots of btu but if you are not lazy and willing to shovel it off it takes a lot less. if you go this route you should  google it and you will find some help. i think i read  use at least 3/4 pipe in the loop as you need to move a lot of gallons to keep the line from cooling to quickly, also your loops will need to be kept  short. google is your friend

[lindnova]

Answer - Depends. 
How much sidewalk? 

Good idea on separating the systems as 180° water will shock and crack the concrete too!  You wouldn't need to run it all the time, but it is hard on concrete to warm up and cool down too fast - will cause cracks. I would recommend 2" insulation under and 1/2" rebar at 2 ft on center to keep the joints from moving and hurting your pipes.  I agree on the 3/4" as all the exterior commercial I have seen has been this size.  Usually there is a manifold close (inside or in a vault in the pavement) to supply from larger supply pipes to the individual loops.  It would be best to have a plumber who has done this before and is familar with it.

The boiler should handle it fine; just use more wood.  I heat a well insulated 1500 sf house (3000 sf 2 levels) and 1100 sf attached garage and fill mine 2 times a day unless it is colder than -10F.  I use mixed box elder, cherry, maple, elm and oak or whatever I can get my hands on with more oak and elm when it is colder.  Lots of variables such as how cold it is outside and what kind of wood you are using. 

If you can swing the upfront cost and extra wood, you will be very happy with a melted dry sidewalk. 

Good luck!

[hoardac]

The Post office just put one in and what a nice thing. When I put my new walkways in I will have it, for what the pex cost and the little time it takes to install it well worth it.

[willieG]

The Post office just put one in and what a nice thing. When I put my new walkways in I will have it, for what the pex cost and the little time it takes to install it well worth it.

you want pex tubes in your cement sidewalks you better prepare for  enough rebar in yoru cement to hold it together and prevent any future cracks from heaving keep your loops short and at least 3/4 (do some investigating)  a lot of snow melts dont insulate under them so you need to deliver more btu to the pipes than in a radiant heating application. depending on the type of snow melt you are looking for will determine the btu requirements you need

[ITO]

 I don't think I would do this, we get lots of snow and ice but I don't like cutting wood more than I need to. I cut and haul all my own wood and that's fine but it's enough for us, I'd rather shovel. Its dark early here and often cold, if it weren't for dealing with the snow and also the wood I would have to go to a gym. Heated driveways have been discussed before, even pics posted, then I could sell the plow.

[willieG]

i agree ito..but some folks liek the idea, that is why i say read up on it al you can. for a minimul snow melt you are looking at about 150 btu per square foot (will melt the snow away but will take a long time)  right up to melting almost as fast as it falls 250 or more btu per square foot!

that is with insulation below the pad  and it is recomended to insulate the sides as well

lets go right in the middle and say yoru snow melt will require 200 btu per square foot....(wow!) now lets look at the  area of ontario , usa border around toronto montreal and the eastern us...the average there is estimated (on teh coldestnight of the year) to heat yoru home is about 40 btu per square foot..so to melt snow would require 5 times that amount!


 

[yoderheating]

 I did a driveway melt system several years ago with a MF5000e. We heated about a quarter mile of asphalt driveway with two pipes per side to make tracks to drive in. The driveway was up a very steep mountain that was too steep to plow even with 4x4 with chains.
 We used a mixing valve and 1 1/4 pipe from the furnace to the drive and then split it up. The system worked best when you would warm the driveway up to about 40 before the snow or ice hit. After the storm you would simply shut it off and only heat the home. It burns a lot of wood when in use but that is only for short periods. 

[LittleJohn]

At least I am not trying to do snowmelt like this: http://www.warmzone.com/site/page/cz-snowmelt

Probably have to call power company before you turn it on; also can you imagine how the electric meter just hums

[yoderheating]

Driveway melt system on a MF5000e. This is about half of the melt system, also have a 2500sq ft home hooked to the furnace.

[mlappin]

Love mine, but in really light snow I fire up the leaf blower and blow most of it off to save fire wood. Also just wait for a warmer day to melt off ice. Enough heavy wet snow and I shovel it off then just run the warmer enough to get rid of what the snow shovel doesn't get.

House stays cleaner and no salt tracked in on shoes or by pets.

It takes a LOT of wood to keep a sidewalk clear, standard width sidewalk but I'm just keeping the middle melted off, total length of 110' or so.

[Sluggo]

I pour concrete for a living and here's my 2 cents...  You obviously live in a cold weather climate so I will make you two guarantees.  1.  Your concrete will get hard
                                        2.  Your concrete will crack
So it snows and you turn the heat to the sidewalk on.  Snow melts and flows into the cracks.  A day goes by and and water temp cools down and you now have ice expanding in your cracks making them even worse.  Every cycle you do this the cracks get worse and worse.  Before long you have a very expensive sidewalk that needs to be replaced.  I would not recommend it at all.  If you have the ambition to cut wood you must have some ambition to shovel the sidewalk!  I would guess you could shovel the sidewalk faster than you could cut,split,and load the the extra wood into the stove.  I see negative returns on this investment.  Also doing this is illegal for some dumb a$$ reason in some places.  Good in theory but I wouldn't recommend it!  In my eyes it would be like installing geothermal at age 85 and using natural gas heat.

[Scott7m]

I am not a big fan.  For what it would cost to do it correct youd be able to pay someone to do it for a long time

Likr sluggo said,lots of varibales.

Yoder had some good ideas there how his customer melts his driveway.   

[johnybcold]

Sounds cool but if there was no snow, then i might not need my tractor or atv and  and love playing with them.

[Sprinter]

Snow melt is a luxury, 99% of the projects I bid or many others bid don't do it. The cost is in the "luxury" range. I did a small stamped & colored concrete sidewalk with company logo, 8,000 sqft roughly was around 200kbtu load, Tekmar 665 controller and 090 snow sensor. Only $28,000 plus the ridiculous gas bill. All for looks in a downtown walkway. None of the snowmelt jobs I have done have anything more than very small cracks. Some 20 years old. They are all floating slabs as well. But then again we don't have flat men trying to sling 2000psi mud to save a buck.

All you can do is have it professionally spec out and price then equipment to give you an idea. Takes some good size pumps and exchangers to move glycol too. Glycol make up kit or pressurized storage feeder. 2" foam board, etc.....