Could we add snow melt?

Glen

We're just in the final stages of a radiant (injection) system. All piping is complete, manifolds tied in - Tekmar 356 will be completed later this week. Customer has been a prince throughout - wanting quality components. Estimated heat loss is 56,000 - boiler net is 63,000. Customer now wants to add snow melt to about 700 square feet of deck. I have been looking for a btu/sqft value for snow melt but haven't found it - I left the customer hanging with the "it depends" answer this afternoon - and I will be chatting with the heaing designer tomorrow. The original design didn't consider any snow melt - and the electrican tells me that any defrosting sytems he has installed aren't appropriate with this install. Can this boiler support additional snow melt? OS design temps here are -22. Comments???
Cheers from the Canadian Rockies
Glen

Floyd

Setup the snowmelt...

so that it only runs IF there is no call for heat.
Usually when it's snowing you will not be at your lowest design temp.
so the heat will be cycling and that will give the snow melt enough run time.

Just a thought:-)

Floyd

Dan Peel

KITEC snowmelt

Check out their suggested - 150 to 250 per square foot.
Underpowered snowmelt just uses fuel and can't get the job done.
Dan

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

hr

Not near enough

Even at a bare minimun 90 BTUs per square foot you are looking at 63,000 output for the snowmelt. I would imagine in your area 125 and up would be a closer number for snowmelt. Just depends how much snow, how fast they want it to disapper.

Don't oversize the house boiler for the snowmelt! You will end up with a short cycling, inefficient arrangement, in my opinion

I would highly recommend separate heat sources for this job. A little condensing heat source would be sweet! Efficient, and easy to plumb and glycol.

hot rod

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Glen

good info -

Since Dan's post - I have been scratching about various sites. I would estimate - 150 btu/ft as minimum - @ 1"/hour and an average winter temp of -10 C. Boiler is too small - HR may have offered best idea - a vitodens hanging on the wall would be sweet - and it was my original boiler suggested for this project - but at $6500 plus ...... Maybe we don't have to snow melt the whole deck??? Just where the valleys of the roof dump all the snow ... just thinking out loud.

hr

Sticker shock

There are some other options for condensing heat sources. Look into the MZ, Munchkin, and a few other recent entries. There are numerous tank type condensing water heaters, although glycol is an issue in large water content heaters $$ wise.

Copper tube boilers are a good option also for snowmelt, although a mixing device would be needed. This adds cost and labor.

From my prospective the condensors are ideally suited to "drop in and fire" snowmelt applications. They thrive at low temperatures. Make sure you have a floor drain to accomodate gallons of condensate

hot rod

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

heretic

Modulating

If you were to run a modulating boiler, it could fire up high when the snow melt calls without being overpowered for space heating.
MZs run at 2 rates. Munchkin, Riello, Veissmann and some others have variable firing.
The Munchkin 140m modulates between 46<->140kbtu, for example.
Just a thought...

Glen

My experience is ..

with the Viessmann products - mainly the Vertomat in the larger commercial applications and have been doing the setup and service for most in the interior of B.C. They are a sweet boiler and a dear to work on - and of course all the less expensive mfgers models would all work equally as well. We had a very serious jobsite meeting this am - and it looks like electric snow melt has won out. Given that this has been a late development - I'm not unhappy with the decision. With all the boiler room piping complete it would have been a bear to redo. I'll post pics once complete. Once again the folks on the wall has been superb with ideas - HR - we have to meet - too bad we didn't cross paths at ISH - maybe in Vegas?? It is - afterall the best party town in the world. The golfing isn't bad either.

Cheers from the Canadian Rockies ---

hombre de oleo

How about an indirect water heater piped off the little boiler? Aquastat at 160-180 F with loops for snow melt off that.All the boiler would have to do is heat the indirect.

Dan Peel

Too Small Anyways

If you had more boiler resources and extreme exchange capacity then using an indirect as an expensive HX will work. When the boiler lacks theoutput resources to satisfy the snow melt in the first place there is no way to leverage it beyond at least not in my head) . Enjoy....Dan

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

marc

electric cable

what happens when the slab cracks and electric cable quits working. snow melt stops working. at least try to put tubing in pour, so when cable fails he has alternative to tearing up slab. how much is your electric costing to gas or other fuel. electric snowmelts are not the 1st choice in the inland northwest. just a thought.

jim f

electric??

not sure what you mean?? are you talking putting electric heating cable in the slab?? why not use a system with a small electric heater

Glen

electric snow melt -

I'm not sure which product will be used for this. I am considering adding tubing regardless - but Dan is right - we don't have the resources (btu's) to presently add snow melt with the current boiler. At 600 sqft and 150 btu/sqft - 90000 btuh is my first guess at heat required. Re cracking - like tubing, electric cabling must be protected at the stress points. Cheers

hr

Do you have

an extra 240 V, 100 amp circuit to power an electric snowmelt? That's about what you will need to supply that many BTUs. I'm not a big fan of residential snowmelt due to the energy it consumes, are you sure electric is the best option for the owners??

hot rod

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Glen

I'm not sure...

it's a 200 amp service single phase - three phase would be better - and even at a couple cents a kwh it would be pricey. Electric would be cheaper (less expensive) to install initially but in the long run ??? - maybe we should plan on a second boiler dedicated to the snow melt. I would dearly love to offer the better alternative (having read Dan's book on Just add h two oh) and as mentioned in an earlier post - I think I should run the hpex back to the boiler room while the ceiling is still open. We're running 2 pound gas in the home so supply of nat gas is not an issue - neither are the depth of the ho pockets - but he's not foolish either - he will opt for the better design. And as an aside - it was a good day hunting - just finished the dressing chores on a nice 4x5 whitey - that would be a nine point for those south of the 49th. My last one was a 6x5 and he too was caught napping!
Cheers from the Canadian Rockies