snowmelt

Troy_3

Go figure. Unhappy customer. We installed a 1400 square foot snowmelt job under uniloc pavers using a Munchkin M199 boiler. It also heats a 1000sq. ft. garage and pool in the summer. Boiler is installed mechanical is finished. Driveway goes in and we now have 3000 sq. ft. Typical! I inform owner we need at least one more boiler. We trunch the back yard to install more gas. Owner pays the gas company $1700 for a 2million btu meter. Then he tells me not to install the additional boiler till next year. Problem---He can't believe how wonderful the snow melts. It has run all winter and has never fallen behind. Question-Don't you know how to design? Why did I spend all this money to upgrade when it is not needed. I am amazed. I usually design to 150btu/sq.ft. Am I way overboard?

hot_rod

Tough to predict

the weather, or in your case snowfall. Generally 150 is the at the low end of snowmelt design. I have done some 125 and a couple 100 BTU/sq. ft.

Just depends on the application and exceptations. In my light snowfall area 100 is usually adequate. However a few heavy snowfalls this year strained the 100 systems. Definitely not acceptable for public walks or stairs. It may be fine for a private driveway however, if a little slush or striping doesn't impede passage.

Tough to get an accurate heatloss for the "great outdoors" I suspect if the job had fallen short and the drive or walkways slushed of fallen behind, with snow accumulation you would have heard about it also.

What type of control? Do you idle the slab or use a snow sensor for instant on?

Here is a good article describing the new ASHRAE design criteria.

http://www.pmengineer.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2732,74679,00.html

hot rod

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