Dedicated basement zone, what radiator type to prevent short cycling?

grant_andrew

I'm finishing about 300 sq. ft. of my basement, and have re-configured my boiler to have a second, dedicated zone. I know that finned tube baseboard is not an option for heating the space, because it would heat and cool too quickly and potentially cause the boiler to short cycle. Ideally I would install a cast iron radiator, since it has a high thermal mass and water volume, and it would match the ones in the rest of my house, but I'm having trouble finding one of the right size/type/condition locally.

Would the Runtal baseboards be an option to consider/ I know they don't really hold more water than slantfin baseboard, but wasn't sure if they have more thermal mass. Any thoughts are appreciated.

I understand another option would be a configure the zone relay so that the basement circulator is controlled by the thermostat, but it will only turn the boiler on when the upstairs zone is also running. This would probably work fine for our lifestyle, but I'd ideally have two dedicated zones.

Boiler is a Burnham Alpine 80, which can do 16-80 MBH. This zone would need abotu 12,000 btu/hr if above grade, so I'm thinking 8000 btu/hr should be safe since it's a basement.

Any insight on radiator type or other solutions are appreciate, thanks!

mattmia2

The runtal or panel style radiators will have a lot more mass than fin tube. You also need to make sure you keep the minimum flow through the boiler when only that zone is calling. New cast iron radiators are also available.

mattmia2

Cast iron baseboard is also an option.

Brewbeer

Cast iron baseboard. Used it in my last house basement project.

grant_andrew

That's a good idea. I just tried searching and could only find one website that sells it. Did you get it locally at a supplier or online?

mattmia2

i believe you need a special tool to join the sections. I think I saw a site that sells the baseboard and rents the tool.

flat_twin

I think you would be better off with more mass for the small zone you're proposing. Panels or cast iron radiators. What supply water temp range will you be running?

Brewbeer

I was able to purchase preassembled ready-to-plumb sections 4 and 8 feet long, no special tool needed. Get several shorties and spread them around the space. Keeping them short makes them easier to move and install.

bob eck

Check out Governale cast iron radiators at

https://file.ac/wLSGgqS3_ng/Governale Product Literature.pdf

Check out Ecostyle steel wall panel radiators at

http://www.qhtinc.com/wp/wp-content/uploads/2019/08/ECOSTYLE-CV-LIT-040819.pdf

F W Webb sells these products.