Staple up radiant

hot_rod

radiant that is that small of a % of the boiler capacity should not be a problem. As long as the boiler has the capacity to handle all loads at design temperature condition, you'll be fine.

Connecting BTU hungry, radiant in concrete slab, would be a different story, if it represents more than 15- 20% of the boiler capacity.

With high operating temperatures be sure the plates are extruded aluminum, well fastened, and the pex loop ends have expansion room, or you will hear about it. 165 is fairly hot to put to the bottom of wood subfloor. 140- 150 is about max. that the plywood and subfloor manufacturers are comfortable with. Maybe additional plates could lower that supply temperature requirement?

hr

MikeyB

Staple up radiant

Hey guys, im looking to add a staple up radiant zone w/aluminum plates to the underside of the 2nd floor, I installed this Weil Mclain HW boiler a couple of years ago in my freinds house, it serves an Indirect, a Hydro Coil in his central air, and one baseboard zone that we just ripped out for the first floor, (This first fl zone will be replaced w/a staple up job down the line as well) And a future basement zone. He already ordered all the tubing/plates, 3-speed Grundfos pump and a thermostatic mixing valve, and the manifolds, my question is what would be the best way to pipe this in while protecting the boiler from cooler water? The guy that sized the radiant says he needs just one row of 3/8 tubing in each joist bay w/the al plates, and insulate under the tubing. There is carpeting and padding throughout the 2nd fl, He say's he will be ok w/165 degree water. I have attactched pics of the existing cast iron boiler (the 2 pumps on the right are now spares). Do you think the install will be ok w/the thermostatic mixing valve alone w/the 3 speed pump or should it be done a different way. Thanks for your help guys

MikeyB

staple up

Thanks for your response HR. I thought the 165 tempp was high as well, my freind will be able to adjust as needed, the staple up will get the additional boost of heat from the air handler on the coldest days of the year, there will also be a section of a hallway (3/4" oak) that will have the tubing suspended from hooks w/out the al plates, what would be the best location for the pump and 3-way valve? supply or return?