radiant floor - whats next after pex/manifold

[bloomingtonmike]

My floor is in and cured etc. I have 9 loops of 1/2" pex and the manifold is on the wall and everything holds pressure.

Gas line is in the building..

I bought a used gas fired water boiler. I need to install it.

What are the procedures for filling the lines/system etc? Is there a good tutorial anyone is aware of for all that?

 

[mygarageone]

If the boiler is not a high eff unit , you'll a tempering valve and a separate pump.

 

[Rookie2]

how many feet of pex, what size building ?
Boiler has to be elevated above floor especially if cars are in a garage.
antifreeze !
2 pump system ?

 

[bloomingtonmike]

2550 ft in a 40X64X16 pole barn - 9 loops of 1/2" - from the blueridge company 2700 Pole Barn Kit. Floor is 5"+ concrete with 1.5" extruded poly styrene foam and 10mil Poly moisture barrier underneath. PEX is on top of 1.5" tall Meshup mesh chairs.

Barn was wrapped entirely with double bubble (ceiling and walls) and I am installing R19 fiberglass batts over that. No ceiling insulation purchased yet.

It is one pump and one zone. It has a Taco pump. I also have an expansion tank and pressure relief valve.

No cars in this shop. Just tools.

Boiler manual said 18" elevated in a garage.

It is a 80% efficient Cast Iron GWA Gas Fired Water Boiler.

Looks similar to this:

 

[Rookie2]

Start here !

http://www.garagejournal.com/forum/showthread.php?t=49557&highlight=Hydronic+heat

Do a search :Hydronic, heat

 

[warren57]

Keep in mind most boilers are not designed to operate at a low enough temp. Radiant in floor heat normally operate between 80-100 degrees. Most boilers aren't designed to be operated that low, as the flue gas doesn't vent well (starts condensing) at low temps. So be sure and check the specs on your particular boiler. The newer high efficiency boilers are designed for low temp flues that's why they vent in pvc pipe, but an older boiler may need operate with a higher flue temp.
Normally we install a mixing valve. (And pump) A mixing valve in the supply piping that can be adjusted to maintain a lower water temp , while keeping boiler water temp up.
I like to operate the boiler around 180degree and adjust the mixing valve around 100 degrees. The mixing valve blends hot boiler supply with cooler system return water, thus cooling the water.
Another option is adding a heat exchanger and pump, but that gets very costly. Normally only used in large capacity commercial systems.

 

[BadgerBoilerMN]

Warren is pretty close. You will need combustion air and chimney for your low efficiency cast iron boiler and as he states a way to protect the boiler from sustained flue gas condensate.

I prefer a sealed combustion condensing boiler or water heater depending on the loads, which eliminates both of these serious issues and will operate at 1/2 the cost of the low efficiency models if sized and programmed properly.