Questions for hydronic guru's.

[The FIB]

I am currently in the process of building a garage/workshop with living area above. I had the HVAC contractor hang heating and cooling equipment for the second floor on the ceiling of the first floor shop, all of the duct work is hung this way as well. The equipment involved is a blower, A/C coil, 10kw electric heat unit, and a forced air hydronic coil. The hydro coil will be for future use after I get a outdoor wood boiler set up. I plan to use Glycol instead of water for winterizing purposes.

I hope to be dry-walling the first floor ceiling soon, so now would be a good time to install the lines that will feed the hydro coil, the run will be about 40' located between the I joists. The joists will have about 3”-4” of sprayfoam above the new lines.

I have been searching the web for a proper way to install the line but have come up with a lot of conflicting information.

The questions I have are:

What temps are typically running to the coil.

Is it OK to use 02 barrier pex for the supply lines (have read pex “softens” at higher heat).

What should I insulate these lines with and how far away should we keep the sprayfoam away, if at all?

Do they have a sharkbite type fitting to go from copper to 02 barrier pex?

The coil will be at the highest piont in the system, should I install something to bleed the air out?

Should the inlet be at the top or bottom of the coil, ( read conflicting views on this).

 

[klrdiant]

1. depends on the manufacturer .. typically 140 degrees
2. yes, use oxygen barrier pex, aka heat pex .. if you don't keep oxygen out of the system you're gonna have corrosion issues
3. you can bury them in the spray foam
4. yes, 1/2" sharkbite fittings work with 1/2" copper, 1/2" pex and 1/2" heat pex .. 3/4" works with 3/4" etc etc .. problem is shark bite fittings can leak over time .. use sweat to pex fittings and crush type pex rings .. i have nightmares about sharkbite fitting seals drying out
5. some heat coil units have air bleeds built in, if not its a good policy to have provision to bleed air at the beginning of each heat season, there's always a little dissolved oxygen in the system and it will accumulate ay high spots and can cause flow issues and corrosion
6. the manufacturer probably spent a bunch of money on r&d .. best to follow their recommendations .. usually the unit will be plainly marked as far as in and out .. if it isnt, in my experience it doesn't really matter unless there's stuff like flow switches or heat sensitive valving in the system

 

[derkperk]

I'll comment in the pex idea.

You will more than likely run a higher supply temp than 140 with a wood boiler. That being said, I would stay away from your conventional pex barrier tubing.

I recommend running type L hard copper pipe and insulating with 3/4" closed cell foam.

Sent from my XT1565 using Tapatalk

 

[Jackfre]

I would not run the piping in the spray foam. While it will insulated, you will have a hell of a time if you have to access that pipe. It is a machine. Build it so you can service it. Not sure what you are intending to use as far as your air handler, but I would suggest picking it out and following their instructions.

 

[pstnbly]

You should go over to hearth.co. klrdiant got you started. There's some bad info on this thread though.