Anyone ever do a dry PEX heating install?

[pinion9]

I am currently doing this. Running the tubing seems easy enough, but a plumber told me there is an art to it. He said it will be noisy. Huh? It is plastic tubing. Anyhow, anyone have experience with this?

 

[Armitage]

What do you mean by dry??
I've run pex + manabloc water supply, and Al lined pex for radiators. Not finished yet, so can't comment on any noise. But my supplier never mentioned anything like that.

 

[pinion9]

Dry for heating, meaning it does not have conrete/lite-crete poured on it. Esentially I staple the pex tubing beneath the subfloor and then put insulation about 3 inches under the tubing. My supplier never mentioned noise, but one plumber did. It sounded like he was looking to do the install...

I was thinking about using a Manabloc for plumbing. Do you like it? Are you running a line to every fixture or do you T close to the fixture (such as for a double sink in the bathroom).

 

[dartworth]

Did you get prices on the Manabloc or the PEX?

 

[pinion9]

Originally posted by: dartworth
Did you get prices on the Manabloc or the PEX?

Not yet (I already have everything for heating.) Manabloc I need for plumbing is about $200 (36 port.) Pex I figure will run around $1000. Hopefully.

 

[dartworth]

I'm just curious...

I am planning on redoing all the water lines in my basement. Looking at the price of copper pipe now...🙁

 

[KK]

I have a manabloc, I had to replace the original one about 8 monthes ago because it cracked somewhere on the hot side. Prior to that, I had to replace the rubber gasket on the hot side input hose.

 

[Armitage]

Originally posted by: pinion9
Dry for heating, meaning it does not have conrete/lite-crete poured on it. Esentially I staple the pex tubing beneath the subfloor and then put insulation about 3 inches under the tubing. My supplier never mentioned noise, but one plumber did. It sounded like he was looking to do the install...

I see - yea, I'm doing that under the bathroom floor as well. I did a good bit of research on it and never heard of noise issues. My guess is he wants to do the install, as you suggested. Only thing I can see is maybe some creaking as the tubing expands. My supplier did reccomend not tightening it up against the subfloor to much to allow for that. Though I thought it was more for wear or fatigue then noise. I didn't use staples for mine - just these clamps that you screw into the floor.

I was thinking about using a Manabloc for plumbing. Do you like it? Are you running a line to every fixture or do you T close to the fixture (such as for a double sink in the bathroom).

I like it so far - but then, nothing is done beyond running the lines and pressure testing it, so it's hard to say. I ran a separate line for everything, including each of the double sinks. But then, saving one or two connections wouldn't get me down to the next smaller (cheaper) size, and one of the reasons I'm doing it is to minimize interference between connections - ie. not getting scalded in the shower if somebody flushes the toilet!

 

[KK]

Originally posted by: KK
I have a manabloc, I had to replace the original one about 8 monthes ago because it cracked somewhere on the hot side. Prior to that, I had to replace the rubber gasket on the hot side input hose.

edit> This site has some prices for the manabloc and pex tubing.

 

[Howard]

Shouldn't you cast the tube in cement or something?

 

[KK]

Originally posted by: Armitage
I like it so far - but then, nothing is done beyond running the lines and pressure testing it, so it's hard to say. I ran a separate line for everything, including each of the double sinks. But then, saving one or two connections wouldn't get me down to the next smaller (cheaper) size, and one of the reasons I'm doing it is to minimize interference between connections - ie. not getting scalded in the shower if somebody flushes the toilet!

Get some of those shower equilibrium pressure balance valves. When I had to shut down the hot side when my manabloc cracked, I couldn't take a shower becuase of this valve. That's the first time I realized I had them.

 

[pinion9]

Originally posted by: Howard
Shouldn't you cast the tube in cement or something?

Normally. That is for a wet install. It gives it the thermal mass. However, you can do a dry install. You use bigger tube and more of it. I am using half inch tube 8" on center. And then you put this low-e reflective insulation (about R-10) below it.

 

[Armitage]

Originally posted by: KK

Originally posted by: Armitage
I like it so far - but then, nothing is done beyond running the lines and pressure testing it, so it's hard to say. I ran a separate line for everything, including each of the double sinks. But then, saving one or two connections wouldn't get me down to the next smaller (cheaper) size, and one of the reasons I'm doing it is to minimize interference between connections - ie. not getting scalded in the shower if somebody flushes the toilet!

Get some of those shower equilibrium pressure balance valves. When I had to shut down the hot side when my manabloc cracked, I couldn't take a shower becuase of this valve. That's the first time I realized I had them.

Well,, that's not the only reason I put it in - it was a whole lot easier then running copper to everything. And it's already in, so I'm not changing it now!