radiant tubing

[racer1]

Hi all, Part of my house is a slab with radiant tubing. The other half is basement with floor trusses for upstairs. I want to run staple up tubing between the trusses for upstairs. With all the plumbing and electrical there isn't room to run long runs of tubing at a time. If I did each truss, 65 ft. of tube, I would need to put a splice to join to the next truss. Would that be ok? I'd need 4 splices per zone. Is that just asking for trouble? or no big deal?...Thanks

 

[mygarageone]

If they will be accessible go for it , joints are never desirable but some times necessary.
Just mark where they are on the joist or a PC of paper for future reference.

 

[yeldogt]

Do some research on the staple up -- you will not get a lot of BTU's out of that type of system.

A proper load calculation needs to be done. I used AL pipe and extruded heat plates ... and I still had to run hotter water than I anticipated. I installed a supplemental Runtal unit in one room.

 

[36truck]

I did my upper floor using light weight gypecrete. Poured 1" thick over the pex pipes. Works great give you a good heat sink. Staple up has a very low BTU through the floor plus over heating the sub floor.

 

[mygarageone]

Do some research on the staple up -- you will not get a lot of BTU's out of that type of system.

A proper load calculation needs to be done. I used AL pipe and extruded heat plates ... and I still had to run hotter water than I anticipated. I installed a supplemental Runtal unit in one room.

Load calculation in radiant heating mostly apply for the boiler size , the standard spacing for all staple up is 8" centers , unless there are some very unusual situations.
Never go less than the industry standard of 8" centers for staple up., I have been on many jobs where they thought they could get away with less. And having to do it all over.

What water temp did you think you needed . I have staple up , insulated floor joist and I'm running low temps. You need to insulated the joist cavity or it won't work as intended.

You don't give enough info to determine what's wrong.

 

[BadgerBoilerMN]

When designing radiant floor heating systems we start with a room-by-room Manual J heat load analysis. This is the only way to determine what, if any, radiant floor system will work.

It is particularly crucial to run accurate heat loads when using sub-floor or sandwich applications. Unless you are living below the Mason/Dixon a true "staple-up" is unwise, requiring higher water temperatures often coming up short of the required output.

Here in Minneapolis, and designs for others in cold climates, we use extruded aluminum plates almost exclusively and haven't used a bare tube, stapled to or suspended from, the sub-floor since 1991.

As far as couplings go, it is expensive and less than ideal. Thread the pipe where you can and use 3/8" PEX if you know how.