Joist trak radiant tube length in last bay

[George C]

I'm installing my first radiant floor system using 1/2inch tubing and joist trak plates. I purchased a 1000 foot roll of tubing and cut it into 5 200' pieces. While running my loops, I'm finding there is either extra or not enough tubing to complete the final bay. I'm able to complete 5 bags but end up with enough tubing left over to complete half the 6th bay. My question is what do you do? Do you complete the 5th bay and cut the remaining creating a shorter loop and undesirable waist or do you complete half the 6th bay and finish it up on the next loop?

If you were to finish it up on the 2nd loop, would it be desirable to go to the end of the 7th bay come back up the 6th bay halfway meeting the hose from the 1st loop and go back down the 6th bay where you would then come back up the 7th bay?

I'm trying to keep loops even while minimizing tubing waist and extra loops, any help would be appreciated.

 

[Jadnashua]

One thermostat controlling all? If the loops are not equal, you may need to use valves on the manifold to balance the return temperatures, but it doesn't hurt. Not sure it's the best idea to cut it prior, but calculate things a bit to try to get them approximately equal so you don't end up with a lot of waste or come up a bit short.

 

[Sponsor]

 

[Cacher_Chick]

There should be extra loops in the bay adjacent to the outer walls, this is why it is best to start there and work inwards.

 

[George C]

One thermostat controlling all? If the loops are not equal, you may need to use valves on the manifold to balance the return temperatures, but it doesn't hurt. Not sure it's the best idea to cut it prior, but calculate things a bit to try to get them approximately equal so you don't end up with a lot of waste or come up a bit short.

Yes I agree, I should not have cut it, so I will couple or replace that piece.

1 thermostat for this zone is all that is desired.

Yes I will use adjustable manifolds. What is the max number of loops with approximately 200 ft per loop on a manifold/ circulator recommended?

 

[Jadnashua]

The max number of loops will depend on the size of the manifold and the size of the pump. Something outside of my expertise to specify. The design will require a certain gpm flow rate to satisfy the heat load. There's a design goal on maximum flow rate, and multiplying that by the number of loops would determine the size of the pump.