Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

Balancing radiant floor heat

petrs's Avatar

Join Date: Dec 2008
Posts: 18

02-06-09, 06:35 AM   #1  
Balancing radiant floor heat


I have question about balancing radiant floor heat.

Last summer I installed radiant floor heat in my 2 floor house. Each floor consist of three loops, each loop about 300 ft (+/- 5 ft) using " PEX tubing with oxygen barrier. Each floor uses its own pump that is set to the medium speed (3 speed setting). The tubing is stapled under the subfloor, I used aluminum distribution plates (on the 1st floor almost continuously), then reflective aluminum foil, R19 insulation under 1st floor and R13 under 2nd floor. Under the 1st floor I put one more layer of the aluminum reflective foil simply since I had a lot of left.

Since the 1st floor is over unheated basement and garage I had little trouble reaching the desired temperature and I was thinking to add 2 extra 300' loops under the 1st floor. My question is how it will be with the balance of my system. I would have 3 loops (300' each) in the 2nd floor and 5 loops (300' each) under 1st floor + maybe a little baseboard radiator in the basement. Currently I had 3x300' under each floor so when both zones were open the flow was distributed evenly into each floor.

Sponsored Links
Furd's Avatar

Join Date: Mar 2006
Posts: 18,332

02-06-09, 04:46 PM   #2  
I personally feel that 300 feet of 1/2 inch tubing is way too long for a loop, I would prefer to see no more than about 100 feet in 1/2 inch and maybe 150 feet of 3/4 inch as the maximums.

Be that as it may. All the loops of a particular zone should be made up to a manifold and they should all have the flowmeter (actually rotameter) fittings to allow precise flow adjustment on each individual loop.

Search this Thread