Radiant help

[cabin_11358]

I have been remodeling a cabin in the mountains. We decided to put in a hydronic radiant floor heating system. I designed the system based on a decent amount of online research. It is an open direct system using a takagi t-h3-dv-p. I have 2 zones. One for the upstairs the other for down. Zone 1 is made up of three 250-275 foot loops. Zone 2 is 4 250-275 foot loops. Each zone has a grundfos alpha to pump the zone. The problem I am having is the the flow rate seems to be low, Zone 1 is maxing out around 1.9 gpm with a delta T of 20 degrees. When I switch the function on the pump to the high setting the flow does not increase and the pressure relief valve pops. Where should I start to look for the problem?

 

[Jadnashua]

What size pex tubing did you use? ANy possibility that there's a kink in the tubing somewhere?

 

[Sponsor]

 

[cabin_11358]

What size pex tubing did you use? ANy possibility that there's a kink in the tubing somewhere?

1/2" tubing. There are kinks in the line I can see them all.
edit no kinks

 

[Jadnashua]

A kink will significantly restrict flow. If it's pex-A, a heat gun and some tweaking may restore the tubing to full diameter. If it's pex-b or -c, you have to cut out the kink and insert a fitting.

 

[cabin_11358]

sorry there are no kinks I got distracted while responding