Heating Help

Radiant loop blocked.

OK here's one we havent seen before. 3/8 heatpex in sandwiched application, between subfloor and 3/4 t&g flooring. The flooring is finished and one of the loops is completely blocked wont pass 120psi air through the loop. inspection of subfloor entry/exit shows no visible kinks or problems. layout of the loop was on 8" centers. With the loop open (no manifold connection) no air will pass at all. Has anyone used nylon fish tape to try and locate a block like this? This would minimize how much flooring to remove in order to locate the block. Loop is about 220ft. Any ideas would be great.

Thanks in advance....

What type

I think it is kinked.
What kind of "sandwich" is it?
Carl

Radiant sandwich

Sandwich is: shiplap subfloor, aluminum flashing, 1/2" plywood, then t&g flooring. It's basically making your own warmboard. Groove spacing on the plywood for the 3/8 heat pex and routed returns on 8" centers

Radius

How are the radius's secured? I have seen 3/8" pex kink after working fine for a while. My theory was that the expansion and contraction of the tubing eventually tightened the radius and caused a kink. That is where I would start looking.
Carl

Radius

They are just pushed in to the routed channel. The flooring holds them down. The re has been no water in the system. This is completely dry.

Is the tubing...

Heatway EPDM rubber or pex.? I have seen Heatway clog plenty of times. Did a nail puncture the tubing and then clog up w/ rust?

Radiant loop blocked

I don't think it can kink in the tracks. If it did kink, it must be in the area between the panel and the manifold. Is it possible that debris entered the tubing during installation?Have you tried pushing air from both sides? The supply and return aren't mixed up?
Carl

Found the block

Thanks all -

It was totally kinked as it passed through one of the joists.