Hydronic in floor loop lengths messed up by contractor

tracs

I am having a 40x60 thickened edge slab poured. The contractor installed the 9 loops of 1/2" pex this weekend while I was away.

I had given them a LoopCAD plan to follow. All 9 loops were to be 265'-282' in length.

I have discovered the spacing must have been slightly off on the 8 loops and on the 9th loop, the total length is only 100' or so!

The other 8 loops and the general spacing look fine. I haven't checked the footage markings on the other 8 loops, but I am hoping they are in the acceptable length range.

The pex is stapled to the foam and the rebar is placed and tied so there is no way they will take it all apart and redo it. Especially since this is a "off the books" job for them as they work for a large company.

So my question is: Since I have a 1" manifold that has flow gauges and flow controls for each loop, can the system be adjusted once running so that all loops no matter the lengths have equal flow?

The 9th loop which is the shortest by over 1/2 of the others is the west loop in the building that runs along the 40' wall which will have the overhead door and entry door. Cold, cold winters here, so maybe a overly hot loop wouldn't be a such a bad thing?

I haven't brought up my concerns to the contractor yet as it is a holiday here today.

hot_rod

yes you can balance down that short loop. The gpm required on the long loops from the design? Maybe .50- .75 gpm?

Balance the short loop to about 1/2 the long loops.

DCContrarian

Balancing down the short loop shouldn't be a problem. I'd be more worried they made the other loops too long.

tracs

https://forum.heatinghelp.com/discussion/comment/1807522#Comment_1807522

I had 9 - 300' rolls. So at least they didn't go over 300'.

GroundUp

This is a very common mistake from contractors and DIYers alike. If you bought 2700ft of tubing, there is no reason not to put all 2700ft of tubing in the slab. The LoopCad program is nothing but an algorithm to fit X tubing to Y space with Z spacing. The reality is that spacing needs to be checked and potentially adjusted several times with every loop, in order to have a proper system. It's unfortunate that there was so much waste from an incompetent installer, but hydronics is very forgiving and there should be no issues with what you have installed heating the space adequately. As you've surmised, yes you can absolutely throttle that short loop back to match the others (or close) and you'll never notice any difference. Potential lesson learned for next time!

tracs

https://forum.heatinghelp.com/discussion/comment/1807541#Comment_1807541

My wife said "before you go off on the contractor, find out if it will be fine".

Thanks for the reply.

HomerJSmith

Sensible, wife—Keep her!

Dave Carpentier

Hoping the pipe spacing in the overhead door area was decent.

Ive got a pic around here somewhere, but from memory I did 3 passes with 6" spacing and then started doing the 12". It touches -40 now and then but my design temp is -21f. No issues with water freezing near the door.

tracs

https://forum.heatinghelp.com/discussion/comment/1807588#Comment_1807588

The loop that they messed up is the one by the overhead door. The spacing is tighter around 8"-10".

GroundUp

The overhead door is often the worst place to have tight spacing. The "tongue" that hangs outside is a constant heat soak, and tends to melt snow during a heat call then freeze over after the heat call which can leave ice chunks or tear off the weatherstrip when opening the door. I made this mistake in my first shop and fought it for 15 years. Ever since then, I keep the tubing back from the OH door at least 18" to avoid this issue.