Determining loop lengths

JimmyJam

Any suggestions on how to determine loop lengths already installed in slab? I was called out to determine why a 10 year old radiant floor heating system has never kept up in cold weather, I found an office area of approximately 750 sq ft, 75' away from supply and return manifolds to be serviced by (2) 1/2" loops (or so the owner states). The loops are supplied off the same manifold as a 1,700 sq ft. shop area that he has valved off as equipment in this area produces enough heat for this area. (This area we believe is serviced by 5 loops of 1/2" tubing.)Copper fin boiler was installed about 6 years ago and of course trips on limit when office area calls for heat, previous contractor has (2) 26-96 pumps in series which tells me???? So to make a long story even longer, is there any way to determine loop lengths that may have been installed for office area? I will need to replumb manifold system but want to determine whether I can correct office heating problem with installed loops.

Thanks for any help!

hr

You are in luck

with compression fittings on the various loops you could disconnect and use a garden hose to fill and purge a loop. Then use an air compressor to blow out the water into a bucket and measure the amount.

Make sure you have a compressor with enough fizz (pressure and cfm) to completly blow out the water.

The water can then be converted into loop length. 1/2" pex (1/2" id) holds .920 gallons per 100 feet of tube.

hot rod

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JimmyJam

Thanks Hotrod!

This is why I visit this sight so often!!!! Does anyone know what the manufacturer is of this tubing? It looks similar to Rehau but has a deeper reddish color to it and I have not pulled off manifold to see if it is PAP pipe yet.

hr

Looks a lot like

DuraPex. It was also sold under the Heatway or Watts Radiant name for awhile. It was sold as a non barrier plumbing tube, dull finish no EVOH barrier.

hot rod

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mike parnell

loop lengths

are there any labels, markings on the tube?? the tupe if been installing is labeled every two feet from 2 ft to 600 ft,if your lucky enough to read them you could figure out the loop length. good luck..........mike