What size pipe for 600' radiant loops?

bruce_21

I am designing a radiant floor for a huge warehouse like space. The building is 450' long and 75' wide. I want to bring all the loops back to a boiler room located in the middle of the building on one side. The longest (because of crossing the width of the building) loops will be about 630'. I'd like to use several small pumps rather than one giant one to move the water. I seems I can have 4 loops on one 007e pump. I'd like to use 3/4" pipe for ease of installation, but I'm not sure if the head required can be supplied by the 007e's.

Gordy

Need to know flow rates , and water temps required for the loops in question.

JohnNY

A 630-ft radiant loop? Is that smart?

Gordy

Not in my opinion. However it is a warehouse, and high loop deltas may not be a concern. However circulator size, and energy usage may be. 3/4" pex is the user choice. Nailing down a head loss needs more questions answered.

That's why digging for details. Is glycol going to be implemented in the system is another question.

Tinman

Like Gordy said, need more info but 600' is pushing it with 3/4" pex.

Tinman

And how far are you willing to push the delta T?

STEVEusaPA

I think the obvious, easy solution is to just put the manifolds where they need to be for smaller loops. They can be locked in a cabinet.
I'd rather run supply/return copper pair for each manifold then the logistics of trying to home run 600 feet of tubing.

Paul Pollets

600 ft loops of 3/4" pex are difficult to install, not to mention the increased pump sizing. I'd go with 5/8" pex and remote manifold locations.

Gordy

Shorter loops are always a plus. Both in maintaining reasonable deltas, and keeping head loss down in ecm circulator capabilities. Let alone wrestling 600' of pex not once, but many times.

However since the OP is designing this system I'm willing to listen to possible logistic concerns of keeping everything centrally located.

Solid_Fuel_Man

Can you place manifolds in each corner of the building? That way you can pipe overhead in copper or iron from the boiler room. I have done a large building like this and it worked out well. 400' gives a reasonable head on 3/4 pex. I would not go over 450' under any circumstance. With the multiple manifold piped overhead (or fed by larger dia pex through slab) you can use a circulator for each manifold.

hot_rod

600' would work out of a coil better. Or two 500' out of a 1000' coil.

Usually with long loops like that it is out and back, not that hard to run a single loop 600' with 3/4" in a large space.

The Radpad shows
3/4 at 12" OC 20 btu/sq. ft 1.2 gpm at 7' head per loop.

A great application for mini tube injection to a remote manifold.

Good thing with warehouses is you can run higher supply and large delta T. Counter flow the loops for best slab temperature consistency.

Zman

If the location of the remote manifolds is an issue, you can use traffic rated in slab manifold boxes. You can run under slab pex supply lines to two boxes and feed the center from the mech room.
Breaking the buildings into thirds should enable you to run loop lengths of more like 400'. At 2' centers you would have 56 loops or so. That would take a whole lot of 007's.You could run a circ for each manifold, it would just have to be a bit bigger