Radiant Manifolds - Harv

Harv

What type of manifolds do you prefer when doing radiant. I use Wirsbo tubing. Some guys use the Wirsbo valved manifolds. Others chooose to make their own with Alberta tees and ball valves. They install thermometers so they can balance by temp drop. They claim it is less expensive this way. Others use alberta tees and no thermometers. Not sure how they balance the system. I am about to do a job with four zones and 16 loops. What do you guys like. I am leaning towards wirsbo valved manifolds on one side and unvalved on the other. Then balancing with the caps the Wirsbo way.

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heatboy

Flow meters

Why not use the valved on the return side and their flow meter manifold on the supply side? That way you can adjust flow directly while having the advantage of positive shut-off on every loop. Yes, it will cost more to buy, but making your own manifolds is labor intensive so it may not cost close to the same in the end.

hb

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M.D.

Radiant Manifolds

I was the Wirsbo Rep in my area from 1988 thru 1996 and learned a lot about balancing manifolds. Long story short, there is too much concern placed on balancing the manifolds. The computer says: Loop #1-2.3 turns, Loop #2-3.4 turns,...etc. I wasted a lot of time and miles on balancing problem jobs because of erratically controlled heating systems. I don't care what the blueprints say is going to be used for building materials, something is going to change, wood, tile, carpet, insulation, or whatever, before we start the system up.

The fix was quite simple:
(1)keep loops dedicated to one type of floor material/covering above.
(2)Keep loop lengths as close to equal as possible (if, say, a bathroom has a 125' of tubing while the rest average 250', an initial adjustment of the balance valve will be in order)
(3)Fully open up all of the balance valves at start-up. If some area overheats, throttle back as necessary.
I hate to disappoint anybody out there, but my designs have been working extremely well for all these years.

I think Wirsbo Manifolds are fine and certainly deliver the quality that goes with their name, but as with most brass manifolds, they are expensive and mostly unnecessary. It is, however, good to have a throttling valve on one side to balance or isolate when necessary.

I now use copper manifolds. For RFH systems, 1" copper with 1/2" drops. One side with Dahl Ball Valves, the other without. I offer the drops in plain, crimp, or male thread. I use Danfoss Zone Valves and Motor Heads on the manifolds when multi-zone systems are called for. For Snowmelts I offer 1 1/4" copper with 3/4" drops, ends are the same as above. Their not real "showy", but contractors know how to use them and put them together. A $.59 end cap on one end, and whatever one likes on the other side is probably on the truck. Did you ever lose a gasket on the job-site? The manifolds I supply are manufactured by Precision Metal Brazing, Inc. and are very well priced. There are many others out there as well.

The bottom line, to me, IS the "Bottom Line". In the earlier days of the resurgence of RFH the close ratio of jobs in my area was probably somewhere around 2 out of 10 quotes ending up as a sale. It's more like 9 out of 10 today. I don't believe in cheap systems, I also don't believe in expensive ones.

Heatermon

Manifolds

We use Rehau's "Pro-Balance" manifolds because they have flow gauges so you can actually "see" the water flow through the individual circuits. They do cost more, but if you make your own, it's hard to make them perfect and you spend alot of time trying. Manifolds and tubing are the two most important parts of your system - Don't skimp. Being able to "see" the flow can be very valuable, especially when the system is acting up. We have sold many customers on our systems with these manifolds. They look "professional" and "seeing is believing". I have noticed other manufacturers are now offering "sight gauges" as an option with their manifolds. I think it's a trend that will continue. Good luck with your project.

Heatermon

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heatboy

Points taken.

I also use copper manifolds under certain conditions. Big areas, with little chance of future zoning and where loop lengths are reasonably close. Ball Valves without an actual balancing port are of little use for anything but shutting of flow. Ball valves were never designed with the intention of balancing in mind, even though people and some manufacturers seem to think so.

I have found that balancing of loops from a manifold when reset systems are involved is less of an issue than with a bang-bang approach. I agree with you that on initial start, let the loops wide open then adjust down if needed.

With me, the bottom line is never the bottom line. Never compromising a clients system just so he will buy it, is my bottom line. I don't get all of the clients, but I get most of the ones I want.

hb

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