warm board

Greg Swob

Haven't used this product, but am considering for a retrofit project. Anyone have comments of the link below?
Surely this is an isolated situation or "The rest of the story..." has yet to be told.

http://hvac-talk.com/vbb/showthread.php?threadid=53325
Thaks-
Greg

Alan(CaliforniaRadiant)Forbes

Warmboard issue

Air noises? I think the noises from the Warmboard were from rapid expansion and contraction of the aluminum skin when there was a call for heat.

The noises went away when the system was modified to constant circulation, i.e. outdoor reset where water temperatures changed gradually as a function of the outdoor temperature.

A good lesson for all of us to confirm the benefits of outdoor reset.

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Terry Alsberg

Noise

Noise is caused by movement of air at a rate faster than 20 cycles per second but slower than 20,000 cycles per second. Expansion of aluminum, PEX, water or other components in a hydronic system, even when shocked by on/off control systems happens over minutes not tiny fractions of a second. Test this yourself. Take an aluminum frying pan. Place it on a burner set at high. It will accelerate in temperature far faster over a greater range of temperature than any radiant floor ever sees. Yet it will make no noise. The aluminum surface of Warmboard makes no noise merely because it expands while heating up (nor for that matter does any other radiant panel).

When we have had noise associated with a Warmboard installation it always has been either, 1) Air bubbles colliding or popping in a tube or, 2) tubing moving in a channel. Warmboard itself cannot and does not make noise. Leaving air noise aside for now, in order for the tubing to make noise from movement in the groove, several conditions need to coincide.

First, per our installation instructions, tubing needs to be glued into our channels using the right amount of silicone and the right amount of pressure (typically applied with a heavy roller). If there are voids in the silicone application or insufficient contact with the wet silicone prior to curing, the first condition for noise is met.

Second, tubing with an EVOH coating for an oxygen barrier has a slightly tacky surface quality. I heard one tubing manufacturer who was well versed in the noises that tubing can make describe this surface as a slip/stick surface. When it slips then suddenly sticks, it makes a clicking or popping noise. This slip/stick surface quality is the second condition that must be met. There are several oxygen barrier tubes available without an EVOH outer surface which are more waxy in nature. All non barrier tubes, appropriate only in non ferrous (non corrodible) installations, also have that same waxy outer surface. Use of any of these kinds of tubing eliminates the possibility of noise.

Third, the supply temperature must be relatively high and the cycling in the tubing must be relatively sudden. Outdoor reset and control strategies that lower supply temperatures and more closely approach constant pumping reduce shocks to the tubing.

In summary, if any one of the three things above are done right, installations that include Warmboard are quiet as church mice. If all three things are done wrong, some noise is possible. Even so, given the huge amount of Warmboard sold over the past six years, we are gratified that noise issues have been very rare. But rare though they may be, we take each instance seriously even though we know it is not our panel that is making the noise. In the particular instance cited above, we made numerous visits to the job site in Michigan which was no mean feat for our region manager who lives in Minnesota or our distributor who is several hours away by car. We brought in John Seigenthaller as a consultant as well. As I understand it the problem was solved by purging air out of the system and changing the control strategy to outdoor reset and constant pumping, per the suggestions in this thread. And now you have the rest of the story.