Radiant in-floor heat noise

DL

Our house is 1.5 years old. It has PEX pipe in the floors (wood floors with gypcrete surrounding the PEX).

Every night I hear once or twice a clunk sound from a certain floor. Once I heard it from downstairs (same spot).

Is it highly unusual to hear a clunk sound or do radiant floors sometimes make noise when expanding/contracting?
Could there be air in the loop?

The house also has an HRV system. Could it be that which is causing the noise?

Thanks

Justin Gavin

Talk to the Designer

It depends on a couple of things.
It may be expanding and contracting and hitting a return bend (a piece of plastic that is hollow that helps maintain a semi-circle as the tube is bent) or a similar piece of plastic that is used to protect the PEX in an expansion joint.

With that said I can't see that would make that loud of a noise.

Talk to the designer/installer and see if they took picures of the tube layout before the gypcrete was laid. Than go to the spot where you heard the noise and you should be able to figure out if that is what it is.

If it is there isn't anything you can do about it other than leaving that zone's temperature up so it doesn't expand and contract.

Also if you have flow meters on your manifold check the meter to see if it fluctuates often when the zone is on. If so it may indicate air in that line and you would have to bleed it out of that circuit.

Good Luck.
Justin

Wayco Wayne_2

Does the sytem

have constant circulation and outdoor re-set? Both of these can help stop expansion noise by making the temp changes more gradual. Worth the investment.
WW

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Uni R

Zone Valves

Is your house zoned using zone valves?

DL

To answer a couple questions:

Yes, the system has 8 or 9 zone valves (silver Honeywell boxes in the mechanical room).

Yes, I have outdoor reset through the Tekmar 363.

I have a feeling it isn't expansion noise as the noise is relatively loud and a fast sound. Like the sound you would hear if a big mouse ran 3 feet inside your wall. (no, I don't have mice).

Could air in the PEX line cause this sound?

Thanks

Mike Kraft_2

Sounds like............

the noise maybe related to your zone valves.Lets say you have more than one zone calling.One of the thermostats become satisfied and the zone valve closes.The other zones are still circulating water through them and the valve is quickly closing the zone that is satisfied.As this process is happening the port is becoming narrower until the valve is closed.At that specific time the tubing will absorb this pressure differential.And ..........BANG!Your noise.

Experiment..turn 3 stats on.Go down by the zone valves and have someone turn off the zone you think is the banging zone.Then listen closely to the valve.Plese report back .

this is something that can be remedied and is not uncommon........That is if I'm correct!

cheese

DL

This seems to make a lot of sense. There seemed to be some pattern to the noise. Each night when I went to sleep I would hear the noise within an hour. Perhaps the zone that had a timer thermostat (for bathroom floors) was always closing around that time.

I hope I can figure out the procedure you are recommending.
Will let you know later, if it work out. Thank You

DL

What should I hear at the zone valve (if it is the banging zone)?

And, what are possible remedies?
I just read on another thread something about this too.
It appears that having the zone valve on the return (rather than the supply) is the way to go.