Ticking and clicking radiant heat system

a03vancouver

Hi all,

Please excuse any noobie questions and statements I might make as I'm new in the community. I've read a number of posts about this topic but have not determined the best course of action.

A house we recently purchased has radiant heat in the upper floor by way of aluminum heat transfer plates screwed directly into the subfloor above. It's hard to identify the tubing type, but I can tell that it's not PEX (more of a peach colored opaque pipe). The transfer plates look to be lightweight bent aluminum sheet type (not "extruded" or anything "heavy"). I'm able to identify this because the basement is unfinished below (about 50%), though insulated in the basement ceiling.

The issue: While the system is great, it's relatively noisy in some parts of the house. When the boiler turns on, the pipes immediately start ticking rapidly (expansion) and this is followed by long periods of contraction noises when the tubes cool down. I think I've isolated the sound down to the pipes rubbing up against the transfer plates.

As we are preparing to finish the remaining part of the basement, we have a chance to remedy the situation, but would like to determine the best way of doing so that is cost effective. 

So far I have considered (but have not tried):
-rtv silicone between the pipe and heat transfer plates

-some type of low friction paper or tape between the pipe and plates

-maybe discussing possibility of lowering temps or using a mixing valve with plumber to slow down expansion

Thanks in advance

EdTheHeaterMan

That type of system that type of installation Will never be noise free. It all has to do with the length of the tube and in which direction it can possibly expand. Unless you completely re-design how the loops are installed so that there is room for expansion (Which is unlikely) The noise is always going to be there.

The only real remedy is constant operation with outdoor reset. By constantly operating the pump, and raising and lowering the temperature of the water in the pipes slowly, the expansion noise will be very subtle. An outdoor reset control will raise and lower the temperature of the water inside the tubing based on the change in temperature outdoor. Since that change is somewhat gradual the water temperature change in the pipe will be also somewhat gradual. 

outdoor reset will basically stop on/off cycling. Your noise is coming from a rapid change in temperature inside the piping/tubing. Eliminate cycling of the pump, then the continuous flow of water and the gradual change in temperature will substantially reduce the noise.  Then, when you hear the subtle noise of expansion, that you will eventually get used to, you will have a good warm feeling subconsciously. Like Pavlov‘s dog test, just that subtle noise of the pipes expanding will make you feel warmer, even if the temperature doesn’t change.   Delete that last sentence.  I'm not a phycologist.  It was just an opinion. LOL

hot_rod

As Ed mentioned. Two sources of noise, the loose fit of the tube in the thin aluminum, silicone may help, but a very messy job.
Then the thin plate itself trying to expand. it's called "oil canning"
One radiant tube manufacturer suggested stapling only one side of those thin plates to allow them to expand. But that sort of eliminates the purpose of them plate to give you good conduction transfer.

Outdoor reset can help a lot, a true constant circulation would be a bit better, but involves some repiping.

mattmia2

You could try securing the plate with a large hole with a washer over it and not screwed tight so that the place can slip in the hole sort of like the slots in vinyl siding. The tube to the plate maybe silicone grease but I don't think there will be anything cost effective for the tube to the plate.

a03vancouver

@EdTheHeaterMan Thanks Ed - from my reading I knew outdoor reset ("OR") would probably enter the conversation and will look into its benefits and have it implemented by the plumber. Being a layman I wasn't able to idenfity an OR by looking at the boiler so I went looking for an outdoor thermostat on the north side of the building (didn't find one). So will follow up on that. I had an idea that OR was beneficial from an efficiency perspective but didn't know it would help the noise side of things. 

About the constant operation - how feasible is this to implement in an already existing ~ 28 year old system (I know I've not given much information about my system - maybe a picture could help), and is is more expensive to operate?

P.S. The Pavlov theory is in full effect, but my family members seem to be getting trained in the opposite direction..
Ticking --> Nagging 😂

a03vancouver

@hot_rod I'd considered the idea that the plates themselves were ticking but this noise seems to come out of 2-3 very specific spots in the house (I.e if it was the plates, it would be all of them... right?). Since it's a localized issue I've started to think that all the expansion is causing movement in the tube in those few areas. This is why the "solutions" I tried to throw out there focused on patch fixing those areas.

You mentioned loose fit. Can a stronger "hold" on the tube really prevent expansion noise? My understanding was that expansion can't really be "stopped" but only accommodated through extra spacing or interfacing through different materials.

mattmia2

Is the boiler a conventional boiler or a modulating-condensing boiler? With a conventional boiler outdoor reset needs to be done with a variable pump or modulating valve. With a mod con it can usually be done with the boiler controls.

STEVEusaPA

If you have the ceiling open it's a good time to watch it in action and see where the problem may lie. It might not have room for expansion, or someone may have clipped the end loops, not allowing expansion.
So fixing those issues may help, along with the above-mentioned ideas.
Lowering the SWT would also help lengthen the cycles, as long as your boiler and control systems will allow it to be done properly.

EdTheHeaterMan

a03vancouver said:

@EdTheHeaterMan Thanks Ed - from my reading I knew outdoor reset ("OR") would probably enter the conversation and will look into its benefits and have it implemented by the plumber. Being a layman I wasn't able to idenfity an OR by looking at the boiler so I went looking for an outdoor thermostat on the north side of the building (didn't find one). So will follow up on that. I had an idea that OR was beneficial from an efficiency perspective but didn't know it would help the noise side of things. 

About the constant operation - how feasible is this to implement in an already existing ~ 28 year old system (I know I've not given much information about my system - maybe a picture could help), and is is more expensive to operate?

P.S. The Pavlov theory is in full effect, but my family members seem be getting trained in the opposite direction..
Ticking --> Nagging 😂

. LOL
Now to implement constant circulation, just wire the circulator directly to the power. (maybe with a manual switch for service and summertime),

The outdoor reset control can be connected to a 3 way modulating valve or a 4-way modulating valve or a variable speed injection pump. Set the reset curve as needed to keep the room comfortable. If it gets too hot, then a room thermostat can shut down the burner and/or just recirculate the floor water with no heated boiler water added. When the room thermostat calls for heat again then the boiler can start adding heat again. There are more sophisticated control systems as HotRod Bob has indicated above

If your boiler is a modulating condensing boiler (usually a newer wall hung, but I have installed floor models as long ago as 2001) then the boiler control should have a location for the outdoor temperature sensor to be wired in. Then it is just a matter of selecting the reset curve.

hot_rod

Dale spent some time and R&D on designing the ThermoFin to have a very tight fit to eliminate any noise. Tight to the point that you need to drive the tube into the channel. A palm nailer if you do a lot of it.

The oil canning sound you can watch in action, the plate moves or distorts. Hard to say why the noise is localized.

How many zones do you have?

Here is the constant circulation method. A 3 way zone valve. It does cost running a circ, I use ECM circs so at the most 43W. An inexpensive amount to get a good nights sleep. Constant circ does even out the floor temperature also, much less striping.

a03vancouver

@mattmia2 See images, I believe it's the original ~28 year old conveniental boiler.

I'm seriously considering the following now:

1) Some type of lubricant or sealant (high flexibility pure silicone? I don't want to affect the piping) between the pipe and plates. Why? I've isolated my issue to a few plates and the noise seems to happen where the plates are somewhat bent and are allowing the pipes to "slide" during expansion. As an experiment it may be worth it. I'm hesitant to leave a side of the plates open because that will reduce heat transfer.

2) @EdTheHeaterMan Outdoor reset / constant circulation: After reading this seems to be a bit of a no brainer. At this point I'm not sure if it's already in my system. I will check with the plumber or if someone here could help point it out from the pictures. I see some temperature leads and a manual mixing value but I think that's for adjusting the tap water temps?

3) @hot_rod New plates. This is lowest on my list because the issue is localized to a few plates as I mentioned. Another thing I can't wrap my head around is how a tighter hold can prevent noise. We know a plate can't prevent expansion.. or can it? I may still inquire about pricing on the Thermofin C, but I really want to avoid replating ~800 sqft. of the stuff. Maybe I can replace the "trouble areas"...

mattmia2

That valve with the knob and scale is a fixed thermostatic mixing valve, it produces the lower temp water for the radiant. It could be replaced with an outdoor reset control. You could also try turning it down until is just heats on the coldest day and see if that helps.

You could also try drilling a large hole in the problem plates at the corners and put a screw with a fender washer through that hole to secure it but don't tighten the screw all the way so it can slide under the washer.

hot_rod

mattmia2 said:

That valve with the knob and scale is a fixed thermostatic mixing valve, it produces the lower temp water for the radiant. It could be replaced with an outdoor reset control. You could also try turning it down until is just heats on the coldest day and see if that helps.

You could also try drilling a large hole in the problem plates at the corners and put a screw with a fender washer through that hole to secure it but don't tighten the screw all the way so it can slide under the washer.

looks like a diverting valve, one inlet, two outlet? Mixing valves are two in one out. But it must be doing its job. or is it?
I agree a motorized valve with actuator would be a nice upgrade to help reduce expansion.

mattmia2

Well, i was close. My point was that it isn't doing outdoor reset, it is a fixed setpoint device.

hot_rod

a03vancouver said:

@mattmia2 See images, I believe it's the original ~28 year old conveniental boiler.

I'm seriously considering the following now:

1) Some type of lubricant or sealant (high flexibility pure silicone? I don't want to affect the piping) between the pipe and plates. Why? I've isolated my issue to a few plates and the noise seems to happen where the plates are somewhat bent and are allowing the pipes to "slide" during expansion. As an experiment it may be worth it. I'm hesitant to leave a side of the plates open because that will reduce heat transfer.

2) @EdTheHeaterMan Outdoor reset / constant circulation: After reading this seems to be a bit of a no brainer. At this point I'm not sure if it's already in my system. I will check with the plumber or if someone here could help point it out from the pictures. I see some temperature leads and a manual mixing value but I think that's for adjusting the tap water temps?

3) @hot_rod New plates. This is lowest on my list because the issue is localized to a few plates as I mentioned. Another thing I can't wrap my head around is how a tighter hold can prevent noise. We know a plate can't prevent expansion.. or can it? I may still inquire about pricing on the Thermofin C, but I really want to avoid replating ~800 sqft. of the stuff. Maybe I can replace the "trouble areas"...

Think of pex embedded in concrete as an analogy for tight gripping plates. The tube in concrete cannot "grow" in length so expansion it handled in the wall of the tube. That is how the tube manufacturers explain it.

I remember back when it was Wirsbo, they offered an adhesive for the tube, we always asked for approved products to buy it locally. So you want to "fix" the tube, not lube it I think construction adhesive was too aggressive, I vaguely remember silicone was approved. Expansion should take place in the loop ends where the enter exit the plates, so never fasten that end loop tightly or restrict its movement.

Hopefully the tube manufacturers learned the thin plate lesson, and only offer extruded now. Most from the same manufacturer with the tight grip plates.