Radiant floor noise on startup only

rickgerv

I added radiant into my home -- installed under the subfloor of my existing hardwood floor. It uses extruded aluminum plates. The system heats well. There is an outdoor reset, proper mixing valves etc. Hired a reputable designer and plumber to do the complex boiler work. I used another contractor for the laborious floor work. One things he didn't do is use the proper plastic inserts in holes drilled in the floor joists.

When the system is running in steady state, it's noiseless and great. The issue is that when the room calls for heat the first time or being off for a while, there is 10 minutes of crackling.

In reading through other posts, the issue is either the pex expansion against wood or something with the aluminum plates. My designer has said the system is designed for constant circulation, leveraging an outdoor reset. So he said despite hole inserts not being there, most of the potential noise is alleviated. Given the system is mostly noise free, i assume he's right. But I'm a bit of a perfectionist.

1) can i insert in the plastic inserts if the pex is already run? I would have to remove the insulation. while tedious I can do it bit by bit. If the insert is continuous, then I assume not. perhaps I could splice them. If this isn't doable. Is disconnecting the pex and running the loops again a big deal? this covers about 900 square feet and 2 zones. Not ideal, but I can remove one side of the insulation to get to the pex and plates.

2) is there a way to tell if it's the plates that are the problem? it's not like these noises keep recurring in the same place so it's very hard to tell where it's happening. I notice that walking on the floors first thing in the morning, the floors seam stiffer (cracking) and noisier than usual. I did not go cheap on the plates. So it's not a flimsy plate.

3) what does constant circulation mean? is it that hot water always circulates no matter what the thermostat does? Does the temperature of the water simply drop even if the room stops calling for heat and but is basically circulating warm water 24/7?

rick

Rich_49

Constant circulation means exactly that or as close to , " on all the time as possible " . If your designer designed for constant circulation and the system was designed by others you need to get them together by whatever means necessary and brainstorm about the programming , setup , water temps to lessen or eliminate the rapid expansion you are experiencing . Plastic straps and the like may or may not make your nuisance noise go away . If the system is on / off that expansion will happen and should be allowed to happen .

Check to see if expansion loops were provided by the installing contractor , your designer may have taken it for granted that installer knew this is necessary .

Don't set back thermostats and fine tune the SWT numbers and reset curve .

Outdoor reset allows for gradual changes in SWT throughout the operating range so this noisy operation is lessened or imperceptable . Among other things .

A heat loss should have been performed and a reset curve should have been suggested by the designer . I think you have a disconnect between the installer and designer .

rickgerv

Rich. Thanks! What does 'Don't set back thermostats' mean? If I understand correctly 'rapid expansion' should be preventable if the water temps are not changing drastically. But gradual expansion is necessary.

Mark Eatherton

Rich is referring to programmable thermostats. Their operation and radiant heating are not compatible. Another possible option would be the use of non programmable non electric thermostats, along with a flat out door rest curve. I have those in two of my homes, and the systems are virtually silent.

Be thankful you didn't get talked into a bare naked staple up, or you'd also be seeking other types of help... Talk about NOISY.

ME

hot_rod

A crackling sound is often the plates moving around, sometimes referred to as "oil canning".

Are they fastened securely, about every 6" ? Are they tight against the bottom of the subfloor? No nails or screws keeping them away from 100% floor contact?

A ticking sound is usually the pex expansion or tube expansion in an under-sized hole.

rickgerv

Great points. I will listen more carefully if the sound is ticking or crackling. it's not isolated which makes it hard extremely hard to troubleshoot. I believe it's likely more cracking. I'm used to the sound of pex gradually expanding. I grew up with expanding pex in my parents house ... I recall it was tick, tick, tick and then after a minute would disappear. That's not what I'm hearing.

What I hear is a cracking sound here and then another sound at the other side of the room, and another somewhere else - very random . Like I said most of the time this is beautifully silent. But in these other occasions, it sounds like my grandma (god rest her soul) cracking her knuckles.

The plates are flush and pretty tight. That was checked thoroughly. A few nails actually penetrated the top floor when it was being done.

I don't have programmable themostats. I didn't want to spend on that as it takes too long to heat up the house in the first place. So I simply run it always at 70 degrees and never touch it unless I'm out for a few days and then drop it to 64. The thermostats are the old fashioned electric analog kind . Mark - when you say nonelectric - are saying the thermostat is battery controlled?

Mark Eatherton

rickgerv said:

Great points. I will listen more carefully if the sound is ticking or crackling. it's not isolated which makes it hard extremely hard to troubleshoot. I believe it's likely more cracking. I'm used to the sound of pex gradually expanding. I grew up with expanding pex in my parents house ... I recall it was tick, tick, tick and then after a minute would disappear. That's not what I'm hearing.

What I hear is a cracking sound here and then another sound at the other side of the room, and another somewhere else - very random . Like I said most of the time this is beautifully silent. But in these other occasions, it sounds like my grandma (god rest her soul) cracking her knuckles.

The plates are flush and pretty tight. That was checked thoroughly. A few nails actually penetrated the top floor when it was being done.

I don't have programmable themostats. I didn't want to spend on that as it takes too long to heat up the house in the first place. So I simply run it always at 70 degrees and never touch it unless I'm out for a few days and then drop it to 64. The thermostats are the old fashioned electric analog kind . Mark - when you say nonelectric - are saying the thermostat is battery controlled?

Google Oventrop non electric thermostatic controls. Or better yet, click on the add to the right hand side of this screen so Mr. H. gets credit!

It's like having your heat emitters on cruise control...

ME

GW

So you have a "fixed mix" install with a basic stat? If yoy want noiseless you want and need constant circulation. I have a Tekmar system for my house. Runs flawlessly. I'll post the model (main control and room sensor) if you're interested

rickgerv

I'm interested Gary. Please post. My system is still in the tweaking phases so perhaps my designer can benefit from this. He's supposed to get back to me this week on next steps and I explained the cracking issue. Hoping it's solvable. My wife and kids are a little creeped out by the noise. i do have a basic thermostat. Not sure what you mean by "fixed mix" install.

mark - thanks for the tip. I assumed the controls on the manifold assembly would do something similar. The designer is probably not going to appreciate getting advice from me through the forum but let's see how it goes.

GW

My house has a tekmar 402, motorized mixing, and a 552 room sensor. This is what we call fully modulating. The motor changes orientation several times a minute for exact water temps. "fixed mix' is just a term I use when the mixing valve is set in one position. It's the entry level of all possibilities.

Viessmann hawk eyes, yes it's an alpha, the boiler is getting about 4 gpm (or so the alpha says), the system works wonderfully. My house have very little heat loss, I don't recall ever seeing it running on the second bar in heating mode (the boiler output tachometer display), so I don't need the full rated gpm to get the max 91,000 BTU

I didn't use a Viessmann 200 and mixing station becasue i simply wanted to have options down the road with tying other heating units into the primary loop, like an oil boiler or a geothermal water to water, even solar.

CMadatMe

As long as you maintain the minimum flow rate Gary it don't matter. Think people get to caught up on maintaining those max flow rates for high fire to get the full load out of the boier. Boiler only going to go to high fire if its needed and as long as the boiler side delta-t doesn't get to about 60 all is good.

GW

Yes Chris, i'm aware of the ins and outs, it's the jobs that need lots of temp that things can get dicey.

Thanks, Gary

rickgerv

Update. Turns out this system was not designed for constant circulation. I got clued in on that when I saw the the circulator (may have the term wrong) was off for the radiant zone. I spoke to the designer who thought I had opted not to do this because of the added cost to implement constant circulation. I was price conscious in all of this so I can understand why he might have thought that. No sense finger pointing. Somewhere signals got crossed.It's not horrible. But it's a nuissance hearing the floor pop... the noises sound like a twigs snapping and knuckles cracking. He said it would be a pretty penny to fix... perhaps i address this another winter... but curious if someone could help me understand what it takes to put in a constant circulation system. I assume that would also run up the electric bill.

Gary can what you described be added in?

bmwpowere36m3

What kind of boiler do you have? I wouldn't imagine it'd take much…. maybe replace the circ with an ECM one (like Taco Viridian VT2218) and adjust the ODR. However more specifics of your system would be needed.

My system with panel radiators is near constant circ… I use Grundfos Alpha pumps due to variable pressure (TRVs) and it runs at a steady 25W (or so the display says). Older PSC circs are on the order of 60+W and I lucked out that my state was offering rebates for ECM pumps (basically cost the same as traditional ones, so no brainer). Haven't notice a difference on my electrical bill.

SWEI

rickgerv said:

I spoke to the designer who thought I had opted not to do this because of the added cost to implement constant circulation.

Added cost? Really?

Zoning costs far more.

GW

Yes these controls can be added. You need to have the mixing valve replaced though. If you post a pic of your current set up we would comment more.

Gary

rickgerv

Gary, I'm curious in your system (nice by the way), how much space are you heating. Is it all radiant?

GW

Yes, it's all 3/8" sandwich (above the deck), about 2700 sq ft. with 3/4" quarter sawn oak, plus tile with concrete board. R-19 in the basement.

I'm truly surprised the Alpha is moving all of the water. I have 3 manifolds. The one in the pic, an original (I had radiant before the big remodel, but it was staple up) maniold that is about 12 circuits I think (memory is fading), and a small 4 looper in the middle of the two manifolds.

It's nice, radiant is expensive, but when you're gonna stay put for the next 20-30 years, it's worth the freight!

rickgerv

designer is recommending Tekmar 356 and another pump to add constant circulation. I plan to talk to the plumber. I can't take the racket of the cracking. I'll have to bite the bullet. Next question is whether the whole house should be constant circ too. I have cast iron rads upstairs. Would their be a reason to have the 2nd floor be running CC? Can that be done with the same injection control?

Mark Eatherton

Constant circ is a European design term. They use a different technology called non electric thermostatic operators. Google Danfoss or Oventrop for some examples. You'd want to use thier remote cap tube control.

If your system is using conventional zone valves, it is difficult to perfectly create a "constant circ" system. Typically, the tekmar control is used to fine tune the temperature of the hot water supply to match the load perfectly to the point that the zone runs "nearly continuously." The controll will alleviate the temperture swings associated with the noises of expansion, but will not completely eliminate them.

You'd have to retrofit the remote cap tube non electric valves to the maniflds in order to make it a true constant circ system. It may take a lot of "tweaking" to find the sweet spot of operation, but it should alleviate the noise issue, but not eliminate it.

In general, constant circ eliminates any cold spots and provides a higher degree of comfort, without compromising system efficiency. The distribution pump used with a non electric system bases its operation on pressure differntial. As the non electric valves close, the pump senses this and backs off on its power consumption.

ME

GW

The 356 isn't the full boat, it's a canoe. It's better than what you have no (flippers), but it seems like your designer is so-so with this stuff. If you want the real deal you would want an indoor sensor. The 356 only takes an 'on-off' signal,

You could get a tekmar to do constant circ on your high temp system and your radiant, now you're getting into speed boat technology. Do you need to spend that much $ on your system? you probably just need to deal with what's ailing you, the noise issues

rickgerv

Gary, Appreciate the response. Not sure I follow the difference between the Tekmar 402 would do vs 356. I think you're saying it's the indoor sensor but not sure what that does. Is 402, 'the full boat'? Price differential isn't much between the two. I agree, I'm not looking to break the bank. Upstairs heat is fine - no noise. Objective is to find the most cost effective way to deal with the expansion noise.

GW

Yes maybe my boating terms are silly (I'm not a boater), I'll try and explain. If the topic is constant circulation you need to keep the water moving. Becasue you have high temp as well, you need a mixing valve. I presume you have a mixing valve.

I used the phrase "fixed mix". That means a simple on-off thetmostat, and you mixing valve doesn't move by itself.

The 356 is good but it appears to operate off of a basic thermostat. Sure, you could crank the start up and then fine tune the outdoor reset parameters on the tekmar. Also you'll need a new circulator to act as your injection pump. It's better than what you have for sure.

The 402 is better becasue it utizes a "Modulating mixing valve" when used with an indoor sensor (Not a basic thermostat ). Several times a minute the mixing valve moves, depending on whether the boiler is firing or not.

does this help?

SWEI

356 provides variable water temp based on outdoor air temp. You can turn it on or off using a thermostat, but recovery time may suffer unless you have a mod/con boiler with appropriate onboard controls that is properly configured.

402 will manage the water temp while monitoring the indoor air temp (even multiple temps) and make appropriate adjustments thereto regardless of the type of boiler.

rickgerv

Thanks Gary. Thankful to be able to bounce this off this forum. Without getting into specific pricing, would you be able to tell me relatively if 402 would be a lot more to implement? Price is higher but relative to labor, may be negligible. A few more details in case it explains the choice of the 356 - I have 3 radiant rooms that today are running of one basic analog thermostat. This was just temporary to test how radiant would work. Heatloss showed radiant wouldn't suffice but I wanted to see. Radiant is a champ but the water temps are getting too high (160) when the temp goes under 25 F. So plumber will go ahead and implement stage 2 of the design.

The update will be to add one 2-stage thermostat TH8320R1003. 2 rooms will have sensors that will be used to average out the 3 room temperatures. A secondary toe kick will be a second stage that will start when the radiant can't keep up.

So the change for the constant circ would be part of this update. I've blown my budget so trying to not get too fancy. The noise is an issue when the temperature has a big change and then the zone kicks back in...horrible noises that wakes up everyone. I vacillate on whether injection control is needed as 95% of the time it's quiet but when the zone kicks in, the noise is really that hellish. Normal pex expansion not an issue for me. It's the sound of the floor sounding like it's breaking that is unnerving. Sounds like twigs snapping. It's not the normal tick tick pex expansion.

On a side note - I've been rather amazed that with my current project of insulating the basement including new ceiling tiles beneath the R19 bat insulation, the first floor rooms have been able to retain heat very well. The first floor got to 73/74 (thermostat set by spouse). Water temp spiked up. I reduced to 68 and for the last 8 hours or so, the room temp has stayed at 72/73 and the zone has not kicked in. Outdoor temp is 27. Perhaps it's my imagination, but i keep running to the basement to check the zone... the radiant zone pump is off. So it's been quiet. Unbelievable to me that the pipes are retaining heat so well without new circulating hot water.

rickgerv

SWEI - I have a mod/con.

SWEI

The need for indoor feedback depends on the use patterns of and external influences on the spaces being managed. Solar gain, woodstoves, kitchen heat, and intermittent occupancy are the primary drivers for zoning and controls in our world.

GW

Yes my floor snapped a couple of times during the first winter we moved back in. I was amazed at how loud it was. Sometimes floors will move and adjust. What you're describing seems extreme.

The floor that snapped (living room) was unique due to the fact we added 6' to the room. So the front wall was wiped out...I actually devised a bolt method and counter sink the bolt heads that secured the old 1950s floor boards. Hard to explain.

Anyway, seems like you need constant circulation in a bad way.

GW

I would think labor would be similar. I'd be planing a full day, based on your descriptions. And if I was doing the wiring maybe some added time the next day. It likely won't be cheap but it's kinda bummer you weren't told all this by your design people.

rickgerv

Gary, SWEI. Thanks for the inputs. The 402 makes more sense I think. I talked to my designer who pointed the finger at me on not asking for this earlier. But how am I supposed to know to ask for it?
Anyway, he's not being too helpful. He was saying with the 356 (his recommendation) that I'm looking at also a pump, piping materials and a complete repiping of the manifold and that it will cost a lot. Also something about putting heating/radiant circulator on a summer/winter switch so the water in the floor was always moving.

Question is setting up the 402 basically the same work of putting in the 356 as this does sound like a major rework. Starting to think I'm just going to have to live with the noise.

GW

My memory is slipping a little, did you post pictures of your piping setup? I quickly scrolled
up and down and did not see any.

The amount of work: it's not a little job, it's not a big job. You would need to get the Tekmar mixing valve installed, Tekmar actuator, mount the 402, get the room sensor installed, wire it all up. If you're not familiar with the Tekmar interface, you may need to call the Rep or call Tekmar to program it. Although, there manuals are really good. You may be able to program it if you're pretty handy but this stuff

SWEI

rickgerv said:

The 402 makes more sense I think. I talked to my designer who pointed the finger at me on not asking for this earlier. But how am I supposed to know to ask for it?

You're not.

The designer's job is to actively seek out that which is available, to understand when and how those products should be used, and to meld that with his (or her) understanding of your requirements and budget in order to deliver as much of the vision as possible.

rickgerv

Many thanks. I know the approach and will seek out a plumber with knowledge of the Tekmar 402. Parted way with the designer who didn't ask for his balance due and is out of the picture now. Not sure that I'll retain the original plumber.

Appreciate the guidance. At least I know what needs to be done.
Thank you.

aircooled81

Is there a way to slowly heat the water at start up, and bring the loops up to temp at a rate so slow their expansion is less noticable? Or is that the idea behind the tekmar and valve change?

bmwpowere36m3

If your boiler has "ramp" settings, then yes. You can set the fire rate of the boiler to slowly build over a period of time. However without ODR or constant circulation the piping will still expand/contract a lot and often.

The best is to slowly heat/cool the system over as long of a period as possible. ODR and constant circulation really take care of that.