Clicks and Snaps from Hot Water Baseboards

numberforty1

Hi, apologies for the common question but all my research still doesn't yield an answer. I just purchased a brand new construction which is very nice, but about 30 days after we moved in, the hot water baseboards started clicking and snapping all over the place.

For the month of December I don't think it made a sound. Now it's all day long, roughly every 5-10 minutes I hear a decisive *click*, as if someone just threw a switch inside the pipe. Every room in the house has it, but it always seems to come from a particular spot. I can't see anything special about the spot it comes from though.

Making it a little more difficult, I have these very nice looking but very unhelpful wooden baseboards that are nailed into the wall, so I can barely see any of the radiators themselves. I have tried putting foam between the fins and their supports, but no change.

My main question - is this intended? Are there valves or something in the pipes that are supposed to make noise and I just have to live with it? If so, why were they quiet for a month before January?

Any suggestions/explanations welcome, and many thanks.

Ironman

Enclosing the Baseboards like that will greatly reduce their output and could also be the cause of the expansion noises that you're hearing. All metals expand when heated and if something is tight against them (like those wooden covers) the noise can be very annoying.

What can of boiler do you have? How about some pics? If it's not utilizing Out Door Reset, doing that can greatly reduce the expansion noises as well as conserve energy.

numberforty1

@Ironman Thanks, but are these noises expected or should these systems be completely silent? The wood covers are not touching the metal inside. I'll get a picture of the boiler, but how would I know if it has Out Door Reset?

Jamie Hall

If you can find where the actual pipe is supported, you may be able to slip thin pieces of plastic -- such as shims cut from a plastic milk jug -- between the pipe and the supports, and that will help. However, as @Ironman said, if you have outdoor reset the circulating pumps will be running all the time with water just warm enough to heat the space, and that will minimize the temperature changes which are the root cause.

I might add -- don't run the thermostat up and down. That will make it worse as the heating elements change to try to keep up.

Ironman

Pics of the boiler, please.

numberforty1

@Ironman Here are pics, I'm just trying to figure out if hot water baseboards are ever silent at all. It seems strange to me people would want to live with all this clicking. Thank you for looking, appreciate it.

mattmia2

What supports the element under the wood? how does it pass through the walls and floors?

That is a conventional boiler, others will know if the controls on that can do outdoor reset, typically that type of boiler has a fixed supply water temp vs being able to be set to modulate water temp based on outdoor temp.

numberforty1

Thanks @Jamie Hall , in your experience do hot water baseboards always make some expansion noise, or should it always be silent with proper shimming/isolation of pipes and fins?

numberforty1

@mattmia2 It's hard for me to see because of the wood boards, but I can see aluminum looking supports that the pipe fins sit in, they are secured to the wall. I've slid a few pieces of foam between a few of the supports and the fins, but it didn't seem to do much. I can only see that the pipe passes through some kind of hole in the floors/walls. In your experience is it possible to make these system silent?

bburd

Noise in hot water baseboard systems is not a question of “always”. Some systems are very quiet; some are rather noisy; some are in between.

Key points for a quiet system:

Pipes and heating elements should be installed so they can move slightly under thermal expansion and contraction without binding on their supports or nearby obstructions. Others have written about using sections of plastic milk bottle between the finned elements and their cradles. High quality baseboard radiation is built with isolators on the cradles. If the pipes are metal it’s good practice to install pipe insulation or other sleeving material where they pass through walls and floors. Pipes and fittings should not butt directly against the sides of openings or adjacent framing.

Careful listening when the system turns on and begins making noise will help you find the trouble spots. You will probably have to open up those wood covers to fix them.

Resetting the supply water temperature according to the outdoor temperature helps to minimize noise because it reduces the water temperature in all but the coldest weather, so there is less thermal expansion in the pipes and radiators. With the water temperature just high enough to keep the house warm, the circulator should operate for long cycles and noise should be minimal. Outdoor reset also improve fuel efficiency and minimizes room temperature swings.

Your boiler’s instruction manual should at least say whether outdoor reset is a factory option. Under some energy conservation codes it is now required. Some pictures of the boiler controls with covers removed may help us see if you have it.

Ironman

I concurr with what Bburd has said.

Your boiler doesn't have an ODR feature, but one can be added with an external control like a Tekmar 256. ODR varies the water temp in the system based upon outdoor temperature: the colder it gets outside, the warmer the water temp and vise versa. This not only saves energy, but also reduces the severe water temp swings which reduces thermal expansion.

It appears that your high limit is set for 190* which is high and adds to the problem when water that hot meets baseboards that have cooled down to room temp. As I mentioned earlier, the output of your baseboards has been reduced by the homemade wooden covers. The water temp may be cranked up to get more output with a higher water temp. The down side is the severe thermal expansion you're experiencing. The covers look nice, but this is why someone who's not a hydronic pro shouldn't mess with the system. Performance has been sacrificed for asthetics.

As mentioned, you have two basic things that you can do:
1. Open the covers up and determine the particular places that the noise is emanating from and make adjustments
2. Install and ODR control which will reduce the water temp swings and thermal expansion.

numberforty1

Thanks @bburd, @Ironman - one outstanding question to me is, how can I tell if the sound is from rubbing against supports/obstructions, or if it is just created by the element itself expanding? Can the element make a clicking sound all on its own, even if it is touching nothing?

Is there somewhere I can purchase isolators for the cradles, or are plastic milk slips really the best thing? I have regular cheap metal baseboards in the basement and they have nice thick plastic isolators, these don't.

The wood baseboards are not homemade, and no one messed with the system, this is the way the system was built by the builder. Unfortunately. But they do have open holes all along the top, they don't trap all the heat.

Ironman

So, the baseboards were factory made?

mattmia2

You can get the plastic carriers from slant fin as replacement parts, but depending on how the element is supported in the enclosures you have, that might not be the right way to support them. They are designed to sit on the metal brackets that are part of the back of the standard steel enclosure. I suppose you could get the brackets that snap in to the back of the enclosure that the carriers sit on and screw the bracket to the wall or the enclosure but there are probably both less expensive and more effective ways to go with pieces of plastic sheet or tube

numberforty1

Ironman said:

So, the baseboards were factory made?

Yes, I just can't tell if the sound is from rubbing against supports/obstructions, or if it is just created by the element itself expanding - can the element make a clicking sound all on its own, even if it is touching nothing?

Jamie Hall

Since the elements are one piece -- or assembled to be one piece -- no, generally they won't make a clicking sound on their own, although there is a possibility of a loose or bent fin making a click. It would be rather rare.

Except...

If the element is tightly constrained at both ends, but has a slight bow, it could make some odd noises as it bends further when it expands. It would need really solid constraint at both ends, though.

numberforty1

Jamie Hall said:

Since the elements are one piece -- or assembled to be one piece -- no, generally they won't make a clicking sound on their own, although there is a possibility of a loose or bent fin making a click. It would be rather rare.

Thanks @Jamie Hall , here are pictures of the supports of the elements. I've tried putting plastic and foam between these support brackets and the element, but it doesn't seem to have changed anything. I read somewhere that the supports should also be loosely screwed in to avoid noises, but I don't know how I could change that. Any idea what you would do with these?

Ironman

You're BBs ARE indeed homemade. Someone used the elements that were factory made, but the hangers and enclosures are indeed homemade. The hangers are nothing more than sheet metal drive cleats that join ductwork.

In an attemp to make something astetically please, something overlooked that eneneering is involved in making a product. I hate the be the bearer of bad news, but something needs not only to be done to the hangers on each one, but the enclosures are allowing air to bypass the elements causing a reduction in heat output and necessitating higher water temps. That reduces efficiency and cause more expansion noises.

I'd recommend you call your builder/installer to correct it.

numberforty1

@Ironman, yes I can tell they made something that would sell easily, but didn't bother isolating anything intelligently. Of course the builder won't want to do anything about it - but my question is, what should I even ask them to do? They aren't going to rip every wall of the house apart and install regular BBs - what kind of isolating of the element could I suggest they do?

numberforty1

@Ironman Also, you had asked if the boiler has outdoor reset - I saw on the wall I do have a "Taco FuelMizer SR501-OR-4 Switching Relay with Outdoor Reset" installed on the wall next to the boiler - it doesn't seem to have any kind of visible controls

Scratch the above...turns out its the SR501 without outdoor reset...

Ironman

Ask them to fix it. Since they took it upon themselves to make them, it's their responsibility to make them right.

numberforty1

Ironman said:

Ask them to fix it.

@Ironman Yes, but in this case, what does "fix it" mean? I'm sure they will look at me and ask the same question. Are you thinking of a different type of cradle that could be used, or something else perhaps?