Noises from 2-tier Runtal Baseboard

Niten_J

Hi. I am reaching out in desperation. We have been struggling with noises coming from our Runtal baseboard when they are heating the rooms. The baseboard creates so much noise that it wakes the kids and my wife up routinely. My plumber and Runtal have been trying to diagnose the issue for the past 2 years with no change. The problem has come to a critical point because my wife is undergoing a medical treatment that physically drains her and she needs to rest at night to recover from it. She is unable to do so with the noises that the Runtal is making or the kids come and wake us up because of the noises. Here's what we've done to try to solve the problem.

1. Lower the boiler temp from 180 to 165 degrees ( I even ran the boiler at 130 degrees by accident and the noises still happened)
2. replace the circulation pump with a low flow pump, a "smart" pump, and a single speed pump
3. remove air bubbles from the system
4. replace the expansion tank
5. replace a section of Runtal with a new one
6. add anti-freeze to the system

Few more pieces of information
1. The entire house is spray foamed
2. A mix of Uponor 3/4 and 1/3 hepex was used
3. The pex was insulated and strap
4. Runtal firmly believes that the noises are coming from pex expansion and contraction (even though they never came onsite)

I've added some photos of the system. We live on Long Island in NY.

Any help would be greatly appreciated.

P.S. I have audio files that I can share so you can hear the noises we're experiencing.

EBEBRATT-Ed

What about radiator pictures?

TAG

That's a big system (all those pumps) ... Are the Runtal units only on small pex manifold?

Was this a retrofit into an old house ? You should be able to tell if it's the Runtals -- my guess with the spray foam and how most systems are sized they go on and off. The PEX is not going to be making much noise ..... they way the runtals mount -- they can make some noise. Do they have the mounts with the plastic spacer

Niten_J

EBEBRATT-Ed said:

What about radiator pictures?

Here are the pictures of the radiators in 2 of the rooms... all of the rooms are making noises but we're concerned about the 2nd floor runtals.

Niten_J

TAG said:

That's a big system (all those pumps) ... Are the Runtal units only on small pex manifold?

Was this a retrofit into an old house ? You should be able to tell if it's the Runtals -- my guess with the spray foam and how most systems are sized they go on and off. The PEX is not going to be making much noise ..... they way the runtals mount -- they can make some noise. Do they have the mounts with the plastic spacer

It began as a retrofit when we redid the first floor. That's when we installed the Runtals and they worked great. The first renovation happened about 10 years ago. In 2019 we added a second story and expanded the system. So when you look at the basement photos, the manifold and equipment to the right of the water tank is for the 2nd floor. After the second renovation, we began to have noises through out all the Runtals. And have been troubleshooting for the past year in earnest because we just dealt with it during covid and my wife wasn't sick back then...

The runtals are spread across both manifolds... first floor runtals and in floor radiant are on the big manifold and second floor runtals and infloor radiant are on the small manifold.

hot_rod

Looks like some looong radiators, I would expect some expansion and contraction over wide temperature swings. Pipe is insulated well through the floor

It would be nice to run constant circulation or outdoor reset to limit temperature swings.

Some pump rep is having a Merry Christmas after selling all those circulators😆

mattmia2

TAG said:

Do they have the mounts with the plastic spacer

What is this plastic spacer?

Niten_J

hot_rod said:

Looks like some looong radiators, I would expect some expansion and contraction over wide temperature swings. Pipe is insulated well through the floor

It would be nice to run constant circulation or outdoor reset to limit temperature swings.

Some pump rep is having a Merry Christmas after selling all those circulators😆

Radiators on the second floor are between 10ft and 14ft long.

Can you suggest a pump model? Also what's an outdoor reset?

Niten_J

mattmia2 said:

TAG said:

Do they have the mounts with the plastic spacer

What is this plastic spacer?

I also forgot to mention that we did an experiment where we took the Runtal off the wall and had it sitting on pieces of wood to eliminate the wall hangers. That experiment still produced the noises at the same volume.

GGross

You have any video of the sound it is making?

Derheatmeister

We have a couple Systems with very long Runtal UF 2/UF 4 series radiators on constant recirc and modulating the temperature based on outdoor reset ..Never had any noise complains..It is probably the Expansion and contraction noise from the PEX! If you gradually change the supply temp based on the Outdoor temp the noise will be not as noticeable

hot_rod

The boiler should have a control function that allows the temperature to increase or decrease based on outdoor temperature. This eliminates wide temperature variation which could be causing  the noise.

Those baseboards need fairly high supply to get good output.

mattmia2

If it is making noise on wood blocks then the only real solution would be outdoor reset. You have a control that sets the water temp based on the outdoor temp so it is just hot enough to heat the house, it is constantly at that temp and replaces the heat as it is lost so it never shuts off and it changes temp gradually. Even that may not eliminate every noise but it will get rid of most of it. If you have a cast iron boiler there will have to be a boiler loop that is kept hot enough to keep the boiler from condensing and a separate loop mixed down to the outdoor reset temp to supply the radiators.

EDIT: I see it is a mod con so you can set the boiler to do outdoor reset directly. It will have to do a higher temp for DHW calls which they usually have the controls built in to do.

Dave H_2

When I hear of noises in a system that are hard to diagnose because the home is finished, it could be the pex and just lowering the temperature can still make the noise. PEX tubing will expand and contract linearly based upon temperature. It does not expand radially. It expands at a rate of 1.1 inch per ten degree rise in water temp per 100 feet of pipe. So lets look at that.

Lets say you have 100 feet of pipe and an operating temperature of 180F. Starting temp is 70 degrees, 180-70 = 110 degree temp change. 110 divided by each ten degree rise = 11.
11 x 1.1 inch = 12.1 inches. That loop of pex that was installed of 100 feet is now 101 feet long and that extra has to go somewhere. The panels look rigidly attached so the pipe has to move and is probably rubbing on the wood.
This will happen everytime a zone turns on and also when it turns off it starts to shrink. Dropping the temp to 165 will still have growth, just a couple of inches less.

Now if we put the system on outdoor reset which means the water temperature will modulate from 180 degrees when it is 15 degrees outside (design temp on Long Island) to something alot lower when its 60 out, lets say like 100. The goal is to keep the zones on longer and lower temperatures. It keeps the house very comfortable and minimizes the cycles and large temp swings in the water.
Your boiler may already have the sensors in place and can be programmed to operate on outdoor reset. If not, there are external controls and or components added to achieve that.
Or we may have to open walls and examine how the pipe is run, add pipe insulators and guides and even add an expansion loop in the pipe to absorb the growth of pex.
Dave H.

Niten_J

GGross said:

You have any video of the sound it is making?

Here are a couple of links to the sounds we hear when the Runtals are on...
https://drive.google.com/file/d/1VNXuLbXGdTe0uN0q7_JR7SRl4rPq0lUV/view?usp=share_link
https://drive.google.com/file/d/1mz08wZvjU40k4wo8b6uxAmdyiqcaHRxG/view?usp=share_link

Niten_J

Quick update. We're having the local Bosch rep come by soon with a person from the installer/plumber to look at our options with respect to "lowering the delta T" between the supply and the return.

Thank you so much for your comments and suggestions. I really appreciate the outside in perspective. I'll keep you all posted on how things progress. I feel like we're on the right track now... crossing my fingers...

Jamie Hall

*[m a little late to the party, but that's almost certainly expansion noise. Make sure the Runtals are supported through slippery plastic hangers -- no metal to metal or metal to wood contact anywhere. Keep the circulating water temperature as constant as you possibly can (that's where the outdoor reset comes into play). And don't turn them off and on or use any setback.

mattmia2

Jamie Hall said:

*[m a little late to the party, but that's almost certainly expansion noise. Make sure the Runtals are supported through slippery plastic hangers -- no metal to metal or metal to wood contact anywhere. Keep the circulating water temperature as constant as you possibly can (that's where the outdoor reset comes into play). And don't turn them off and on or use any setback.

These brackets are what Runtal give you to hang them. They are metal to metal and the carriage bolts thread in the bottom corners to adjust to make it plumb.

https://www.supplyhouse.com/Runtal-UFB-2-Mounting-Equipment-for-Under-60-Runtal-Baseboards

hot_rod

In the meantime

Jamie Hall

Um... Ok... but those brackets are only intended for units less than 5 feet long. I gather yours are a bit longer? Makes a difference. It would not be hard to modify them to have a slippery compliant fit...

mattmia2

Jamie Hall said:

Um... Ok... but those brackets are only intended for units less than 5 feet long. I gather yours are a bit longer? Makes a difference. It would not be hard to modify them to have a slippery compliant fit...

There is a different kit with 3 brackets for longer radiators.

TAG

My Runtal units have a heavy white metal hanger that the radiator drops onto .... they come with a plastic cap that insulates metal to metal contact.

Anytime you allow a radiator to cool and then pump hot water through it you are going to get expansion -- all of my panel and most of my Runtal units use constant circulation. Running off the outdoor reset of the boiler -- this way they never see wide temp fluctuations. The exception is my towel racks in one house we have them on a thermostat -- they are thin and tall and Make very little noise .. every once in a while. My guess the on and off is the issue .... with spray foam the heat loss dropped so this may allw the units to really cool between cycles.

What are all the other pumps doing ? With modern pumps you can run system with very few and outdoor reset with constant circulation solves lots of problems

Niten_J

TAG said:

My Runtal units have a heavy white metal hanger that the radiator drops onto .... they come with a plastic cap that insulates metal to metal contact. Anytime you allow a radiator to cool and then pump hot water through it you are going to get expansion -- all of my panel and most of my Runtal units use constant circulation. Running off the outdoor reset of the boiler -- this way they never see wide temp fluctuations. The exception is my towel racks in one house we have them on a thermostat -- they are thin and tall and Make very little noise .. every once in a while. My guess the on and off is the issue .... with spray foam the heat loss dropped so this may allw the units to really cool between cycles. What are all the other pumps doing ? With modern pumps you can run system with very few and outdoor reset with constant circulation solves lots of problems

The other pumps are for the radiant floor heat.  It looks like we have one pump for each radiant floor loop, one pump for domestic hot water, and pumps for the runtal zones (3 on the second floor, 3 on the first floor)

Paul Pollets

You may be "over-pumped". I'd be using one pump and 3 zone valves and outdoor reset, as TAG mentioned. Aside from expansion noise, most Runtals are installed with either Danfoss or MNG union valves and unions. You'll have a hard time refitting what you have.

Chi

I don't think you described the noise. Is it just when the system starts and stops pumping?

2 of my 3 Runtals make a rattling noise when starting and stopping and I think it is due to a mistake made in filling the system that subjected those radiators to 60psi. The overpressure may have broken some internal spot welds in the flat panels or somewhere else. This was done several years ago but aside from the noise, they work great. Those particular radiators are in the living room and dining room and so don't disturb anyone's sleep.

mattmia2

Mine makes both expansion noise and a nose when the circulator stops and it was never overpressurized but it is a 9 ft long panel with 4 tubes and mounted on a wall with a bit of a belly in it.

There is a link to the sounds somewhere in the middle.

psb75

It's unfortunate that those are not ECM circulators. They would be best adapted for constant circulation. They would save much electricity. I would think that use of the outdoor reset function on the Bosch mod/con boiler is a no-brainer. DO NOT use set-back strategy with the thermostats. "Set...and FORGET" is the mantra for constant circulation with outdoor reset control.

Niten_J

Hi Everyone! Thank you for all the suggestions. I have shared them with my installer. I also have a small update. Bosch came by on Tuesday with the installer to review the boiler. They did some tests and found that there is a 40 degree difference between the supply and return temperatures. He believes that this is causing the noises we are hearing because of the large temperature variation the PEX goes through while the system is running. He looked at the heat exchanger and found that the side with the flame is clean. He couldn't check the water side but believes that there is a lot of sediment build up on that side and suggests that we run a cleaner a few times through the whole system and then introduce an inhibitor. We're going to try a cleaning and inhibitor product from Sentinel. The products are slated to come next week. I'll post an update and let you all know if it works.

Niten_J

mattmia2 said:

Mine makes both expansion noise and a nose when the circulator stops and it was never overpressurized but it is a 9 ft long panel with 4 tubes and mounted on a wall with a bit of a belly in it.

There is a link to the sounds somewhere in the middle.

Ours makes noises constantly when the pump is on... the noises vary from banging to clanging to pinging.

Niten_J

Chi said:

I don't think you described the noise. Is it just when the system starts and stops pumping?

2 of my 3 Runtals make a rattling noise when starting and stopping and I think it is due to a mistake made in filling the system that subjected those radiators to 60psi. The overpressure may have broken some internal spot welds in the flat panels or somewhere else. This was done several years ago but aside from the noise, they work great. Those particular radiators are in the living room and dining room and so don't disturb anyone's sleep.

The noises are constantly occurring when the system is on. They only stop if the pump isn't running.

mattmia2

If it is 40 degrees difference between supply and return that is not enough flow and probably too high a supply temp, although that differential is great for the efficiency of a mod con boiler.

psb75

How about something like: having close to constant circulation of a temperature based on an odr curve in the boiler's control logic--generally getting no hotter than 140°F. The return temps would almost always be condensing (under 130°F). The rads would stay warm all of the time w/o large temperature fluctuations and thereby wouldn't make noise.

Niten_J

psb75 said:

How about something like: having close to constant circulation of a temperature based on an odr curve in the boiler's control logic--generally getting no hotter than 140°F. The return temps would almost always be condensing (under 130°F). The rads would stay warm all of the time w/o large temperature fluctuations and thereby wouldn't make noise.

So at one point I decided to change the boiler temp from its max setting to 3 just to see if the noises went away. They didn't... and what I didn't know was that when I did that the boiler temp was around 130 degrees (installer came and measured the temp). So even with that low of a temp we still had noise... and the magnitude of the noises didn't change... which completely blew my mind... :-(

Niten_J

Hi Everyone! Quick update. The installer came and cleaned the system with the Sentinel product. That fixed an unrelated problem with a howling from the system but it didn't fix the noises from the Runtals. I asked them to re-enable the outdoor reset this week and I'm monitoring Runtals. So far they're still making noises constantly for the entire time the zone is calling for heat. The installer is sourcing a cast iron radiator for one of the rooms to confirm that the noises are caused by PEX expansion. Will keep you posted.

mattmia2

you also have to set the outdoor reset curve so that it very nearly never shuts off.

Niten_J

Gotcha. The Bosch is showing an AD fault error at the moment so its defaulting to max temp regardless of the outdoor temp. I'm trying to get the Bosch rep back to work his magic to resolve it.

Niten_J

Hi Everyone! Apologies for the long delay on the update. We got the boiler error resolved and now the outdoor temp reset is working. Even with the outdoor temp reset enabled we still experienced the banging and noises.

The next step was to create more slack in the PEX pipes to allow them to expand and contract more easily. The installer worked in all of the unfinished spaces to create the slack.

With the above 2 steps we didn't see any reduction in the banging/noises from a loudness and frequency perspective.

As a last resort the installer removed a section of runtal from a heating zone and replaced it with cast iron. The rationale for this step is to determine if the PEX is truly causing the noises. The Runtal support team stated that the PEX expansion noise would be heard regardless of the heating element (Runtal or Cast Iron). We just completed the cast iron install and the banging/noises are completely eliminated.

In the video below the Runtal and Cast Iron are in the same zone. The Runtal is banging away and the cast iron is absolutely silent. I'm at a loss at this point and would like some advice on next steps.
https://www.icloud.com/sharedalbum/#B0gGfnH8tGsDuxo

Thanks in advance

dko

The runtal units from the first renovation 10 years are also making the same noises?

I would have said some fin manufacturing defect with the welds or tolerances, but if the ones that were fine are also making noises then have to reconsider that.

Unless during 2nd renovation, people who were testing the system with new piping may have over pressurized damaging all the units? It's not unusual (not that it's correct) for people to test systems to 100psi while the Runtals are only tested to 74psi. Overpressurizing definitely warps Runtals indefinitely. I have had people bring me Runtals with tennis ball size bulges.

To test this theory, have your tech come pick up a 10footer from me and install it. If it doesn't make noise, then you can safely assume your Runtals are damaged. If it still makes noise.. then i'm no more help. No charge, just to satisfy my curiosity. Does it still makes noises when you restrict flow at the flow meter on the manifold? System static pressure increased since renovation?

Message me if interested in testing a new 10fter.

Niten_J

dko said:

ion?

Message me if interested in testing a new 10fter.

Sent you a PM.

Niten_J

dko said:

The runtal units from the first renovation 10 years are also making the same noises?

I would have said some fin manufacturing defect with the welds or tolerances, but if the ones that were fine are also making noises then have to reconsider that.

Unless during 2nd renovation, people who were testing the system with new piping may have over pressurized damaging all the units? It's not unusual (not that it's correct) for people to test systems to 100psi while the Runtals are only tested to 74psi. Overpressurizing definitely warps Runtals indefinitely. I have had people bring me Runtals with tennis ball size bulges.

To test this theory, have your tech come pick up a 10footer from me and install it. If it doesn't make noise, then you can safely assume your Runtals are damaged. If it still makes noise.. then i'm no more help. No charge, just to satisfy my curiosity. Does it still makes noises when you restrict flow at the flow meter on the manifold? System static pressure increased since renovation?

Message me if interested in testing a new 10fter.

We did get a replacement piece of Runtal and it didn't make a difference. I don't recall if they pressure tested the zone after it was installed, but I asked if they did and at what PSI.

Does it make sense to call Runtal again and show them the video?

hot_rod

Niten_J said:

dko said:

The runtal units from the first renovation 10 years are also making the same noises?

I would have said some fin manufacturing defect with the welds or tolerances, but if the ones that were fine are also making noises then have to reconsider that.

Unless during 2nd renovation, people who were testing the system with new piping may have over pressurized damaging all the units? It's not unusual (not that it's correct) for people to test systems to 100psi while the Runtals are only tested to 74psi. Overpressurizing definitely warps Runtals indefinitely. I have had people bring me Runtals with tennis ball size bulges.

To test this theory, have your tech come pick up a 10footer from me and install it. If it doesn't make noise, then you can safely assume your Runtals are damaged. If it still makes noise.. then i'm no more help. No charge, just to satisfy my curiosity. Does it still makes noises when you restrict flow at the flow meter on the manifold? System static pressure increased since renovation?

Message me if interested in testing a new 10fter.

We did get a replacement piece of Runtal and it didn't make a difference. I don't recall if they pressure tested the zone after it was installed, but I asked if they did and at what PSI.

Does it make sense to call Runtal again and show them the video?

It would be unusual to see a system pressure tested much over 28 psi if it is all connected to a boiler. Even 74 psi would be a stretch for pressure on most home plumbing systems.

Take the removed one to a shop where you can run high temperature through it and watch it behave. Even a garden hose connected to your homes hot water flowing across the radiator should show any expansion movement. Flow the water through it, not pressurizing it.
That would eliminate the piping in the home from the equation