Nighttime banging pipes waking up the house

katiejune

Hi everyone. I've been reading this page since we bought this house in August and started really using the hot water heat. I can't figure out if this issue I have is water hammer, zone valve, or pipe padding related.

We had a lot of banging and I padded some of the pipes in the basement that were hitting studs and it has helped, but I have very loud bangs in my upstairs master bedroom at night and not sure what to do. I turned pump down from high to low and it still happens but might be a bit quieter (?).

I've had two guys out who say everything is normal, this is costing me a fortune. I'm willing to pay for a third company but want to see if there's anything specific I should note?

I have 3 kids under 3 and it's scaring us all

4 zones: Basement, Family Room, 1st floor, 2nd floor

Honeywell zone valves, baseboard radiators that appear fixed and I don't see bleed valves

Last night it appeared to happen when the 2nd floor calls for heat and the family room zone is on. From what I can tell the basement zone and 1st floor zones were off.

Otherwise I hear only small swishes, drips, and light chirps occasionally.

Thank you for looking at my post!

ETA last week we suddenly had no heat and the guy came to replace aquastat. Been fine since then.

Ironman

There are some things that I don't care for in the piping arrangement, but I don't think they're the cause of the banging. I don't have time to go into the technical details now.

Here are some things to look for:
1. Was the check valve removed from the Grundfos circulator when it was installed?
2. What temp is your aquastat set for? Try it at 170* for now.
3. There may not be room for thermal expansion of the piping. Check where it goes from vertical to horizontal below the floor joist. If it's tight against the bottom of the joist, that may be the problem. Also, any holes that the pipes pass through should be 1/2" larger in diameter than the pipe.

Let us know if any of this helps.

katiejune

Thank you for commenting

#1 I'm not sure how to answer that, it was like this when we bought the place but if there's a way to look I'd love to know what to look for.

#2 it is set to 180, I can change that down

#3 everything is buried in the walls so I will note that and check when/if I need to explore later, thank you

I saw a video on maybe a baseboard like mine from This Old House about opening them up and checking inside for friction areas but that video had a two pipe system and I also can't figure out how to open my baseboards.

Mark Eatherton

What model of Grundfos pump do you have there? Normally these systems don't require a high head capacity pump, and that will cause zone valve hammering.

Also, as Bob Boan noted, the boiler is not piped ideally. The pump should be pushing fluid away from the expansion tank connection, and the zone valves should be on the return.

Moving the expansion tank to the inlet side of the pump might help, but if you're going to take the time and money to do it right, go all the way.

With this set up the way it is, it is entirely possible that if under a certain combination of valves opening and closing, the pump is creating enough negative pressure, that with water that is near 180 degrees F will FLASH to steam when it see's this negative pressure, causing a significant BANG...

Recreating this "condition" is difficult. The valves do appear to be installed in the correct direction as it pertains to flow, which would have been my first thought. One of them (round top) is a slow closing valve design. Replacing the valves with all slow operating valves (Taco for example) may help, but reconfiguring the whole near boiler piping configuration is the only guaranteed way to bring the system design into complete compliance.

Going to a low head circulator will probably help as well, but in order to correctly and completely diagnose that condition, we'd need to know exactly how much pipe (size), valve and fitting and baseboard are in each circuit. If you want to go to that extent, I'd be glad to do the calculations and show you exactly what pump is needed to do the job without major overkill.

The conditions you are living with are not "normal" conditions. Other than the normal, expected expansion and contraction of pipes, these systems are normally virtually silent.

ME

katiejune

Thanks so much

I tried turning down the temp to 170 but it looks like 180 is the lowest.

Going to run some errands I will come back later I appreciate the help learning

I have a picture of the pump here, I'm not exactly sure how to identify it

GW

Katiejune if the loudest noises are at the bedroom I would focus my attention there. There are a million boilers that aren't piped ideally but don't wake people up or keep them from sleeping.

That first pic in the first post, simply grab onto that "end cap" and pull it off the wall. These end caps sort of "snap" into place. And they snap out too. It may be scary when you pull it the first time. It's easier to do than it is explaining how to do it

Anyway once you have the end cap off you can now observe the piping coming though the floor at each end of each baseboard.

Is the pipe(s) touching the wood/subfloor/finish floor? I have a hunch it is. Sometimes floor guys have little regard for our simple piping systems.

If you can't see in the hole for whatever reason, you may try poking some small wire like item around the circumference of the hole to feel of there is at least minimum clearance and no wood is touching the piping

Of you have contact with the floor that is likely your noise problem. Cutting away the wood takes a skilled operator with certain tools. I've done this a few times when I was doing new construction in my 1990s new construction days, the floor guys were not careful.

A heating guy familiar with baseboard heating should quickly be able to look at this. Some HVAC guys have never installed baseboard heating so it's unlikely that technician would be fully able to find the issues.

If the noise is driving you nuts I would advise an interim patch/fix.... simple disable that zone by opening it manually, and turn that thermostat down . You may now overheat yet I suspect it would reduce the noise.

JUGHNE

The picture of the baseboard looks to have new flooring or not?
As GW said, they might have jammed the flooring around the pipes. Careful wood chiseling around the pipes might be needed.
Running at high temps the copper will expand a lot.
Lower temps with longer runs may lessen the rubbing/banging.

One end of the BB may have a hinged door for an air vent, that door should/would open easily and you could see how the end caps could come off.

Mark Eatherton

The pump is a Grundfos 1558 FC, meaning it came with a flow check in it. I wonder if the FC is working in such a manner that it is causing some sort of kinetic hammering when all valves close due to fluid interia...

In any case, I'm thinking a low head pump would help this a lot.

Is that the original pump, or has it recently been replaced?

ME

JUGHNE

Also, it they added another layer of wood flooring over existing, they may have raised the BB element up so the end caps would look right.
This would pull up the horizontal pipe below the floor. If the horizontal piping was drilled thru floor joists and then pulled up it would be now be tight against the top of the drilled hole, causing noise when expanding. FWIW.

Ironman

You can't have a flow check with zone valves: it will cause water hammer.

As Mark pointed out, the pump comes with the flow check installed in it. It needs to be removed.

To do so, the pump has to be removed from the piping and the check pulled out from the discharge opening of the pump. That will require isolating the boiler and draining it to remove the circulator, then refilling it and purging the air from it.

The check is in here:

DanHolohan

This may help:

https://heatinghelp.com/systems-help-center/banging-zone-valves/

Mark Eatherton

Wham bam, thank you ma'am...

DanHolohan

The Honeywells were famous for that around here.

katiejune

Thank you all. You've given me lots to investigate.

We did have new floor put in our living room only and I checked just now and it is up against the pipe in a couple spots. This room is directly under our bedroom so that might be it. Our bedroom clearances appear fine.

My sons room is right next to ours and has a different version of the same radiator. His has hinges and is a bit more clangy when I opened it up so it's possible there's something there causing this noise.

My husband thinks there is air in our lines. How would we know and would this be an issue? One of our zones had a very very small drip at the spicket which I assume is a cleanout spot but it has stopped.

Thanks I will keep checking out all the suggestions and will update if I fix it!!

katiejune

Thank you Dan, I did read that a while back and think it might still be an issue for me, but the trouble is I can't seem to recreate the bangs. So if it were the valves I thought I would be able to recreate it. (?)

katiejune

Iron man thank you so much. The pump came with the house and I don't know it's history. I will keep that in mind about the check valve. I'm nervous to open anything up or mess with it. I'm afraid I'll break it or ruin it.

katiejune

Does anyone feel this can be caused by air in our system? My husband is familiar with industrial projects and his hunch is that we need to drain our system and refill it to purge air. Is there a way to purge air without draining? Is regular draining a recommended maintenance procedure? Thank you.

lchmb

Where are you located? Maybe someone here can help....just a thought

Harvey Ramer

Katie,
Here is a quick little test you should do before doing anything else. Turn on all zones and let them run till all the return pipes from the zones are hot and the boiler is hot. Then turn off all zones so they don't run for at least an hour or so. Make sure all the baseboards are cooled off. Then turn on one zone. Listen. If you hear a bang at that point, you have a flow check in the pump and it will have to be removed.

What happens is this. When all zones are on, the whole system is filled with hot water. When all zones turn off, the water in the zones cools off and becomes denser. In layman's terms, it shrinks. Since all zones valves are closed and a check valve in the pump, the baseboard side of the system can't be replenished with water from the expansion tank. So it falls into a vacuum. As soon as the first zone valves opens again, bang! You get water Hammer as the system pressures equalize all in one second.

@Dan Holohan
You think maybe by removing a spring from the valve you weakened the closing force on the ball which allowed water to bleed through equalizing the pressures?

Ironman

I doubt that air would cause the problem. The check valve is the first thing that should be addressed.

And no, you don't drain the system to purge air and you don't do it to maintain it. Draining it should only be done when it's necessary to open the system for a repair. It causes the iron oxide coating to be removed which actually helps protect the system from corrosion. It also causes fresh minerals and oxygen to be introduced into the system which are harmful to the ferrous metals in the system.

DanHolohan

Harvey, yes, that was always the off-the-books advice by the local guys. It worked for some, but not for us.

katiejune

Thank you all again. I am doing the test for the check valve right now as described above. I'm letting it all heat up really well too, thinking that if it is a pipe expansion issue with my new floors, that I will maybe hear it bang on the heat up if I stay near that room. Then will let it all fully cool and turn on one zone to test. Thank you.

I am definitely interested in having someone come out to resolve my issue in person. I've already had 2 people out to check on it, and paid for their fees just to show up, for them to tell me everything is "normal". I am hoping to do a little of my own leg work here and try to recreate the bang so that I can point them in the right direction next time someone does come out. I did find a provider through this website in my area, I am near Cleveland, Ohio, and he seemed to be really knowledgeable when I called him to see if he would be my right guy. I am a mechanical engineer, been out of work home with my little kids for a few years, but will be back working next year. So these concepts aren't completely foreign to me and I do enjoy actually figuring it out, but this was never my area of expertise (although those in the field who do piping work are paid SO WELL haha).

Thanks I will keep you posted and you are all so helpful. I really appreciate people with the heart of a teacher and I am just so thankful.

Ironman

This may be easier than you think. Can you get a pic of the part where I've indicated that's more clear? It looks like it may be the slot that operates an isolation valve in the pump flange. If that's true, it would be very easy to remove the pump.

Harvey Ramer

I am curious. Have you resolved the issue with the banging pipes?

katiejune

Hi everyone. Thanks so much for keeping me in your thoughts. I have a lot to tell you although I'm not sure I found my solution.

First, Harvey, I did do your test for the flow check. I did not hear any bang when I started it back up. However, the day that I tested it the outside temperature was near 45F I think, so I wonder if there was a sufficient temperature differential to properly conduct the test. I do want to repeat it, but now its nearly 10F where I am, so I will wait just out of fear I will break the whole system. What was interesting is that when I turned on the family room zone during this test, I did hear a bang. That zone is the only zone on slab, and the way that the room is set up, the heat is very inefficient so that zone right now is always on and I have not heard any bangs.

I have also not heard any bangs since setting my aquastat temp down as low as I could. 180F is technically the lowest number on there but I did try to set it lower.

So I'm not sure if the lower overall temperature has fixed my problem; or if my family room zone has a pipe friction issue somewhere; or if my flow check test was conducted accurately. However, I do know that *for the time being* I am only being woken up by my new baby.

I am pondering all of this and watching intently and will keep an eye on it all.

Thanks so much everyone you are so valuable and I hope you have great holidays!!