Water Heater Flue Pipe Making Knocking Sounds

[Ganq]

City/county are not going to be any help.
I doubt an outside inspector will have anything to contribute. Even the WH mfr customer service # might have something to contribute. That noise is way-extreme if it is just expansion/contraction.

Unfortunately, if the builder does not respond reasonably, first, a complaint to Contractor's license board if you have such. And an attorney, though, frankly, an attorney's retainer alone may cost more than a complete replacement with either another brand of forced draft or go to a condensing tankless with plastic venting. My favorite, Navien 240A2 series can travel 60' in 2" PVC, or tie in to the existing at the 2" or the 3"

Thanks for the response. Never thought about reaching out to the Bradford White WH customer service - will probably do that.

How do I go about finding the contractors license board for Chicago/Illinois? - is this related to the builder or the plumbing company?

Yes a lawyer could be expensive and hopefully we won't come to that. One of the Plumbers from the company did mention that a tank less WH would be ideal but not sure if the Builder is willing to replace the current one with a tank less.

And thanks for the Navien recommendation, will look into that. The latest update I have is that the Plumbing Company is recommending the Builder to replace the WH and see if that fixes the issue but at this point no one is sure what exactly is the root cause of this. I never thought it could be the WH and mostly the pipes but who knows.

 

[Ganq]

While I know at least one member above is sure the city won't help, I might suggest calling the plumbing inspector and asking - this is a gas vent, CO hazard, state code enforcement takes CO danger seriously.

That said, if the knocking happens for a period and then stops with the heater still running, it's thermal expansion - if it's constant, then it's probably not secured, may need seismic/perpendicular restraint in the attic, if it's on long hangers it could be swinging (literally) via vibration from the power-vent blower.

Hi, thanks for the response. When you say Plumbing Inspector, are you talking about a regular home inspection?

Will try a CO tester/monitor and see if the levels are high.

The knocking happens when the WH turns on the pipe gets warm and then when the WH turns off and it starts cooling. It's not constant and happens all through out the day and night. The plumbers told us that's 'cause the WH turns on/off automatically to keep the water at a certain temperature.

I am not sure what these things are called but the entire flue pipe is on these clamps all over the attic and we were told by the Plumbers that the pipe needs to be slanted at a certain degree so that any moisture/water flows back - Please see attached pic.

 

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[GrumpyPlumber]

Each town has it's own plumbing inspector that works for that town and inspects new installations, new construction.

As for the noise, I asked about timing because it's PVC piping which has a high thermal expansion ratio - 3/8" per ten foot/100 degree F, the sound being most prominent when heating up or cooling down tells us the problem, going by your description, that's what it is.

PVC piping needs to be installed with consideration to thermal expansion/contraction, sounds like it's tightly secured or a fitting is too close to a solid surface....Your plumber might be wasting time/money if he's considering a full replacement....and, ironically, it won't fix the actual problem above.

You may have noticed sometimes in your's or other homes when you pour hot water down a drain you hear ticking or squeaking, similar to your own problem now.

Last, humorous note, woke up this morning to an obnoxious tapping sound, turns out I hadn't noticed your looped video had sound (had tv on in background while here last night) I fell asleep with my laptop next to me on the night table - so, yeah, that sound would drive me nuts too.

 

[Jeff H Young]

Yes, we do have quite a bit of email communication over the last 2 years about the knocking issues. I don't exactly recall what all the emails say but there is definitely an acknowledgement on the builders part that a problem exist and this kind of loud knocking isn't normal - I have email/text messages from the builder rep + the construction manager saying this isn't normal knocking sounds a pipe should be making over text.

In the last 2 years the plumbers have been here for atleast 7-8 times for this particular issue.

I did hear back from builder and it seems the plumbing company is asking them to replace the water heater and see if that fixes it. The builder is okay with that but they did ask the company if that will that fix the issue? and the plumbing company isn't sure so we are kind of in a limbo right now.

This is a little crazy They agree there is a problem they dont know what it is so they cant fix it? replace the water heater and if that dosent work replace the entire vent system or vice versa no matter how dumb it sounds that should fix problem.
I belive these guys are dragging thier feet because they dont want to demo out a bunch of drywall exposing the vent system, grasping at straws but hey I dont know could be water heater (i really doubt it) has the water heater rep been called to job?

 

[Ganq]

Each town has it's own plumbing inspector that works for that town and inspects new installations, new construction.

As for the noise, I asked about timing because it's PVC piping which has a high thermal expansion ratio - 3/8" per ten foot/100 degree F, the sound being most prominent when heating up or cooling down tells us the problem, going by your description, that's what it is.

PVC piping needs to be installed with consideration to thermal expansion/contraction, sounds like it's tightly secured or a fitting is too close to a solid surface....Your plumber might be wasting time/money if he's considering a full replacement....and, ironically, it won't fix the actual problem above.

You may have noticed sometimes in your's or other homes when you pour hot water down a drain you hear ticking or squeaking, similar to your own problem now.

Last, humorous note, woke up this morning to an obnoxious tapping sound, turns out I hadn't noticed your looped video had sound (had tv on in background while here last night) I fell asleep with my laptop next to me on the night table - so, yeah, that sound would drive me nuts too.

Thanks! will find the plumbing inspector contact for our city and reach out if we don't get to a favorable solution soon.

Lol yeah - the sounds almost like someone using a hammer and if it's in the middle of night, it's even louder with no other sounds + if the HVAC is also off.

 

[Ganq]

This is a little crazy They agree there is a problem they dont know what it is so they cant fix it? replace the water heater and if that dosent work replace the entire vent system or vice versa no matter how dumb it sounds that should fix problem.
I belive these guys are dragging thier feet because they dont want to demo out a bunch of drywall exposing the vent system, grasping at straws but hey I dont know could be water heater (i really doubt it) has the water heater rep been called to job?

No, no one I know has reached out to the WH contact. Apparently the Plumbing company is the one who install these WHs in our place and all other homes around from the same builder.

Wonder if we replace the current WH with a tankless one like @Breplum mentioned - Do we still have to have a flue pipe?

Is a tankless WH better than a regular one and doesn't make much noise compared to a regular one? - not sure if I should explore this idea and bring this to the builder.

 

[GrumpyPlumber]

Tankless is more expensive for initial install, but better in all ways but one, delay time.

As for the vent going all the way to the roof, not knowing your home's layout, in my area we would run the vent out the sill at 1rst floor level, I'm thinking you live in a townhouse condo where there's no room to vent out the side of the structure, or there's obstructions at ground level around the house.

 

[Ganq]

Tankless is more expensive for initial install, but better in all ways but one, delay time.

As for the vent going all the way to the roof, not knowing your home's layout, in my area we would run the vent out the sill at 1rst floor level, I'm thinking you live in a townhouse condo where there's no room to vent out the side of the structure, or there's obstructions at ground level around the house.

What is a delay time? - Does it take longer for the water to heat up? Will there still be a flue pipe?

We are in a 2 floor townhouse and the vent goes out the roof.

 

[GrumpyPlumber]

The water takes usually about 30 seconds longer than conventional.

As to the vent, I assume your present setup is for a reason, as stated above, which means the tankless would be the same.