Water hammer after replacing zone valves

[bobk26]

Hi, I own a split-level house with three zones for our hot water baseboard heat. We recently had a local HVAC guy replace the three zone valves after some issues we had with heat not coming on.

We now have heat, but we also got something new: a water hammer in our heating pipes. It's fairly loud - I can feel the pipes vibrating in the floor when it happens.

However, it doesn't happen all the time, and it's not consistently repeatable. I can't just cycle a zone on and off and hear it happen, and I'd love to have some more certainly before I have him come back for a potentially lengthy follow up service call.

I haven't counted every time it's happened, but it happens at least a few times a day. I never heard a water hammer ever in this house before this zone valve replacement job.

I have two questions:

1. Is there a common reason a water hammer would occur after replacing a zone valve?
2. I assume this water hammer problem is bad and needs to be fixed, right? It's not just something I should live with?

Thank you!

- Bob

[GREGHVACGUY]

1- yes there is a main reason to why it happen. ( this is not a DIY site so can't give to much help) Look at the way the water flows.
2- yes have it fixed it will cause issue over time.
Try running other zone calling for heat when you turn other ones on and off.

[bobk26]

Thanks for your message! I'm not looking to fix it myself, just trying to understand the issue. Can you help me understand what the main reason is? Thanks!

[bobboan]

There's an arrow which indicates the direction of flow through the valve, if it's backwards, hammering can occur.

Was a new pump installed or any of the piping arrangement changed?

[dan sw fl]

Thanks for your message!

I'm not looking to fix it myself,
just trying to understand the issue.

Can you help me understand what the main reason is?

Thanks!

What is the Duration of the Noise?

Waterhammer duration is a Very Short Event.

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https://www.thebalancesmb.com/solve-...-issues-844851

[pecmsg]

Get it corrected. Water hammer leads to piping failure.

What type of valves did they install, Solenoid or ball valve? Pumping away or toward the valve?

[Poodle Head Mikey]

Is there a 15-20º difference between the boiler's supply water temperature and the boiler's return water temperature?

If not; I would start looking for the problem there.

PHM
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Hi, I own a split-level house with three zones for our hot water baseboard heat. We recently had a local HVAC guy replace the three zone valves after some issues we had with heat not coming on.

We now have heat, but we also got something new: a water hammer in our heating pipes. It's fairly loud - I can feel the pipes vibrating in the floor when it happens.

However, it doesn't happen all the time, and it's not consistently repeatable. I can't just cycle a zone on and off and hear it happen, and I'd love to have some more certainly before I have him come back for a potentially lengthy follow up service call.

I haven't counted every time it's happened, but it happens at least a few times a day. I never heard a water hammer ever in this house before this zone valve replacement job.

I have two questions:

1. Is there a common reason a water hammer would occur after replacing a zone valve?
2. I assume this water hammer problem is bad and needs to be fixed, right? It's not just something I should live with?

Thank you!

- Bob

[VTP99]

Did the tech change valves like for like ?

[kangaroogod]

What manufacturer of valves? The reason this occurs is that as the water (which has mass) is running through the piping and the zone valve closes, the mass of water needs to stop immediately (which it cannot without dissipating its energy) thus the banging. This is similar to a vehicle hitting an immovable wall. The energy is absorbed into the vehicle as it collapses.

Zoning with zone valves (which is common In residential) causes challenges. 1 zone may be long and 1 zone may be small. Each zone would in theory require different circulators as it is either oversized or undersized. This is the reason that it is preferred to zone with circulators instead of valves. There are ways to help/eliminate the banging depending on the manufacturer or valves and the piping arrangement of your system

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[bobk26]

No new pump was installed, nor was any piping changed. It was just the three zone valves that were replaced.

Thanks for the heads up about the arrow direction; I'll see if I can see anything, and ask my installer about that. Thanks!

[bobk26]

[QUOTE=dan sw fl;25857764]What is the Duration of the Noise?

Waterhammer duration is a Very Short Event.



It's a loud, short bang. The pipes vibrate for a second, and then it's done.

[bobk26]

Get it corrected. Water hammer leads to piping failure.

What type of valves did they install, Solenoid or ball valve? Pumping away or toward the valve?

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I believe it was a ball valve. If it matters, I just looked at the sticker, and it's a Honeywell V8043F1036.

Being the homeowner, I'm not sure about direction of water flow and such. I can try to poke around more, but sorry I don't have more info.

[bobk26]

Is there a 15-20º difference between the boiler's supply water temperature and the boiler's return water temperature?

If not; I would start looking for the problem there.

PHM
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Thanks, PHM. I'll try to do some looking into the different water temperatures.

[bobk26]

Did the tech change valves like for like ?

VTP99, I believe he did. I know he needed to drain the heating system to replace the actual ball inside the valve, but he said in the future I'd probably be able to just change out the motorized actuator in the event of a failure. I don't know if any of this matters for the water hammer problem, though. But thanks for asking!

[BALloyd]

Are you sure your boiler pressure relief has not been intermittently relieving since the work was done? The relief valve trying to reset can be loud and sound like water hammer.

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[bobk26]

What manufacturer of valves? The reason this occurs is that as the water (which has mass) is running through the piping and the zone valve closes, the mass of water needs to stop immediately (which it cannot without dissipating its energy) thus the banging. This is similar to a vehicle hitting an immovable wall. The energy is absorbed into the vehicle as it collapses.

Zoning with zone valves (which is common In residential) causes challenges. 1 zone may be long and 1 zone may be small. Each zone would in theory require different circulators as it is either oversized or undersized. This is the reason that it is preferred to zone with circulators instead of valves. There are ways to help/eliminate the banging depending on the manufacturer or valves and the piping arrangement of your system

Sent from my SM-N960U using Tapatalk

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Hi Kangaroogod, thanks for your helpful reply. It makes sense that there are downsides of using zone valves. The thing that confuses me is that I never had this issue before the zone valve repairs happened, which makes me think it's not a flaw in the layout, but rather something that happened during the installation. Do you have any thoughts on this?

[bobk26]

Are you sure your boiler pressure relief has not been intermittently relieving since the work was done? The relief valve trying to reset can be loud and sound like water hammer.

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BALloyd, I'm not sure about that, I can have him look into it. It happens multiple times a day, so I don't know if that's normal for a pressure relief valve or not. Thanks for the idea!

[BALloyd]

BALloyd, I'm not sure about that, I can have him look into it. It happens multiple times a day, so I don't know if that's normal for a pressure relief valve or not. Thanks for the idea!

You pressure relief valve is a safety device and should never operate unless there is a problem. In fact they are often required to be replaced on a regular basis to ensure proper operation in an emergency so your boiler does not explode

It definitely should not be activating several times a day and if so, is a sign of a serious issue with your system.

If you know where it drains to on your system, you should probably be able to see water on the drain of it has opened recently.

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[VTP99]

VTP99, I believe he did. I know he needed to drain the heating system to replace the actual ball inside the valve, but he said in the future I'd probably be able to just change out the motorized actuator in the event of a failure. I don't know if any of this matters for the water hammer problem, though. But thanks for asking!

Wait, to be clear, are you saying he just replaced the ball and not the entire valve ?

[BALloyd]

Wait, to be clear, are you saying he just replaced the ball and not the entire valve ?

He might mean that whole valve was replaced. If I remember, the old Honeywell zone valves could not have the actuator changed, but the new style have the ability to change the actuator if the valve is still functioning.

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