Water Hammer. Need your help!

e123b123

Hi all,
I have a hot water heating system in my home. 6 Zone Valves and 1 circulator. The circulator runs when any zone (thermostat) is calling.
My issue is that when one zone valve closes and another is still calling which means the circulator is still running i get very intense water hammer. any suggestions would be appreciated. see attached photos.

Jamie Hall

The direction of flow through most zone valves matters. If the valves are oriented so that the flow assists closing, they can close much too fast ;-- and hammer. Also check your expansion tank.

Mad Dog_2

Not too many years ago, We'd add in a 
Differential bypass Valve for zone valves and Panel Rads that has TRVs.  Now, A Smart pump control the banging issues by ramping up & down based on Delta  P.  Taco has all kind of Options.  Where are you located?  The Find A Contractor feature here has VG pros that can assist you if needed.  Mad Dog 🐕 

hot_rod

One recommendation is to have a pressure activated bypass when you have 4 or more zone valves.
Another option is to use a delta P type ECM.

e123b123

Jamie Hall said:

The direction of flow through most zone valves matters. If the valves are oriented so that the flow assists closing, they can close much too fast ;-- and hammer. Also check your expansion tank.

So actually the arrow of the valve is facing the direction the water is coming from but i don't understand why it was installed that way. i was thinking it was installed backwards. why would that be?

e123b123

hot_rod said:

One recommendation is to have a pressure activated bypass when you have 4 or more zone valves.
Another option is to use a delta P type ECM.

My pump is on the return line and zone valves are on the return, the drawings are showing different.

e123b123

Mad Dog_2 said:

Not too many years ago, We'd add in a 
Differential bypass Valve for zone valves and Panel Rads that has TRVs.  Now, A Smart pump control the banging issues by ramping up & down based on Delta  P.  Taco has all kind of Options.  Where are you located?  The Find A Contractor feature here has VG pros that can assist you if needed.  Mad Dog 🐕 

Where would i install the differential bypass?

HomerJSmith

I have encountered this problem before. The problem as I see it is that you are using an ECM pump and Honeywell ZVs. The ZVs are closing faster than the pump can rev down. The solution as given on this site many times and that I did to remedy the situation was to remove one of the springs on the valve, there are two springs on the valve. This will slow the closing of the ZV and give the pump time to rev down.
The water hammer should happen when the last ZV closes.

e123b123

HomerJSmith said:

I have encountered this problem before. The problem as I see it is that you are using an ECM pump and Honeywell ZVs. The ZVs are closing faster than the pump can rev down. The solution as given on this site many times and that I did to remedy the situation was to remove one of the springs on the valve, there are two springs on the valve. This will slow the closing of the ZV and give the pump time to rev down.
The water hammer should happen when the last ZV closes.

The ECM Pump you see on the wall is for something else. i have the taco pump on the boiler its a standard taco 0015. would removing 1 spring still help?

Teemok

e123b123 said:

Jamie Hall said:

The direction of flow through most zone valves matters. If the valves are oriented so that the flow assists closing, they can close much too fast ;-- and hammer. Also check your expansion tank.

So actually the arrow of the valve is facing the direction the water is coming from but i don't understand why it was installed that way. i was thinking it was installed backwards. why would that be?

This is the issue. Why it was done is not a fruitful question at this point. You may or may not need a pressure bypass but the water hammer cause is solved. I doubt you "need" a bypass valve with just that pump on the return. Bypasses help when the circulation pump needs to be large for the 100% zone call but is then large enough to push open spring closing zone valves. Looks like the capped one was installed correctly. Unsoldering and flipping them can be a pain. Be careful to not over heat the valve body and make sure the rubber door inside the valve is all the way open before heating them.

e123b123

Teemok said:

e123b123 said:

Jamie Hall said:

The direction of flow through most zone valves matters. If the valves are oriented so that the flow assists closing, they can close much too fast ;-- and hammer. Also check your expansion tank.

So actually the arrow of the valve is facing the direction the water is coming from but i don't understand why it was installed that way. i was thinking it was installed backwards. why would that be?

This is the issue. Why it was done is not a fruitful question at this point. You may or may not need a pressure bypass but the water hammer cause is solved. I doubt you "need" a bypass valve with just that pump on the return. Bypasses help when the circulation pump needs to be large for the 100% zone call but is then large enough to push open spring closing zone valves. Looks like the capped one was installed correctly. Unsoldering and flipping them can be a pain. Be careful to not over heat the valve body and make sure the rubber door inside the valve is all the way open before heating them.

I cant imagine they were installed that way by accident. there must be a reason. if i go and turn them around i may be hurting something else. so step one would be to learn why they were installed the opposite direction of flow.

HomerJSmith

Oh, I see, you are talking about the Taco pump on the return to the boiler. Is this a recent issue, if so what has changed? The Taco 0015 is a high head pump. Your pump appears to me to be a 3 speed pump? If so run it on the lowest speed. I don't think that removing one spring would work on a fixed speed pump although you can try it on one ZV and see what happens. Water hammer happens when the momentum of water slams against a brick wall with a sudden thud.
As hot_rod suggested a pressure activated bypass valve would work which would be more costly, I think I would add a Extrol 15 expansion tank at sys pressure or several pounds higher air charge as an air arrester and place it on the output of the Taco pump or further away on hot water supply piping.

Teemok

HomerJSmith said:

Oh, I see, you are talking about the Taco pump on the return to the boiler. Is this a recent issue, if so what has changed? The Taco 0015 is a high head pump. Your pump appears to me to be a 3 speed pump? If so run it on the lowest speed. I don't think that removing one spring would work on a fixed speed pump although you can try it on one ZV and see what happens. Water hammer happens when the momentum of water slams against a brick wall with a sudden thud.

Water hammer happens when a door type zone valve: ERIE, TAC, Caleffi is installed backwards. It often happens when two small zones are calling and one zone closes. The higher water velocity slams the rubber flapper door closed when the motor no longer holds it open. When they are installed correctly they close against flow. The closing spring slowly unwinds the motor elongating the time interval of closing. No hammer.
There's no question it was a mistake.
It happens. I've found it on experienced installers systems installed when they were having a bad day.
The only bad that can come from flipping them is burning the rubber door and solder joint leaks.

Teemok

The motors/actuator heads pop off the valve body. Open them manually with the side lever and press the button or small lever on the side and pull away from the body. Mark them well before removal.

Teemok

It's amazing your flue allows non-foil duct tape to live on it. I know foil tapes covers bad sheet metal cuts and joint fitment well. If the flue is design well, there's negative pressure inside it. There nothing coming out of well fitted joints, just very small amounts of air going into the pipe. Foil tape glue just dries out anyway. Same types of folks put pipe dope their flare connections as well as install zone valves backwards.

Teemok

A 0015 on high can push open some valves. I didn't note how big it is before. As advised above you can try lowering the speed. You might find with all zones calling a few will take longer to satisfy. Another option is the bypass valve or replace it with an ecm constant pressure pump. I'd flip the valves and see what it does and go from there.

e123b123

HomerJSmith said:

Oh, I see, you are talking about the Taco pump on the return to the boiler. Is this a recent issue, if so what has changed? The Taco 0015 is a high head pump. Your pump appears to me to be a 3 speed pump? If so run it on the lowest speed. I don't think that removing one spring would work on a fixed speed pump although you can try it on one ZV and see what happens. Water hammer happens when the momentum of water slams against a brick wall with a sudden thud. As hot_rod suggested a pressure activated bypass valve would work which would be more costly, I think I would add a Extrol 15 expansion tank at sys pressure or several pounds higher air charge as an air arrester and place it on the output of the Taco pump or further away on hot water supply piping.

The output of the pump is going into the boiler. 

hot_rod

Looks like the pump is on the return pumping down, check the arrow on the pump

Then check the arrow on the zone valves. They should be the same direction as the pump

has this always been an issue ? If not, has any thing changed in the system

Teemok

@hot_rod look at the valves. Not the closest one capped off. Erie pop tops I think. I went to the truck and got one to check it. They are backwards the manual open lever is on the inlet side.