Discovering Water Hammer

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Discovering Water Hammer

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bringtheheat

This post seems to describe exactly what is happening in my system. Our local HVAC company has been of no help and did not even come up with the idea to remove a spring from the zone valve. So what I need to learn is what I can recommend to them to fix the problem. Would I recommend a Circulator or a smart pump?

hot_rod

The first step would be to confirm the proper circ was installed. With zone valves a flat curve circulator is the best match.

If the system requires a higher curve circulator, then a pressure bypass could be used. some suggest any system wither that 4 zone valves should have a properly adjusted pressure bypass installed.

Yet another option is a delta P type circulator that has the ability to modulate based on flow requirements.

removing a spring only treats the symptom not the problem, it's a "non-professional" method to solving a problem






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bringtheheat

Thanks for the reply @hot rod We recently had the zone motorized valves replaced due to age and corrosion and since doing that the removing of a Spring trick is no longer working. Our system only has two zones (upstairs and downstairs).

bringtheheat

Here is some details about the system. Can you tell with this information if this is the right Circulator for this system?

Two Zones (Upstairs and Downstairs)

Boiler: Weil McLain HE II
Zone Motorized Valves: Honeywell V8043 E 1012
Circulator: Taco Cartridge Circulator Model 007-BF4-JW (max pressure 125 psi)

After reading the information @hot rod provided My questions would be:

1. Is our Circulator the right one for this system
2. Would a Variable Speed Circulator Control solution be best?
3. Is a Smart Pump essentially a Variable Speed Circulator or is this a different product and if so is this a better idea?

This system has been installed for over 20 years if that matters

hot_rod

Did the banging recently start, or has it always been a problem?

The bang is started by closing a valve off against a high flow rate, usually indicating the fluid is moving fast when the valve springs closed.

Possibly some of the piping fasteners have come loose allowing pipe movement? If it is a new condition?

What size boiler? how many feet of fin tube? Typically that model circulator doesn't have problems with zone valves, but it sounds like an over pumping condition.

bringtheheat

The banging has been happening for at least 5 years. Previous to that it either was not recognized or one of the zones was not used as much. It did go away for a year possibly two once we removed one of the springs on one of the zone motors.

The noise returned after having both of the zone valves replaced due to age (both of the new zone motors have one of the springs removed)

I did examine the pipes and none of them have any loose fasteners.

I am including a photo for details on the boiler since I am not entirely sure which details determine the size.

There is approximately 100 feet of fins installed and of course more copper piping to feed all of them.

hot_rod

yeah, I feel the ECM, delta P type of circulator would solve the zone valve noise.

The zone valves are installed in the correct flow direction, I assume?

Furthermore the ECM pumps consume 50% or less electrical energy, so two wins!

In some areas there are rebate programs to upgrade to ECM technology, check for programs in your area.

All major pump brands offer small ECM, delta P circulators

Grundfos 15-55 Alpha
Armstrong Compass
Taco Viridian
Wilo ECO
B&G Vario
AquaMotion Einstein

bringtheheat

Well I can only assume the Valves are installed on the correct flow direction.

bringtheheat

Looks like a $100 rebate is available.

Will installing one of these require a major makeover of the existing system or should there be a replacement circulator that can fit into the same configuration of the current one? Might be difficult to answer without seeing our system but still wondering.

Will I only need a new ECM(Delta P) Circulator, or will this require a DPBV (Differential Pressure Bypass Valve) to be installed into the system as well? Obviously I have no clue on this stuff so I am trying to figure out how many new parts will need to be put into our system.

hot_rod

Correct the delta P circulator should fit in the same location and mounting. it will not require an additional bypass valve.

It should be a simple switch, I surprised it was not offered by the installer?

bringtheheat

Yeah me too now that i know about this option. Is there such a thing as a non-ECM Delta P Circulator, or is the ECM required as part of this type of circulator in order to change the flow speed?

hot_rod

correct, it is the electronics "E", the microprocessor onboard that becomes the brains of the pump. Putting the pump in AutoAdapt for example, allows the computer to learn the hydraulic profiles of the system and optimize the flow rate.

Jamie Hall

Not on topic, sorry -- but some of the folks might be interested in a project I currently have going. A 48 inch raw water main under 300 feet of head. The rocket scientists in suits have decided to put a hydroelectric generator on the system -- there's enough extra head to generate some useful power and make some bucks and some good PR for the company. It will feed to the grid. My job is to figure out what to do about the water hammer in that 48 inch main when the generator goes off line and the governor on it slams the valve to it shut... actually, the first job is to persuade the suits that there is a potential for catastrophe here. Wish me luck.

Gsmith

Definitely consult an experienced hydraulic engineer. If the main is long, or if the flow volume of the generator is significant compared to the total flow in the main, or if the water velocity in the main is high (>5 fps or so), or if the speed at which the valve changes the velocity is high (short time to change either increase or decrease), then at that pressure there is significant likelihood the main or fittings will be damaged. The most important criteria is speed of velocity change. That is one reason why valves on public water systems take 20 to 40 turns to close--so persons operating the valves cannot easily close or open them fast, and why check valves on critical mains have slow closers. Be very careful.

Jamie Hall

For better or worse, @Gary Smith, I am the experienced hydraulic engineer (50 years experience in the field) on that project. And am well aware of the problems. Perhaps more to the point, I have several design options to manage the problem. The problem is convincing the suits that it is a problem... and getting them to spend the money.

It would be a good deal cheaper to fix the problem than to blow the poorly anchored 90 degree elbow about a mile upstream...

hot_rod

Jamie Hall said:

For better or worse, @Gary Smith, I am the experienced hydraulic engineer (50 years experience in the field) on that project. And am well aware of the problems. Perhaps more to the point, I have several design options to manage the problem. The problem is convincing the suits that it is a problem... and getting them to spend the money.

It would be a good deal cheaper to fix the problem than to blow the poorly anchored 90 degree elbow about a mile upstream...

Jamie, have you seen the Lucid Energy systems that generate power from turbines inside water mains?

The latest issue of IAMPO News has an article on a few systems.

http://lucidenergy.com

Jamie Hall

Those are neat gadgets! The turbine I'm playing with is a Kaplan turbine, but the general idea of extracting power from the excess head in a water main is quite reasonable.

As I mentioned above, though, the thing that folks seem to forget is that if the generator trips off line, the governor valve to the turbine will close very fast indeed -- and one has to cope with the resulting water hammer. Interesting project.

lchmb

bringtheheat make sure your circulator does not have an IFC...Your installer should know what that is...

Jamie...good luck...sounds like you'll need all you can get....

bringtheheat

Thanks @lchmb , I will mention that. What is an IFC ?

lchmb

internal flow check. it's not needed with zone valves and can be known to cause issues if installed. What town do you live in?

bringtheheat

ok

bringtheheat

@hot rod and @lchmb

ok the contractors I have contacted are not familiar with these products so I am doing the research on what to try. I have narrowed it down to the following:

Taco 00e Series VR1816
OR
Taco 00e Series VT2218

I spoke to a rep at Taco and he indicated either of these would work but neither of them specifically say Delta-P and one of them actually is a Delta-T so I am confused on which one would be the one to use.

Another idea he suggested was to just install a Zone Valve Control box like one of their products which is the:

ZVC403 Zone Valve Control

I am uncertain if just installing one of these would be a solution to my problem.

Do you guys or anyone else have any suggestions?

Thank You

hot_rod

I think a delta P circulator may solve the problem of banging zone valves. Or add a pressure bypass valve to the pump you currently have.

I like the Delta P circ solutions it provide 3 benefits. it will adjust flow rate as the various zone valves open and close, it should eliminate zone valve banging, and it will do all this with less electrical energy consumption.

I don't see how a ZCV would help with the zone valve banging, it does clean up and simplify the wiring if you need or want to redo that also.

If a new Taco is the final answer the VR 1816 is the one I'd use. It has plenty of adjustability to dial it in for your system.

bringtheheat

OK good to hear your thoughts on the ZVC @hot rod I was confused how that would help.

So the VR 1816 is a Delta-P then? Ok so this new circulator has adjustments. Fun I hope the installer knows how to adjust it properly.