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Water hammer in hydronic system

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Mark_4
Mark_4 Member Posts: 13
in THE MAIN WALL
Haven't seen much of it in recent years, but a few yaers back , when the older style close coupled circulators were replaced with the newer higher velocity "cartridge" circulators , the spring tension that closes the zone valve would shut it to quickly. This would usually only happen if two zones were calling & one would close while the circulator was still running, causing water hammer. The remedy was (back then) to remove one of the springs on the zone valve, so it would not slam closed.

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  • Randy_7
    Randy_7 Member Posts: 23
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    Severe water hammer in hydronic system

    I recently moved into a home that is 30 years old, has a newer boiler, 3/4" copper piping, 3 heat zones with original Honeywell valves, and water hammer that wakes us at night when zone valves close. Even during the day it sounds as though someone is beating on joists with a hammer whenever a valve closes. The hammering seems to have become louder since the ceiling mounted expansion tank was replaced with boiler mounted Amtrol (though that may be my imagination).

    Wire pipe hangers have been replaced with Flexi-fin plastic hangers and many additional hangers have been added, but all that seems to have accomplished is to relocate the hammering into areas that are not accessible.

    Suggestions would certainly be appreciated as all this noise is going to make for a long winter. Many thanks.

    Randy
  • Gary Fereday
    Gary Fereday Member Posts: 427
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    Slamming !

    check to see that the valves are installed correctly as to direction of water flow. If a new pump was installed at the time of the new boiler, it could have been installed 1. wrong way around, 2, to large ability of a pump for the system. (you may temporally throttle it some as a test to see if you can ease the hammering.) 3. end switches on the valves should shut off the pump when all valves are closed. Does this happen ? There, some guesses from way out west. bigugh
  • Randy_7
    Randy_7 Member Posts: 23
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    Gary and Mark: Thank you for your valuable responses. The newer boiler (1990)does have a properly mounted Grundfos circulator on the return line (lowest pipe on boiler and the directional arrow in direction of water flow) but it appears as though the 3 Honeywell zone valves are improperly installed for the present boiler configuration.

    They are on the supply side of the boiler (upper pipe on boiler that gets hot first) but the directional arrows on the valve bodies point toward the boiler (which is opposite of water flow) plus the IN/OUT designation on the valve body is also OPPOSITE of water flow. I assume Honeywell has valid reasons for wanting these valves installed in a certain direction. Does this sound like a potential cause of the water hammer? The valves are Honeywell # V8043E 1012 4 if that is any help.

    Many thanks again.

    Randy
  • Gary Fereday
    Gary Fereday Member Posts: 427
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    Indeed!

    The flow of the water is shoving hard against the seating of the of the valve. Aiding in closeing it big time. I cannot think of any reason that they would be installed wrong way around. You might Buy Dan's book "Pumping Away" from books and more here on the wall and do youe self a favor and change the pump location also. May as well do it ALL correct and enjoy a system that just plain works! bigugh
  • Gary Fereday
    Gary Fereday Member Posts: 427
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  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
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    sounds like

    they replaced an Edwards boiler, which would explain the backwards zone valves(G).

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  • Jackchips
    Jackchips Member Posts: 344
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    Hi Dave,

    what is, or was, an Edwards boiler?

    Happy, Healthy New Year to all.
  • Jim_13
    Jim_13 Member Posts: 18
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    Hangers?

    You can add all the hangers you want but in the end all you'll get is a well hung system. Back to the complaint. The valves are in backwards and the pump should be pumping away and not as you've described. A one day service call to reverse the valve installation and re-install the pump to pump away complete with air removal and you'll be soooo happy. Just curious,what model of pump is it?
  • Randy_7
    Randy_7 Member Posts: 23
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    Jim: Pump is a Grundfos UP 15-42F.

    All: Thanks much for feedback.

    Randy
  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
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    Edwards

    was a boiler that taught me a lesson! First time I encountered one of them, was for a dead B&G 100. Sure as heck looked like it was mounted on the return. After all it was the lower pipe tapping and the zone valves were manifold mounted on what should have been the supply - highest tap on the boiler. That night's no heat call revealed I hadn't paid attention to the volute on the pump!

    The Edwards was a counter-flow boiler. Threw off more than one service tech. Got to where I actually liked the little beasties & other techs would defer their service to me.

    I've seen more than one job where the Edwards was replaced & the installers failed to recognize the system's direction of flow! Bang go the zone valves.

    I've converted a number of them by replacing the zone valves with circs and spring loaded or standard flow checks & once that's done, you can also reverse the flow & pump away. Works slicker than poop through a goose!

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