# Hot water pipes (closed system) vibrate very loudly.



## Viper16 (Sep 22, 2009)

I would think about getting a water hammer arrestor. I wonder if the expansion tank has the correct preset air pressure on the air side of the diaphragm. Where was this tank pressure gauge located?


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## Peety (Feb 5, 2010)

*Question about arrestor*

Thanks for replying.

Excuse my ignorance but I don't think this system has any quick-closing valves, like those on the hot water heater system for the house - does that matter? Actually I don't think there are any valves at all (except the shut off valve on the cold inlet pipe.

The water gauge is a dual gauge located on top of the tank itself for altitude and water pressure. It is set for thirty feet and about 6-8 psi at the moment.

I removed the cap on the expansion tank (it was dry) and was going to measure psi with a tire gauge, but I don't know what it should normally read - right now I have the system off and will check it when the temp comes down on the water.

This just happened after a very long time, would I need a certain type of arrestor?


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## JohnH1 (Jan 9, 2009)

If it only happens when the pump operates then it has to do with the pump not water psi or hammer. Is this a 3 piece pump with a spring coupling that joins the motor to the bearing assembly? Post a pic if you can.


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## Peety (Feb 5, 2010)

*pictures*

ok thanks. Here's my artwork. I can feel a slight vibration nearer the pump, but it sounds like a rocket engine by the time it is transferred up stairs 


edit: as I look at the pictures I note the corrosion on the flow regulator leading from the tank in the second picture, lower left (as posted). I'm going to drain the tank a bit and dissemble that puppy. Could it be a corroded flow valve is straining the pump? No idea.


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## JohnH1 (Jan 9, 2009)

I would guess that it is the spring coupling in the pump slightly out of alignment due to sagging motor mounts. At the ends of the motor part of the pump there are rubber rings. Eventially they will sag and cause the shaft of the motor not to line up / or be perfectly leval with the pump shaft. This can cause the spring coupling to make noise and eventually break and when that happens you will really here it. I would change out the ring set and coupling.
http://www.bellgossett.com/homeown/manuals/boosterpump.htm


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## beenthere (Oct 11, 2008)

And or minor cavitation from being slightly low on water for a 2 story house.


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## JohnH1 (Jan 9, 2009)

Yep I did not think of that. Especilly since the pump is on the return with the diaphram tank on the supply all the head is on the suction side it would definetly be in the negitave.

2 story aprox 15 to 20 ft height at the most. Say 6-8psi + 4 extra No more than 10-12 psi will be needed.


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## Peety (Feb 5, 2010)

*Thanks!*

Ok thanks everyone for responding and info and thanks JohnH1 for the Service Manual and Guide link.

We've got some work ahead of us which will take us awhile and this thread may close so I'm going to say now THANKS! 

:thumbsup:


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