Re: water hammer from boiler
Posted by Moore on November 08, 1999 at 00:34:44:
In response to Re: water hammer from boiler
The loud bang is a result of the zone valve closing at a rapid rate, and the steam under force, hitting the valve blades and slamming them shut against the valve seats. Several things can be done, but the problem is that the packing and manufactured thickness of the valve stem is being worn, which allows the valve to shut too rapidly. In the event the loud bang is in one register only, and you want to quiet the noise without the cost of valve replacement, you can build a noise inhibitor. Commercial buildings like hospitals and factories that deal with this all the time contact steam pipefitters for a solution. They go to the insulation supply house and get valve packs and encase the valve with an insulation that can withstand the heat and humidity, and then lace the packing with stainless steel wire. If your installation is in a home, and the baseboard heater is readily available from Sears or a plumbing supply house, you can take the serial and model numbers off the offending heater in that zone, buy the replacement heater, bring it home, turn off the steam, open the union, remove one, and replace the other. If this is a commercial unit and requires special treatment, e-mail me. and we'll discuss options. e-mail me at

: When the house reached the pre-set temp. and the zone valve shuts off the hot water flow to the baceboard heaters, there is a loud bang. Will bleading the system correct the problem or does it requers something more drastic?

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