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Posted by Joel on May 11, 2004 at 08:33:43:
In Reply to: Bang when zone valves close. posted by Bob on January 11, 2004 at 10:00:41:
: Last year I bought this 16 year old house. It has a new furnace, 2 years old. I have read some info on zone valves. Some suggest putting them on the return end of the loops, some suggest a hammer arrester, or seperate circulator on each line and some suggest putting in a differential pressure buypass. I tried removing one of the springs on each Honeywell v8043 but that didn't help much. Any thoughts out there to what is the best to do????
I had a similar problem in a dormatory. What I finally found fixed the problem was turning the set temperature of the boiler down by 10 or 20 degrees. There have been no problems since. My theory is that the combination of the high temperature water and the slight negative pressure in the line downstream of the valve as it closed caused a water vapor bubble to form briefly. When the negative pressure was relieved the bubble collapsed back into liquid and the slug of water hammered back into the valve causing the noise. Turning the temp. down makes it less likely for the bubble to form (water further from its boiling point) and eliminating the banging. That's my theory and I'm stickin' with it but I'd be interested if others have any ideas.
Joel