Intermittent banging noise on wall mounted boiler.


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Old 09-27-06, 09:21 PM
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Angry Intermittent banging noise on wall mounted boiler.

I have a potterton netaheat 8e wall mounted gas boiler with 3 zones. 1 zone is for a 30 gallon triangle tube phase 3 indirect for hot water. and the other 2 go to baseboard in the front and the rear of the house (all 3 have honeywell zone valves on them ). There is a strap on manual reset type high limit set at 170 degrees(Tradeline L4006 A 1004) and an operating limit of 140 degrees (honeywell L6006 A 1269 probe style) all are mounted on the supply side of boiler, there is an amtrol 30 exp tank and an amtrol air scoop, plus an additional 1/8 air eliminator. The circ is a grundfos with built in check on the return side of the boiler, picking up all 3 returns before going back into the boiler. t& p guage is normally 12-14 psi @ 140 degrees. sorry if I seem winded I am just trying to give as much info as I can. The cold water feed(watts common style dont know model #) is into top of air scoop. Ok here we go after using the water for a period of time a loud banging is coming from the near boiler piping that you can hear through the whole house.It seems to originate around the supply side of boiler by air scoop and expansion tank as I said "seems" I have noticed that while this is happening the psi goes up to 20-22 psi and the temperature shoots up to 220 degrees which sets of the manual reset in turn shutting down the boiler till I manually push the reset. Now last nite after reseting and not using water for a couple of hours I heard the banging again and it was the same thing pressure and temp shot up tripping the high limit(both high and low are brand new limits ) any ideas before I break down and call for a PRO.....just to let you know exp tank is good ,relief valve is not popping ,zone valves are in working order and right direction , circ is in right direction ,air is fully purged from both heat zones and indirect. Any help would be greatly apprieciated, I really cant afford a pro and can handle most things on the boiler. Cant wait to see the responses,will be glad to offer any additional info...thanks guys
 
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Old 09-28-06, 08:48 AM
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Is this a new install?

Can you post some pics of the near-boiler piping?
 
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Old 09-28-06, 09:09 AM
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Sounds like you may have an air pocket in there. Water molecules will expand 16,000 times in an air pocket causing popping and banging sounds.
 
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Old 09-28-06, 10:00 AM
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pics and air pocket

will try to get some pics of near boiler piping on here ....in the meantime I will repurge all lines again just to make sure I did not miss any air, and recheck the expansion tank...lwill let you know how I make out .....thank you for the speedy replies
 
 

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