Re: Yet another pipe noise questions...
Posted by CM on January 25, 19101 at 16:16:05:
In response to Re: Yet another pipe noise questions...
You may be out of luck and have to add vent(s) yourself. The air is going to tend to stay trapped at the high points, even if the water flow rate is high. Manual and automatic air vents are available at supply houses, and the installation is not too hard if your system is copper and you are comfortable making sweat connections.

Also, bubbles of air trapped in the flowing water and dissolved oxygen in the water can ultimately damage your circulating pump and reduces the efficiency of heat transfer surfaces.

The problem is not necessarily zone-specific, but depending on how the system is laid out, it may be isolated to one of the zones.

To prevent the problem in the future, make sure that your system expansion tank is not waterlogged (if it's full of water, drain it down to 1/4 full when the system is cold), or if it is a diaphagm type, that the pressure on the air side of the diaphragm is sufficient (you may have to get an engineer or heating specialist to calculate the proper pressure). This will keep the system pressurized sufficiently so that the high points of the system (where the pressure is lowest) will leak water out instead of air in in the event of a leak. If the system was installed without an expansion tank, you need to add one. Air eliminators that are piped in-line are also available to maintain an air-free system (although if you have trapped air already it will not eliminate this).

I know I've said quite a mouthful here. Don't hesitate to email me if you can give me more specific information or have other questions.

: Thanks, CM.

: I checked for the vent valve and don't see one (This is not surprising the additiona was built by the owner (literally) and he was a general contractor, not a plumber or heating specialist). There are 3 zones in the house. Is it correct to assume that this is zone-specific? Is there any other way to vent the system?

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