boiler system full of water?

JohnNY

I'm a plumber for 25 years and I don't know what "empty pipes" sound like.



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kevin_49

boiler system full of water?


Guys,

I can tap on the return lines of my hot water boiler and they sound empty. I assume the lines should be full of water all of the time. I have bled the radiators and not much air in them. When I open the purge valves on the return manifolds all water comes out. The system is working well with the exception of the relatively short run cycles (some as low as 7 minutes some as long as 12 minutes) I was thinking maybe there is air in the system. I have checked things out and it seems ok with the exception of the pipes sounding hollow. The last thing I just tried is opening the watts valve to allow more water in the system. This water came out the pressure relief valve. How can I verify that the boiler if full of water and not air?

Kevin

Brad White_152

If it ain't broke, don't fix it....

Aside from the pipes 'sounding hollow', the system works. When you open drain valves water comes out. When you vent the radiators, not much air comes out. (Does water come out of the highest radiators in the system?) When you add water to the system the pressure relief valve spews. ((What is the pressure when this occurs? Should be 30 psig).


All told, sounds normal to me, but I would want to see my pressure between 12 and 18 psig for a 2-story or 3-story house, respectively.

kevin_49

When I opened the fill / watts valve it sent the pressure to about 42 PSI. Not surprising that it opened the pressure relief. When I close the purge valve bleeders and the watts valve is closed the pressure is about 20 PSI.

When I had the bleeders and fill valve open I could feel the pipes were cold from the fresh water input. They sounded the same. I think that this was a false alarm and I now agree with JohnNY that you cannot tell by tapping on the pipe. I bled each loop last night for about 10 minutes each and no air came out. This is a good sign that no air is present. Thanks for your help on this.

Kevin