Posted by Tom Fischer on December 24, 2000 at 10:04:56:
My new CG5-A Weil-McClane boiler makes a very loud boiling noise in the boiler (and conducted through the pipes) for about 46-90 seconds at the beginning and end of each heating up cycle. Strangely enough, it only does this when just one of the 5 zone controls calls for heat. The boiler is only 3 months old. The previous boiler and system never made this sound.
Coin vents have been installed in each room on each floor of the home to bleed all air out of the system. But the noise remains and is quite annoying, especially at night when all are sleeping.
Does the boiler need extra venting? A strong pump? Anything else? It does not make the noise if the temperature is reduced from the normal 180 degrees to 150. Unfortunately, when the boiler is at the lower temperature the house doesn't heat sufficiently for Michigan winters.