Hammering boiler?

Thorn

This is our second winter in a 110-year-old house with a Weil-McLain HE II boiler installed in I think 1995, per the notes the prior owner sharpied on the side. We started hearing some knocking (not sure it rises to the level of hammering) a few weeks ago and my partner has been trying various things to make it stop. It started again just now when the heat came on and I went down to the basement to pinpoint the noise and it truly does seem to be inside the boiler, not any of the pipes or anything.



I'm not having any luck googling for this since every comment about hammering pipes talks about the boiler too, but any ideas what's going on here? The pressure is at the low end of normal (11 when the notes marked say 11 to 25 is what you want) and we might not be adding water the right way since I'm not sure whether the knob on the water pipe needs to be turned or not, but we're hoping there's a simple solution. (Also that this isn't the setup for a horror movie. Help! The sound is coming from inside the boiler! Sheesh, maybe I need to get out more and not focus on heating on Friday nights.)

Jamie Hall

This might be better...

on the Main Wall, as from the pressures you quote it sounds as though this may be a hot water, rather than a steam, heating system.



And I am certainly not a hot water heating system expert!  But there are a number of really knowledgeable folks on the main wall who are.



That said, my first guess would be that the water temperature is set too high -- but as I say, what do I know?

pipeking

THORN

 LET SEE..... do u have steam or hot water? so this is easy for u so find out, do u have a sight glass on the side of the boiler that looks like this

Hap_Hazzard

Sounds like cavitation noise.

But, as Jamie said, you're better off asking about this on the main wall. Cavitation can be caused by air bubbles, running too hot or restricting the flow to the circulator, so about all I could suggest is bleeding all the air out of your system and checking the temperature, though I'm not familiar enough with HW systems to even tell you how to do it or what the normal temperature should be.

ttekushan_3

Weil McLain HE II boilers

Are hot water boilers and were typically supplied with an AMTROL Fill-trol that adjusts the water pressure in the system. The diaphragm tank MUST be properly charged for this system to work, or you have insufficient pressure and boiling will begin to occur within the boiler. It can be quite startling.



I usually use a bicycle pump on the schrader valve at the end of the fill-trol diaphragm tank to pump it up to 12 lbs or so. Use a tire pressure gage. Or you can replace it with a new one. It will be precharged to 12 psi.



Here's what you probably have:



http://www.amtrol.com/filltrol.html