Hi everyone. This is my first post here, but felt like I should tell my story and why I (hopefully) am glad to have Pumping Away as a lethal force weapon to use with the local Chicagoland HVAC companies.
I had a new NTI modcon direct-vent combi boiler installed to replace an old 80% efficiency (probably more likely running at 65-70% given how crappily it was originally set up) cast iron unit going through my house's flue. My goal was to get rid of the flue requirement so I can eventually yank out my very old chimney, and to better utilize the basement space. The installer achieved that. The hot water works just fine.
However, as I found out shortly thereafter, my radiators now had all kinds of bubbling / cavitation noises going on, especially upstairs. I didn't really know why, so I called the company back out. They refilled the system, upped the static pressure a couple PSI, and left. Of course, the prior, junky cast iron boiler didn't exhibit this problem, probably because it was pumping away from the tank. More on that in a few sentences.
...and, as I'm sure those of you who have read Dan's book can attest, the bubbling noise came back despite the raised pressure. I had to basically educate this company after reading Pumping Away and checking out Dan's site here about how modern hydronics works, and why the fact that they had the B&G pumping into my Amtrol tank, and then into the boiler return, was pulling air out of solution at my top radiators. I had to remind them that both Amtrol and NTI say to put the darn pump after the tank, and in both cases, also after the supply side of the boiler.
Today this installer was back after having agreed to pipe everything the correct way, according to basically all of Europe and Asia, as well as the NTI and Amtrol manuals. Nevertheless, all the installer did was move the spirovent from the return side to the supply side and hike the static pressure to 20psi for my average two story home (!!!). He tried to call it a day, at which point I called the HVAC company and effectively told them that's not what their operations manager actually agreed to do, and why it won't solve this problem. They are finally piping it the correct way. I'm hopeful that Dan is in fact correct (and I'm pretty sure he is) and that my bubbling problems will now go away.
I tell this story as a cautionary tale for anyone who might be running a hydronic heating system. Spend the money on Dan's book. Do some basic research on the Internet. And then ask your HVAC company on any potential install, where will they be piping the tank and pump? If you don't, you might get an installer like I did that says "this is how we've always done it and we don't have problems."