Hydronic baseboard system nightmare

mattmia2

the tapping for the vent is npt, usually 1/8"

hot_rod

get rid of these boiler drains and replace with a full port ball valve and hose adapter. You will move a lot more flow. Also flowing backwards through a bib type valve, like you have can pop the washer off and block flow.

Also buy, or build some 3/4 hoses instead of the 1/2 or 5/8 washer hoses. That alone will take you from 8- 10 or 11 gpm capacity. I sacrificed an older 3/4 garden hose and made a bunch of jumper hoses for purge and flushing. 5 and 10 footers are handy. Some with only one end for purging.
If you try to purge through 35 or 50' garden hose you reduce flow also, keep the hoses fat and short

Cherny

Just wanted to give an update and some closure to this saga (spoiler alert: it's not over yet)

Since removing the Spirovent sludge plug and running some cleaner through the system, we had about 3 weeks of flawless performance. I was able to turn the boiler temperature down to 170 degrees and the efficiency setting to MAX. The house was nice and warm.

All was well until 3 days ago when we were awoken by a LOT of air noise in the baseboards in our bedroom. The baseboards were hot, the noise quieted down after a couple of minutes, and everything seemed to be well. I thought maybe just some air in one of the zones I had not purged completely when re-filling - left it alone as the system seemed to be running OK.

Over the next 2 days I started noticing the boiler cycling on and off a bit more than usual given outside temps. Then one morning our bedroom got really warm. The thermostat was OFF and not calling for heat, yet the baseboards were warm to touch. Checked the zone valve and that was operating correctly. Went down to the boiler room and noticed the water supply line near the pressure tank was VERY COLD, indicating there was water coming into the system... which could only mean one thing. We had a leak - that would explain the sudden air, and figured out that we were probably getting flow through the zone BACKWARDS, up the return line and out wherever the LEAK was. I went ahead and started following the supply line (which runs in the slab) to where it comes out to go up to the second story and right where it comes out of the floor I could hear some turbulent flow through there. After some investigating with a thermal camera, I found a 3-4ft diameter heat stain on the tiled floor near that spot. The tiles were quite warm to touch. No surface water though but obviously a leak below.

So, our suspicions/fears about the poly-b were correct so we have decided to go ahead and re-plumb the system with PEX in a couple of months. It will be a huge job as we will be opening up the ceiling and walls in our finished basement to replace all the lines currently running in the slab, but we have no choice at this point. We got lucky with this leak not causing any damage, and know the next one could be a different story.