Well, its be -20 here in Indiana the last 2 nights.
On Wednesday evening, my wife was nagging that the house was getting cold. I went downstairs and grabbed the boiler line and it was cold, I started thinking I lost the fire, but when I go outside to check the boiler is registering 248. I go into my garage, and the wind was bad enough that it actually froze my return lines on my radiant heat lines. Water was going in at 135 and by the time it was returning it was 28, and caused the lines to freeze. So the supply 3/4" line next to the pump burst and lost all my water from the boiler. I shut the valves on the radiant in the garage and hook up my hose in the basement. Good thing I installed a fill port inside the house... Slowly start filling the boiler with hot water, and then turn the pumps back on to start circulating the water, it takes 20 minutes to get the boiler below 180.
Now the boiler was keeping up with the cold until Wednesday, now its not keeping up, and was 64 in the house this morning, normally 72. I'm thinking that there may be air block in the water coil. I'm not losing water anywhere as the water level has settled. Thoughts?