The pipe to the radiator finally rusted through & started to leak. I didn't figure out for a couple of weeks exactly why the carpet in the kitchen was wet or connect that up to the water streaks showing in the downstairs wall, but I found the drip & knew it had to be replaced.
First I had to figure out what was needed, so I couldn't do anything until Saturday evening, after work.
Why does trial and error always involve so much error, first?
I called Dave, who installed the original system, and asked him how to drain it, then turned off the water to the house, then drained the system and then went to the hardware store.
Why does everything I do require three trips to the hardware store and at least two tools that should have nothing to do with whatever I'm doing?
Of course, I work until 7 PM, so getting to the hardware store is contingent on when it's open. Not a lot of time.
First trip, on Saturday evening after work, I got the part, then found out that the part they gave me is the wrong size, but by then the stores were all closed. So I turned the heating back on, but the leak was apparently worse than before, so I went with neither heat nor water for Sunday. Sunday evening, I got what appeared to be the right part from the store that was open, but discovered, after I'd completely broken open the pipe, that it was, in fact, still a wrong part. No heat or water for another day. -11C with a windchill of -23C.
Finally on Monday, I went back, got everything I thought I might need, got the radiator detached, then found that I still did not, in fact, have the correct part, but could still perform a temporary repair.
Then I had to turn the water on & re-fill the system. Somehow, the pressure valves got stuck, & I ended up with a pretty flooded basement before I got everything squared away.
End of story: the kitchen radiator is not on, the pipe ends are plugged & the radiators filled, the heat & water are back on.
As usual, a 'simple' plumbing repair lasted three days and three trips to the hardware store.
If I ever have to move, I'm moving next door to a hardware store, just to save time.