we purchased a home a few months ago and now that winter rolled around, just realized the radiators in the basement aren't working. And I apologize for the long post, tried to explain everything I've discovered. Luckily most of the pipes arent hidden behind walls in the basement so I could track the route.

So it comes out of the heating system here, and seems to be hot: enter image description here

The pipe that goes to the basement radiators in that pic gets cold about fifteen feet later. There's no branches or valves or anything, it seems like its just a straight shot in that pipe and gets cold. Don't know whether its blocked somewhere or something? And maybe it gets cold just because its not moving?

Next noticable thing on the pipe before it gets to the radiator is this, no idea what it is/what it does: enter image description here

Then it gets to the first of two basement radiators, pictured here. It doesn't appear to have a valve before it (like I see in most youtube videos). I do notice that maybe there's too much extra paint on it, maybe blocking the little steam blow off thing? But I have no idea if that's the problem.

enter image description here enter image description here

Then it goes straight to the second of two radiators, here: enter image description here enter image description here

Then straight back to the heating system, pictured here where it meets back up with the pipes from the first floor (that do work): enter image description here

I was curious if that zone valve pictured (like the one in this youtube video) was somehow shut and blocking everything. Based on that video I don't think it is (think it would get hot there if it was?), but I also slid the little switch to "open" instead of "automatic" just in case to check, and didn't notice a difference.

Any ideas of what to check next?

Update for anyone checking now

It was definitely the zone valves as suggested. Yesterday switching it to manual didn't do anything, but I suspected that as the system goes in cycles, it may not have been "pulling" anything with the circulating pump at the moment. So today I switched the zone valve to manually open again and cranked the heat wayyy up. All of a sudden both downstairs radiators got hot. So now the question is just WHY the zone valve didn't work. Time to figure that out.

  • Here check tbis mate youtu.be/PAo6yG89vyM
    – Frank
    Dec 26, 2021 at 12:50
  • Does the zone valve get warm (from the electricity)? Does it definitely move, making a little whirring sound as it opens or closes? I found the motors fail, had to replace two inn a less-maintained house. They usually have a manual override lever at the back.
    – tomnexus
    Dec 26, 2021 at 22:46

1 Answer 1

  1. The pipe gets cold because heated water is not circulating.
  2. That item is an air vent to release trapped air.
  3. This is not steam. The thing on the radiator is also an air vent. There's no valve because heat (should be) controlled by thermostat and zone valve, not a valve on the hot water radiator.
  4. Either the zone valve is the problem, or trapped air is.

Circulator pumps are very wimpy .vs. trapped air bubbles in pipes. That's why a properly built system includes plenty of air vents to remove any trapped air in the circulating fluid. Operate each of those "air bleeders" until you get water (usually) or "fluid" (occasionally systems are filled with non-toxic antifreeze rather than plain water, but it's not common) rather than air. Check the pressure gauge on your boiler (which is what a water heating device for heating your house gets called even though it is NOT making steam - and also if it is...) and make sure there's still reasonable pressure on it (typical for the gauge to be marked at maximum) and/or that the automatic fill (if so equipped) is working or enabled, or fill manually to get the pressure to a suitable range (variable depending on your house, but 20-30 PSI is "typical")

Note that it is common (and should not be a problem if not leaking) for a fill system that appears otherwise completely automated to have a manual shutoff valve that is normally kept closed. Leaking is a problem that should be fixed, and fixing it is not just leaving the auto-fill enabled all the time...One reason being that each time you add new water, you are also adding new dissolved air in the new water, and then that has to be bled out of the system. And new dissolved air also screws up the typical assumption that any oxygen not bled out of the system will rust out a small bit of the steel/iron components and then rusting will stop, due to no more oxygen being added. So then you can have rust problems from your leak problems.

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