Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Almost all of the radiators (forced water) in my house heat up fine. However, a single radiator needs regular bleeding (~1/day) in order to heat. Note, this radiator is not at the highest point in the house (it's a split level; I'd say it's around 3/4 of the way up), and radiators higher up are plenty hot.

Also, there no obvious water/corrosion stains around this radiator.

What might be causing this problem, and how do I fix it?

share|improve this question
Is the radiator at the end of a long run? Is it in any way different from the other radiators? – Freiheit Oct 18 '12 at 20:38
@Freiheit I am not sure if it's at the end of a long run. There are other radiators on the same floor, but I'll try to trace the pipes tonight. To the best I could figure out, I think it's the same radiator as others in the house. – Eli Lansey Oct 18 '12 at 20:50
It wouldn't necessarily have to be the highest radiator to collect the air, the pipes would have to follow a sort of upward route of least resistance for the air to collect in it. – Mark W Jan 11 '13 at 11:31
This could happen if the radiator is the first one on the run starting from the boiler. The air will want to collect at a high point but if the pipe goes down after this unit then it may get stuck there if the flow is not fast enough to push it back down. You might consider that there is a leak that is letting water out of the system causing too much makeup water to enter, which will add the air. You could also think about putting in an air scoop between the boiler and this radiator to get the air out before it gets stuck in that loop. – Bob A. Feb 26 '13 at 16:24

When you do your daily bleed of this radiator if you don't actually get air coming out, just water. You don't have an air problem, you have a water flow problem.

If your system a diverter-tee system (a "one-pipe" system), check to make sure that the tees that feed this radiator are installed the same way as the tees that feed your working radiators. The diverter tee for this radiator should be on the return side, and the stripe (or other indicator of orientation) should be between the branches. An incorrectly installed tee could cause the exact problem you're describing.

share|improve this answer
Your questions are not an answer. They belong as comments to the question. – ShoeMaker Mar 13 '13 at 11:45

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.