air trapped in radiator

Discussion in 'Home energy' started by suicra05, Jan 20, 2009.

  1. suicra05

    suicra05 Frequent Poster

    Posts:
    184
    I recently replaced an old radiator in a bedroom with a brand new radiator. This new radiator is causing problems as it is constantly getting airlocked. I have taken the air out on numerous occasions using a key. A few days later there is air in it again. When the air is in it there is very little heat from the radiator. Can anybody offer me any solutions. It has happened about ten times now over past few weeks.
     
  2. Conshine

    Conshine Frequent Poster

    Posts:
    451
    Did you do it when the radiator was on? If you do it when it is off, there will be no pressure, so the airlock wont be cleared.
     
  3. suicra05

    suicra05 Frequent Poster

    Posts:
    184
    I always do it when the radiator is on.
     
  4. DavyJones

    DavyJones Frequent Poster

    Posts:
    1,976
    This is a symtom of a system fault. If you have a vented system (small tank in attic feeding radiators) it may be pitching. This is a term used to describe hot water expanding up the expansion pipe and pouring into tank. This causes air to enter system as it refills. The problem rad may be the last on the circuit and the air gets pumped back to it. Pitching should be easy to fix.

    If you have a sealed system or indeed a vented system, the air may be caused by a leak. IF you have a sealed system your pressure will drop. A vented/unsealed system refills itself. Tie up the ballcock feeding small tank in attic to prevent it filling itself. Note water level in tank and leave for a few days, if level drops, then you can safely assume you have a leak.
     
  5. suicra05

    suicra05 Frequent Poster

    Posts:
    184
    If it is scenario 1 as you say Pitching. How do I fix Pitching as I think it is the last radiator in the circuit.
     
  6. DavyJones

    DavyJones Frequent Poster

    Posts:
    1,976

    I may have to give you a crash course in heating :).

    Have you changed circulating pump recently?

    There are three settings on pump, high, middle, low. Check these settings.

    go to attic when system has been running for a few hours, check small tank. you will see the expansion pipe, it rises over tank and bends into it. Place a finger in this pipe and see if it is wet, it will confirm or discount pitching.
     
  7. noelf

    noelf Registered User

    Posts:
    77
    I agree with davies advice, but I think its more than pitching.
    Why did you have to repalce a rad?
     
  8. JBS

    JBS Guest

     
  9. theengineer

    theengineer Frequent Poster

    Posts:
    187
    may i ask, did you have this problem before you changed the radiator? did the old one work ok?
     
  10. noelf

    noelf Registered User

    Posts:
    77
     
  11. DavyJones

    DavyJones Frequent Poster

    Posts:
    1,976