# air trapped in radiator



## suicra05 (20 Jan 2009)

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.


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## Conshine (20 Jan 2009)

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.


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## suicra05 (20 Jan 2009)

I always do it when the radiator is on.


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## DavyJones (20 Jan 2009)

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.


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## suicra05 (20 Jan 2009)

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.


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## DavyJones (20 Jan 2009)

suicra05 said:


> 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.




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.


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## noelf (20 Jan 2009)

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


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## JBS (21 Jan 2009)

DavyJones said:


> I may have to give you a crash course in heating .
> 
> Will non return valve on expansion pipe help?
> Why this expansion happens anyway?
> If this is a seald system, will leakage sealant help?


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## theengineer (21 Jan 2009)

may i ask, did you have this problem before you changed the radiator? did the old one work ok?


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## noelf (21 Jan 2009)

JBS said:


> DavyJones said:
> 
> 
> > I may have to give you a crash course in heating .
> ...


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## DavyJones (21 Jan 2009)

JBS said:


> DavyJones said:
> 
> 
> > I may have to give you a crash course in heating .
> ...


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