Cold spot on radiator after bleeding

[Pineapple123]

Hi,

I have a radiator on the top floor of my home that keeps getting a cold patch a day or so after bleeding it. It starts top right and slowly moves across the rad.

Any thoughts or suggestions of anything else I could check before I call on a heating engineer?

Air must be getting into the system somewhere and it just happens to accumulate in that rad (highest and/or furthest away?)

Thanks!
Ian

 

[CBW]

Have you checked for a leak?

 

[Pineapple123]

Have you checked for a leak?

Nothing on the radiator and no noticeable wet patches (near the radiator in question)

 

[Pineapple123]

Any thoughts from anyone else? I spoke with a central heating engineer and they suggested trying a silicon based sealant product they can add via the header tank that may or may not help.

 

[John the plumber]

Hi,

I have a radiator on the top floor of my home that keeps getting a cold patch a day or so after bleeding it. It starts top right and slowly moves across the rad.

Any thoughts or suggestions of anything else I could check before I call on a heating engineer?

Air must be getting into the system somewhere and it just happens to accumulate in that rad (highest and/or furthest away?)

Thanks!
Ian

You say keeps getting a cold spot every time you bleed it so by that I’m assuming your constantly needing to bleed the rad,is it just this rad that does it ? Are all the other rads ok?

 

[Pineapple123]

You say keeps getting a cold spot every time you bleed it so by that I’m assuming your constantly needing to bleed the rad,is it just this rad that does it ? Are all the other rads ok?

That's correct, all other rads remain piping hot. If I bleed the radiator in question a few days later the cold patch starts growing starting at the top left. Based on location I'd say it's the highest point in the system.

 

[cjcoffin]

?Failed shaft seal on pump sucking in air?

 

[Pineapple123]

?Failed shaft seal on pump sucking in air?

This is probably the point at which I've reached my limitations as a layman!

Our boiler is 19 years old so we were already considering whether to replace it, so would probably include a new pump at the same time.