Bleeding a radiator

deadanonymau5

If a radiator is hotter at the top and cooler at the bottom, does this mean it needs to be bled?

I read online that "if the top is noticeably cooler than the bottom, there is a good likelihood that there is air in the radiator"

altor

deadanonymau5 wrote: »

If a radiator is hotter at the top and cooler at the bottom, does this mean it needs to be bled?

I read online that "if the top is noticeably cooler than the bottom, there is a good likelihood that there is air in the radiator"

That is correct, the radiator needs to be bled. There should be a bleed hole at the top.

deadanonymau5

altor wrote: »

That is correct, the radiator needs to be bled. There should be a bleed hole at the top.

Cheers

brian_t

deadanonymau5 wrote: »

If a radiator is hotter at the top and cooler at the bottom, does this mean it needs to be bled?

I read online that "if the top is noticeably cooler than the bottom, there is a good likelihood that there is air in the radiator"

I'm confused.

The bottom statement is certainly correct. Air rises to the top of a radiator and this keeps the hot water towards the bottom. Opening the bleed screw located at the top of the radiator allows this air to escape.

But your main question refers to the top of the radiator been hot and not the bottom but mabye this is just a mistake.

Buford T Justice

Its more likely that you're radiator is sludged up blocking the water travelling through the bottom of it. Bleeding it will do no good.

Try cracking open the lockshield valve a full turn and back again and see if it helps.

deadanonymau5

brian_t wrote: »

I'm confused.

The bottom statement is certainly correct. Air rises to the top of a radiator and this keeps the hot water towards the bottom. Opening the bleed screw located at the top of the radiator allows this air to escape.

But your main question refers to the top of the radiator been hot and not the bottom but mabye this is just a mistake.

What I wrote is correct? what i read on the internet differs to what I feel when I feel the temp on my radiators

brian_t

deadanonymau5 wrote: »

What I wrote is correct? what i read on the internet differs to what I feel when I feel the temp on my radiators

Bleeding your radiators will not solve your problem.

Try the suggestion of Fingers McGee or wait and see if you get more responses.

figs

OP - normal condition for trapped air is for it to be cooler at the top than the bottom (as air doesn't transfer heat). your problem doesn't sound like air.

a few more details would help... where are the water entry points on the radiator? top or bottom? Is it a standard rad with a flow and return on either side? Age? General condition?

deadanonymau5

figs wrote: »

OP - normal condition for trapped air is for it to be cooler at the top than the bottom (as air doesn't transfer heat). your problem doesn't sound like air.

a few more details would help... where are the water entry points on the radiator? top or bottom? Is it a standard rad with a flow and return on either side? Age? General condition?

Bottom.
its around 10 years old.
Not sure about the rest?

DoneDL

If the system is clean and well balanced the radiators should be equally hot all over. It could be just that the boiler is set too low to bring the radiators fully up to temperature. If the boiler temperature is increased and the rads are still cold around the bottom the system is sludged up.

Buford T Justice

Its sludge I'm willing to bet. I'm plagued with it in my own house. same symptoms as you have.

harry21

Is the coolness at the lower end of the rad limited to the middle of the rad??

Is so, sludge is your problem.