Radiators go cold after 20 minutes

[Harvest Fields]

Pump seems to be fine. Might try facing a fan directly on the thermostat and then see if boiler stays on.

Seems?

 

[Chris54321]

Seems?

Had a plumber fit a brand new one last winter.

 

[Harvest Fields]

Had a plumber fit a brand new one last winter.

That does not mean much If there is a lot of sludge in your system!

 

[Chris54321]

That does not mean much If there is a lot of sludge in your system!

The radiators would be cold at the bottom in this case but there not.

 

[Harvest Fields]

I have had pumps almost blocked but the rads still get relatively warm all over.

 

[Chris54321]

I have had pumps almost blocked but the rads still get relatively warm all over.

My rads get hot to the point where you can barely touch them.

 

[Harvest Fields]

Probably not the pump then

 

[Chris54321]

Probably not the pump then

Nope. The boiler gets up to temperature fine but then it just stops and rads get cold and it won't fire up again even after temperature in the house has dropped.

 

[ShaunCorbs]

Probably not the pump then

Could be if it's not getting the heat fast enough from the boiler

And the boilers shutting down from being upto temp

 

[Harvest Fields]

Could be if it's not getting the heat fast enough from the boiler

And the boilers shutting down from being upto temp

That’s what I was thinking. But if that was the case surely the boiler would be cycling on and off until the rads were hot?