New radiators cold at bottom

[Newbie1]

Hi we have had a new boiler and central heating radiators/pipe work  fitted. The radiators in two rooms (towel rads) are working fine.
 

The other three are only hot at the top and become progressively cooler to the bottom.

 

We also have problem to get all of these three radiators giving enough heat in all the rooms, setting the same  thermostat temp on each radiator, all given different heat (all three rooms are same size).
 

If we turn the radiators off and turn only one on - then they do get fully warm throughout, so not thinking we have sludge or air (we have bled and it’s completely new system anyway).

frustrating as we can’t get all rooms to a comfy temp. How can we resolve? 

 

thanks for any ideas!

[markc]

Sounds like a balancing problem, anything under pressure will always take the easiest route, balancing rads forces water to go around the whole system by restricting the outlet of rads.

look it up on YouTube etc.

 

Edited December 7, 2021 by markc

[ProDave]

What does your installer say?

[Newbie1]

Installer says this is normal…..thanks will try balancing tomorrow. I will let you know if resolved thank you.

Edited December 7, 2021 by Newbie1

[Temp]

How do the pipes connect to the rads? Diagonally opposite corners? Both in and out at the top?

[Newbie1]

In and out both at bottom, opposite corners.

[ProDave]

Locate the circulating pump and turn it up to a higher setting.

[PeterW]

The lockshield is open too far on the rads. Working from the closest to the boiler, close them all and then open first by one half turn, second by 1 full turn and third by 1 1/2 turns.  Now push all the thermostatic valves to 5 and trigger the heat source. 

 

Then see what the heat is like.
 

You can adjust them from that point but it should balance properly from that. 

[Newbie1]

Hi so I have been trying to balance. I have two towel radiators and both inlet outlets are exactly the same. I have opened both valves fully. Hot water inlet seems to be on opposite sides for each towel rad (temp readings on pipes)

 

I am not sure which side is the one I should close/adjust - is it the inlet? It looks like both towel radiators are 1 and 2 out of the five to heat up. 

2 hours ago, PeterW said:

The lockshield is open too far on the rads. Working from the closest to the boiler, close them all and then open first by one half turn, second by 1 full turn and third by 1 1/2 turns.  Now push all the thermostatic valves to 5 and trigger the heat source. 

 

Then see what the heat is like.
 

You can adjust them from that point but it should balance properly from that. 

 

[Newbie1]

Hi thanks for all your suggestions, balancing seems to have worked. 5 working radiators now.