Radiators only getting luke warm

[Sue66]

Hi guys i have a customer who just moved into the property and the boiler settings for heating and water were on low. When she turned them up the expansion vessel and prv started leaking water. I ordered new parts and changed both they are now working fine. Turned heating on to maximum but radiators won't heat up properly. Had them all boiling individually but they won't stay piping hot all at once. Tried balancing them and they are then just Luke warm. The radiator in the kitchen is teed into the bathroom one in 10mm pipe which is obviously a problem but even if both those rads are turned off the others in the house don't all get hot at the same time. Do you think the pump is going and needs to be changed or do you think the pipework is problematic through house. She does not have a lot of money after buying house and I'm trying to advise her the best i can. I am not long qualified so any help would be appreciated. Radiators are old and i guess there could also be a sludge issue but they do heat up at the bottom when on individually so i think the problem is more than just this.

 

[Sue66]

 

[heatservice]

What boiler is it?

 

[Chester]

whats the condition of the heating system water?

 

[Old Account]

Have you got everywhere 10mm bore? Any filters fitted below boiler? Have you tried to close all rads except the ones which are cold or like warm ( bathroom or living room) ?

 

[Sue66]

Yes 10mm pipe everywhere. No magnetic filter. Its a main eco combi 25kw. Have not checked the radiator water yet but when i drained the boiler to change parts it was clear.

 

[Sue66]

I have closed all radiators and had every one hot individually with all others closed off

 

[heatservice]

If the HW is OK then it suggests the pump is working, when you say youve balanced the system how aggressive were you, try with upstairs lock shield valves open just a 1/4 turn for starters.

 

[Sue66]

I was really careful it took me hours. Managed to get them all on. Then anther plumber came in after me and tried as well. He couldn't get them all hot either just said. Try a powerflush if that doesn't work you need the pipework redone. You don't think its the pump then? Ok that rules that out.

 

[Sue66]

Its as if there's enough heat to make two radiators really hot but when its balanced across the system everything is shared out and it's luke warm. There is just simply not enough heat to make everything hot at once. I'm going to take some floor boards up today and check the pipes are properly sized on the landing then maybe she will have to have the system cleaned. Problem is that the boiler is in the bathroom and the pipes there are all under a laminate floor. Typical.