Radiator not getting hot

[merton69]

Thanks John for your indepth help and knowledge.

This certainly a job for after this weekends wedding mayhem!

I will report back when the job is done.

 

[merton69]

I have decided (now I know it is a relatively easy job to do) to disconnect and flush through the two rads upstairs that are no longer getting hot since the double rad downstairs has started working again.

But I have one question to ask please...

...it is mentioned in this thread about controlling the flow from one rad to another using incremented turns on the lockshield valves. But why, all of a sudden, do I have to do this please? It is not as if somebody has accidently turned the valves to disrupt the CH? It has never been a problem before so why is it needed now?

Thanks for your time!

 

[JohnD]

It might be that your TRVs are old and worn out and have failed wide open, it might be that you have sediment in the pipes, it might be that the pump is worn out, it might be that you have a bypass that is too wide, it might be that God wants to punish you for immoral behaviour.

 

[merton69]

Thanks for the points made.

I can use them to do a 'process of elimination'.

 

[merton69]

Okay...the next part of the process done!.....

..Disconnected the 2 non working rads upstairs and flushed out thoroughly.

Reconnected, filled with water to correct pressure.......only 2 out of the three are working!

Any more suggestions please?

 

[JohnD]

turn off the hot ones.

 

[merton69]

I have done as you have asked and turned off the hot rads upstairs and unfortunately the cold rad stayed cold!!

Suggestions please?

 

[cbucket]

What happens if you take the top of the Thermostatic valve. I had a problem recently where a radiator was cold but when I took the top of the valve it opened the valve and the radiator started heating up. There is a (silver) nut at the bottom of the white part which you have to unscrew. Once you get the top off there should be a pin visible which sticks up.

 

[merton69]

Thanks for that but unfortunately I have taken apart all the tower valves and cleaned them including the pin that moves up and down to control the flow of water.

All appears to be okay with this!

 

[cbucket]

Not sure I understand. So are you saying with the cap removed that the radiator still does not heat up ?

 

[merton69]

Sorry...didn't explain myself properly and left vital info out!

I have retested the 'cold' rad with the other to 'hot' rads turned off and YES! the rad has got hot.

So what dos this mean please?...and what to do?

As always...thanks!

 

[D_Hailsham]

Did you reset the lockshield valves to their original positions? No?

Then the system needs balancing

Read How to balance a CH system.

 

[merton69]

All lockshields are fully open.

As yet I have not done the lockshield increment turns test yet.

I am waiting for the rads to go cold to test if all the upstairs rads get hot when all tower valves are on and fully open.

 

[JohnD]

All lockshields are fully open.

that'll be the trouble then.

 

[merton69]

How come?