Radiator on CH system not heating up

[shaunyab]

Hi,
A customer called saying that a rad wasn't working on their system. The system is 10mm microbore. Initial thoughts were balancing, so tried to force it to force heat into the system to no avail, rad only got luke warm at the top with what looked like the rad being classically sludged up with the heat profile. Next flushed the rad out, not much sludge came out, to no avail, rad just warmed up slightly, same heat profile.
I noticed that the flow into the radiator cycles heat wise, so thought that it was the TRV, changed that, no change. The flow pipe cycles heat wise so the radiator never gets fully warm.
The only thing I can think of is that maybe a lump of solder is moving in the pipe and partially blocking the pipe as its moving....not too sure though. So maybe full system clean, but will only do chemical clean not powerflush on microbore system.Not suggested this yet!!
Has anyone ever come across a similar situation? The other rads are piping hot!

 

[JohnD]

so tried to force it to force heat into the system to no avail

Do you mean you turned off all the others?

 

[Agile]

So what was the result of the bucket test?

Tony

 

[shaunyab]

Yes I switched all radiators off but the effected one, not sure what you mean by the bucket test Agile.

By the way its a a pressurised system.
Hope this helps.

 

[xr4x4]

Was the hot water off?

Bypass?

 

[shaunyab]

Hot water was off.

 

[shaunyab]

This only happens to this rad, the others do not cycle so I doubt the bypass.

 

[shaunyab]

Also forgot to say, this rad has always had this problem according to the customer!

 

[xr4x4]

I mean, is the bypass passing.

You need to check the flow from each pipe outlet to check for blockages in the pipes.

 

[Plumbkinobi]

Trv not stuck? Sludgy system ?

 

[Plumbkinobi]

Whoops, should read post 😁

 

[Plumbkinobi]

Single rad not working on the system, would check the pump as a matters of course maybe a blocked manifold or over soldered manifold if has always been a problem

 

[Plumbkinobi]

Had a run of similar problems with rads and has come back to the ch pump many times plus heavy sludging. Sludging being the symptom of poor design

 

[Plumbkinobi]

If it's always been a problem rad maybe there was an initial f up and flow connected to flow or return to return?

 

[shaunyab]

I assumed the pump was fine as the other rads get nice and warm, I agree I do think over soldering, Not sure where the manifolds are but will try to find them and double check for the kcuf up with the F & R- got to admit didnt think of that one!
Thanks for that!!