One rad not heating?!?

[TJ81]

Afternoon all,

I'm at a lose with a radiator problem that I'm hoping someone may be able to shed light on. I'm renovating a house and took all rads off early on for cleaning and painting.
All got fitted back and worked bar one, after some fault diagnosis I sumized that the valve was not opening correctly. I drained down the CH system and replaced the valve, fitted rad opened it and heard water coming in and bled until it was full. That rad wasn't getting hot, so checked: the tank in the attic to ensure it was filling, knocked the pump up one notch (as rad is furthest away from boiler), and closed all other rads to reduce demand.
Still no luck.

I then took rad off, put it in garden and flushed through with hot and cold water until I could see through from each opening. Then connected hose to both ends of existing pipework and drained off until constant flow from each, it spluttered a bit but then pipes started getting hot, which I thought was good as proved pump was getting hot water as far as rad. Fitted rad, filled and bled and it got hot so I thought all was good.

Turned heating off and came back next day, turned heating back on but rad didn't get hot . Thought it may be something to do with the other rads being off, so quarter turned each valve on, on every rad and bled each still nothing.

Today I've left the rad bleeding slowly into a bowl to try and encourage the hot water up but still not getting hot.

I'm at a lose now and can't phathom what it might be. I've had hot water in the pipework, and the rad when flushing pipes but can't get it up again from cold!

Before I replace the rad itself (not sure if that will fix prob) I'd appreciate anyones advice in case I'm missing something obvs!

Thanks in advance
Tj

 

[Scott_1979]

Last time I had this issue it was the pipework that was blocked. It was still getting hot along with the valve but wasn’t allowing circulation. What size is the pipework? When you have the radiator off the wall have you tried opening the valves to see what kind of flow you are getting through the pipework?

 

[ShaunCorbs]

Have you tried turning all the other rads off and just leaving that one on ?

 

[TJ81]

Last time I had this issue it was the pipework that was blocked. It was still getting hot along with the valve but wasn’t allowing circulation. What size is the pipework? When you have the radiator off the wall have you tried opening the valves to see what kind of flow you are getting through the pipework?

Yes I have, I had a hose connection on both sides and flowed through them as I thought air might be stopping heat further down the pipework but didn't work. Pipes are 15mm

 

[TJ81]

Have you tried turning all the other rads off and just leaving that one on ?

Yea all the other rads were off and this one was the only one on, even after purging the pipework

 

[ShaunCorbs]

Any pipes warm to the rad ?

 

[TJ81]

Any pipes warm to the rad ?

Unfortunately not. One pipe did warm slightly earlier when I left the bleed valve open and trickling, but after turning bleed valve off it cooled.

 

[ShaunCorbs]

Strange on

And you don't have any other problems with the rads?

 

[TJ81]

Strange on

And you don't have any other problems with the rads?

Nope all other rads good if the rads duff and I need to replace it that's fair enough, but I don't understand how it could be if I've had hot water up and through the pipes and into the rad thereafter? Could the rad not circulate if it's broken internally?

 

[ShaunCorbs]

easy way to tell is link out the rad

eg 2 1/2 female irons to 15mm copper and a piece of copper

remove the valve tails from the rad

 

[TJ81]

easy way to tell is link out the rad

eg 2 1/2 female irons to 15mm copper and a piece of copper

remove the valve tails from the rad

I'll have to get hold of some of those bits, as I am but a mere novice

 

[ShaunCorbs]

https://www.NoLinkingToThis/p/female-coupler-15mm-x/93992

 

[garygvl]

Last time I had this issue it was the pipework that was blocked. It was still getting hot along with the valve but wasn’t allowing circulation. What size is the pipework? When you have the radiator off the wall have you tried opening the valves to see what kind of flow you are getting through the pipework?

best answer so far

 

[TJ81]

best answer so far

Pipework blocked?

 

[ShaunCorbs]

Pipework blocked?

Since you've tested the flow from each very unlikely

 

[TJ81]

Well slaved in the copper and still no heat, turned all other rads off again to make sure and still bought, not even in either of the supply pipes time to call a plumber I think unless anyone has any other suggestions?

 

[TJ81]

Well slaved in the copper and still no heat, turned all other rads off again to make sure and still bought, not even in either of the supply pipes time to call a plumber I think unless anyone has any other suggestions?

 

[ShaunCorbs]

One of the pipes must be blocked / something wrong

 

[gmartine]

Have to ask, are those lockshields definitely open?

 

[TJ81]

Definitely open. After that I took the copper out and put my hose and coupling back on and purged both pipes again, this induced hot water, I did this on and off 3/4 times each side, there was a little splutter on one side but not the other.
I'm not back there until tmw now, but I'll put the copper back in as in theory the pipes should be primed again now!?!