Cold Rad

[leslie50]

Hi
I posted a thread the other day regarding a cold rad, went back today, shut down all rads,apart from the cold one, did not do the trick, took about a bucket of water from the bleed valve ,no good, the pipe under the floor going to the rad is hot,but not above floor, undid the valve nut on rad and let water out and the pipe above floor started to get hot,but then went cold when nut was done up.It has a new tvr valve on i tested the pin and it seems ok, there is not a build up of sludge ,when drained it comes through quite clean.Also there is a another rad which is on the other side of the wall this is directly connected to the cold rad,and does not lead on,this rad gets hot, what can I try next.
Regards Les

 

[AWheating]

run a magnet over the copper pipework, if it magnatises to any part of it then its probably sludged up or blocked. Worth a try and dont cost anything to do.

i would remove the rad, attach a hose pipe to rad valves and open to see what flow and water is like. this may also pull any air locks out.

 

[jncalderc]

Sounds to me like these rads are connected together and not separate feeds from a manifold. We have had this problem plenty of times in the past particularly when someone has tapped off existing system to feed an extra radiator or two in a conservatory or conversion. You will end up pulling your air out trying to balance it.

 

[Hybrid]

Change the trv and lockshield. You're wasting a lot of time fault finding a rad for the sake of a few quid.

 

[AWheating]

Change the trv and lockshield. You're wasting a lot of time fault finding a rad for the sake of a few quid.

no point in changing the rad valves if the exsisting ones do not have a problem, hence the need to fault find.

 

[leslie50]

If this is the case as you say what is the best answer.

 

[jncalderc]

Tell the client it has been done wrong from the outset and the only way to fix is to re-pipe back to the manifold providing access is available. Otherwise why as the guys have said take the heartache for someone else s poor work. If they agree you can fix properly if not then you have lost nothing.

 

[SimonJohns]

Take rad out.

Full system

Open trv and asses flow

Open lockshield and asses flow. Not looking for drips here or how much comes out of the bleed nipple

My betting is that one of them will be blocked

Btw don't have the heating in when you do this. 80c water can hurt when you get it on you

 

[jncalderc]

Valid way of assessing valves except if it is sludged u could end up with a miffed client if any goes on her floor/carpet

 

[Hybrid]

no point in changing the rad valves if the exsisting ones do not have a problem, hence the need to fault find.

The other rads have been shut down and still no flow to cold rad so that rules out a balancing issue. Also the fact that a hot rad tees off the same branch tells me it's unlikely to be a blockage or air lock.
When the rad valve nut was undone the pipework to the rad warmed. Because the trv is new and the pin moves freely doesn't mean it's working it also doesn't mean the lockshield isn't blocked or such like.

It's a flow issue through the rad imo

 

[willys warmer]

sounds like both ends of the rad are coming off 1 pipe. has the rad ever worked ?