New radiator fitted- hot at the top cold at the bottom

[Leaxx215]

Hi
I hope someone can help
We've recently had a radiator fitted. This was a brand new radiator.
We needed a bigger (longer) radiator for the size of our room)
The top is hot but the bottom is cold.
The valve where the TRV is is very hot. But the opposite valve is cold (I believe this is called the lock shield)
Thanks in advance for any suggestions

 

[Tibbot]

You have an air lock or system needs re-balancing or a bit of both. Unless the lockshield is not open of course.

 

[Leaxx215]

Wouldn't an airlock cause it to be cold at the top?
The lock shield is definitely fully open.
Should both valves be hot?

 

[Tibbot]

Air in the top of a rad is not an air lock. The air lock is in the system.

 

[doitall]

Air in the top of a rad is not an air lock. The air lock is in the system.

And best place to look is a partial blockage in the return.

 

[Leaxx215]

Ah ok. Thank you
Soooo... How do you get an airlock out? A plumber fitted this and doesn't seem to know what it is. He's played with valves on other radiators, bled radiators, and scratched his head a lot!

 

[doitall]

Turn most of the other rads off and see whether it pushes it out, you have some circulation as the top gets hot already.

We'll assume it's a two and not a one pipe system.

 

[Leaxx215]

It's a 1 pipe system. Does this make a difference? Sorry forgot to mention that.

 

[doitall]

Yes it will make a lot of difference, from being connected wrong to the wrong TRV as well as an air lock in the return

 

[Leaxx215]

Should this plumber of piped it as a 2 pipe off the one pipe?
Heard one pipes are illegal now?
What's the chances of sludge getting into the new rad?
Thanks

 

[doitall]

Should this plumber of piped it as a 2 pipe off the one pipe?
Heard one pipes are illegal now?
What's the chances of sludge getting into the new rad?
Thanks

No, can you post a pic showing the connections or a line drawing.

Not illegal and never will be.

A good chance if you have a problem with sludge. In which case get the system problem sorted sooner than leter.

To make the rad work better, if you have top tapping on the rad, extend the flow end to the top of the radiator

 

[Leaxx215]

Plumber been back round- still scratching his head!
He's spent about 2 hours balancing and also turned all the radiators off apart from this one. Still no luck!!

 

[St0rmer66]

For a one pipe radiator to work effectively it'll need the inlet pipe going in at the top of the radiator and out at the bottom of the other end. Normal TRV will also cause problems as they are quite restrictive (not a problem on 2 pipe system). "high lift" TRV's are available for one pipe but they are crazy expensive! Try the pipe alteration first and see how it goes with the regular TRV or fit a manual valve for a cheaper option. The pump should also be set at the lowest speed unless it's a huge number of radiators.

 

[oilhead]

What size is the pipework feeding the rad and how big is the rad?