New Radiator sometimes hot sometimes cold

[milovisk]

I have just had a conservatory fited and the company recommended that I had a radiator fitted in there off my existing system. I live is a 4 bed detached with a vented system and Pottertod Suprima 40L boliler.

The new radiator in the conservatory sometimes gets mildly warm to hot but nowhere near as hot as the others and gives out very little heat into the conservatory, it is a quite a big double radiator but only raises the tempaerature by about 5 degerees above outside temperature even when at it's hottest. The radiator that it is connected off gets red hot and I have noticed that when the rad in the conservatory is cold the pipe leading to the TRV is cold yet the pipe at the other end with the shieldlock valve ( which is fully open) is red hot as per the radiator it is feeding off.

Is there a logical explanation for this? When I aske dthe company who fitted it they said it is because my boiler is not powerful enough to heat the system but I can't understand how this could be if the others get hot.

 

[Foobix]

The pipework to the radiator could be under sized or partially constricted somewhere.
If it's a micro bore system then it shouldn't be fed from another radiator.

 

[milovisk]

It isn't micro bore

 

[HERTS P&D]

Where did they get the 'feed' from? was it from the radiator circuit or was it from the flow and return from the boiler?

Post some pictures.

Andy

 

[milovisk]

The pipe work is behind the wall now but basically there is a single radiator in my breakfast area in the kitchen which is about 24" x 24", he took a tap of the feed and return from this radiator (not from the main feed and return pipe) and it goes trogh what was the external wall (now the inside conservatory wall) to a double radiator which is about 60" by 15". The distance between the 2 radiators is abour 4 feet.

The original radiator always gets very hot sometimes too hot to keep yoor hand on, while the new radiator is sometimes hottish, more often luke warm and sometimes cold. When it is cold the inlet pipe on the side with the TRV is stone cold yet the other side which has the shieldlock valve is too hot to touch.

 

[Whitespirit66]

What happens if you turn off the small rad that the new rad is linked to?

As the new double rad is much bigger than the single rad it is linked to, the water flowing through them has two choices of route. Go through the big rad, which offers much greater resistance, or take the easy route through the small rad. It's doing the latter.

Try almost closing the lockshield valve on the small rad to increase its resistance to flow to even things up a bit. The lockshield on the small rad should be only open enough to let it heat up properly, no more. Make sure all valves on new rad are fully open.

Why don't you get the installer back to balance things? They should have checked the new rad before leaving.

 

[bengasman]

Probably not balanced.

 

[milovisk]

When I turn the small one off the big one does get hot