Chrome Radiator

[Moondance]

I have just replaced a standard radiator with a chrome radiator (from B&Q designer radiator). Problem is that the radiator gets really hot, too hot to hold but it doesn't actually give out any heat. It is supposed to be 3774 BTU which is more powerfull than the old one. Even when half inch from it you can't feel the heat. I really don't understand why. The water must be flowing ok as you can't hold on to it.
Are Chrome radiators just rubbish. There was nothing wrong with the old radiator.
Ps, I do have a chrome towel rail in the bathroom which is the same. Is this a chrome thing?

With thanks for any help....

 

[glasgowgas]

could you post a pic of both chrome rads?

your chrome towel rail (sometimes called towel warmer) does what it says on the tin, it warms towels where a radiator radiates and convects heat

 

[Moondance]

The radiator is from B&Q "Contemporary Alto Grasso Heater Chrome Effect" (not sure if I'm allowed to post a link?).

I did buy a couple of white designer rads as well from B&Q and they really pump out the heat! Different design though.

The towel rail is probably a heater, I'm not worried about that one (although I don't unerstand how something that gets hot doesn't radiate heat).

 

[Tipper]

Unfortunately it's basic physics.

Shiny silvery objects don't do well at radiating/loosing heat whereas dull and preferably matt black objects do.

Therefore the best colour for a radiator is matt black and shiny chrome is the worst.

 

[mogget]

Chrome does radiate less than other surfaces (i think this might be called emissivity). Its similar to the way that dark colours get hotter in the sun - it works in reverse too.

Also it may be worth checking that there's no btu/h vs watts confusion going on.

 

[bhm1712]

did you set up the LSV on the rad?

if you have installed the rad as was from b and q then the lock shield valve may be fully open allowing hot water to pass straight through it rather than there being some restriction allowing heat to be emmitted to the room.

as a starting point try turning the LSV down so its only one whole turn open

 

[Moondance]

The radiator was quite slow to heat up, I put that down to the amount of water it holds.
If it gets hot to the touch can it be down to LSV being open too much? (I'll give it a go though).
If chrome is poor as a radiator why is the BTU so high? I thought this was a sign of how much heat would be produced?
Thanks for all the advice so far, it all makes sense.....

 

[Moondance]

The radiator was quite slow to heat up, I put that down to the amount of water it holds.
If it gets hot to the touch can it be down to LSV being open too much? (I'll give it a go though).
If chrome is poor as a radiator why is the BTU so high? I thought this was a sign of how much heat would be produced?
Thanks for all the advice so far, it all makes sense.....

 

[bhm1712]

i would honestly hope that a radiator is hot to the touch otherwise they would be pointless, however, having just balanced my own system, i know that although a rad can feel hot, its not necessarily being efficient. upon closing down some of the LSV on my rads i could feel the heat suddenly radiating from them and within 15 mins the rooms became alot warmer. so it could be a factor in your problem.

assuming your system was balanced, use some pipe clamp thermometers to measure the temps at the flow and return pipes on another one of your rads, then whatever the temps are , using the LSV on your chrome rad try and match the difference. there is usually around 10-12 degrees celsius difference between flow and return which means that the heat is being radiated rather than just circulating round the pipes

 

[Goldspoon]

i know that although a rad can feel hot, its not necessarily being efficient. upon closing down some of the LSV on my rads i could feel the heat suddenly radiating from them and within 15 mins the rooms became alot warmer.

Vey interesting. Can anybody else confirm that reducing flow through a rad can make it emit more heat?

 

[mogget]

Vey interesting. Can anybody else confirm that reducing flow through a rad can make it emit more heat?

I can't!

 

[Moondance]

Tried to balance all the radiators and then in the end just had a couple running to force the water through the rad. It does take a long time to warm up, the main tube along the bottom gets hot fast and eventually the rest after about an hour. Very strange as the original worked so well. I'm thinking its a dodgy design so it's probably going to go back to B&Q in exchange for one of the other ones I got and know to work well.

 

[Moondance]

On removing the radiator I think I found out why it takes so long to warm up.
The bottom pipe (about an inch and runs straight through) connects to the virtical columns (also about an inch diam) via holes of about 5mm. Would I be right in thinking that this would drastically reduce the amount of thermo-syphon action (hot water rising and cold water falling and all that)?
Although this wouldn't explain the lack of radiating heat once it had warmed up..

Anyway thanks for the advice but B&Q have agreed to take it back and a different one ordered.

I'll post if the new one works ok once it arrives and been fitted..