Radiator size change advice needed please

[Nicole679]

Hi, I am a bit clueless, about this and am hoping for some professional advice.

I have a very small kitchen 6ft by 9ft which has a very large radiator (around 2ft by 3ft). I'm not sure why you'd put such a big radiator into a room that gets generally quite warm during cooking. The combi boiler is located in the kitchen. The oversized radiator isn't one of those new trendy, statement ones but your bog standard Kudox Premium Type White 22 Steel Panel ones. It takes up half the wall.

My bedroom has a medium sized radiator that I'd like to increase the size of, as it seems too small for the room - obviously corresponding to the recommended BTU

I would very much like to reduce the size of the one in the kitchen.

So my neighbour (another clueless female, but who thinks she's a heating engineer as well as being an expert on absolutely everything!) tells me that I can't reduce the size of the one in the kitchen as it is the lead radiator (I've never heard of this before).

Is it possible to reduce the size of the one in the kitchen and increase the size of the one in the bedroom? (I'm assuming the effect on the combi boiler will be the same as I'm just redistributing the sizes).

 

[Madrab]

Hey hey - tell her someone that does this stuff day after day has just told you that there isn't such a thing as a lead radiator. Or does she means one made out of lead

What she may be referring to is that when older CH systems were designed and thermostatic radiator valves (TRV) were brought in, 1 radiator was left without one, this was to ensure that at least one radiator was always open so when all the other TRV's shut down, the boiler would still have a minimum flow through it before the main thermostat shut the boiler down, that was called a bypass.

A lot of newer boilers either have an internal bypass or the system pipework has an auto bypass valve added to perform that function now as using a radiator is no longer standard practice.

Absolutely no reason not to make the kitchen rad smaller and the bedroom one larger though - even just swap them about - and if needed just don't put a TRV on the kitchen one and it can still act as a bypass, even though it is not strictly correct any more.

 

[trojanhawrs]

Do the radiators both get as hot as each other? Is it possible it could be a one pipe system @Madrab ?

 

[Madrab]

Is it possible it could be a one pipe system @Madrab ?

Of course it could be, though I'm not sure why that would come into it though if just looking to change the size of the rads and in effect just swapping 2 rads around by the sounds of it?

 

[trojanhawrs]

Just thought it might affect the rads further down the line making them colder, might be big because its end of line and not putting much heat out.

 

[Madrab]

Unlikely given the boiler is in the same room but hey never say never. TBH though a larger rad wouldn't give out any more heat than a smaller one if I understand the scenario, as there would be a reduced amount of heat reaching it regardless of the size but that's not really how a 1 pipe system should be set up.

It's a really fine balancing process and correct pump settings that's key to a successful one pipe system, and they were used successfully and were around for a long time. The trick is to set it up properly to ensure all the rads get their fair share of the available heat. So rad 1 on the system is throttled down with each subsequent rad throttled that little bit less and so on, that and ideally there were injector tee's on the return of the rad, to promote circulation. Typically the system will take time to heat up evenly though and that was one of it's major drawbacks, especially as they increased in size.

 

[Nicole679]

Thank you Madrab.

All the rads get hot and seem to be working normally. The one in the Living Room doesn't have a TRV.

That's very good news! As I'd like to eventually get a new kitchen and reducing the size of the radiator in there opens up design possibilities.

Once again, thank you.

 

[Madrab]

As I'd like to eventually get a new kitchen and reducing the size of the radiator in there opens up design possibilities

Try and avoid modern designer column tubular rads if you are heating any space larger than a smallish room as they are terrible at space heating.