11 radiator to a 22?

[Chivas69]

Hi
My daughter has single 11 radiators in her kitchen and lounge and after working it out they are way too small for the area. Her boiler seems constantly on trying to get to thermostat temperature.
I'm going to change them for her and was thinking about a straight swap for a 21. However I was wondering if it was likely to be a straight swap if I went for 22s instead. Obviously they'd be fatter. Problem may be that there's not much play in the pipes as they're coming up from floor. I'd also have to hang the new rad in exactly the same position and no doubt the wall brackets will be completely different.
Am I better just changing to 21s as there would hardly be any movement of pipes and they're only slightly under the btu rate (less than 100)
Thanks for any advice

 

[Swwils]

A boiler being constantly on is not something to be worried about if it is setup correctly. It's actually desirable.

A boiler with the flow temperature too high is a problem though, and will waste money.

Your best bet is to actually upsize the radiator as well (maybe swap some others whilst it's drained); the pipe job isn't that much more effort and then you've actually planned to do the work if anything does crop up.

 

[Madrab]

You're right, the 21's and 22's will be further from the wall than the 11. So if the rad is hard piped then the valves may not fit without some alterations. If the 11 uses asymmetric brackets and it's currently on the long edge then they may be able to be swapped to the short edge to fit. You won't know until you measure up.

 

[Chivas69]

Thanks guys. The thermostat is in her kitchen and it takes forever to get to 19 degrees, hence why I mentioned the boiler constantly being on. It's trying to get to 19 and taking hours. I am hoping, if I increase the heat output it will reach 19 much quicker to save the boiler running at max trying to get to temperature.

 

[Madrab]

Quite a strange place to have a thermostat.

Is the kitchen cold and is the target to get the kitchen warmer?

If not then that's not really the way a CH system is meant to be implemented. Ideally you want the thermostat in the coolest space - typically the hall, which doesn't need to be as warm as the living spaces - then use TRV's in the other rooms to provide a semblance of zone control in each. The goal then isn't to get the room with the stat up to temp setting so the boiler shuts down rather get the other rooms up to temp and then adjust the stat down so it's at it's switching point.

If all the other rooms are warm enough and the kitchen doesn't need any more heat, albeit isn't up the stat setting then turn the stat down or move it.

 

[mizuno]

Are you able to do a straight swap? I suppose you have measured the old 11 radiators and there's type 22 radiators available that are the same width.
If the pipes are 10mm then they will have a little bit of flexibility and might fit a 21, but if they are coming out straight out of the wall and then a 90 degree bend into the radiators, then even the 10mm will probably need alterations.
I've replaced a few type 11 to 21 radiators for myself, and the brackets allow perhaps 20mm of sideways alignment, so you can get away with a little bit of a measuring error.

 

[fixitflav]

Thanks guys. The thermostat is in her kitchen and it takes forever to get to 19 degrees, hence why I mentioned the boiler constantly being on. It's trying to get to 19 and taking hours. I am hoping, if I increase the heat output it will reach 19 much quicker to save the boiler running at max trying to get to temperature.

If the rads are too small and failing to heat the room, I'd expect the rads to be very hot and the boiler cycling on/off on its control-stat. Is that what's happening?

 

[Johntheo5]

Just measure each rad, width x height and the total output can be calculated.

 

[Chivas69]

Quite a strange place to have a thermostat.

Is the kitchen cold and is the target to get the kitchen warmer?

If not then that's not really the way a CH system is meant to be implemented. Ideally you want the thermostat in the coolest space - typically the hall, which doesn't need to be as warm as the living spaces - then use TRV's in the other rooms to provide a semblance of zone control in each. The goal then isn't to get the room with the stat up to temp setting so the boiler shuts down rather get the other rooms up to temp and then adjust the stat down so it's at it's switching point.

If all the other rooms are warm enough and the kitchen doesn't need any more heat, albeit isn't up the stat setting then turn the stat down or move it.

Thanks
It's in the dining room really which is in with the kitchen as one big room, this then enters an open living room. So it's quite open plan. Almost like a horse shoe. It's wired smack in the middle of the living room and dining room. Was like this when she moved in. She hasn't got a hall really as the front door opens on to the stairs. There is no rad by the stairs or on the landing. These are the only rooms downstairs which are warmed by these two rads. All other rads are in bedrooms and one in bathroom. The two rads downstairs don't give enough heat out to heat the space they need to. Quite a bit short with btu calculations.

 

[Chivas69]

If the rads are too small and failing to heat the room, I'd expect the rads to be very hot and the boiler cycling on/off on its control-stat. Is that what's happening?

Yes. All rads are very hot. Upstairs is controlled individually by valves. The upstairs rooms gets hot very quick but I think downstairs the rads are not sufficient for the area. Her downstairs is like a horseshoe with a living room/kitchen/dining area, virtually open plan, heated by just two single 11 1200mm rads.

 

[Johntheo5]

Still don't know what the total rad output is, a 1200 X 400?? mm rad has a output of 0.732 kw, IF all 11 rads are similarly sized then total demand is - 8 kw.
What is the boiler output and more importantly its minimum output? Also make/model?

 

[fixitflav]

Still don't know what the total rad output is, a 1200 X 400?? mm rad has a output of 0.732 kw, IF all 11 rads are similarly sized then total demand is - 8 kw.
What is the boiler output and more importantly its minimum output? Also make/model?

Unless I'm much mistaken, 11 denotes the type of rad, not the number of them.

Difference between Type 21 and Type 22 radiators | Victorian Plumbing

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[Chivas69]

Still don't know what the total rad output is, a 1200 X 400?? mm rad has a output of 0.732 kw, IF all 11 rads are similarly sized then total demand is - 8 kw.
What is the boiler output and more importantly its minimum output? Also make/model?

Think you've got the wrong end of the stick mate.

 

[Roddy Young]

Would you not be wiser to explain why he has the "wrong end of the stick" - you are asking for people's help after all.

 

[Chivas69]

Would you not be wiser to explain why he has the "wrong end of the stick" - you are asking for people's help after all.

Someone already did but ok.
11 is a type of radiator. It's a single panel. I'm wanting to change to a double which will guve off mote heat!