Right radiator for boxroom? T11, T21 or T22?

pieroabcd

Hi,
I have a very old flat panel radiator in my boxroom that must absolutely leave this house, no appeal granted.
It seems to be a T11 type, with a single row of fins, 50 cm wide and 60 cm high.
I want to replace it with a 50x50 cm radiator  (lower to make space for my table) with a more modern style, possibly column (but I couldn't find one), or as a last resort with a convection one.
I don't know if this boxroom is warm enough in winter but i don't wan to risk to have an undersized radiator. On the other hand I've already seen (like discussed in another thread) that my system is already quite imbalanced: at the second floor the loft conversion and the adjacent bathroom are already receiving too little water when the radiators at the lower floors are on.

If i installed a T22 with some choking of the inflow valve would this have the same effect as installing a T11/T21?
I don't want to buy something with less thermal power and  take the risk to freeze in winter. If necessary I can sacrifice a bit the loft conversion. Better having more power and choke the valves than not having enough capacity when it's needed.

Thanks.

FreeBear

I have a 500mm wide, 600mm high T21 in a box room roughly 2.4m by 2.7m - Keeps the room nice and warm, but I have insulated the walls (solid brick) and fitted a new window. But what works for me, may not be suitable for you.

You need to punch some numbers in to a heat loss calculator. This one works for me - https://www.stelrad.com/basic-heat-loss-calculator/ - Gives higher outputs than some of the other offerings out there (not a bad thing). Would be worth oversizing the radiator so that you can reduce the flow temperature (which aids boiler efficiency).

Once you have selected and fitted a radiator, it important to balance the whole system. If done right, all the radiators in the house should be radiating heat effectively - That said, it may be possible that the pipework to your loft conversion is too small for the distance and radiator sizes up there.

pieroabcd

FreeBear said:

I have a 500mm wide, 600mm high T21 in a box room roughly 2.4m by 2.7m - Keeps the room nice and warm, but I have insulated the walls (solid brick) and fitted a new window. But what works for me, may not be suitable for you.

You need to punch some numbers in to a heat loss calculator. This one works for me - https://www.stelrad.com/basic-heat-loss-calculator/ - Gives higher outputs than some of the other offerings out there (not a bad thing). Would be worth oversizing the radiator so that you can reduce the flow temperature (which aids boiler efficiency).

Once you have selected and fitted a radiator, it important to balance the whole system. If done right, all the radiators in the house should be radiating heat effectively - That said, it may be possible that the pipework to your loft conversion is too small for the distance and radiator sizes up there.

Thanks.

Uhm I wasn't considering the distance from the wall to the pipes, that definitely I can't replace. 
Considering that it's 66mm a T21 seems to be the only option.

Any idea how to rebalance the system?

CSI_Yorkshire

pieroabcd said:

FreeBear said:

I have a 500mm wide, 600mm high T21 in a box room roughly 2.4m by 2.7m - Keeps the room nice and warm, but I have insulated the walls (solid brick) and fitted a new window. But what works for me, may not be suitable for you.

You need to punch some numbers in to a heat loss calculator. This one works for me - https://www.stelrad.com/basic-heat-loss-calculator/ - Gives higher outputs than some of the other offerings out there (not a bad thing). Would be worth oversizing the radiator so that you can reduce the flow temperature (which aids boiler efficiency).

Once you have selected and fitted a radiator, it important to balance the whole system. If done right, all the radiators in the house should be radiating heat effectively - That said, it may be possible that the pipework to your loft conversion is too small for the distance and radiator sizes up there.

Any idea how to rebalance the system?

That was described on that other thread.

Read the bits about adjusting lockshield valves.

https://ukradiators.com/advice-centre/the-simple-guide-to-balancing-radiators/

edit: although you don't necessarily need to be as precise as the "12 degrees" bit on that link.

FreeBear

A couple of cheap digital thermometers from Amazon/Ebay/AliExpress, pipe clips, and time is all you need.

BUFF

pieroabcd said:

Hi,
I have a very old flat panel radiator in my boxroom that must absolutely leave this house, no appeal granted.
It seems to be a T11 type, with a single row of fins, 50 cm wide and 60 cm high.
I want to replace it with a 50x50 cm radiator  (lower to make space for my table) with a more modern style, possibly column (but I couldn't find one), or as a last resort with a convection one.
I don't know if this boxroom is warm enough in winter but i don't wan to risk to have an undersized radiator. On the other hand I've already seen (like discussed in another thread) that my system is already quite imbalanced: at the second floor the loft conversion and the adjacent bathroom are already receiving too little water when the radiators at the lower floors are on.

If i installed a T22 with some choking of the inflow valve would this have the same effect as installing a T11/T21?
I don't want to buy something with less thermal power and  take the risk to freeze in winter. If necessary I can sacrifice a bit the loft conversion. Better having more power and choke the valves than not having enough capacity when it's needed.

Thanks.

modern equivalent radiators tend to have less water capacity than older ones. A more decorative radiator style most likely will have less output than a convector for the same size.
do you have the depth to go to a T21 or T22 from a T11? https://www.stelrad.com/wp-content/uploads/2015/04/21160_Elite_Web.pdf
Fit a thermostatic valve on inlet, lockshield on outlet.

pieroabcd

BUFF said:

pieroabcd said:

Hi,
I have a very old flat panel radiator in my boxroom that must absolutely leave this house, no appeal granted.
It seems to be a T11 type, with a single row of fins, 50 cm wide and 60 cm high.
I want to replace it with a 50x50 cm radiator  (lower to make space for my table) with a more modern style, possibly column (but I couldn't find one), or as a last resort with a convection one.
I don't know if this boxroom is warm enough in winter but i don't wan to risk to have an undersized radiator. On the other hand I've already seen (like discussed in another thread) that my system is already quite imbalanced: at the second floor the loft conversion and the adjacent bathroom are already receiving too little water when the radiators at the lower floors are on.

If i installed a T22 with some choking of the inflow valve would this have the same effect as installing a T11/T21?
I don't want to buy something with less thermal power and  take the risk to freeze in winter. If necessary I can sacrifice a bit the loft conversion. Better having more power and choke the valves than not having enough capacity when it's needed.

Thanks.

modern equivalent radiators tend to have less water capacity than older ones. A more decorative radiator style most likely will have less output than a convector for the same size.
do you have the depth to go to a T21 or T22 from a T11? https://www.stelrad.com/wp-content/uploads/2015/04/21160_Elite_Web.pdf
Fit a thermostatic valve on inlet, lockshield on outlet.

Thanks.
The distance bewteen wall and center of the pipe is 66mm, that seems to work well with this one
https://www.screwfix.com/p/flomasta-type-21-double-panel-plus-single-convector-radiator-600-x-500mm-white-2280btu/784xp

BUFF

I thought that you wanted a 500mm high rather than 600?
That would be https://www.screwfix.com/p/flomasta-type-21-double-panel-plus-single-convector-radiator-500-x-500mm-white-1960btu/411xp & ~300btu or ~13% less output than the 600 high but likely still above your existing T11's output.

pieroabcd

Yes but then I thought that the desk would be right on top of the radiator, like a cap, so it's not really a good thing, even more so considering that it's only a T21 instead of a more powerful T22