Balancing radiators - specific question

[wizbongre]

I'm re-balancing our system after fitting new radiators across most of the house...

One of the existing rad's, which hasn't been replaced (and won't be for some time due to access issues and the fact its only a couple of years old anyway) I'm struggling to balance. No matter what I do, I can't get it to a decent surface temp and temp drop across flow and return.

I start off with just a quarter turn of the lockshield, which keeps the whole rad only warmish. Gradually opening the lockshield eventually gets the top of the rad hot (its a tall vertical rad) but the return side doesn't get to a decent temp.

Am I right to think if I open the lockshield too much it won't heat up as all energy will pass through too quick? I'm trying to figure out if I need to slowly open the lockshield or close it down!

 

[terryplumb]

Has the tall vertical rad ever heated up properly ? They very often have to be plumbed in a specific way ,or they just will not work fully.

 

[wizbongre]

I managed to grab half hour around work t'other day and whipped the rad off the wall and replaced it after turning it around, essentially swapping flow/return. It now appears to be heating up better overall, however its just reinforced my fear that it is undersized for where it is. With our new boiler set to 70degrees flow and the rads balanced, its hard to put my hand on the radiator without it burning pretty quickly, yet the room it is in is cold. Its the main entrance hallway to our house, probably the most drafty of the whole house and of course has to deal with a lot of doors opening/closing and exterior air coming in.

I've swapped most other radiators around the house aiming for a 60degree flow temp from the boiler and sizing calculated at delta30 (assuming flow of 60, return of 40 and mean of 50 with target temp of 20.) I obviously need to do the same with this rad, however its slap bang in the middle of three rooms that all have laminate floor laid as one continuous run, so its going to be an absolute nightmare to lift without damaging. And there's not enough space where the current rad is to fit anything much bigger in.

I reckon I've got 2 options - 1) find somewhere that will make truly custom radiators to build me something that will fit in a pretty compact space and still hit pretty high output levels or 2) pay the flooring company to come and lift a big section of our downstairs flooring so I can swap the rad to a better location where I can fit a decent size one. (Option number 3 is me lift the flooring, however I can guarantee I'll break some of it on the way and then SWMBO will be less than impressed.)

Wish I'd understood more about "proper" radiator sizing before getting the flooring laid!