Hello Community
My first post so please bear with any stupid questions or comments
I have an issue where a single radiator is not working

Background - I moved into this 3-bed, double-storey, terraced house few years ago, nothing has been changed until now. I don't ever remember the front room radiator (see attachment for setup) working properly but then again we've never really used that room for living and got-by by using the gas fire in the back room.
I've recently started to work on the house and wanted to make some changes, the front room radiator was in the way as you walk from the front of the house into the back, was in the way when heavy items were moved into back of the house or kitchen. So it was decided that I'd move the radiator to the other wall (shown in green from above, red block is the old position of the rad), the 15mm copper pipes were visible coming in from upstairs so I thought this would be a good opportunity to hide these by feeding them from upstairs, into the store room and out the bottom by drilling holes from store into the front room.
However, BEFORE I did this I also added a 2nd Type 22 radiator in the 2nd bedroom upstairs which is above the back living room, this was done by adding pipework running under the floorboards in the hallway upstairs (yellow box), added the feed and return from the existing run/pipes coming from the boiler. All boiler including new 2nd bed one worked fine after bleeding etc.
Pipes from the boiler go up into the 3rd bedroom (on top of the kitchen), one radiator is connected in this room, pipe then runs into the hallways connecting to the hallway rad and then the 1st bedroom rad, existing pipes were then modified (which were going to the front room connecting to the old position of the radiator) and then re-routed into store room, the old length (to old rad) was ~3-4M (each for feed and return), new run was a little longer running at an angle (not sure this matters?) before coming out the drilled hole into the front room.
So, after moving the front room radiator, bleeding etc everything worked fine except this one. Pressure bar on the boiler reads between 1.5-2. Feed pipe is warm but no heat from rad. My calculations show the existing number of radiators doesnt overload my boiler?
One thing of note is I connected the feed/return opposite to the way it was originally connected, this was an error on my part but I didnt think this mattered as my thermostatic valve shows arrows that it can be connected either way.
The feed pipe is warm when touched but no heat from the radiator. After a lot of bleeding etc I decided to shut-off all the upstairs radiators, I then got full heat from the front room radiator which hopefully proves the rad to be in good working order as well as the vavles?
I haven't tried to balance the system as all other radiators warm up the same. So my question is, is it my boiler thats not powerful enough to drive all the radiators? I took the kW power of all rads and divided into 24kW and I think the boiler should be more than capable driving all these rads. Am I missing something obvious?
thanks for all the help
Jay
My first post so please bear with any stupid questions or comments
I have an issue where a single radiator is not working

Background - I moved into this 3-bed, double-storey, terraced house few years ago, nothing has been changed until now. I don't ever remember the front room radiator (see attachment for setup) working properly but then again we've never really used that room for living and got-by by using the gas fire in the back room.
I've recently started to work on the house and wanted to make some changes, the front room radiator was in the way as you walk from the front of the house into the back, was in the way when heavy items were moved into back of the house or kitchen. So it was decided that I'd move the radiator to the other wall (shown in green from above, red block is the old position of the rad), the 15mm copper pipes were visible coming in from upstairs so I thought this would be a good opportunity to hide these by feeding them from upstairs, into the store room and out the bottom by drilling holes from store into the front room.
However, BEFORE I did this I also added a 2nd Type 22 radiator in the 2nd bedroom upstairs which is above the back living room, this was done by adding pipework running under the floorboards in the hallway upstairs (yellow box), added the feed and return from the existing run/pipes coming from the boiler. All boiler including new 2nd bed one worked fine after bleeding etc.
Pipes from the boiler go up into the 3rd bedroom (on top of the kitchen), one radiator is connected in this room, pipe then runs into the hallways connecting to the hallway rad and then the 1st bedroom rad, existing pipes were then modified (which were going to the front room connecting to the old position of the radiator) and then re-routed into store room, the old length (to old rad) was ~3-4M (each for feed and return), new run was a little longer running at an angle (not sure this matters?) before coming out the drilled hole into the front room.
So, after moving the front room radiator, bleeding etc everything worked fine except this one. Pressure bar on the boiler reads between 1.5-2. Feed pipe is warm but no heat from rad. My calculations show the existing number of radiators doesnt overload my boiler?
One thing of note is I connected the feed/return opposite to the way it was originally connected, this was an error on my part but I didnt think this mattered as my thermostatic valve shows arrows that it can be connected either way.
The feed pipe is warm when touched but no heat from the radiator. After a lot of bleeding etc I decided to shut-off all the upstairs radiators, I then got full heat from the front room radiator which hopefully proves the rad to be in good working order as well as the vavles?
I haven't tried to balance the system as all other radiators warm up the same. So my question is, is it my boiler thats not powerful enough to drive all the radiators? I took the kW power of all rads and divided into 24kW and I think the boiler should be more than capable driving all these rads. Am I missing something obvious?
thanks for all the help
Jay