New Radiator and Pipework not heating up

[Deafman52]

Hi all, I have just rejoined the forum and would like advice on a problem I have experienced with a kitchen radiator. We originally had two small radiators fed by 8mm micro bore pipe fed from a sub 15mm pipe manifold which in turn connected to 28mm main manifold supply and return manifolds. These two radiators were problematic being slow to heat up so it was decided to replace the two small radiators with a larger unit with greater output during a kitchen upgrade and use 15mm pipe. On getting access to the ceiling void the 15mm sub manifold not only fed the kitchen radiators (8mm) but also the bathroom and one bedroom on the upper floor. The 15mm pipe would have enough capacity to feed the new radiator (15mm) and the existing radiators according to information received. The microbore pipes were cut and capped and new 15mm pipework tee'd in between the bathroom and bedroom radiator just along from the original location for the 8mm pipes.
On refilling the system and bleeding everything through, it became obvious that the new radiator and pipework were not heating up even though the bedroom radiator upstream and bathroom radiator downstream were. I have tried balancing the system and at present all lock shield valves are only set at less than quarter turn open yet the kitchen radiator remains cold. I also shut off the bathroom and bedroom radiators but still no joy.
i haven't tried shutting all the radiators off and just try running the kitchen yet but I suppose that is the next logical step.
Apologies for it being a bit long winded but this has got me stumped.

 

[unguided1]

Just read the post properly!
Possibly an air lock, can you post pics of the joints you've done?

 

[ShaunCorbs]

You sure you haven't tee into the cylinder flow and return ? Unless you mean they were 22mm ?

 

[Deafman52]

Just read the post properly!
Possibly an air lock, can you post pics of the joints you've done?

This was my first thought with it being on a dropped circuit but the only vent I have is the one on the radiator, not counting an auto air vent on the system pipework (28mm).
Here are some photographs of the joints

Pic 1 shows connection to the existing supply and return pipework and redundant 8mm drops

Pic 2 shows pipeworgpk through joists and the drop down the wall

Pic 3 shows the drop down to the radiator.

 

[Deafman52]

Just read the post properly!
Possibly an air lock, can you post pics of the joints you've done?

This was my first thought with it being on a dropped circuit but the only vent I have is the one on the radiator, not counting an auto air vent on the system pipework (28mm).
Here are some photographs of the joints
View attachment 28009
Pic 1 shows connection to the existing supply and return pipework and redundant 8mm drops
View attachment 28010
Pic 2 shows pipeworgpk through joists and the drop down the wall
View attachment 28011
Pic 3 shows the drops down to the radiator left being supply and right is return.

 

[Deafman52]

British Gas installed 28mm to and from the boiler and the main manifolds are the same when the heating system was changed in 2001. The same manifolds that the 8mm pipework were connected to are used for the new radiator. I found several kinks in the 8mm pipes when I took it out so this could have been the cause of the smaller radiators being slow to heat up.

 

[Last Plumber]

Airlock ?

 

[unguided1]

I can't see where there is an air lock on the pipework!
So I would try this
1. You had to change both valves on rad, make sure they're both open.
If no result
2. Close both valves on the rad, drain the rad only, disconnect the flow and return valves from the rad and open the valves individualy to see if one or both feed pipes are blocked.
Out of interest what state was the system in? Have you a magna clean on the system?

 

[Deafman52]

After shutting all the other radiators of and draining the kitchen radiator I broke the return connection and opened inlet and outlet in turn to ensure flow from each (as suggested by Unguided1 later on) there was some air in the return leg. Once reconnected and opened up the radiator slowly heated up. The system has been balanced again and radiators have been okay all day, here's hoping it will continue after the overnight stop.
Thank you for responding to my post.

 

[unguided1]

Nice one, so it was an air lock, well done for persevering! Good job

 

[Deafman52]

I had tried your paragraph 2 prior to reading your reply and doing that relieved the airlock but thank you for responding.
Just out of interest a new set of radiator valves were fitted and the system was clean with minimal suspended solids. We do not have any type of filter in the system but I use inhibitor in the system which every couple of years drain down and renew the charge.