Help 20 rad system top ones not getting hot

[Super Mario]

Ive flushed the system but the top 2 wont get hot not even legs i sucked it through return with wet vac and it was roasting but now gone cold again tried balancing but no joy system is clean no air lock bled alk rada and pumped with mains anyone know? Cheers

 

[Gasmk1]

pump not big enough ?

 

[ShaunCorbs]

Should be a 25-80 pump if sealed

 

[Super Mario]

Open vented system oil boiler

 

[jonnyswamp]

Have you installed the system, has it worked properly previously

 

[Super Mario]

Have you installed the system, has it worked properly previously

I changed the rads like for like after i flushed it

 

[Super Mario]

Should be a 25-80 pump if sealed

What if it aint sealed?

 

[ShaunCorbs]

What if it aint sealed?

You can try a 25-80 but might pump over

 

[Gasmk1]

I changed the rads like for like after i flushed it

you didnt answer whether it worked ok before, never assume the customer tells you the truth. 20 rads in system im still going for pump not big enough

 

[Super Mario]

you didnt answer whether it worked ok before, never assume the customer tells you the truth. 20 rads in system im still going for pump not big enough

No it didnt work before what size pump does it need