Open Vented system not re-filling

[allenvb]

Help, my open vented system is not re-filling. I have just fitted a new pump but when I tried to re-fill the system, nothing happened the water level in the expansion tank stayed the same and even when trying to bleed the rads, no air is being pushed out as there is no water entering.

I have bled the system, the pump, the power is on, I tried to flush the system with mains pressure through the tank but nothing is happening.

 

[Bahco]

Did you open the 3 port valve to heating side to allow water to your rads

 

[kevplumb]

or the feed is blocked

 

[cstokes]

Did you close the isolator valves when changing the pump?

 

[kevplumb]

why if he drained the system

 

[allenvb]

Thanks for the prompt replys. I should have mentioned this before, but I have drained down the entire system before, and it re-filled but very slowly, I am wondering wether the copper from the tank down to the boiler is furred up, if this is the case is there a way to clear the copper other than replace it.

I did close the iso valves to repalce the pump and have opend them now it is replaced.

Sorry, I am a bit of a div, what is the 3 port valve.

V

 

[kevplumb]

a square box on the pipework usually near the pump
your not a div but your not a plumber either
(dont tell but im really a welder )