need help again please

[hitthingswithhammers247]

got a potterton puma boiler that is really starting to wind me up now it was working ok but one of my thermastatic valves got stuck in closed so dropped pressure to change it noticed quite alot of black nasty looking water so put some fernox f3 cleaner in which seems to be working ..
bleed the full system but now i aint got any rads coming on at all
have tried evrything i can think of but getting the 14lb hammer out
oh yeah the 22mm pipes are getting hot both flow and return and have made sure the boiler isn't air locked any help would be great
cheers

 

[jackthom]

How is the heated water getting back to the return, is there a bypass valve in the external system ?

 

[hitthingswithhammers247]

i dont know have only felt the pipes around the boiler got told it was kettling and released a bit of air out the boiler but still nothin

 

[hitthingswithhammers247]

update on problems
my pump has a small bolt on the front of it so i undid it , it wont come all the way out but black water came out ..
do you think i should flush out the system and put more cleaner in i used fernox f3 super concentrated and is the stuff from screwfix any good cos i can get 2 tubes for the price of fernox i can feel hot water been pumped round in the pipes next to my boiler but not much in the rads do you think my valves could be knackered on the rads as i dont know when this system was last flushed out