central heating

[premierfc]

vented central heating system. pipes banging when hot water switched on and water and steam coming from expansion pipe into header tank also some rads upstairs need regular bleeding. i suspect this is gas/corrosion in system. any ideas please

 

[ChrisR]

You're probably right. Sounds like a blockage where the feed pipe joins the circuit.
You can add desludging chems, run for a week and see what happens, but hard blockages can need the pipe cutting out.

 

[premierfc]

thanks chris. someone suggested fernox i am going to give that a try. am i best to drain system and add to header tank or feed into bleed screw on rad. thanks

 

[gas4you]

When heating is cold and you bleed upstairs rads do you get air then water, or air then nothing? If the latter then it will confirm blockage in cold fill.

I would recommend cutting it out and replacing

 

[premierfc]

seems to be air and then nothing. if this is the case should i try fernox ,if not how do i locate the blockage thanks

 

[premierfc]

actually come to think of it .i have had air then black sludge and also air and then nothing if that makes sense

 

[gas4you]

Sounds to me it is a blockage in the cold fill. 99/100 times it is where the cold fill t's into the heating pipe work. it shouldn't be too big a job. maybe a little draining of the system and cut the T out and replace pipe work.

Once this is done put cleanser in the system and let flush through completley, drain fully then fill up with new inhibitor added

 

[premierfc]

thanks for all your replies. i will give that a try and let you know if it worked

 

[2face]

possibly low head to .. raise the tank onto a stand .. this will help with the air build up .. ...