cant refil my central heating. i suspect a blocked cold feed

[Buildaman]

i cant refill my central heating after draining the system. everything is in the loft but i cant be sure as to which is the cold feed. i have pics but no idea how to attach any ideas?
[/img] View media item 51221 View media item 51222

 

[45yearsagasman]

The cold feed is the pipe that goes from the air separator to the BOTTOM of the small header tank, The other pipe from the air sep is the vent that goes over the same tank.
Looks like the RH pipe in the second pic.

 

[Buildaman]

Pete

thanks for the response, where would the blockage be is it from the blue air seperator on the right or left of it?

 

[45yearsagasman]

On the right where the pipe from the tank outlet enters the air sep. It may blocked anywhere around there. The only cure is to bung the tank outlet and get the hacksaw out and get cutting.

 

[Buildaman]

Pete

Thanks

John

 

[HERTS P&D]

You can check the blockage with a magnet as it will stick to the copper pipe where the blockage is.

Andy

 

[Buildaman]

Cheers Andy

John

if its not blocked there then i dont know why it wont refill lol

 

[HERTS P&D]

Follow the pipe work from the expansion tank going down and see where the magnet sticks, this is where the blockage is.

Andy

 

[Buildaman]

oh i thought it would be by the air seperator

thanks

 

[45yearsagasman]

oh i thought it would be by the air seperator

It IS more likely to be blocked there.

 

[Buildaman]

thanks i have the axe ready for the morning lol

John the wood butcher

 

[Buildaman]

right Friday's update
drained down the system that wouldnt fill yesterday at all but did overnight. got my trusty hacksaw and suddenly remembered what Pete had said just in time which was to block the tank, i had found a baby bath in the loft and brought the flexi hose from my henry hoover up to drain the water off. i put my hand in the tank and felt for the out let when whoosh all the water drained out. i have now taken the tank out and cleaned it and reinstalled. the water is running freely now.

this is stage one as i dont know if this will solve all my problems but would just like to thank you both for taking time to answer me. cant afford the necessity of a plumber at the mo as myu divorce solicitor is taking all my money lol bad times

thanks again

 

[JohnD]

if it seems to be flowing at the moment, this would be a good time to add a litre of Sentinel X400 (which is a very mild sludge-loosener, not acidic) and leave the system running as usual for four weeks, then drain, rinse and refill, using X100 corrosion inhibibitor in the final fill.

You have to drain at least a bucketful out of the drain cock so that it will draw the chemical down from the F&E tank. Bale out any mud from the F&E and sponge it clean first.

Make sure you fit a lid to the tank. Your problem might have been sediment, or an air bubble, or the rotting corpse of a drowned mouse.

 

[Buildaman]

oooo thanks for the thought of a rodent corpse mmmm. i took the tank out and gave it a thorough clean and all back in. only thing is i have only 2 rads working and no hot water. i have taken the motor part of the 3 port valve off and turned it so that both should be on. but to no avail. does it sound like my grundfos pump has given up with the possibility of it being run dry with the blocked f and e tank?

thanks

John

 

[JohnD]

does the pump spin freely when you put a screwdriver through the hole behind the central screw?

A pump which is dry or jammed feels very hot, hotter than the pipes around it.

Have you bled all your rads, and are they all full?

Turn off the two hot rads and see if the pump the pushes the flow to another. Keep turning off each rad when it is fully hot, and keep bleeding them. It might be air or blockage in the pipes.