Air lock i think

[Johntheo5]

ill do that then, so once water starts coming out of the vent, i block it with my hand to force pressure back down?

Its to force the pressure to build up in the air separator and hopefully clear the blocked cold feed.
The 3 pipes come together in the air separator, the cold feed from the F&E cistern, the cold feed out of the separator to the rads etc and the vent that comes out of the separator and goes up and over the F&E cistern.

 

[Ray1000]

If I’m not mistaken, backfilling a system through one of the downstairs radiators, all of the downstairs radiators could be filled if the bleed valves were open and closed in turn, and then the same with all of the upstairs radiators before the water reaches the F&E tank outlet and finally the vent pipe.

If it gets to the vent pipe BEFORE it gets to the F&E tank it means the outlet from the tank is blocked and may be freed by blocking the vent pipe.

I’m no expert so wait for confirmation before starting.

Sorry ... I wrote this before seeing John's post ...

 

[Johntheo5]

It doesnt matter once it clears the blockage, the rads can be vented in the traditional manner later.

 

[scotthud]

If I’m not mistaken, backfilling a system through one of the downstairs radiators, all of the downstairs radiators could be filled if the bleed valves were open and closed in turn, and then the same with all of the upstairs radiators before the water reaches the F&E tank outlet and finally the vent pipe.

If it gets to the vent pipe BEFORE it gets to the F&E tank it means the outlet from the tank is blocked and may be freed by blocking the vent pipe.

I’m no expert so wait for confirmation before starting.

Sorry ... I wrote this before seeing John's post ...

How can i backfill if the bleed valves are open, wont the water just spray out of them all? or do you mean one at a time as its backfilling and should i only open the tap a little and not full

 

[Johntheo5]

Just stick the hose on, crack it open a little , when water starts coming out the vent, block it with your hand, pressure will build up and hopefully unblock the cold feed, no vents open.

 

[Ray1000]

How can i backfill if the bleed valves are open ... or do you mean one at a time

... all of the downstairs radiators could be filled if the bleed valves were open and closed in turn,

Yes, I was referring to closing them as each radiator filled in turn.
I was imagining if I were following the instructions, I'd be alone, I'd have to put one of those plastic stop ends on the vent pipe.
I understand if all the bleed valves were closed the only path for the mains water would be up the F&E outlet and into the tank.
Presumably, if you left the mains on it would fill the tank and overflow outside, proving the top up pipe was clear.

The only reason I mentioned filling the downstairs first by opening the bleed valves is it would rule out you having several blockages.

 

[scotthud]

So came home after work, no air or water in any radiators, so did the backfill as in #50 Johntheo said, blocked off fent pipe with hand Some gurgling but still the same result no air or water in rads.

Can someone tell me please if this is my actual drain valve for the system (didn't even know it was there until this evening)

As apposed to this one which is on every radiator in the house.

if so have I been draining/backfilling wrong all the time (although the back fill still went up the vent pipe to F&E tank)

 

[Ray1000]

If the blue pipe is emerging from underground it appears be your mains supply fitted with a drain above the mains stop tap.

 

[scotthud]

yes thats my mains feed into the house but the valve above is that the drain valve i should be using to drain the system down or would that empty everything include the immersion cylinder ?? im basically at a loss now seem to be going round in circles.

Would it make any difference if i backfilled from an upstairs radiator since they are the ones ive had all the issues with? allthough im having issues with them all now

 

[Ray1000]

The only connection between the mains water supply and the CH is the mains feed going into the F&E tank.

 

[Ray1000]

I’m interested to know how your radiator valves operate, how do you open the drain off / hose connector in order to feed the mains into the system?

 

[scotthud]

ive been doing it by unscrewing the valve i n the second picture above (#52) on each downstairs radiator and open the bleed valves to speed it up, then to backfill ive been using the same valve on the radiator closest to the backdoor.

 

[terryplumb]

So water is coming out of the vent pipe ,and into the f&e cistern,but no radiators are filling with water when you are back filling the system with mains pressure water ? That makes no sense at all ,the vent pipe is the highest point in the system and water would have to fill at least some of the ground floor radiators before the water level got anywhere near the vent pipe.
Something about what you are telling us isn't right.

 

[scotthud]

So water is coming out of the vent pipe ,and into the f&e cistern,but no radiators are filling with water when you are back filling the system with mains pressure water ? That makes no sense at all ,the vent pipe is the highest point in the system and water would have to fill at least some of the ground floor radiators before the water level got anywhere near the vent pipe.
Something about what you are telling us isn't right.

What do you mean by that statement. When i got home this evening the rads had no water a couple had some air in but not as much as last night. I connected a hose to the downstairs radiator and connected that to outside tap and cranked it open, went into loft and waited for about 10mins for the water to start coming out of the feed pipe. (the one that loops over the tank) i then blocked it with my hand as per #50 suggestion and then let it flow, once the water started going out of the overflow i ran downstairs and turned the water off at the tap. i then waited whilst he hose drained down and disconnected it from the radiator and put the valve back in and tightened it up. I then went around every radiator in the house 9 downstairs and 6 upstairs, no water in any of them when bleeding and only some had a little air in. I haven't opened the drain valves on the radiators down stairs as in this picture



As it didn't produce any water or air from the radiator bleed vavle.

 

[Ray1000]

... and waited for about 10mins for the water to start coming out of the feed pipe. (the one that loops over the tank) i then blocked it with my hand and then let it flow, once the water started going out of the overflow

While you were blocking the vent pipe did any water come into the tank thro what is normally the outlet pipe to the system?