Air lock i think

[terryplumb]

Manual lever is used when draining or filling a system ,so on a 3 port valve it is latched open to mid position ,both ports ( hot water cylinder and central heating).
When system is filled ,manually unlatch the valve.
In certain circumstances,for instance if you can't get boiler to work for heating ,but it works for domestic hot water, latching the valve would give you some Central heating ,when boiler is set for domestic hot water. Unfortunately once the hot water in the cylinder is up to temperature the boiler would cut off.

 

[Ray1000]

Thank you for that

 

[scotthud]

The best way to do it is to let the cistern mt, connect up the hose, put your hand over the vent, force the water back through the cold feed otherwise you will have the same problems with air ingress etc.

cheers ill give that a go next, at least ive managed to clean the F&E tank out so its not full of sludge etc

 

[scotthud]

Manual lever is used when draining or filling a system ,so on a 3 port valve it is latched open to mid position ,both ports ( hot water cylinder and central heating).
When system is filled ,manually unlatch the valve.
In certain circumstances,for instance if you can't get boiler to work for heating ,but it works for domestic hot water, latching the valve would give you some Central heating ,when boiler is set for domestic hot water. Unfortunately once the hot water in the cylinder is up to temperature the boiler would cut off.

is that the small grey box above my pump its hard to see as its quite tight in my cupboard?

"When system is filled ,manually unlatch the valve." which setting do you move it to? and when you say manually do you mean backfilling it? Sorry for been a complete novice.

 

[terryplumb]

Yes ,that is a motorised valve. They have a lever that you slide as far as you can,then latch it in that position . With all electric power to the system switched off ,you would be sliding the lever against a spring pressure. Once at the end of the levers travel it would " latch" into a groove to keep it there.
By " manually " ,I am only referring to latching the valve by hand.

 

[scotthud]

Well back to square one, no water getting to upstairs radiators, although the downstairs ones did fill although not all of them, ive drained the downstairs ones again, header tank still full (valve closed and ballcock strung up) if it does slowly drain down again ill go for the back fill approach as in #15.

Is the vent the one at the bottom of the tank or the one coming over the top of the tank?

 

[terryplumb]

The vent is the open ended pipe that extends higher than the f&e and points downwards to it.
Why are you draining water out ,when trying to fill up ???

 

[Ray1000]

If from an empty system even one of the downstairs radiators fills up properly it puts doubt on the top up pipe being blocked.

If one of the downstairs radiators fills up but only slowly then eventually they will all fill up and you’ll be running normally but with a partially blocked pipe from the F&E tank, which presumably a lot of people have.

Unless it’s being caused by something else like an air lock, or closed valves.

 

[scotthud]

I think I've been getting the operation wrong, i thought backfilling comes up through the outlet and not the vent? so what is the purpose of the vent, if backfilling does it go through the air separator? if not then their is not much point in bothering doing it as i thought it might dislodge or at least try and dislodge any blockage? Sorry for my lack of knowledge.

 

[scotthud]

If from an empty system even one of the downstairs radiators fills up properly it puts doubt on the top up pipe being blocked.

If one of the downstairs radiators fills up but only slowly then eventually they will all fill up and you’ll be running normally but with a partially blocked pipe from the F&E tank, which presumably a lot of people have.

Unless it’s being caused by something else like an air lock, or closed valves.

Thanks I think it maybe an air lock then as all valves as far as I know are open (all the ones I've touched are open)

 

[Ray1000]

Before you cleaned out the tank was there just a "normal" level of sludge ... a few mm in the bottom ?

It wasn't higher than the outlet presumably ?

 

[scotthud]

Yes thats right, the water level was just below the outlet and the rust / sludge was all settled down there BUT i think when i first originally drained the tank i could have disturbed all the sludge during the re fill when i untied the ballcock, that would have been about Wednesday (3rd April)

 

[Ray1000]

I just wondered if a lot of sludge had got into the system and there were a number of blockages spread through the house.

The gravity fed water from the top up tank doesn't need much to stop it - hence the advice being given to back fill it using mains pressure.

 

[scotthud]

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

 

[Ray1000]

I've never had to do it but that's what I understood John to have said earlier.