Help Replacing Old Mains Tank Float Valve

[pollys13]

I think this is quite straightforward, though I don't want to mess up and have water leaking out of new valve, then have to turn mains water off etc, etc.
The old float valve needs to be replaced so bought a new one. Any tips advice appreciated, I've got stillsons, mole grips that sort of stuff.
So first steps, turn off the mains, empty the tank.......then?
In photo A with red arrow assume nut is tightened onto a collet, put ptfe tape around it before tighten nut back on?
Cheers.

 

[AndyT]

Don't worry, it's a straightforward job.
All ordinary right hand threads.
The external connection is like you find under a tap - a fibre or rubber washer is compressed onto an end. Make sure the end is smooth. Best to replace the washer while you are at it, as this joint is under mains pressure while the valve is shut.
Be sure to clean off any limescale, which will probably be reinforcing the connections.
Hold the body with stilsons and use a spanner on the nut.

No need to empty the tank.
When the mains is off, force the arm down to open the valve. There should be no flow. If not, proceed.

(There should be an isolation valve near the tank. If not, this is a good time to add one.)

 

[Phil Pascoe]

You didn't need to drain the tank. Just undo everything and put the new one back with a new washer - nothing difficult about it. Fit a service valve close to the tank while the water is off if it hasn't already got one, then watch it refill in case the float is a bit high - bend the arm down if it is. If your tank is empty it may pay to stir any dirt in the bottom up and drain the tank into the bath to get rid of the dirty water - you're bound to stir some up anyway,especially if it's an old (possibly uncovered) tank.

 

[sunnybob]

Why go to all that bother?
Turn the water off.
buy a new one, remove the inner valve from the old one and replace with new. fit the new float arm. adjust the float for water level. put the new unused parts and the old parts in the brass scrap bin. go get a beer.

 

[Phil Pascoe]

Why go to all that bother? Just replace it.

 

[hawkeyefxr]

It is a straight forward job as others have said. There are a couple of things you can do to help yourself later down the line maybe, replace or in stall a new shut off valve locally(if you already have one it will be years old and may not work when you want it). Fit a 15mm ball lever valve they will always shut of where as normal stopcocks don't when they get old, the washers go hard and the thread mechanism jams. When you use new fittings or olives they are generally brass now and they are really tight to do up, they creak and groan as you tighten them, smear a bit of Boss White on the olive and it will do up really nice.
Alway check for leaks no matter how good things look, use a bit of toilet paper to check, coloured toilet paper is even better (lol seriously) it changes colour and it dead easy to see water leaks.

 

[Phil Pascoe]

Coloured paper. Brilliant, I'd not thought of that. Of course it would work for small oil leaks etc. as well.

 

[pollys13]

You didn't need to drain the tank. Just undo everything and put the new one back with a new washer - nothing difficult about it. Fit a service valve close to the tank while the water is off if it hasn't already got one, then watch it refill in case the float is a bit high - bend the arm down if it is. If your tank is empty it may pay to stir any dirt in the bottom up and drain the tank into the bath to get rid of the dirty water - you're bound to stir some up anyway,especially if it's an old (possibly uncovered) tank.

OK cheers.

 

[pollys13]

Don't worry, it's a straightforward job.
All ordinary right hand threads.
The external connection is like you find under a tap - a fibre or rubber washer is compressed onto an end. Make sure the end is smooth. Best to replace the washer while you are at it, as this joint is under mains pressure while the valve is shut.
Be sure to clean off any limescale, which will probably be reinforcing the connections.
Hold the body with stilsons and use a spanner on the nut.

No need to empty the tank.
When the mains is off, force the arm down to open the valve. There should be no flow. If not, proceed.

(There should be an isolation valve near the tank. If not, this is a good time to add one.)

Cheers Andy.

 

[pollys13]

Why go to all that bother?
Turn the water off.
buy a new one, remove the inner valve from the old one and replace with new. fit the new float arm. adjust the float for water level. put the new unused parts and the old parts in the brass scrap bin. go get a beer.

Thanks for reply.

 

[pollys13]

It is a straight forward job as others have said. There are a couple of things you can do to help yourself later down the line maybe, replace or in stall a new shut off valve locally(if you already have one it will be years old and may not work when you want it). Fit a 15mm ball lever valve they will always shut of where as normal stopcocks don't when they get old, the washers go hard and the thread mechanism jams. When you use new fittings or olives they are generally brass now and they are really tight to do up, they creak and groan as you tighten them, smear a bit of Boss White on the olive and it will do up really nice.
Alway check for leaks no matter how good things look, use a bit of toilet paper to check, coloured toilet paper is even better (lol seriously) it changes colour and it dead easy to see water leaks.

OK thanks for the helpful tips, appreciated.

 

[Lons]

What the others said but definitely replace the whole unit. Just a couple of things though.

Looks like it's a plastic tank so be careful not to twist the fitting unduly or you could damage the plastic, just make sure spanner each side and loosen / tighten one against the other.

If your new valve doesn't have a silencer pipe either take it off the old one or fit one as it makes a big difference. You can make one out of scrap plastic or copper pipe.

Make sure the water fill stops at the correct level, as said bend the arm to adjust.

If no cover then make one and insulate around and over the tank, not under, while you're up thare - assuming it's in the loft.

Bob

 

[Phil Pascoe]

I used to tell my wife not to drink water from the bathroom. She didn't take the blindest bit of notice until I had to replace the tank. Due to the configuration of the roof space, I needed to get rid of the old uncovered galvanised tank so went up with a jigsaw to cut it in half so it would go through the hatch. I passed the first half down to her and she was nearly sick when she saw what was in it - about two inches of sludge, bird skeletons, mouse skeletons, you name it. One of the first things I did when we moved house was plumb the bathroom basin tap to the rising main.