Switching isolation valves off

[mp3wizard]

I am trying to put some central heating leak sealer into a magnaclean.

Unfortunately the magnaclean is in the very corner of a corner cupboard, I’m having to lay on my back and twist myself under the sink trap and have a very narrow space to work in.

After much trial and error I realise there is off written on the valves but I’m pointing the 2 black handles to that direction yet there is still water flow when I’m trying to remove the magnaclean.

One attempt I tried undoing the top nut and water was spirting out and scared me, another time I twisted the main magnaflow loose a little and it was spirting out.

Does the black knob need to be pointing directly at the off? I’ve probably gone round a rotation or 2 clockwise, will this matter? And to ensure I don’t cause a massive flood which would be the safer way to see the valves are off to loosen the top nut or to twist the main magnaclean a little?

Thanks

 

[MeldrewsMate]

Your first and third photos show the valve in its OFF position, but if the plastic head is loose on its drive dog then the valve will still be open. You need both valves shut to isolate the Magnaclean body.
It doesn't matter how many revolutions you've made.
Try opening both, then run the pump. There will be a noticeable woosh when one valve is nearly closed. Note its position, open it, and repeat on the second valve; then place both valves just beyond their respective woosh position. Open the bleed key on the top to see if you have been successful; if you have the water will soon stop.

 

[terryplumb]

I would think twice before putting leak sealer into the system if I were you ,can cause more issues. If you have a leak ,find it ,and fix it.

 

[Madrab]

I wouldn't think at all about putting leak sealer into your system, nasty stuff and no matter what they say it plays havoc with all the narrow waterways/valves/sensors that are inherently contained within most boilers and systems. I have had to repair boilers that have had sealer added and it's gunged them up. It will only help with very slight weeps, anything else and it's hit an miss with the risk of causing damage to the boiler internals as it sticks to everything, especially if the boiler isn't anything but squeeky clean.

Yes the markers need to be exactly at off, as they are ball valves they need to be closed properly.

 

[mp3wizard]

Thanks for the guidance, I will return the leak sealer to the shop then, I have a corroded column radiator with a slight leak, I used a leak sealer on the outside, my thought was to sort the outside and put something in to sort out the inside.

 

[Madrab]

Thanks for the guidance, I will return the leak sealer to the shop then, I have a corroded column radiator with a slight leak, I used a leak sealer on the outside, my thought was to sort the outside and put something in to sort out the inside.

Appreciate that it seems a fair option, the problem with sealer is that you can't just put it where it's needed, it always circulates and gets into everything. Anything it comes across that acts as a leak (really small gaps) it can start to seal that too.

If the rad has a pinhole that has worked through from inside then sealer may work short term but by the time the rad has pinholed, it is significantly corroded internally and unfortunately really needs replaced.