A Filling Loop Story...

[morningster]

Hello.

Gentlemen, ladies (?), got a boring one for you central heating folk, but it's causing me a novice's headache...

The filling loop feeding our Worcester 24i system boiler is leaking. (The boiler is in the basement and feeds 11 rads on 3 floors.)

I've attached a high-res photo (presumably zoomable) of the loop in situ. My untrained eye tells me there is a quarter-turn shut-off valve with plastic lever at mains supply end and a double check valve at boiler feed end (which connects to piping upstream of external 3-way (?) valve).

The leak comes from the (15mm) shut-off valve; at first, it leaked when re-pressurising, now it leaks regardless.

What I want to know is how to fix this without draining the system! Can I replace just the shut-off? If I isolate mains supply upstream of the shut-off, does the nut which is mid-point on the double-check valve provide a shut-off position so I can isolate that end as well? If it is possible, can someone point me to the right model valve on some site like ScrewFix?

What am I getting wrong, what am I missing?

Your help appreciated.


P.S. No, I don't want to remove the loop, I have an ancient heating system that leaks and gets gassy, like a poor old sod

P.P.S. Just noticed the full photo resolution hasn't been uploaded by DIYNot. Grrrr...

 

[easyflow]

Freeze it then change it.

 

[Nozzle]

http://www.toolstation.com/shop/Hea...Straight+Braided+Filling+Loop+-+Part+L/p83963

Give that bad-boy a shot. And if you're regularly topping it up, then the entire system will become damaged due to oxygen. You can dose the system at the same type as fitting the new filling loop

http://www.toolstation.com/shop/Hea...d3235/Cal-Shot+Total+System+Protection/p77217

Nozzle

 

[morningster]

Thank you, Nozzle and easyflow for your quick responses.

Problem is... Just had 3 new rads fitted, system has been emptied and re-filled a number of times then dosed with expensive Sentinel X100!

I don't think I would be comfortable using a freeze kit, easyflow (assuming I understood you correctly), but I'm fairly certain replacing just the shut-off is do-able for me, and it would avoid pain and money to call the heating engineer back, drain, refill, re-dose, blabla...

So if what I suggest is possible, what's the procedure for my type of loop/ valve arrangement and where to find the right shut-off replacement?

Thanks again.

 

[Nozzle]

You might find that with the motorised valve shut, and the pump discharge and suction shut that you only need to drain down a small section - if this loop is between the two. Or you could try doing it with the water "hung up" in the radiators, but that could end in tears/very wet floor. It looks to me like the compression fitting is leaking. Another option is tighten it slightly with a large spanner - but be aware this might not make it better, and it might well make it worse.

Nozzle

 

[morningster]

Thanks Nozzle. Just got back from supplies shop with new shut-off valve. I'm pretty certain it's not the compression fitting but will see how it goes...

 

[endecotp]

if you turn off all radiator valves (both ends) then you drain at most the contents of the pipes; depending on your system (especially the pipe diameters) that may mean you keep most of the treated water.

 

[it's not that hard]

If it's just the shut off valve just turn off the cold water mains and replace it, when you undo the braided hose from the shut valve there shouldn't be any water coming from the heating system,you can always reconnect if the check valve isn't holding,

 

[morningster]

Thank you one and all for your input.

I've not yet had time to do the replacement but I have a shiny new isolation valve with metal lever (first non-plastic one I've seen) from a local plumbing supplies shop that looks the business...

 

[morningster]

If it's just the shut off valve just turn off the cold water mains and replace it, when you undo the braided hose from the shut valve there shouldn't be any water coming from the heating system,you can always reconnect if the check valve isn't holding,

Yep... Fitted new valve. Leak gone. No backflow from double check when flexi was disconnected, which is reassuring. Didn't get to use shiny new valve nut though, as old one stuck between olive and pipe bend. Still, satisfying result, however small the job.

Thanks!