Replacing diverter valve

[Kevin W]

Hi, this is my first post.. hoping it's an easy one that someone can help me with.
I've got a standard system (not a Combi.. just a Bosch gas boiler and a hot water tank).
Anyway.. everytime the CH valve turns off, I get a REALLY LOUD clunking noise from the system.

I've done some reading around and one forum suggested that the Diverter Valve may have been installed "the wrong way round" - so i checked... and it has been !
So, all I need to do is disconnect the brass valve, turn it round and re-install - happy days.
Here's my question... what do i need to do in-order for loads of water (under pressure) not to shoot-out when I remove the diverter valve ?
Is it just a case of taking the CH pressure down to zero by removing 'some' water from one of the downstairs radiators until the pressure dial goes to "zero" ?
And then re-fill the system / bleed the radiators after I've spun the valve round ?

 

[Deleted member 120897]

So I’m guessing it’s a system boiler? It’s not a diverter valve you have, unless it’s a W plan? Post a photo of airing cupboard/hot water cylinder - there maybe some valves on it.

 

[Kevin W]

You're 100% right... apologies, it's not a "Diverter Valve" - just a simple valve that's controlled with a servo / motor that's connected to the boiler. There's one for the Central Heating and one for the Hot Water.
I've attached a photo (with the motor removed).
My plan is to simply un-do the top and bottom nuts, hope there is enough play in the pipes for me to remove it, spin it round and wack it back on (what could possibly go wrong ?!) - any advice / insight in how to remove the pressure first (and any water that may be held in the boiler that is 'above' the valve) or any other tips appreciated. Photo attached. Many thanks.
PS The noise when it closes is REALLY loud !! but read somewhere that, if it's installed wrong way round, you can get a noise.
I'm assuming the "shutting" is more sudden if it's not installed the right way round and it's this SUDDEN CLOSING that's causing the loud bang (due to the mechanical design of the valve ?).

 

[ShaunCorbs]

2 port valve do you have a bypass valve

 

[Deleted member 120897]

Yes, valves installed the wrong way around will bang. If you have an open vented system, then you can use a plugging kit. If you have a system boiler, then drain the boiler pressure, and that should be enough to work on it, you may get some excess water when swapping around.

 

[Kevin W]

Yes, valves installed the wrong way around will bang. If you have an open vented system, then you can use a plugging kit. If you have a system boiler, then drain the boiler pressure, and that should be enough to work on it, you may get some excess water when swapping around.

Is there an easy way to do this ?

 

[Gasmk1]

Is there an easy way to do this ?

Yes pay a plumber or RGI to do it

 

[Kevin W]

Thanks Gasmk1
Being the DIY part of the forum, I thought someone might be able to give me some help on how I might do it myself - I'm guessing there's no way other than bleeding one of the upstairs radiators until I see the pressure drop to "0" on the pressure gauge. Is there another / more simple way ? Any advice appreciated

 

[Gasmk1]

Thanks Gasmk1
Being the DIY part of the forum, I thought someone might be able to give me some help on how I might do it myself - I'm guessing there's no way other than bleeding one of the upstairs radiators until I see the pressure drop to "0" on the pressure gauge. Is there another / more simple way ? Any advice appreciated

no simpler way than what you have mentioned, is the valve definitely in the wrong direction as would be a fruitless task if it isn’t, looking at the photo don’t know how much play you have as you need quite a bit as the pipe will be approx 1/2 inch into the valve each side.

 

[Kevin W]

Yeah, it's definitely the wrong way round (have double checked).
And I think you're right in there not being enough 'play' to remove the valve... I've just checked and all the fittings are pretty solid.. no wiggle-room at all. So I'll have to use a couple of those pre-soldered sleeve-couplers I guess.

 

[Basher]

Yeah, it's definitely the wrong way round (have double checked).
And I think you're right in there not being enough 'play' to remove the valve... I've just checked and all the fittings are pretty solid.. no wiggle-room at all. So I'll have to use a couple of those pre-soldered sleeve-couplers I guess.

You will need to drain the water out of the system, at least in the vicinity of this valve, if you want to solder a coupler.
You won't make a decent soldered joint with water in the pipe!
I'd use compression if water's about.