How to recharge an expansion vessel?

[ElricTheRed]

Hi,

When my boiler (regular vented I believe) is on there's a constant trickle of water flowing out a pipe to outside (coming off the red vessel in the image below). It's happened in the past and IIRC the expansion vessel needs recharging. I'm pretty sure it's the case again as when I take the top off (the white vessel) and press the valve nothing comes out. No air or water.

I don't know if it's Covid, the busy winter season or it's just not worth their time (I wouldn't prioritise this if the roles were reversed) but I'm failing miserably to get a plumber to come out and do it. So I'm hoping to take matters into my own hands.

From what I've seen on YouTube and various "how to posts" I should be isolating the system, running the taps to drain the pressure to 0 (on the red vessel), pumping the white one up to 3 bar and then stop isolating.

Is that roughly right? If it is, unfortunately I'm failing immediately. Here's a photo:

The top level is labelled "All hot and cold taps". If I turn that off and try to run the taps barely anything comes out and then they stop. The pressure gauge on the red ball stays at 1.

It's the only thing I can see to turn "off". The only two other switches are already off. I use them to refill the heating system after bleeding all the radiators.

Is what I'm trying to do sensible for a DIY-er? If so, could someone please point me in the right direction as to what I'm doing wrong?

Thanks

 

[ShaunCorbs]

You need a heating engineer as you won’t stop the trickle

 

[Aquarius]

That’s not a vented system, it’s unvented and any work performed on that part of the system needs a G3 qualified and registered engineer, not something you can do yourself.

 

[ElricTheRed]

Thank you both. I struggled to get anyone out, now I need to find someone with a certain qualifications At least I know.

 

[moonlight]

You need a heating engineer as you won’t stop the trickle

I can't see a gauge on the hot water vessel. But its still something a diy person should not do their self.

 

[ShaunCorbs]

If it’s trickling out of the heating pipe don’t need to be g3 also your on a sealed system

 

[ElricTheRed]

If it’s trickling out of the heating pipe don’t need to be g3 also your on a sealed system

It's coming out of the pipe that you can just about see going out from the red vessel at the bottom of the picture, through the outside wall.

You need a heating engineer as you won’t stop the trickle

I've finally managed to get someone to come out. They turned the top switch, ran the hot water, pumped up the white vessel to 1 bar (took a long time and a lot of water came out), turned the water back on and it's sitting at just under 3 bar. Does that sound right?

Another question if you don't mind. How much water should come out of that pipe? It used to be almost constantly dripping, maybe 100ml/hr. Since the recharge it's much less, but still drips at maybe 5ml/hour.

Does that sound right?

 

[moonlight]

1 bar is not enough it should be 3 bar for domestic hot water. There should be no water dripping out of the pipe. After it is fully repressurised and you still have water dripping out, it will be another problem and you will need a qualified G3 engineer.

 

[EvilDrPorkChop]

Your main issue is that you have no understanding of what each vessel is doing - if you thinking turning the hot water off and opening the tap to let the water out will allow the gauge on the red vessel to go to 0 bar then you honestly don't understand the system - as others have said you need a Qualified Engineer out.

 

[ElricTheRed]

Your main issue is that you have no understanding of what each vessel is doing - if you thinking turning the hot water off and opening the tap to let the water out will allow the gauge on the red vessel to go to 0 bar then you honestly don't understand the system - as others have said you need a Qualified Engineer out.

I did get an engineer out, that is exactly the procedure he did. I haven't touched it.

I guess I'll try and find another engineer.

 

[Ben-gee]

He’s had an engineer out now evildrpork; OP as moonlight says above 1 bar is probably not enough.
Moonlight I think you set the vessel to just below the incoming main pressure- or 3bar if the reducing valve is set to that.
ie if mains only 2bar, set the vessel to 1.9bar.

 

[moonlight]

Pressure relief is 6bar. Pre-charge should be around 3bar