External/internal overflow constantly dripping

[Markso552]

I have recently had a new boiler fitted, viessman vitodens 100w, and since then my external overflow has been constantly dripping, i dont know if its due to the boiler change or just a coincidence.
While lying in bed last night i heard a constant rush of water from the airing cupboard, and when investigating there was a constant stream of water flowing down into a black open cone like thing down to a pipe in the floor.
The pipework above this constant drip comes from a red expansion tank. Turning iff the main stop valve to the upstairs pipework stopped the flow, but im guessing it will stop the upstairs cold working as well?

What is going on here, has the expansion tank seal broken or something? The pressure was about 1.5 bar cold. Photo of the cone thing attached, with the stream of water inside it.

I have a hot water tank, and 2x expansion vessels in the airing cupboard. I dont have a cold water tank or heating expansion tank in the loft. I have assumed the metal vessels are replacing the standard plastic tanks.

Many thanks.

 

[oldbutnotdead]

The cone thing is called a tundish. Usually fitted on the outlet of a pressure relief valve on a pressurised hot water cylinder. Expansion vessel should be white for tap water.
Was the water hot or cold? Very little DIYable on pressurised dhw.

And which overflow is dripping- is it the white condensate pipe from the boiler (which will emit water regularly, should be running into a drain) or the boiler pressure relief valve (copper disc) or something else?

 

[Markso552]

The cone thing is called a tundish. Usually fitted on the outlet of a pressure relief valve on a pressurised hot water cylinder. Expansion vessel should be white for tap water.
Was the water hot or cold? Very little DIYable on pressurised dhw.

And which overflow is dripping- is it the white condensate pipe from the boiler (which will emit water regularly, should be running into a drain) or the boiler pressure relief valve (copper disc) or something else?

It is fitted below a red expansion tank, and also connected to the overflow of the hot water cylinder. The water running through it was cold.

Its a copper pipe which sticks out the side of the house at ankle level and drains directly onto (not into) the ground. There is nothing on the other side of the wall to this pipe, i suspect it runs down from the ensuite, and so boxed in. Its not the condensate of the boiler as this runs out a different side if the house.

 

[Markso552]

Some more photos with colour coding for pipework alignment

The black stop valve lever in the bottom right is what i turned off to stop the dripping.

 

[JohnD]

The red vessel? What does the pressure gauge on your boiler read? Show us the pipes and valves under the boiler.

Does it run when your boiler is cold, or only when it is hot?

 

[muggles]

If it stopped dripping when you turned the black lever valve off then it's an issue with the cylinder side and not the heating side. You need a G3 registered engineer to investigate. Cylinder either needs a service (should be done annually but most people don't get it done for whatever reason) or there's a fault with the combination valve.

 

[Markso552]

The red vessel? What does the pressure gauge on your boiler read? Show us the pipes and valves under the boiler.

Does it run when your boiler is cold, or only when it is hot?

The red vessel is 1.7 bar when cold
Is there a way to release pressure from the red vessel?

It drips when boiler is hot and cold

 

[Markso552]

If it stopped dripping when you turned the black lever valve off then it's an issue with the cylinder side and not the heating side. You need a G3 registered engineer to investigate. Cylinder either needs a service (should be done annually but most people don't get it done for whatever reason) or there's a fault with the combination valve.

released some pressure from the red vessel with the knob on the pipe as it was well over the red line while cold

Also turned the black level back on and its constantly dripping into the tundish again (thanks oldbutnotdead) guess one of the valves has gone? All the other red PRVs are turnable and work. The grey one is not?

 

[dilalio]

The red EV is the CH system, the white EV is the hot water system.

They are both piped to the same tundish.

It is the white vessel or combination valve below it that needs attention.

White EV may have depleted air or membrane has split. Or combination valve or part thereof is defective.

 

[Markso552]

Thanks guys. As its easter monday, i guess ill call homeserve or wait til tomorrow.

 

[Madrab]

Don't use the red valve (PRV) on the CH to release pressure, you can inadvertently cause another issue whereby the valves don't close properly and needs to be replaced.

As suggested, you have an expansion issue on the unvented hot water, you need it serviced and they will fault find it. Check your Homeserve info as the unvented HW may not be covered and they'll charge you a fortune if it isn't.

 

[JohnD]

released some pressure from the red vessel with the knob on the pipe as it was well over the red line while cold

What does the pressure gauge on your boiler say?

 

[Markso552]

What does the pressure gauge on your boiler say?

It actually doesnt. Its a viessman vitodens 100-w, the new range, i cant find any way to see the pressure setting on my boiler. The manual refers to seeing it on the main screen by continuing pressing the 3lines, but the button combinations don't work and do t display anything other than the boiler temperature.
Pg14

https://boilerhut.co.uk/wp-content/uploads/2021/02/Viessmann-Vitodens-100-W-Operating-Instructions.pdf

 

[JohnD]

... Show us the pipes and valves under the boiler.

Does it run when your boiler is cold, or only when it is hot?