Constant running overflow problem

[astra_dtm]

Hi all... hoping I get a prize for the clearest explanation of a problem

In short, the overflow outside is a constant poor and it leads up to the pipe you see coming out of the airing cupboard floor and into the black overflow viewer (...a Tundish?)

The overflow is constantly running and I expected to find a water tank in the attic so I could change the ballcock, but there's no header tank and that's where my knowledge of plumbing systems starts to fail me!

The valve (Combination valve?) was supposedly renewed by a plumber less than 12 months ago for one he had on his van for the same problem. I do have my doubts it was genuinely a new part but it was shiny so can only assume it was new but lets just say I have my doubts!

I'm wondering if.....
- the valve wasn't new and its the only part that could be faulty?
- the pressure in the system is too high for the relief valves?
- the cold pressure relief valve is faulty ....testing the hot water one releases hot water into the tundish so I assume it isn't the one leaking. The cold one releases the cold water at a higher pressure
- The cold water pressure needs turning down somehow? (is that the valve in the background?)

Thanks in advance for help!

Cheers
Paul

 

[Crofton Gas]

Your system is unvented, which is why you don't have a tank, often when the valve let's by, it wont reseat.

You need to get an unvented qualified engineer to work on this system. The red handle valve is a pressure relief valve PRV which is a safety device.

The whole caleffi block doesn't need to be changed as just the PRV can be replaced.

 

[just pumps]

Hope you stop twisting the knobs now and tell the engineer what you`ve been doing when he/ she attends.

 

[astra_dtm]

Your system is unvented, which is why you don't have a tank, often when the valve let's by, it wont reseat.

You need to get an unvented qualified engineer to work on this system. The red handle valve is a pressure relief valve PRV which is a safety device.

The whole caleffi block doesn't need to be changed as just the PRV can be replaced.

ok thanks.... if it isn't a DIY thing, I'll leave well alone

Hope you stop twisting the knobs now and tell the engineer what you`ve been doing when he/ she attends.

The pressure relief valves can't be tested by twisting them? ....albeit not really a 'test'as such.

 

[just pumps]

PRV is there for a reason, to alert you to a problem within the whole pressurised system. When was it last serviced?