Any idea what's gone on here?

[Mjward]

Just moved back to my rental property and noticed a very tiny drip/leak in the basement corner where the pipes from the boiler/CH system go to an outside below ground drain.

Picture below

It's happened before where the lightwell on the other side gets filled with rubbish and tenants don't clear out, then clogs the external drain opening and after heavy rain it back spills into basement.

Ok so this morning, it was much more than a drip, a big leak. Yet there has been no rain. Only change is had gas engineer over yday as boiler kept losing pressure. He said expansion vessel had water in it so he fixed all that and repressurised system. Could any of that caused a lot of water to be discharged from central heating system to cause this kind of leak or completely unrelated and I just need plumber to look at drain and pipes pictured?

 

[ShaunCorbs]

What’s the 22mm pipe from ?

 

[Mjward]

What’s the 22mm pipe from ?

Part from system boiler but also looks like independent expansion vessel and hot water cylinder connected to it. This is the pic below the boiler with the white plastic and 22mm off to the right the ones that end up at that leak

 

[ShaunCorbs]

So likely to be dripping / leaking out of the joint as it looks like it’s been siliconed in

 

[Mjward]

So likely to be dripping / leaking out of the joint as it looks like it’s been siliconed in

Makes sense, doesn't look the best of fittings where these go into the wall and onto the drain. To have that amount of water though, is there any chance that be dispensed from the central heating system overnight or most likely it's leaking out from water on the drain side and through into the basement? Just trying to figure out if I need these gas Safe guys back as weren't cheap or I can get a domestic plumber in

 

[Mjward]

Update: cause of big "leak" was gas engineer emptying bucket after bucket of water down the lightwell "drain". Said drain being completely filled with soil and therefore running through the pipe in the wall and out the weak joint between it and the boiler pipes.

Have cleared drain, snake pipe clean the pipe through wall and sealed and tightened the joint to the boiler pipe. It's a short term fix, don't have all my tools with me but basically could do with core drill out the 100yr old pipe through wall and feed new one and make a better connection to boiler pipes