Check valve leak under combi

[C Ish]

Came home tonight to find this leaking under my combi boiler. The pipe feeds up into the Adey cleaner/filter, which then runs into the boiler. Reading up it is a check valve.

The bottom end cap was very loose and I could hand tighten it some way. I have nipped up the bottom end cap and repressurised and it seems fine.

I have not touched it before this and to be honest never noticed it.

I did drain the system and remove a radiator today upstairs, but did not touch that particular valve. Could this have been the cause or is it just a big coincidence?

In the past I have drained systems many times and fitted a few radiators without issues.

Thanks in advance.

 

[oldbutnotdead]

Coincidence/vaguely possible that the depressurise/repressurise cycle dislodged something. Fairly poor check valve- water shouldn't pass opposite the direction of flow (the arrow on the body)