Watermark on brick work

[Sri1234]

Wondering if anyone can point me in the right direction. Seem to large watermark near the boiler flue. Trying to figure out what’s the issue?

PS: The black pipe near the flue is an aircon pipe inside which the refrigerant pipes are there. The aircon has not been used for 3 months.

 

[Gasmk1]

Judging by the staining the water is coming from the air con covers.

What is higher up from the picture?

 

[Sri1234]

Judging by the staining the water is coming from the air con covers.

What is higher up from the picture?

4 meters length of aircon pipe vertically and nothing else

 

[Chuck]

As @Gasmk1 implies, I think it's likely that the weatherproofing at the of the air-con installation is not stopping water getting into the conduit and its coming out at the bottom.

If not, take a look next time there is heavy rain. (A small pair of binoculars will be helpful.) Could be something like an overflowing gutter with the aircon conduit acting as a guide for the spilled water.