Collector head needs cleaned.
A mortar wash cap is rated the worst at protecting brick. This is evident in the cracks in the mortar.
No sealant joint at clay flues.
Brick spall; this is due to moisture freeze damage over time.
There is defects in this sealant everywhere. This style of sealant application is ineffective against moisture intrusion at the brick.
This entire chase needs repair and reconstruction.
MAT(masonry absorption test): Highly absorptive.