I think the dropping of the ZC is simply a marketing decision.
Apparently, the Pioneer series have hot faces. The smaller Pioneer II also has 16" clearance to the header.
FWIW, the Quad 7100 clearances:
» 1” fireplace to back wall
» 1” fireplace to sidewall
Apparently, the Pioneer series have hot faces. The smaller Pioneer II also has 16" clearance to the header.
FWIW, the Quad 7100 clearances:
» 1” fireplace to back wall
» 1” fireplace to sidewall