ACV Sight glass furigas (assembly) 50423365

This boiler housing part is a sight glass assembly that includes a glass pane, a metal frame, and a holder for fixing. It is a replacement part for ACV Prestige Box Mono 100 Smart E Plus HeatMaster 101 units. The assembly is installed as a complete set.

Sight glass assemblies of this kind are selected by boiler model and the original part number; glass diameter, thickness, and gasket profile vary by housing. Before ordering, compare the mounting arrangement and check whether the original uses a separate frame or an integrated holder. When installing, verify the seal and fixing hardware against the boiler's exploded view, and avoid overtightening the retaining screws or clips because that can crack the glass. The assembly should sit flush in the cutout to maintain the gas-tight seal.

A damaged sight glass of this type usually shows scratches, clouding, or cracks, which obstruct the view or break the pressure seal. A cracked glass can allow flue gas leakage or outside air to enter, leading to unstable combustion or soot deposits. Burner irregularities or a smell of combustion products may be the first signs. During routine service, inspect the glass and check that fixing screws are not loose or overtightened.