Navien Pan Head Screw (+) M4 x 12 SCM435

A pan head screw with a cross (+) drive, sized M4 x 12 and manufactured in SCM435 alloy steel. It is supplied by Navien for use on NCB300 and NCB500 combi boilers, where it secures internal components and panels. The pan head spreads clamping load over a flat bearing surface, making it suitable for fixing brackets, covers and assemblies.

• The screw is missing from its fixing point, leaving a cover, bracket or assembly loose.
• The cross recess is rounded or chewed, so the driver slips instead of turning the screw.
• The head or shank is corroded, with visible rust or pitting.
• The thread is stripped or cross-threaded and will not tighten to a secure hold.
• The screw has been over-tightened and the head has sheared from the shank.

• Confirm the thread size and length required at the fixing point — M4 x 12 is not interchangeable with other sizes.
• Check the drive type matches the tooling you have; this screw uses a cross (+) recess.
• Verify your boiler model against the manufacturer's parts list before ordering.
• Check how many fixings are needed, as screws are typically ordered individually.