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Navien Flat Head Taptite Screw M4x10 S18A 20038753A

Navien

Navien Flat Head Taptite Screw M4x10 S18A 20038753A

Flat head Taptite screw, M4 x 10, Pozidriv drive, S18A, for Navien NCB300 and NCB500 combi boilers.

Manufacturer part no.
20038753A
Showing prices

£3.91

£3.26 ex. VAT · VAT at 20%

Available to order · 3 working days
Available to order · 3 working days
Not certain it's the right part? The technical team verifies fitment before dispatch — no charge, and it stops a second trip.Call the technical teamSend a technical question

Same-day dispatch

Ordered by 4pm Mon–Fri, 10:30am Sat.

30-day returns

Unused, in original packaging.

What it is

A flat head Taptite screw manufactured by Navien, sized M4 x 10 and identified by the S18A designation. Taptite thread-forming screws cut their own mating thread as they are driven, so they are used where a component is fixed into a plain or part-formed hole on the appliance. This screw is used across the Navien NCB300 and NCB500 combi boiler ranges.

Signs this part needs replacing

  • The Pozidriv recess is rounded or chewed, so the driver slips under load
  • The head is corroded, scaled or has lost its flat seating face
  • The thread has stripped or will no longer bite in the hole
  • The screw is missing or has been lost during a service or repair
  • The component it retains is loose or has begun to weep or rattle

Before you order

  • Confirm your boiler model against the fit list above
  • Check the existing screw is M4 x 10 with a Pozidriv head
  • Check the thread form — Taptite screws are not interchangeable with machine screws
  • Confirm how many screws are required for the job

Not sure which part?

Search by part number, product name or brand — our technical team confirms fitment before anything is dispatched.