Navien
Navien Flat Head Screw M4 x 14 S18A 20038760A
Flat head Phillips screw, M4 x 14, S18A, for Navien LCB 700 and NCB 300/500 series boilers.
£3.91
£3.26 ex. VAT · VAT at 20%
Same-day dispatch
Ordered by 4pm Mon–Fri, 10:30am Sat.
30-day returns
Unused, in original packaging.
What it is
A flat head screw with a Phillips (+) drive, M4 x 14 thread size and S18A material designation, supplied by Navien. It is used as a fixing on Navien LCB 700 and NCB 300/500 series gas boilers, securing components and casing parts during assembly and service.
Signs this part needs replacing
- A fixing is missing after a service or component removal, leaving a panel or bracket unsecured
- The screw head is chewed or rounded, so the driver no longer grips it
- Corrosion or surface pitting on the screw body or head
- A casing or cover panel rattles or lifts because a fixing point is empty
- The screw has been cross-threaded or will not tighten down fully
Before you order
- Confirm the thread size and length required at the fixing point — M4 x 14
- Check the head type and drive match the recess on the component being secured
- Count how many fixings are missing before ordering
- Verify your boiler model against the fitment list above
No specification data held for this part.
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| NAVIEN LCB 700 COMBI EXTERNAL 21KW (Serial Number 1705) | — | — | — | |
| NAVIEN LCB 700 COMBI EXTERNAL 21KW (Serial Number 1705) | — | — | — | |
| NAVIEN LCB 700 COMBI EXTERNAL 28KW (Serial Number 1710) | — | — | — | |
| NAVIEN LCB 700 COMBI EXTERNAL 28KW (Serial Number 1710) | — | — | — | |
| NAVIEN LCB 700 COMBI EXTERNAL 36KW (Serial Number 1709) | — | — | — | |
| NAVIEN LCB 700 COMBI EXTERNAL 36KW (Serial Number 1709) | — | — | — | |
| NAVIEN LCB 700 COMBI INTERNAL 21KW (Serial Number 1704) | — | — | — | |
| NAVIEN LCB 700 COMBI INTERNAL 21KW (Serial Number 1704) | — | — | — | |
| NAVIEN LCB 700 COMBI INTERNAL 28KW (Serial Number 1706) | — | — | — | |
| NAVIEN LCB 700 COMBI INTERNAL 28KW (Serial Number 1706) | — | — | — |
Showing 10 of 48 compatible appliances.
Documents & drawings
Everything we hold for this part. Where a document exists but we don't hold it, the technical team will source it from the manufacturer — usually the same working day.
NAVIEN appliance manual — LCB 700 COMBI EXTERNAL 21KW (Serial Number 1705), LCB 700 COMBI EXTERNAL 28KW (Serial Number 1710), LCB 700 COMBI EXTERNAL 36KW (Serial Number 1709), LCB 700 COMBI INTERNAL 21KW (Serial Number 1704), LCB 700 COMBI INTERNAL 28KW (Serial Number 1706), LCB 700 COMBI INTERNAL 36KW (Serial Number 1708), LCB 700 REGULAR EXTERNAL 21KW (Serial Number 1474), LCB 700 REGULAR EXTERNAL 28KW (Serial Number 1478), LCB 700 REGULAR EXTERNAL 36KW (Serial Number 1482), LCB 700 REGULAR INTERNAL 21KW (Serial Number 1472), LCB 700 REGULAR INTERNAL 28KW (Serial Number 1477), LCB 700 REGULAR INTERNAL 36KW (Serial Number 1481), LCB 700 SYSTEM EXTERNAL 21KW (Serial Number 1471), LCB 700 SYSTEM EXTERNAL 28KW (Serial Number 1476), LCB 700 SYSTEM EXTERNAL 36KW (Serial Number 1480), LCB 700 SYSTEM INTERNAL 21KW (Serial Number 1434), LCB 700 SYSTEM INTERNAL 28KW (Serial Number 1475), LCB 700 SYSTEM INTERNAL 36KW (Serial Number 1479)
manualmanualNAVIEN appliance manual — NCB300-28K COMBI - (Serial Number 3710), NCB300-37K COMBI - (Serial Number 3734), NCB300-41K COMBI - (Serial Number 3711)
manualmanualNAVIEN appliance manual — NCB500-1S+/32K COMBI - (Serial Number 3924), NCB500-2S+/41K COMBI - (Serial Number 3712), NCB500-2S/37K COMBI - (Serial Number 3735)
manualNo technical questions yet for this part.
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