Navien
Navien Flat Head Screw M4 x 6 SCM435 20038859A
Flat head Phillips M4 x 6 screw in SCM435 steel, used across Navien LCB 700 and NCB300/NCB500 boiler models.
£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
The Navien flat head screw is a Phillips (+) M4 x 6 fastener manufactured in SCM435 chrome-molybdenum alloy steel. It is used to secure components within Navien LCB 700, NCB300 and NCB500 boilers. It is a service-level fixing rather than a functional assembly in its own right.
Signs this part needs replacing
- The screw head is rounded or chewed, so a driver no longer grips it
- Corrosion or rust is visible on the head or thread
- The screw is missing after a service or component removal
- The thread is stripped or cross-threaded at the mounting point
- The component it secures is loose or vibrating
Before you order
- Confirm your appliance model and serial number against the fitment list
- Check the existing screw is M4 x 6 with a flat Phillips head
- Check the mounting point thread is undamaged before refitting
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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