Navien
Navien Packing Orifice (Inner) 20054478A
Inner packing orifice for Navien NCB300 and NCB500 combi boilers, part number 20054478A.
At a glance
- Part type: packing orifice (inner)
- Appliance family: NCB300 and NCB500 combi
£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 packing orifice (inner) is a Navien component used within the gas valve assembly of NCB300 and NCB500 combi boilers. It forms part of the internal sealing and metering arrangement, sitting inside the valve body to maintain correct gas flow through the appliance. It is listed by Navien under part number 20054478A.
Signs this part needs replacing
- Gas leakage detected around the gas valve assembly during a tightness test.
- Combustion readings that cannot be brought within specification despite correct setup.
- Unstable or erratic flame picture at the burner.
- Ignition faults or lockouts linked to gas valve internal sealing.
- Visible damage, deformation or contamination of the orifice on inspection.
Before you order
- Confirm the boiler model and serial number against the fitment list above.
- Check the part number 20054478A matches the item removed from the appliance.
- Verify whether the inner or outer packing orifice is the component required.
- Confirm gas valve work will be carried out by a competent, registered engineer.
No specification data held for this part.
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| NAVIEN NCB300-28K COMBI - (Serial Number 3710) | — | — | — | |
| NAVIEN NCB300-28K COMBI - (Serial Number 3710) | — | — | — | |
| NAVIEN NCB300-37K COMBI - (Serial Number 3734) | — | — | — | |
| NAVIEN NCB300-37K COMBI - (Serial Number 3734) | — | — | — | |
| NAVIEN NCB300-41K COMBI - (Serial Number 3711) | — | — | — | |
| NAVIEN NCB300-41K COMBI - (Serial Number 3711) | — | — | — | |
| NAVIEN NCB500-1S+/32K COMBI - (Serial Number 3924) | — | — | — | |
| NAVIEN NCB500-1S+/32K COMBI - (Serial Number 3924) | — | — | — | |
| NAVIEN NCB500-2S+/41K COMBI - (Serial Number 3712) | — | — | — | |
| NAVIEN NCB500-2S+/41K COMBI - (Serial Number 3712) | — | — | — |
Showing 10 of 12 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 — 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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