Navien
Navien Main Heat Exchanger 30030931A
Main heat exchanger for the Navien NCB300-28K Combi boiler, part number 30030931A.
At a glance
- Appliance family: NCB300-28K Combi
£308.47
£257.06 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 main heat exchanger is the primary component that transfers heat from the combustion circuit into the heating and domestic hot water circuits on a Navien NCB300-28K Combi boiler. It is manufactured by Navien and supplied under part number 30030931A. The unit sits at the centre of the appliance's water circuit, so its condition directly affects heating performance and hot water delivery.
Signs this part needs replacing
- Heating or hot water output that has dropped noticeably and cannot be restored by servicing
- Kettling, banging or gurgling noises from the appliance during operation
- Repeated overheat lockouts or high-limit trips on the boiler
- Water traces, weeping or staining around the heat exchanger body or its connections
- Unstable domestic hot water temperature that fluctuates between hot and cold
Before you order
- Confirm the appliance model is NCB300-28K Combi and check the serial number against the unit being worked on
- Verify the part number 30030931A against the manufacturer's parts list for your appliance
- Inspect the system for sludge or scale before fitting, as debris is a common cause of heat exchanger failure
- Confirm the appliance is isolated, drained and depressurised before removal of the existing component
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) | — | — | — |
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.
No technical questions yet for this part.
Not sure which part?
Search by part number, product name or brand — our technical team confirms fitment before anything is dispatched.