Navien
Navien Clip High Limit Stat 20054283A
Clip-on high limit thermostat for Navien NCB300 and NCB500 combi boilers, marked STC5 15.
At a glance
- Part type: clip high limit stat
£4.08
£3.40 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 clip high limit stat is a clip-mounted high limit thermostat used on Navien NCB300 and NCB500 combi boilers. It is marked STC5 15 and measures 44.7 x 23.5 x 0.6T. The stat monitors boiler temperature and interrupts the burner demand if the limit is exceeded, protecting the appliance from overheating.
Signs this part needs replacing
- Boiler locks out or shuts down before reaching the set flow temperature
- Repeated overheat faults that clear on reset and return once the boiler runs
- Burner cuts out early and the appliance cycles short of demand
- No heating or hot water because the limit stat holds the burner off
- Visible damage, corrosion or a loose clip at the stat body
Before you order
- Confirm the boiler model and serial number against the fitment list
- Check the marking on the existing stat reads STC5 15
- Inspect the mounting clip and wiring connections for damage before fitting
- Verify the fault is with the limit stat and not the control thermistor or PCB
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)
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