Wilo Circulating Pump UNRS15/5-3 P Ref. 4509739
Wilo three-speed circulator pump, reference 4509739 (OEM equivalent 95260696). It circulates water in the heating circuit. It is replaced when the motor does not start, makes noise, seizes up, or stops moving water with correct power supply. Compatible with specific models from Baxi, Buderus, Domusa, Baxi Roca, and Saunier Duval.
VAT included
Consult via WhatsAppWilo boilers compatible with reference 4509739
Circulating pump with reference 4509739. Seven confirmed compatibilities: Gavina (NYL-43-15) and GB122.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Wilo Gavina (NYL-43-15) | Baxi | Contrasted |
| Wilo GB122 | Buderus | Contrasted |
| Wilo (NYL-43-15) | Domusa | Contrasted |
| Wilo Laia (NYL-43-15) | Baxi Roca | Contrasted |
| Wilo Duval Isomax Condens F35 E | Saunier | Contrasted |
| Wilo Duval Isomax F28 E | Saunier | Contrasted |
| Wilo Duval Isotwin F28 E2 | Saunier | Contrasted |
Can't see your model or have questions? The printed reference takes precedence. How to check it · Send us a photo via WhatsApp.
How to check if ref. 4509739 is the part for your boiler
What determines it is not the boiler model, but the reference printed on the part you already have installed.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 4509739. If it is not visible, do not identify the part from its shape alone.
- Check the full boiler model on its data plate and look for it in the model associations on this page.
- Compare the connections and physical body with the original part before installation.
- If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.
Symptoms and faults that the circulator pump 4509739 resolves.
The circulation pump circulates the water in the heating circuit. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The radiators do not heat up even though the boiler starts without showing any fault.
Cause: If the rotor does not spin, the hot water circulates only within the boiler and does not flow to the system.
Touch the supply and return pipes near the pump: if one is hot and the other is cold, confirm that there is no circulation.
- 02
The pump has been stopped all summer and now it won't start.
Cause: It is very common for the rotor to get stuck due to small deposits after months of not turning, without the motor being damaged.
Before the first startup, try to manually unlock the shaft with a screwdriver on the central front screw.
- 03
There is a vibration or rattling noise when it operates.
Cause: It may be due to air in the circuit or a worn bearing in the pump body itself.
Bleed the air from the pump and the circuit before replacing the motor due to noise.
- 04
The motor does not start despite having power at the connector.
Cause: With correct power supply and no rotation, it is usually a mechanical blockage of the rotor, not an electrical fault.
Try to free the shaft by hand before buying a new pump; often it is enough to unclog it.
- 05
There is water dripping from the shaft or the body of the pump.
Cause: The mechanical seal has lost tightness after years of use or due to abrasive sediments in the water.
Dry the area and check after a heating cycle if the leak reappears before confirming the replacement.
Fault codes Wilo that this part solves
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.75 | Pump fault/lack of water: when the pump starts, a sufficient pressure increase is not detected. | If the Wilo UNRS15/5-3 P pump is blocked, running slowly, or without power, the pressure sensor does not detect the increase and the boiler enters F.75; check power supply to the pump, bleed, and consult d.149 (substates: 1=pump blocked, 2=electric fault, 3=dry running, 6=no response, 7=wrong pump). |
| E125 | Circulation fault in the primary circuit. | If the Wilo UNRS15/5-3 P pump does not rotate or is seized, there is no flow, and the unit detects overtemperature/gradient; check the voltage to the pump, unblock it via the front cap, and confirm there is circulation. |
| A1 281 | Pump blocked or operating with air (the heating pump is not generating pressure). | If the Wilo UNRS15/5-3 P pump is blocked or has air, it does not generate pressure and the boiler locks with A1 281; bleed the circuit and check that the rotor turns and receives power. |
These symptoms can have more than one cause. If your boiler displays a fault code, send it to us via WhatsApp along with a photo of the labeling, and we'll tell you if this is the part.
Data sheet for the Wilo circulator pump 4509739
- Catalogue reference
- 4509739
- Brand
- Wilo
- Type of part
- Pumps
- Units in stock
- 2 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- Return
- 14 days
Data read on the part and in the manufacturer's documentation
What we have not been able to verify does not appear here.
- Manufacturer
- Wilo
- Model (according to label)
- UNRS15/6-3 P
- Wilo reference
- 4509739
- Boiler OEM equivalence
- 95260696
- Engine number
- 4505521
- Voltage/frequency
- 230V~ 50Hz (400VDC)
- Condenser
- 2.6 µF
- Degree of protection
- IP42
- Nominal pressure
- PN10
- Thermal class
- Class F / TF110
- Speed III
- 2200 min-1, 0.38A, 88W
- Speed II
- 2000 min-1, 0.27A, 60W
- Speed I
- 1600 min-1, 0.18A, 40W
- 4505521 is the motor number, not the complete pump number; do not use it as an order reference.
Frequently asked questions about the circulator pump 4509739
Is reference 4509739 the same part as OEM code 95260696?
How many speeds does the pump installed in the Buderus GB122 have?
What IP protection does this Wilo pump Ref. 4509739 have?
Does this pump work for a Baxi Gavina with motor NYL-43-15?
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