Isomax F 35 H MOD Heating Circulation Pump Ref. 0020036839
Isomax F 35 H MOD features the Wilo heating circulator pump, reference 0020036839. This pump is responsible for moving water through the heating circuit, thus ensuring proper heat distribution. If it fails, you will notice cold radiators, strange noises, or even overheating and blockages due to lack of circulation. It is compatible with the Isomax F 35 H-MOD range, among others. It is recommended to replace it when symptoms of malfunction appear or if errors such as 11: Pump blocked or 05: Overheating fault occur.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference 0020048255
Circulating pump with reference 0020048255. A proven compatibility: Isomax F 35 H-MOD.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Isomax F 35 H-MOD | Isomax F 35 H-MOD | 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 the reference 0020048255 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 0020048255. 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 0020048255 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 heating takes a long time to warm up or does not heat at all.
Cause: The pump has low flow and the heat is not distributed well throughout the system.
Make sure that all the radiator valves are open and that there are no closed areas in the circuit before suspecting the pump.
- 02
A loud buzzing is heard when starting the heating.
Cause: It could be trapped air in the rotor or a worn bearing.
Bleed the highest radiators in the house and check if the buzzing decreases.
- 03
After the summer break, the pump does not start when requesting heating.
Cause: The rotor can seize up if it doesn't rotate for months.
Before replacing it, try to free the shaft manually with a screwdriver on the front screw.
- 04
Water appears at the base of the pump or on the floor under the boiler.
Cause: The shaft seal may be worn and allow water to leak slowly.
Dry the area, turn on the heating, and locate where it is leaking before deciding on the replacement.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| 11 | Pump blocked | The motor/rotor of the circulator is seized or not rotating, resulting in no circulation; check the voltage at the pump terminals and unblock the shaft from the bleed cap to confirm it starts and moves flow. |
| 05 | Overheating fault | If the heating pump is faulty or blocked, there is no recirculation and the flow temperature exceeds the safety threshold; check that the circulator is receiving power and starts, bleed the circuit, and confirm flow. |
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 Saunier Duval circulator pump 0020048255
- Catalogue reference
- 0020048255
- Brand
- Saunier Duval
- Type of part
- Pumps
- Units in stock
- 5 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- 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.
- Thermal class
- Class F - TF96
- Pressure / degree of protection
- PN3 - IP44
- Condenser
- 3.6 µF
- Voltage / frequency
- ~230V-60Hz
- Manufacturing code
- 4520246
- Reference printed on the label
- Ref 0020036839
- Article/serial number (WILO)
- N° 4517736
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Saunier Duval Isomax F 35 H-MOD Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the circulator pump 0020048255
What voltage does the pump of the Isomax F 35 H MOD need?
What capacitor does the pump of the Isomax F 35 H MOD use?
Spare parts related to Saunier Duval Isomax F 35 H-MOD
