What does the fault code F.75 mean in Wilo?

Pump fault/lack of water: when the pump starts, a sufficient pressure increase is not detected. If the Wilo RS 15/6-3 Ku is blocked, seized, or not receiving power, the expected pressure increase at startup does not occur. Verify by bleeding the circuit, checking the shaft rotation through the front plug, and measuring the pump's consumption/flow rate while in operation.

What does fault code F.23 mean in Wilo?

Safety shutdown: The temperature difference between flow and return is too large. A blocked or underperforming Wilo RS 15/6-3 Ku pump reduces the flow rate and causes a large temperature difference between the flow and return NTC sensors. Check by listening/observing the pump's rotation and measuring flow/ΔT in the pipes.

What does the fault code F.24 mean in Wilo?

Safety shutdown: temperature rise too quickly. If the Wilo RS 15/6-3 Ku pump is blocked or delivering low flow, the water does not circulate and the boiler temperature rises rapidly, triggering the protection. Check bleeding, pump rotation/consumption, and abnormal ΔT between supply and return.

RefurbishedWilo Pumps

Wilo Circulating Pump RS 15/6-3 Ku P 3 Speeds P/N 4527335

Name: Wilo Circulating Pump RS 15/6-3 Ku P 3 Speeds P/N 4527335
Brand: Wilo
SKU: MBWRSB15/63
Price: 75 EUR
Availability: InStock

75 €VAT includedIn stock · 1 unit

Circulating pump: reconditioned spare part that circulates water in the heating circuit. Useful if there is noise, water is not circulating, or radiators do not heat evenly. Reference 4527335. Includes a one-year warranty and delivery within 2–4 working days in the EU.

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Delivery in 2–4 working days

1-year warranty

14-day return

Technical support

Key Data

Reference: 4527335
Brand: Wilo
Type of part: Pumps
Available units: 1 unit in stock
Status: Refurbished
Warranty: 1 year
Shipping: 2–4 working days (EU)
Return: 14 days

Fault codes related to this part (not the entire boiler). They usually have more possible causes: first rule out electrodes, wiring/connections, and gas supply. Verified with ≥3 sources.

Code	What does it mean?	Cause and diagnosis (this part)
F.75	Pump fault/lack of water: when the pump starts, a sufficient pressure increase is not detected.	If the Wilo RS 15/6-3 Ku is blocked, seized, or not receiving power, the expected pressure increase at startup does not occur. Check by bleeding the circuit, verifying the shaft rotation through the front plug, and measuring the pump's consumption/flow rate while in operation.
F.23	Safety shutdown: the temperature difference between flow and return is too large.	A blocked or underperforming Wilo RS 15/6-3 Ku pump reduces the flow rate and causes a significant temperature difference between the flow and return NTC sensors. Check by listening/observing the pump's rotation and measuring flow rate/ΔT in the pipes.
F.24	Safety shutdown: temperature increase too rapid.	If the Wilo RS 15/6-3 Ku pump is blocked or delivering low flow, the water does not circulate and the boiler temperature rises quickly, triggering the protection. Check bleeding, pump rotation/consumption, and abnormal ΔT between supply and return.