Saunier Duval Block Circulator Pump Body Thema NOx F25 B 1 Ref. 0020037988
RefurbishedSaunier DuvalPumps

Saunier Duval Block Circulator Pump Body Thema NOx F25 B 1 Ref. 0020037988

30 €VAT includedIn stock · 1 unit

Circulating pump: refurbished spare part that circulates water in the heating circuit. Useful if there is noise, water is not circulating, or radiators do not heat evenly. Compatible with Thema NOx F25 B, Themafast F25 E, Themafast F30 E (ref. 0020037988). Includes a one-year warranty and delivery within 2–4 working days in the EU.

1
Consult via WhatsApp
Delivery in 2–4 working days
1-year warranty
14-day return
Technical support

Key Data

Reference
0020037988
Brand
Saunier Duval
Type of part
Pumps
Available units
1 unit in stock
Status
Refurbished
Warranty
1 year
Shipping
2–4 working days (EU)
Return
14 days

The same part (ref. 0020037988) equips these models. Verified compatibility; check the reference before purchasing.

Saunier Duval

  • Thema NOx F25 B
  • Themafast F25 E
  • Themafast F30 E
  • Themafast Condens F30
  • Sémia Teck F24
  • Sémia C 24
  • Thema Condens F25
  • Thema C 25 E
  • Themaplus C 25 E
  • Themaplus F30 E
  • Isotwin Condens F30
  • Isofast Condens F30
  • Isomax Condens F35

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.

CodeWhat does it mean?Cause and diagnosis (this part)
F.75The control does not detect an increase in pressure when the pump starts (lack of water/pressure or pump/sensor fault).If the circulator (block 0020037988) is blocked, does not start, or does not respond, the pressure sensor does not detect the expected increase and the boiler locks out with F.75; check electrical/PWM start-up, consumption, and that the rotor spins after bleeding.
F.23Safety shutdown due to excessive temperature difference between flow and return.A blocked pump or one working at minimum power prevents circulation, increases the ΔT, and triggers F.23; check that the circulator is rotating, its consumption and flow rate, and bleed the primary.
F.24Safety shutdown due to excessively rapid temperature rise.If the circulator of block 0020037988 is seized or has insufficient power, the water does not dissipate heat and the temperature rises quickly; check the pump's rotation/consumption, PWM signal, and bleed the circuit.
F.20Safety shutdown of the temperature limiter (overheating).The lack of circulation due to a blocked pump in block 0020037988 causes overheating in the heat exchanger; check the start and flow of the circulator, free the shaft if it is seized, and bleed.
How do I know if this circulating pump is the one for my boiler?
Verify the reference 0020037988 printed and ensure your model is on the list of compatible ones; also compare the connections with the original part. It is a Saunier Duval part.
What is it used for?
The circulating pump circulates the water through the heating circuit.
Noise, water not circulating, or cold radiators?
Typical symptoms: humming, seized rotor after a long stop, or radiators that do not heat evenly.
Which models is it suitable for?
Part shared by various models (see Compatibility). If your model does not appear, send us a photo of the marking and we will confirm it.
Installation and recommendations
Bleed the air from the circuit and the pump; check the pressure at 1–1.5 bar with the boiler cold.
What does refurbished mean and what coverage does it have?
Part removed from a boiler out of service, inspected and tested. Includes 1-year warranty and 14-day return policy. Delivery within 2–4 working days in the EU.

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