Junkers Air Pressure Switch ZW23 1 AE23 S3705 Ref. 8738709736
RefurbishedJunkersPressure switches

Junkers Air Pressure Switch ZW23 1 AE23 S3705 Ref. 8738709736

15 €VAT includedIn stock · 1 unit

Pressure switch: refurbished spare part that controls air or water pressure to authorize operation. Useful if the boiler does not start or shows a draft error. Compatible with ZW23-1AE23, ZW23-1AE31, ZW23 AE 31 S2805 (ref. 8738709736). Includes a one-year warranty and delivery within 2–4 working days in the EU.

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

Key Data

Reference
8738709736
Brand
Junkers
Type of part
Pressure switches
Available units
1 unit in stock
Status
Refurbished
Warranty
1 year
Shipping
2–4 working days (EU)
Return
14 days

The same part (ref. 8738709736) equips these models. Verified compatibility; check the reference before purchasing.

Junkers Euroline (ZW23 / ZW24)

  • ZW23-1AE23
  • ZW23-1AE31
  • ZW23 AE 31 S2805
  • ZW24 AE 23 S2805
  • ZW24 AE 31 S2805
  • ZW24-1LH AE23

Junkers ZS23 (AE / Euromaxx)

  • ZS23-1AE23
  • ZS23-1AE31
  • ZS23 AE 23 S2805
  • ZS23 AE 31 S2805

Junkers WT/WTD water heaters and ZW20

  • ZW20-1AME23 S2805
  • ZW20-1AME31 S2805
  • WT11 AM1E 23 S2805
  • WT11 AM1E 31 S2805
  • WT14 AM1E 23 S2805
  • WT14 AM1E 31 S2805
  • WTD14 AM1E 23 S2805
  • WTD14 AM1E 31 S2805

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)
C1The differential pressure switch has been activated during operation.The air pressure switch opens during operation due to a fatigued diaphragm, stuck contacts, or incorrectly connected/blocked pressure ports/hoses. Verify by measuring continuity between C and NO and the Δp with a micromanometer while the fan is running.
C4The differential pressure indicator does not open with the fan disconnected.The pressure switch remains closed at rest due to a seized diaphragm, incorrect adjustment/calibration, or improperly mounted Pitot tube/hoses. Check that with the fan stopped, the C–NO contact is open and inspect/clean the pressure switch inlets and hoses.
C6The differential pressure switch does not close.The minimum Δp is not reached or the micro does not switch due to a damaged diaphragm/faulty pressure switch or obstructed ports. Check for electrical closure between C and NO when the fan starts and measure the pressure drop at the pressure switch ports; if it does not switch within its threshold, replace it.
How do I know if this pressure switch is for my boiler?
Verify the reference 8738709736 printed and ensure your model is on the list of compatible ones; also compare the connections with the original part. It is a Huba piece.
What is it used for?
The pressure switch controls the pressure/draught (of air in sealed systems) or water to authorize operation.
Is the boiler not starting or showing a draught fault?
If the fan spins but does not ignite, check the pressure tubes (loose/blocked), the diaphragm, and the fan.
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
Check the tightness of the pressure pipes and the switching of the contact.
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.

Spare Parts Related Boiler ZW23 1 AE23 S3705

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