Junkers Air Pressure Switch ZWE 24 2KDG 31 S2800 Ref. 8717406050
If your boiler does not start or gets blocked despite having the correct pressure, the problem may lie in the Junkers ZWE 24 2KDG 31 S2800 air pressure switch, reference 8717406050. This part checks the air pressure and authorizes the operation of the boiler. When it fails, you may notice that the differential pressure switch activates for no reason (C1), does not open when it should (C4), or does not close upon starting (C6). It is compatible with models from the Eurostar and Novatherm ZWE ranges, among others. It is recommended to replace it upon detecting these symptoms to avoid malfunction.
VAT included
Consult via WhatsAppJunkers boilers compatible with reference 8717406050
Pressure switch with reference 8717406050. Four confirmed compatibilities: ZWE 24-2KDG 31 S2800 and ZWE 24-3MFA.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Junkers ZWE 24-2KDG 31 S2800 | Junkers Eurostar ZWE | Contrasted |
| Junkers ZWE 24-3MFA | Junkers Eurostar ZWE | Contrasted |
| Junkers ZWE 28-3MFA | Junkers Eurostar ZWE | Contrasted |
| Junkers ZWE 24-2KDG | Junkers Novatherm ZWE | 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 ref. 8717406050 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 8717406050. If it is not visible, do not identify the part by 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 pressure switch 8717406050 resolves.
The pressure switch controls the air or water pressure to authorize operation. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The boiler tries to ignite, the fan is running, and it shuts off before the flame lights.
Cause: The pressure switch does not close the flue confirmation contact and the control board does not allow gas to pass.
Listen to see if the fan reaches stable operation before suspecting the pressure switch.
- 02
A ventilation fault code appears every time you try to turn it on.
Cause: The pressure switch detects less air pressure than it needs to approve the ignition.
Check that the flue gas outlet to the outside is not obstructed by leaves, snow, or a foreign object.
- 03
The silicone tubes of the pressure switch are loose or have water inside.
Cause: A poorly connected pressure tap prevents the pressure switch from reading the actual air circuit depression.
Check and blow out the silicone tubes, empty the condensate if there is any, before replacing the part.
- 04
The fault is intermittent: some days it starts without any issues and other days it gets stuck during startup.
Cause: A pressure switch with a worn contact may switch erratically even if the pressure is correct.
Note if the fault coincides with changes in weather or wind in the area of the external terminal.
Fault codes from Junkers that this part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| C1 | The differential pressure switch is activated/opens during operation. | The air pressure switch opens due to loss of pressure or internal fault (membrane/contacts). Verify by measuring that the contact switches to open with the fan running and checking connections/venturi and hoses. |
| C4 | The differential pressure switch does not open at rest (with the fan stopped). | The pressure switch remains 'stuck' closed or there is residual depression in the line. Verify that with the fan stopped, the contact is open and that the pressure switch changes state when blowing/sucking on the inlets; check hoses/Venturi. |
| C6 | The air pressure switch contact does not close on start-up. | The required depression is not reached or the pressure switch fails (rigid diaphragm/calibration/blocked inlets). Verify by applying depression and checking that the contact closes with a multimeter; inspect the tubes towards the venturi/fan and the flue line. |
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 Junkers pressure switch 8717406050
- Catalogue reference
- 8717406050
- Brand
- Junkers
- Type of part
- Pressure switches
- Units in stock
- 3 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- Return
- 14 days
Frequently asked questions about the pressure switch 8717406050
Does this part fit a Junkers Eurostar ZWE28-3MFA boiler?
Spare parts related to Junkers Eurostar ZWE
