Honeywell Air Pressure Switch for Saunier Duval Isomax F 28 E2 - Ref. S57440
Honeywell air pressure switch (factory code C6065FH1276:2) mounted on Saunier Duval boilers from the Isomax, Isofast, Opalia, and Themafast ranges. It checks the vacuum generated by the extractor before allowing ignition. Set to open at 0.53 mbar, maximum allowable pressure 6 mbar, contact of 1.5A at 250V~. It is replaced when the boiler does not validate the fan draft and locks without igniting.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference S57440
Pressure switch with reference S57440. Ten verified compatibilities: Isofast F 28 E and Isofast F 28 E1.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Isofast F 28 E | Isofast | Contrasted |
| Saunier Duval Isofast F 28 E1 | Isofast | Contrasted |
| Saunier Duval Isomax F 28 E | Isomax | Contrasted |
| Saunier Duval Isomax F 28 E2 | Isomax | Contrasted |
| Saunier Duval Isotwin F 24 E | Isotwin | Contrasted |
| Saunier Duval Opalia F 11 E | Opalia | Contrasted |
| Saunier Duval Opalia F 14 E | Opalia | Contrasted |
| Saunier Duval Opaliatherm TF 11 | Opaliatherm | Contrasted |
| Saunier Duval Opaliatherm TF 14 | Opaliatherm | Contrasted |
| Saunier Duval Themafast F 24 E | Themafast | 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 ref. S57440 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 S57440. 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 pressure switch S57440 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 screen shows a fault code related to the pressure switch or air, not with the flame.
Cause: The control board identifies the type of fault based on which sensor is not validating; if the pressure switch does not close, the warning directly indicates that problem.
Note the exact code displayed by the boiler before purchasing anything; confirm if it indicates pressure switch/air or flame, and avoid replacing the wrong part.
- 02
The fault disappears for a moment if the pressure switch casing is gently tapped.
Cause: An internal contact with poor support can intermittently close due to vibration, even if the part is at the end of its useful life.
Do not leave it as a solution: if the fault changes when touching the part, it is a clear sign that the pressure switch is faulty, and not the rest of the installation.
- 03
The fault worsens when it is very windy or the boiler is in a very exposed area.
Cause: The wind at the exit terminal alters the depression generated by the extractor and may prevent the pressure switch from reaching its set point.
Check the location and condition of the flue terminal; if it is very exposed to the wind, rule out that cause first.
- 04
The extractor sounds different than it used to, more strained or weaker.
Cause: If the extractor does not create the usual depression, the pressure switch -even if it is functioning properly- never receives the signal it needs to switch.
Compare the sound and speed of the extractor with those before the fault; if they have changed, first check the extractor.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| 02 | Airflow fault. | The air pressure switch S57440 does not switch correctly (open when the fan starts or stuck/open circuit), so the PCB does not 'test' the draft; check continuity at its terminals during the ignition sequence, condition of the intake tubes (obstructions/leaks), and wiring/terminals. |
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.
Saunier Duval S57440 pressure switch datasheet
- Catalogue reference
- S57440
- Brand
- Saunier Duval
- Type of part
- Pressure switches
- 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.
- Manufacturer
- Honeywell (Yamatake-Honeywell)
- Factory code
- C6065FH1276:2
- Opening setting
- P= 0.53 mbar
- Maximum pressure
- Pmax. 6 mbar
- Contact
- 1.5(0.5)A / 250V~
- CE mark
- CE-0063AP3085/1
- Internal microswitch contact
- 1.5A-250VAC
Frequently asked questions about the pressure switch S57440
Is the S57440 pressure switch from the Saunier Duval Isomax F 28 E2 an original part from Saunier Duval?
At what pressure does the pressure switch of the Isomax F 28 E2 open?
What fault does this pressure switch resolve in the Saunier Duval Isofast F 28 E?
What electrical contact does the pressure switch S57440 have?
Is the S57440 suitable for the Saunier Duval Themafast F 24 E?
Spare parts related to Saunier Duval Isofast
