
Honeywell Pressure Switch C6065FH1243:2 For Saunier Duval Thema NOx F24 - Ref. 49003733
Honeywell pressure switch, manufactured by Yamatake Corporation, for Saunier Duval/Hermann Thema NOX F24 and Supermicra Ecoplus 24 SE boilers. It operates at very low pressures (set at 1.15 mbar, maximum 6 mbar), a range typical of an air pressure switch that validates the fan's operation. It is replaced when the boiler does not ignite or locks with the fan running.
VAT included
Consult via WhatsAppHoneywell boilers compatible with reference 49003733
Pressure switch with reference 49003733. Three confirmed compatibilities: Thema NOX F24 and Supermicra Ecoplus 24.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Honeywell Thema NOx F24 | Saunier Duval/Hermann | Contrasted |
| Honeywell Supermicra Ecoplus 24 | Saunier Duval/Hermann | Contrasted |
| Honeywell Supermicra Ecoplus 24 SE | Saunier Duval/Hermann | 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. 49003733 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 49003733. 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 49003733 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 does not ignite or locks out with the fan already running, without supplying gas to the burner.
Cause: This pressure switch operates at very low pressures; if it does not detect the minimum depression, it does not close the contact and the boiler does not start.
Check that the fan starts normally and that the pressure intake pipes have no leaks or obstructions, no matter how small.
- 02
Intermittent lockouts appear with the same pressure switch fault code on the display.
Cause: When handling such tight pressure ranges, any minimal loss of tightness in the circuit causes the signal to fluctuate.
Check the connections and fittings of the pressure switch pipes one by one, even those that seem well placed at first glance.
- 03
The fan can be heard running, but the boiler remains stopped without moving to the flame phase.
Cause: If the internal contact of the pressure switch does not switch despite the actual depression being correct, the fault lies in the part and not in the fan.
Before replacing it, check that the fan reaches its usual revolutions and does not take too long to start.
- 04
Blockages occur more on windy days or under specific external conditions.
Cause: A pressure switch that sensitive to pressure can react to draft variations that would not affect another model.
Note if the blockages coincide with strong winds: focus more on the flue than on the pressure switch.
Fault codes from Honeywell that this part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F2 | Safety Flue Test (SFT) or pressure switch / air flow fault. | The air pressure switch does not switch because it does not detect depression during pre-ventilation or is faulty; check continuity at terminals during fan start-up and inspect/clean hoses and venturi of the pressure switch. |
| F33 | Air flow fault. | The air pressure switch does not switch (St33) due to not reaching the expected depression or due to an internal fault; check the switching with a multimeter and the differential pressure with a manometer/U-tube, as well as clean the tubes and venturi and verify the extractor. |
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.
Honeywell 49003733 pressure switch datasheet
- Catalogue reference
- 49003733
- Brand
- Honeywell
- Type of part
- Pressure switches
- Units in stock
- 4 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.
- Component manufacturer
- Honeywell (Yamatake Corporation)
- Model code
- C6065FH1243:2
- Electrical contact
- 1.5(0.5)µ, 250V~
- Set pressure
- P=1.15 mbar
- Maximum pressure
- max. 6 mbar
- CE code
- CE-0063AP3085/1
- Secondary code
- 0905M












