
SIT 845 SIGMA Gas Valve for Fagor CE, FA, FE, and FEE - Code 0845061
SIT gas valve model 845 SIGMA, manufactured in Italy (Padova), installed in Fagor boilers from the CE, FA, FE, and FEE series. It regulates the gas inlet and outlet to the burner through two solenoid valves (EV1 and EV2) and a modulator (MD), with a maximum inlet pressure of 60 mbar and a modulated outlet between 1 and 37 mbar. It is replaced when there is a failure in ignition or flame modulation.
VAT included
Consult via WhatsAppFagor boilers compatible with reference MU0809100
Gas valve with reference MU0809100. 12 verified compatibilities: FE-20E/2N and FE-20E/2B.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Fagor FE-20E/2N | Fagor Eco Compact FE-20E | Contrasted |
| Fagor FE-20E/2B | Fagor Eco Compact FE-20E | Contrasted |
| Fagor FE-20E | Fagor Eco Compact FE-20E | Contrasted |
| Fagor FE-24E | Fagor FE (rest of series) | Contrasted |
| Fagor FE-27E | Fagor FE (rest of series) | Contrasted |
| Fagor FE-24NOX | Fagor FE (rest of series) | Contrasted |
| Fagor FA-20E2N | Fagor FA | Contrasted |
| Fagor FA-23EN | Fagor FA | Contrasted |
| Fagor FEB-20E | Fagor FEB | Contrasted |
| Fagor FEE-20 | Fagor FEE | Contrasted |
| Fagor CA-20EN | Fagor CA | Contrasted |
| Fagor CE-20E | Fagor CE | 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. MU0809100 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 MU0809100. 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 gas valve MU0809100 resolves.
The gas valve regulates and modulates the gas flow to the burner. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The boiler does not ignite: you can hear the click of the spark but there is no flame, or the flame goes out immediately.
Cause: The solenoid valve EV1 of this valve does not open the gas flow to the burner, so there is no fuel even though there is a spark.
Check that the ignition electrode is sparking and that the ionization cable is properly connected, to rule out an ignition fault before inspecting the gas valve.
- 02
The flame fluctuates abruptly, as if the boiler cannot regulate the power.
Cause: The MD modulator is not dosing the gas properly between ignition and normal operation, and the gas valve is allowing more or less gas than it should.
Check that the modulator connector is properly fitted and free of oxidation before confirming the fault: a poor connection produces the same symptom.
- 03
The boiler display shows a warning or lock related to the gas valve.
Cause: The control unit detects that the EV1, EV2, or the modulator are not responding as they should and locks the boiler for safety.
Note the exact code displayed before requesting the spare part: that code indicates which part is faulty and prevents changing the gas valve if the blockage comes from elsewhere.
- 04
There is a slight smell of gas near the control panel or the gas valve itself.
Cause: The solenoid valves of this type of valve can lose tightness with use and allow some gas to pass even when they are closed.
Apply soapy water to the threaded connections of the inlet and outlet before suspecting the gas valve: a leak in a gasket does not require replacing it.
Fault codes for Fagor that this part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F1 | Lockout due to ignition fault (flame not established). | The faulty/stuck gas valve may not open or modulate at startup, and insufficient gas may reach for ionization; check voltage in coils during the ignition attempt and pressure/flow in the ramp, ensuring the valve opens. |
| F6 | Flame detection with the burner at rest (parasitic flame). | If the gas valve does not close hermetically, it allows gas to pass and a residual flame persists; check the valve's closure/sealing when stopped and rule out a false ionization signal. |
| F10 | Fault in the control or closure of the gas valve. | Fault in the valve or its control circuit (coils/relays) prevents proper opening/closing; check coil continuity, control voltage from the PCB, and ensure the flame extinguishes when closure is commanded. |
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 gas valve Fagor MU0809100
- Catalogue reference
- MU0809100
- Brand
- Fagor
- Type of part
- Gas valves
- Units in stock
- 1 unit
- 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
- SIT
- Model / family
- 845 SIGMA
- Inlet pressure (Pi max)
- 60 mbar
- Outlet pressure (Po)
- 1-37 mbar
- EV1 (1st solenoid valve)
- 230V~50Hz, 9.2 VA class B
- EV2 (2nd solenoid valve/modulating)
- 230V~50Hz, 2.8 VA class J
- Modulator MD, max. voltage.
- 17V DC
- Maximum current
- 165 mA
- Ambient temperature
- 0/60°C
- Code (SIT)
- 0845061
- Manufacturing (week/year)
- 0512
- Batch
- 2507180
- Nr
- 1191





