SIT 845 Sigma Gas Valve - Hermann Micra 2 - Ref. 845063
SIT gas valve model 845 Sigma, installed in Hermann Micra 2 boilers and compatible models under reference 845063. It combines two solenoid valves (EV1 and EV2) that regulate the gas input and modulation to the burner, with an adjustable pressure output between 1 and 37 mbar. The replacement requires first confirming the fault of the part through technical diagnosis, even when the boiler does not ignite, does not modulate the flame properly, or locks up during startup.
- Type of part
- Gas valves
- Status
- Refurbished
- Catalogue reference
- 845063
- Warranty
- 1 year
Hermann boilers compatible with reference 845063
Gas valve with reference 845063. Seven confirmed compatibilities: Micra 2 and Supermicra.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Hermann Micra 2 | Micra | Contrasted |
| Hermann Supermicra | Micra | Contrasted |
| Hermann Habitat 2 | Habitat | Contrasted |
| Hermann Spazio Basic | Spazio | Contrasted |
| Hermann Spazio Plus | Spazio | Contrasted |
| Hermann Spazio Tekno | Spazio | Contrasted |
| Hermann Supermaster | Master | 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 reference 845063 is the part for your boiler.
The part reference, model, and equipment revision must be verified against the manufacturer's documentation.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 845063. 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 that require diagnosis in the gas valve 845063
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 takes time to ignite or the burner starts with a delay.
Cause: The main solenoid valve opens slowly or does not reach the necessary pressure.
Check that the incoming gas pressure in the house is normal before considering the gas valve as defective.
- 02
The flame changes from minimum to maximum abruptly, without a smooth transition.
Cause: The valve modulator does not properly regulate the gas flow to the burner.
First, rule out a fault in the flow sensor or in the modulation signal sent by the PCB.
- 03
The boiler locks up when starting, with or without a fault code on the screen.
Cause: The control board does not receive confirmation of the gas valve opening and cuts off the gas for safety.
Perform a reset and check if the lockout occurs at the same point in the ignition cycle every time.
- 04
A small knock or vibration is heard in the area of the gas valve when turning it on.
Cause: The solenoid valve hits when opening due to internal wear of the mechanism.
With the boiler in front of you, listen to see if the noise coincides exactly with the moment the burner ignites.
Hermann fault codes that require diagnosis
| Code | Fault | Technical checks |
|---|---|---|
| 35 | Parasite flame (presence of flame when it shouldn't be). | A faulty gas valve (not sealing tightly or sticking) can allow residual gas flow, and the electronics detect a flame with the burner 'off'. Check the valve's tightness and closure (pressure test at outlet/VENT and absence of voltage in coils) and the ionisation signal without demand. |
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 Hermann 845063
- Catalogue reference
- 845063
- Uniclima internal SKU
- VGHM2
- Brand
- Hermann
- Type of part
- Gas valves
- Units in stock
- 6 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- Return
- 14 days
Part data and available documentation
Contrast the label codes, PCB, and revision with the installed part; they are not necessarily equivalent references.
- Manufacturer
- SIT (Sit S.p.A., Padua, Italy)
- Model
- 845 Sigma
- Factory code
- 0063AS4831
- SIT internal code
- 0845063
- Maximum inlet pressure (Pi max)
- 60 mbar
- Regulated output pressure (Po)
- 1-37 mbar
- Solenoid valve 1 (SV1)
- 230V~50Hz, 9.2 VA, class B
- Solenoid valve 2 (EV2)
- 230V~50Hz, 2.8 VA, class J
- Modulation (MD)
- max. 9V DC, max. 310 mA
- Working ambient temperature
- -15 to 60 °C
- Batch/date
- Date 0717, Batch 2711663, No. 1631
Frequently asked questions about the gas valve 845063
Who manufactures the gas valve Ref. 845063 for the Hermann Micra 2?
What voltage do the solenoid valves EV1 and EV2 of this SIT 845 Sigma valve operate at?
Does this valve Ref. 845063 fit a Hermann Spazio Plus boiler?
What is the output pressure range of the Hermann Micra 2 valve?
When should this gas valve be replaced in a Hermann Micra 2 boiler?
How many models are compatible with the SIT 845 Sigma gas valve?
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