Immergas Boiler Air Pressure Switch 44/36 Pa – BDR Control 120.003.010, 1.012849 Compatible

The BDR Control 120.003.010 air pressure switch is the safety part that monitors flue draft in Immergas room-sealed boilers. It does not close its contact until the fan is running and has created sufficient vacuum in the flue line; the board does not ignite the burner without this confirmation. In other words, this is the part that prevents the appliance from operating with a blocked flue or a stopped fan.

Its switching value is 44/36 Pa, and it is an equivalent of the original air pressure switch with Immergas spare part code 1.012849. The BDR product code 120.003.010 is printed on its body and box.

What Does 44/36 Pa Mean?

• 44 Pa — upper switching point. When the fan vacuum reaches this value, the contact closes and the board receives ignition confirmation.
• 36 Pa — lower point. If the vacuum falls below this value, the contact opens and the boiler shuts off the gas.
• The 8 Pa difference between them (hysteresis) is intentional. It prevents the contact from constantly opening and closing in wind and flue fluctuations, i.e. the appliance repeatedly locking out and resetting.

The switching point is set at the factory; it cannot be adjusted on the part. This is why a pressure switch with a "close" Pa value will not do the job.

If the Wrong Pa Value Is Fitted

• If a higher value is fitted (for example 60/50 instead of 44/36), the boiler fan may not be able to produce that vacuum; the contact does not close. Result: the fan runs but there is no ignition, and the appliance goes into flue safety lockout.
• If a lower value is fitted (for example 40/25), the safety margin is lost. Even with a partly blocked flue or in windy weather the contact stays closed and the boiler keeps running. This creates a risk of flue gas leaking into the room.

Before ordering, read the Pa value on the body of the removed part; if the value is 44/36 Pa, it can be replaced with this part.

Technical Specifications

• Brand / product code: BDR Control 120.003.010
• Equivalent OEM code: Immergas 1.012849
• Switching value: 44/36 Pa
• Contact rating: 0.2 (0.1) A – 30 V~
• Connection: 2 hose nozzles, plug-in electrical connection
• Setting: Fixed (factory set), CE marked
• Design: Turkey