44/36 Pa Huba Combi Boiler Air Pressure Switch – Immergas 1.012849, Huba 605.99A69

The Huba Control 605.99A69 air pressure switch is the safety component that monitors flue draft in room-sealed combi boilers. It corresponds to the Immergas air pressure switch with spare part code 1.012849; the body of the part reads Huba Control and its label reads 605.99A69. The switching value is 44/36 Pa.

What Does It Do?

When the fan runs, a vacuum forms in the flue line. When this vacuum reaches a sufficient level, the pressure switch closes its contact and the board receives ignition permission. If the fan has stopped or the flue is blocked, no vacuum forms, the contact does not close and the boiler burner does not ignite. In other words, this is the part that prevents operation with a blocked flue.

What Does 44/36 Pa Mean?

• 44 Pa: upper switching point. When the vacuum reaches this value, the contact engages.
• 36 Pa: lower point. If the vacuum drops below this, the contact disengages and the boiler shuts off the gas.
• The difference between them (hysteresis) prevents the contact from constantly opening and closing in wind and with flue fluctuations.

The switching point is set at the factory; no adjustment can be made on the part. Before ordering, read the Pa value on the label of the removed part; if the value is 44/36 Pa, it can be replaced with this part.

If the Wrong Pa Value Is Fitted

• If a higher value (for example 60/50) is fitted, the fan may not be able to produce that vacuum; the fan runs but there is no ignition, and the appliance goes into flue safety lockout.
• If a lower value (for example 40/25) is fitted, the safety margin is lost; the boiler may continue to operate even when the flue is partially blocked. This creates a risk of flue gas leaking into the indoor space.

For a more economical option with the same value, you can look at the BDR Control 120.003.010 (Immergas 1.012849 compatible) air pressure switch.

Technical Specifications

• Brand / model: Huba Control 605.99A69
• OEM code: Immergas 1.012849
• Switching value: 44/36 Pa
• Contact rating: 0.2 (0.1) A – 30 V~
• Maximum pressure: 1500 Pa
• Label code: 60010121 STANDART
• Connection: 2 hose nozzles, plug-in electrical connection
• Markings: CE, UKCA