Pressure sensor is alternative to CO monitor

Manufacturers of flue-type heaters can reduce the cost of CO monitoring and safety shut-off systems using the Omron D8M-R micro pressure sensor.

Manufacturers of flue-type heaters can reduce the cost of CO monitoring and safety shut-off systems using the Omron D8M-R micro pressure sensor.

As a lower cost alternative to installing CO sensors in the flue output, the D8M-R is capable of measuring minute changes in the intake air pressure to sense abnormal combustion.

The sensor allows the system to conform to the ANSI Z21.86b flue block standard, which specifies a maximum carbon monoxide density in the exhaust of forced or induced draft wall furnaces.

Instead of detecting carbon monoxide directly, using relatively expensive CO sensors, the D8M-R displays a capacitance proportional to the flue intake pressure and outputs a signal whose frequency increases linearly with air pressure.

This also allows the fuel flow to the furnace to be easily modulated in order to restore combustion efficiency.

The D8M-R is also useful for monitoring ventilation systems in houses and apartments, allowing air flow regulators to be controlled to maintain constant ventilation.

Ventilation levels can thus be kept constant in all rooms, regardless of duct lengths and routing.

(This was Engineeringtalk's Top Story on 27 May 2002).

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