Kromschroder Air pressure switch DL3A-3 84444400

The Kromschroder DL3A-3 air pressure switch, SKU 84444400, is a diaphragm-type pressure switch designed to regulate positive, negative, or differential air and flue gas pressures. It has an adjusting range of 0.2 to 3 mbar and features a tempered LSR diaphragm sensing element. The housing is made of glass fibre reinforced PBT plastic, and the electrical connection is via screw terminals. The switch operates with a microswitch conforming to EN 61058-1 and is safety class 2. It is approved under CE-0085AP0466 and complies with EN 13611:2015+AC:2016 and EN 1854:2010 standards, with a designed lifetime of 10 years.

When selecting a replacement air pressure switch of this type, ensure the pressure range, connection thread (Rp 1/4), and electrical ratings match the original. The switch must be suitable for the medium (air or flue gas) and ambient temperature range. Mounting orientation and electrical connection (screw terminals) should be compatible with the existing setup. Verify the switch's safety class and standards compliance for the application.

Common failure modes for air pressure switches include diaphragm rupture or leakage, leading to loss of pressure sensing and improper burner operation. Symptoms may include burner lockout, failure to start, or erratic flame modulation. Check for physical damage, contamination, or loose electrical connections. Verify the switch's setpoint and operation using a manometer.