Honeywell Gas boiler control unit S4965R2000B

This control box is designed for gas domestic heating installations and works with VK41 series gas regulators. It provides programmed safe ignition and flame monitoring via ionisation detection, operating at 230 V (tolerance +10% -15%) and 50 Hz (49–51 Hz). The ignition sequence includes 3 start-up attempts, a safety time of 5 s, pre-purge time of 30 s, pre-ignition time of 0.2 s, flame loss reaction time of 1 s, stabilization time of 0.2 s, and pumping time of 600 s. It has up to three external 230 V outputs (0.8 A each, total 2 A) and a 230 VAC 50 mA valve output. Operating temperature is -20 to 60 °C with maximum humidity 90% at 40 °C; connectors are Molex Minifit and Microfit, and it has a 2.8 mm spark terminal and 4.8 mm flame rod.

Control boxes of this type are selected by supply voltage, frequency, and compatibility with the gas regulator series (such as VK41). Typical connections include Molex Minifit for 230 V, Molex Microfit for low voltage, and Faston terminals for spark (2.8 mm) and flame rod (4.8 mm). During installation, the high-voltage ignition cable must be kept at least 10 cm from other wires, and an external fuse should be used. This type supports Y-plan systems and is intended for gas domestic heating installations.