Honeywell Gas boiler control unit S4565CD2029U

The Honeywell S4565CD2029U is a gas boiler control unit that manages ignition and flame supervision in gas-fired heating equipment. It operates at a supply voltage of 220–240 V and is designed for use with gas regulators from the VK41 series. The unit features a connector on top for simplified installation and requires a 15-second wait time before resetting after a lockout. It is compatible with Ferroli PEGASUS 45-56, PEGASUS 23-32 (old), and RENDIMAX N EL boilers.

When selecting a control unit of this type, ensure the supply voltage matches the boiler's electrical system and that the unit is compatible with the specific boiler model and gas valve series. The connector on top allows for direct mounting onto compatible gas regulators, and the unit can be oriented within a 90-degree angle from vertical. Verify the boiler's ignition system type (spark or pilot) and the required reset wait time before installation.

Typical failures of this control unit include lockout without ignition, intermittent operation, or failure to reset. When the unit locks out, the boiler will not ignite and may require a manual reset after the specified wait time. Check for proper voltage supply, correct wiring to the gas valve, and ensure the flame sensor is clean and positioned correctly.