Resideo pa404b1023/u Pressuretrol Controller Steam

Product Description

The RESIDEO pa404b1023/u is a pressure-actuated controller designed for steam heating systems. This model makes the fan circuit when a rise in steam pressure confirms the presence of steam, enabling proper fan operation in suspension-type unit heater applications. At its core, a sensitive diaphragm expands and contracts in response to pressure changes, moving a lever mechanism that operates an SPST MICRO SWITCH snap-acting switch. Set point adjustment is accessible via a screw on top of the case without removing the cover, and the differential is set using a dial located inside the case. Licensed HVAC and steam heating technicians are the typical installers for this control.

The pa404b1023/u is intended for use with suspension-type unit heaters in steam heating systems. When steam pressure rises to the set point, the controller closes the fan circuit, signaling that steam is present and the unit heater fan should operate. This makes it well suited for commercial and industrial spaces where suspended unit heaters deliver radiant or forced convection heat from a centralized steam boiler. It is not a high-limit safety control; it functions as a make-on-rise pressure switch in the fan circuit.

Key Features

• Pressure-actuated diaphragm responds to steam pressure variations for reliable switching
• SPST MICRO SWITCH snap-acting switch provides positive, low-bounce circuit make and break
• Set point adjustment via external screw without removing the controller cover
• Differential adjustment via internal dial for fine-tuned pressure control
• Makes fan circuit on pressure rise, confirming steam presence in suspension-type unit heaters

Compatibility

Designed for use with suspension-type unit heaters in steam heating systems where a make-on-rise pressure control is required in the fan circuit.

Installation Notes

Installation should be performed by a licensed HVAC or steam heating technician familiar with low-pressure steam systems. Shut down the boiler and relieve all system pressure before connecting or disconnecting the controller. Ensure wiring to the fan circuit complies with applicable NEC requirements for the voltage and load involved. Verify the set point and differential settings match the system design before returning the boiler to service.

Technical Specifications

• Switch Type: SPST MICRO SWITCH snap-acting
• Actuator Type: Pressure-actuated diaphragm
• Action: Make on pressure rise (fan circuit)
• Set Point Adjustment: External screw, cover-on access
• Differential Adjustment: Internal dial

Standard Information

• Brand: RESIDEO
• Manufacturer Part Number: pa404b1023/u