WHITE RODGERS (EMERSON ELEC)
White Rodgers 90-112 Transformer Relay 24V 120/240V DPDT hvac control
Combines a 24 V transformer with a DPDT relay to switch fans, pumps and forced-air or hydronic systems from low-voltage controls
- 24 V coil enables safe low-voltage control of line-voltage equipment
- Integrated transformer steps 120/240 V primary to 24 V secondary
- DPDT switching handles both fan and pump motor circuits
- 8 A at 120 V and 6.9 A at 240 V full-load ratings support 3/4 hp loads
- UL listed for forced-air and hydronic heating/cooling systems
Purpose and fit
The White Rodgers 90-112 transformer relay switches line-voltage fans, pump motors and forced-air or hydronic heating and cooling systems from a 24 V low-voltage control signal. It is intended for HVAC technicians and installers who need a single component that combines a step-down transformer with a DPDT relay for junction-box mounting.
What the bundle changes
The integrated transformer steps 120 V or 240 V primary voltage down to 24 V for the coil, eliminating the need for a separate transformer and reducing wiring inside the enclosure. A DPDT switch rated at 3/4 hp handles 13.8 full-load amps at 120 VAC and 6.9 full-load amps at 240 VAC, while UL listing confirms the assembly meets the relevant safety standard.
Compatibility checks
Verify that the control circuit supplies 24 VAC to match the coil rating and that the load does not exceed the listed horsepower and ampere limits for the supply voltage in use. Confirm the mounting footprint fits a 4 x 4 in junction box and that local code accepts the UL-listed assembly for the intended application.
Highlights
- 24 V coil enables safe low-voltage control of line-voltage equipment
- Integrated transformer steps 120/240 V primary to 24 V secondary
- DPDT switching handles both fan and pump motor circuits
- 8 A at 120 V and 6.9 A at 240 V full-load ratings support 3/4 hp loads
- UL listed for forced-air and hydronic heating/cooling systems
Specifications
| Brand | Emerson |
|---|
Questions about this item
Will the 24 V coil or the DPDT contacts need replacement first?
The 24 V coil and DPDT contacts are sealed inside the same relay module; neither is user-serviceable, so the entire unit is replaced when either fails.
What stops continuous duty first — the 13.8 A / 120 V or 6.9 A / 240 V contact rating?
The contact rating of 13.8 A at 120 VAC or 6.9 A at 240 VAC is the hard limit; exceeding either value causes overheating and contact welding before any other component.
How hot does the built-in transformer get when the relay runs 24/7?
The integrated transformer is UL listed for continuous operation at rated load; it runs warm but stays within the temperature rise allowed by the listing.
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