Fan Relays

Voomi Supply carries fan relays from White-Rodgers, Carrier, Mars, Emerson, York, Marley, and Allied Air, in SPST and SPDT configurations across 24V, 120V, and 208/240V coil voltages. A fan relay uses a low-voltage control signal, typically 24V from a thermostat or control board, to switch the higher-voltage circuit that actually powers a blower, condenser, or combustion fan motor, isolating the low-voltage controls from the power the fan draws. Every order ships with Voomi's 30-day return policy and free help matching a relay to your system.

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Relay Types We Carry

Fan relays in this collection differ mainly by switching configuration and coil voltage:

Type

What It Does

Common Coil Voltage

SPST (single pole, single throw)

Simple on/off switching for one fan circuit

24V

SPDT / DPDT (double throw)

Switches between two circuits, such as high/low fan speed

24V, 120V

Time delay relay

Delays fan start or stop by a set interval, such as post-purge on a combustion fan

24V, 120V

Enclosed / pre-wired relay

Comes housed and wired for a specific application rather than bare terminals

208/240V, 277V

 

Matching a Replacement Relay

Beyond coil voltage and switching configuration, confirm the terminal layout and mounting style match your existing relay, since a White-Rodgers 90-series relay and a Carrier OEM relay can both be rated SPDT 24V but use different terminal arrangements. Some brands, like Goodman and Heil Quaker, use board-mounted relay assemblies rather than a standalone unit, so check whether your system needs a bare relay or a full board replacement before ordering.

AC & Combustion Fan Relays

An AC fan relay switches power to the outdoor condenser fan motor, cycling it with the compressor to keep the coil cool during operation. A combustion fan relay, like the Heil Quaker DPST combustion fan relay in this collection, instead controls the draft-inducing fan on gas-fired equipment, and often works alongside a time delay relay to keep the fan running briefly after burner shutoff to purge remaining combustion gases. These aren't interchangeable even when the coil voltage matches, since the wiring and timing logic differ by application.

Selecting a Fan Relay for HVAC

Choosing the right fan relay HVAC part involves checking voltage compatibility, durability, and brand quality to ensure your system performs smoothly.

Frequently Asked Questions

Signs of a bad fan relay include:

  • Unresponsive fan operation: Fan doesn't start or stop as expected.
  • Intermittent fan behavior: Fan operates erratically or inconsistently.
  • Unusual noises: Clicking or buzzing sounds from the relay.
  • Overheating: Relay or surrounding components feel unusually warm.

To diagnose, use a multimeter to check for continuity and proper voltage at the relay terminals.

Consider replacing the fan relay if:

  • It fails to activate the fan when the system calls for cooling or heating.
  • It frequently overheats or shows signs of wear.
  • There is visible damage or burn marks on the relay.
  • The fan operates erratically or not at all, and other components like the capacitor and motor are functioning correctly.

When choosing a fan relay, ensure it matches:

  • Voltage and current ratings: Compatible with your system's specifications.
  • Coil voltage: Common options include 24V, 110/120V, and 208/240V.
  • Configuration: Single Pole Single Throw (SPST) or Single Pole Double Throw (SPDT), depending on your system's requirements.
  • Mounting type: Ensure it fits your system's design and space constraints.
  • Brand compatibility: Some systems may require specific brands like White-Rodgers or Carrier.

Yes, a malfunctioning fan relay can prevent the fan from operating correctly, leading to inadequate airflow. This can cause the system to overheat, potentially damaging components like the compressor or heat exchanger.

Replacing a fan relay can be safe if you have experience with HVAC systems and electrical components. Always disconnect power before servicing. If you're unsure or uncomfortable, it's best to consult a professional technician to avoid potential hazards.

Yes. Multi-unit orders qualify for quantity-based pricing, and contractors and service companies can set up a trade account for faster reordering. Contact our support team to get pricing on a bulk order or set up an account.