HVAC Relay Replacement Parts

DPST relays are widely used in HVAC control systems to manage electrical circuits safely and efficiently. A double-pole single-throw relay controls two separate circuits simultaneously, allowing HVAC equipment such as compressors, fans, and heating elements to operate reliably under controlled electrical conditions.

A DPST relay contains two poles that open or close together when the relay coil is energized. This design allows technicians to control two electrical lines at the same time, improving system safety and ensuring balanced power distribution within HVAC equipment and electrical control panels.

HVAC systems use several DPST relay types including sequencing relays, flange mount relays, 6-terminal fan relays, control relays, and electrical heat relays. These components help regulate electrical flow, manage heating elements, and coordinate fan operation for consistent system performance and reliability.

A failing DPST relay may cause HVAC equipment to stop running, cycle improperly, or fail to start entirely. Other warning signs include clicking noises, overheating relay contacts, or inconsistent power delivery to fans, compressors, or heaters within the system’s electrical controls.

PartsHnC offers HVAC DPST relays, including plug-in relays (12V–24V), panel mount relays (24V–120V), heavy-duty switching relays (120V–240V), compressor relays (24V–208V), and fan control relays (24V–120V) from Honeywell, Siemens, Schneider Electric, and Johnson Controls, with fast shipping available.

How do I diagnose a compressor relay that fails to start the compressor?

Check the relay coil voltage and verify that both contact poles close when energized. If the compressor does not receive power, the relay contacts may be faulty.

Are DPST relays commonly used in heating equipment?

Yes, DPST relays are often used in electric heating systems to control heating elements and ensure safe electrical switching.

Why is my 6-terminal fan relay not starting the blower motor?

Check if the relay coil is receiving control voltage from the thermostat or control board. If voltage is present but the fan motor does not start, the relay contacts may be worn or damaged.

How can I repair a relay with loose or burnt terminals?

Tighten all wiring connections and inspect the terminals for heat damage. If the relay shows signs of burnt contacts or insulation damage, replacement is usually required.

How do I fix a DPST relay that is not switching properly?

First, check the coil voltage using a multimeter to confirm the relay is receiving power. If voltage is present but the contacts do not close, the relay is likely faulty and should be replaced.

How can I test a DPST relay using a multimeter?

Set the multimeter to resistance mode and measure the coil terminals. Then apply the rated coil voltage and verify that both contact pairs close simultaneously.

How can I check if a fan control relay is operating correctly?

Apply the correct control voltage and listen for the relay click. Then confirm that the output terminals supply voltage to the blower motor circuit.