Carrier 38HQ660014 Relay

The Carrier 38HQ660014 Compressor Lockout Sensing Relay is a specialized OEM control board designed to monitor electrical conditions and safeguard compressors in residential and commercial HVAC systems. Functioning as a high-precision current sensing lockout relay, this component detects abnormal operation and trips to prevent catastrophic compressor failure. It operates within a standard 24VAC control circuit and is rated for 208-230V applications, frequently found in Carrier 38, 48, and 50 series units. By monitoring the current through a dedicated sensor loop, it ensures that if a safety switch (such as a high or low-pressure switch) opens, the compressor remains locked out even if the switch resets, preventing the short-cycling that destroys windings. This relay is a direct replacement for HN65CT003, HN65CT003B, HN65CT004, HN65CT005, 38HQ660008, and 38HQ680014, offering a drop-in solution for legacy lockout timers and sensing boards.

Key Benefits for Technicians

• Enhanced Compressor Protection: Actively monitors the current sensing loop to prevent automatic restarts during fault conditions, protecting the motor from startup surges and mechanical stress.
• Wide Compatibility: Serves as a universal Carrier factory authorized part for various heat pumps and package units, superseding multiple older part numbers including 35401254 and P771-7009.
• Simplified Diagnostics: Features an "X" terminal output that can be wired to a thermostat alarm circuit or fault light for immediate troubleshooting of lockout events.
• OEM Precision: Guaranteed 208-230V voltage compatibility and 18-30 VAC control rating with exact lead lengths (34") for professional integration into tight control compartments.

Common Questions

How do you reset the 38HQ660014 lockout relay?
The relay is a manual reset device that requires power to be briefly interrupted at the 24V control input (Terminal 2). Once the fault condition is cleared and power is cycled, the relay will close the normally closed contacts between Terminals 2 and 3 to re-energize the contactor coil.

Can this relay replace the HN65CT003 series?
Yes, the 38HQ660014 is the current engineering replacement for the entire HN65CT sequence (003, 003B, 004, and 005) and the 38HQ680014, providing updated current-sensing logic for improved system reliability.

What triggers the lockout response?
The relay monitors the current sensing loop. If a safety device opens and the current drops below approximately 0.5 amps while the control circuit attempt is active, the relay energizes its internal coil to open the compressor contactor circuit and stay locked out.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.