Absolutely not. Using #14 AWG wire with a 25 amp overcurrent protection device (OCPD) is a violation of the National Electrical Code (NEC) and is unsafe. Even though #14 is rated at 20 amp it cannot be used.Here's why: NEC 240.4(D) Small Conductors

This section of the NEC specifically addresses the overcurrent protection for small conductors (#14 AWG, #12 AWG, and #10 AWG). It states that these conductors must be protected at their ampacity rating unless a specific exception applies. None of the exceptions would apply here.

NEC 440.22 Hermetic Refrigerant Motor-Compressor

Overcurrent protection for HVAC equipment containing hermetic refrigerant motor-compressors is dictated by this section. It specifically states that the maximum overcurrent protection device (OCPD) shall not exceed 175% of the motor's rated-load current (FLA). However, this does not allow you to use a smaller wire size than required by the NEC.Therefore, you would need to use #12 AWG wire in this scenario.Here's the safest and most correct approach:1.

Confirm the Nameplate

Double-check the HVAC unit's nameplate to verify the FLA and Max OCPD values.2.

Use #12 AWG Wire

Given the 16.6 FLA and 25 amp max OCPD, #12 AWG copper wire is the appropriate choice.
3.

Communicate with the Installer: Clearly explain to the HVAC installer why you cannot use #14 AWG wire. Emphasize that it is a code violation and could create a safety hazard. Explain the reasoning from the NEC as stated above.Your responsibility as an electrician is to ensure that the wiring is safe, code-compliant, and will reliably operate the HVAC equipment. Don't compromise on safety to save a few dollars. Flag for review