Comfortmaker Heat Pump Error Code Yellow ALERT – 4 Flashes: Locked Rotor

Comfortmaker heat pump showing code Yellow ALERT - 4 Flashes on the Comfort Alert module (ICP; Comfortmaker AC & heat pump)? The compressor motor is drawing locked-rotor current (it is trying to start but the rotor will not turn). Frequently indicates a failing run capacitor, electrical fault, or mechanically seized compressor. Here is what it means, what you can safely check, and when to call a licensed CANRO technician in an urgent situation across Metro Vancouver.

Likely causes of Comfortmaker code Yellow ALERT - 4 Flashes

• Failed or weak run capacitor
• Excessively high head pressure preventing start
• Welded or failing compressor contactor
• Compressor bearing/mechanical seizure
• Low line voltage

What you can safely check first

• Set the thermostat to OFF to stop repeated start attempts
• Clear debris and confirm the outdoor coil is clean
• Call for professional service (capacitor/compressor diagnosis required)

What not to touch: beyond these checks, do not open the unit or touch the gas valve, wiring, control board or refrigerant lines. In BC, gas and HVAC repairs must be done by a licensed technician — both for your safety and to keep your manufacturer warranty valid.

Repair or replace your Comfortmaker heat pump?

A single fault code rarely means you need a new heat pump. The deciding factors are the unit’s age, the cost of the failed component versus its efficiency, and whether it’s a recurring problem. Our technicians give you an honest diagnosis and a written repair-or-replace recommendation — never a scare-sell. Explore more heat pump guides and services or browse all HVAC error codes we fix.

Frequently asked questions

Applies to Comfortmaker Comfort Alert module (ICP; Comfortmaker AC & heat pump). Code behaviour can vary by model and control board — our technician confirms the exact cause against your unit before any repair.

CANRO Heating & Cooling — TSBC Class-A gas-fitting licence · Red Seal HVAC certified · WorkSafeBC and liability insured · 4.9★ from 85+ Google reviews · Serving Metro Vancouver since 1999.