How do I select the correct evaporator fan blade pitch for a Heatcraft unit cooler?

Heatcraft unit coolers use propeller fans with pitch angles matched to the motor RPM and airflow requirements. Do not change blade pitch without re-testing motor current — increasing pitch increases airflow but also motor current, potentially exceeding motor FLA. Use the Heatcraft parts catalog to find the correct replacement fan blade for your specific unit model and coil configuration.

What defrost type does Heatcraft recommend for low temperature applications?

Heatcraft recommends electric defrost for low temperature (below -10°C) display cases and unit coolers. Hot gas defrost is an option for medium temperature applications but requires additional piping and solenoid valves. Off-cycle defrost is only suitable for medium temperature applications with moderate frost loads. Consult the Heatcraft application guide for your specific unit cooler model.

How do I calculate the defrost heater wattage needed for a Heatcraft evaporator?

A general rule of thumb for Heatcraft electric defrost: 130-150% of evaporator capacity in watts. For a 5kW evaporator, plan for 6.5-7.5kW of defrost heaters. Actual Heatcraft specifications are in the unit cooler installation manual under electrical specifications. Undersized heaters cause incomplete defrosts and frost buildup; oversized heaters can damage coatings and packaging.

Refrigeration

Heatcraft error codes, decoded.

Look up any Heatcraft fault code below. Each one is grounded in Heatcraft's own service documentation — the meaning, the symptoms, the causes, and the steps to clear it.

By Octavian Ghindea

Co-founder & CTO · Reviewed August 2026

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Heatcraft sits in our Refrigeration coverage. Every page here is transcribed from the manufacturer's manuals, not scraped from forums.

What error codes does Heatcraft display?

Tap a code for the full breakdown — meaning, symptoms, causes, and fix steps.

Frost buildup

Incomplete defrost — check heaters and termination thermostat

No airflow

Fan motor or capacitor fault

High suction pressure

Overloaded evaporator or EPR valve issue

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Common questions about Heatcraft equipment

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