Marine Heat Pumps: Service, Maintenance, and How to Extend the Life of Your System

Marine heat pumps are the heart of your boat’s climate system. In warm weather, they cool your cabin. In cooler weather, they reverse cycle and provide heat. They’re powerful, efficient, and incredibly reliable — when they’re properly maintained.

As a factory-trained technician (Dometic, Flow Marine Systems, Frigibar) and former owner of a marine HVAC company in South Florida, I’ve serviced hundreds of heat pump systems on yachts, trawlers, and sportfishing boats. The problems I see are common, predictable, and completely preventable.

How Marine Heat Pumps Work

A marine heat pump works like a traditional A/C in the summer — removing heat from your cabin and transferring it into seawater through the condenser coil. In winter, the system reverses the cycle, pulling heat from the seawater and sending it into your cabin.

Because seawater is the heat source and the heat dump, proper water flow is everything.

Most Common Marine Heat Pump Issues

1. Low or Restricted Seawater Flow

This is the #1 cause of failure.Typical symptoms include:

• High-pressure faults

• Unit shutting down after a few minutes

• Poor heating performance

• Reduced cooling output

Causes:

• Dirty seawater strainer

• Worn or clogged pump

• Barnacles or algae in the plumbing

• Scale buildups in the condenser coil

2. Reverse Cycle Valve Failure

If your system cools well but can’t heat, the reversing valve may be sticking or electrically failing.

3. Electrical & Control Failures

Marine environments destroy electronics through corrosion and vibration.

Common culprits:

• Printed circuit boards

• Thermistors & temperature sensors

• Digital thermostat failures

4. Refrigerant Leaks

Even a small leak can cause:

• Reduced cooling

• Freezing coils

• Higher energy use

• Compressor damage

Recommended Maintenance Schedule

To maximize performance and extend system life:

Every 30 Days

• Clean seawater strainer

• Check pump operation

Every 6 Months

• Check refrigerant pressures

• Clean evaporator coil

• Inspect electrical connections

• Test heating and cooling cycles

Annually

• Flush seawater circuit

• Deep clean condenser

• Inspect reversing valve

• Full system performance test

Why Routine Heat Pump Service Matters

Marine heat pumps operate in harsh environments — saltwater, humidity, vibration, and constant thermal load. Proper service ensures:

• More stable cabin temperatures

• Longer compressor life

• Lower energy consumption

• Reduced risk of mid-season failures

• Maximum efficiency in both heating and cooling modes

Professional Marine Heat Pump Service

Americus Refrigeration provides specialized heat pump service across:

Savannah, GA – Jacksonville, FL – Panama City, FL – Destin, FL

As a factory-trained marine technician with over 12 years operating a marine HVAC company in South Florida, your system is serviced with precision and experience.

Keep your vessel comfortable year-round.Schedule Marine Heat Pump Service Today.