Reverse Cycle Heating Troubleshooting
Warmth on
the Water.
It's called "Reverse Cycle" because it literally reverses the flow of refrigerant. If your thermostat calls for heat but the vents blow cold, your system is stuck. We make it shift.
The Reversing Valve
This brass component is the heart of the heating system. It physically redirects the refrigerant flow. If it sticks (common after long periods of disuse), you get no heat.
The Solenoid Click
An electric coil activates the valve. When you switch to heat, you should hear a distinct "whoosh-click." If you don't, the solenoid may be burnt out or getting no voltage.
Heat from the Sea
Your boat extracts heat from the ocean water. Even 50°F water contains heat energy! However, if water flow is restricted, the unit will freeze up and shut down.
Troubleshooting Path.
Diagnosing the chill, step by step.
Voltage Check
We test the thermostat output to ensure it is sending the 110V/24V signal to the reversing valve solenoid when "Heat" is selected.
Solenoid Test
We check the magnetic coil for resistance. A burnt coil is a cheap fix. We replace it to restore the valve's ability to shift.
Valve Freeing
If the coil is good but the valve is stuck, we use specialized techniques (pressure differential shifting) to "unstick" the slider inside.
Sensor Calibration
Sometimes the ambient air sensor is touching a cold hull wall, giving false readings. We reposition it for accurate temperature control.
Comfort Restored.
Don't let the cold ruin your night aboard.
Component Logic.
We service the critical parts of the heat pump.
Common Questions
Why does it blow cold first?
This is normal. The fan usually starts before the compressor builds heat. However, if it stays cold for more than 2-3 minutes, the reversing valve has likely failed to shift.
Will it work in freezing water?
Marine heat pumps struggle when water temps drop below 40°F (4°C). In Southern California, this is rarely an issue, and they work efficiently year-round.