INDIRECT COOLED ENGINE Engine cooling circuit – schematic

Cooling water circulates through the coil in the C-Warm heater in parallel with the flow through the engine heat exchanger.

Check your engine manual for installation details, or ask your engine supplier. The instruction manual supplied with C-Warm explains how to adapt the engine cooling circuit to incorporate the storage heater.

The temperature of the stored water can approach that of the water in the engine cooling circuit: 80 deg C or higher. Thermostatic control may be used to limit the stored water temerature. The temperature of water available from hot taps should not exceed 65 deg C.

The CW276 cylinder thermostat simply limits the stored water temperature. The CW272 blender valve adds water to hot, to achieve the desired temperature, and effectively increases the amount of hot water stored.

DIRECT COOLED ENGINE Engine cooling circuit – schematic

The temperature of the stored water heated by a direct-cooled engine is less predictable. Many engines are designed to run with a relatively high water temperature in the engine block, while the exhaust is cooled to a lower temperature. With suitable take-off and re-entry, an adequate stored water temperature can often be achieved.

Check your engine manual for details, or ask your engine supplier.

The instruction manual supplied with C-Warm explains how to adapt the engine cooling circuit to incorporate the storage heater.

Thermostatic control may not be necessary with direct cooled engines.

How long will the Engine take to heat the Water?

About 15 – 20 minutes. Heating time is almost independant of storage heater capacity. Larger heaters have longer coils and thus more surface area for heat exchange with the greater volume of water.

All but the smallest marine engines discharge more than enough waste heat for satisfactory performance with C-Warm storage heaters up to the largest standard sizes (136 litres, 30 gallons).

How long will the Water stay Hot?

Depending on heater volume and on ambient temperature, the stored water will drop from a nominal 55 deg C to 35 deg C (still warm enough for a comfortable shower) over a period of about 12 – 20 hours after the engine has stopped. The larger the volume of the heater the more slowly the stored water will cool.