The Whalen Company - Two-Pipe Unit

The standard two-pipe unit uses continuous water circulation through the riser heat-exchanger. The building owner provides chilled water in the summer and warm water in the winter. The thermostat cycles the fan on and off to maintain the thermostat temperature setting. Summer/winter changeover of the thermostat action is automatic, and the user has manual fan speed selection of HI, LO, or OFF.

The two-pipe face and bypass unit uses continuous water circulation through the riser heat-exchanger in the same manner as the two-pipe fan cycle control unit. Fan operation is continuous. The thermostat cycles an internal face and bypass damper which either directs the air over the riser heat-exchanger when cooling or heating is required, or allows the air to bypass the riser heat-exchanger completely. The fan recirculates room air when neither heating nor cooling is required. Summer/winter changeover of the thermostat action is automatic, and the user has manual fan speed selection of HI, LO, or OFF.