Issue
Tested the Viconics VT7600x1000x for Cool CPH set to 3. Manually heated the thermostat and let it cool to cycle the cool stages and it cycled on and off 7 times before stopping the test. According to the documentation it should have stopped after 3 on/off cycles.
Product Line
Field Devices
Environment
- SSL SE7000
Cause
Cooling/heating has to be within 15-85% of the proportional band.
Resolution
With the Viconics VT7600x1000x series products, the CPH only works when the cooling/heating demand is within 15 to 85% of the proportional band. The thermostat has a 2 degree proportional band (fixed) so at a setpoint of 72 and CPH of 3 (cooling CPH adjustable 3-4), if the temperature stays between 72.3 and 73.7 the CPH is at 3. Outside of that band the cooling/heating is allowed to cycle as often as needed.
