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Along with tutorials on navigating through our iSmart Air Handling Unit Software, this forum is home to troubleshooting guides for products such as CAREL, Belimo, Titan, Axio, Sontay and many more. Please get in touch if you have a query that you haven't found an answer to below. 

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Stefano Lanzani

--Stefano Lanzani--

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--Stefano Lanzani--
Stefano Lanzani
On 12/5/17, 11:48 AM

If you are controlling on Return Temperature:
The Changeover from Heating to Cooling is done automatically based on the return air temperature. Should the return air temperature be higher than the sepoint, the Controls will be operating in Cooling. If the return temperature is lower than the setpoint the Controls will be operating in Heating.

Should the return temperature be less than the setpoint, the controller would be in Heating mode and would command the DX units to be in Heating mode as well. The P+I algorithm will modulate the 0..10Vdc outputs to the DX Units to proportionally deliver the heat to maintain the setpoint on the return. Should the Return Temperature hit the setpoint, the Integral action would stop proportionally increasing the Heating output. Should the Return Temperature overshoot the setpoint, the P+I Alrgorithm will be gradually decrease the Output to reduce the Heating supply to the building. Should the Return temperature exceed by 2 Deg (Cooling Change over the threshold - Adjustable setpoint) from the return air setpoint, after a selectable period of time, the controls will revert to cooling mode.

In Cooling model, should the return temperature be greater than the setpoint, the controller would be in will command the DX units to be in Cooling mode as well. The P+I algorithm will modulate the 0..10Vdc outputs to the DX Units to proportionally deliver the coolth to maintain the setpoint on the return. Should the Return Temperature hit the setpoint, the Integral action would stop proportionally increasing the Cooling output. Should the Return Temperature overshoot the setpoint, the P+I Alrgorithm will be gradually decreasing the Output to reduce the Cooling supply to the building. Should the Return temperature be less by 2 Deg (Heating Change over threshold - Adjustable setpoint) from the return air setpoint, after a selectable period of time, the controls will revert to Heating mode.


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Asked: 12/5/17, 11:44 AM
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Last updated: 12/5/17, 11:49 AM