EN - How to control a modulating CO2 valve

Question

How do i control a modulating CO2 valve ?

Answer

A normal CO2 control is with on/off valves.

When the valve is a modulating valve, then it can be controlled the best by the +CO2 module.

An alternative solution is to use a uni-switch per valve with an analog output.

For every valve you need a uni-switch with an analog output.

Choose "control loop"

The position of the valve is from 0 to 100%. This correspondence with an output of 4-20 mA.

Each greenhouse has it's own settings for CO2 control.

When the CO2 control is on, the CO2 valve position will be 30%.
The position can be different for each greenhouse. For example a greenhouse nearby the CO2 source 30%, a greenhouse at the end of the distribution line 50%.

Attention: A much better control is via the +CO2 module. In that case every greenhouse gets it's own +CO2 unit. The modulating valve is controlled and the demanded CO2 value is summed in the CO2 manifold. The produced CO2 can be adjusted very precisely to the demand.

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