CMV FUNCTION WITH TIMETABLE AND/OR VOC SENSOR

Owned by Marco Serpelloni
Last updated: Sept 11, 2023
4 min read

The REG System can manage controlled mechanical ventilation (CMV) units both via timetable and via VOC sensor and via a combination of both.

For these functions it is necessary to load onto the REG-DIN-8 at least version 4.28 and a RegConfig version 4.28 must be used. 

Introduction

To manage CMV it is necessary to enable the CMV enable on the Configuration/1 - System Settings page:

as with other global enabling (DHW, System, and Seasonal set), the CMV can also be managed via an external dry contact on the CMV Enable Channel:

1. Timetable management

Once the CMV is enabled, we move on to timetable creation on the Dehumidifiers page, where for example, we choose to dedicate a Dehumidifier to CMV management, then in Auto Ventilation Function (CMV) we associate a timetable, e.g., timetable 04 “Ventilation”:

Then it is possible to set 3 speed values for the Ventilation (CMV): Economy, Comfort, and Boost. This setting can be made if the speed on the CMV is changed by the REG via the 0/10V outputs connected to a 0/10V input on the ventilation unity board.

Boost function is activated only when the Boost Mode Timer is different from zero (the value to be entered is the minutes for which you want the CMV unity to run at high speed). Once the time is exhausted, the unity will go back working in Economy or Comfort depending on how the timetable has been set.

In the Actual Status can be seen the tick on the renewal request if active and at what speed.

Finally, in outputs it necessary to associate (in the pages REGDIN OUTPUT or IO/A or IO/B OUTPUT) the dry ON/OFF contact as digital output and the speed as analog output:

The speed can also be sent to the CMV via digital output (low = economy; medium = comfort; high = boost).

Finally, on the timetables page within the associated timetable (in this case, Timetable 1 Living room), the OFF, Economy, and Comfort program can be set

2. Management via VOC sensor

VOC sensor (code REG-AQ-Sxx) must be configured with the address from 8A to 8F (as indicated in the product data sheet) without set (s/set) as it has no display and associated with a dedicated zone for renewal within the Zones – Configuration Zone/1 page; furthermore, the ventilation unit must be associated as integration unit:

 This special zone manages temperature and humidity in different way:

  • In temperature there are the ppm (parts per million) of CO2, so if you read 40 that’s 400 ppm.

  • In humidity you can see the VOC parameters in ppb (parts per billion), then if you read 30 that’s 300 ppb of VOC. This is true for the old VOC sensor REG-AQ-SXX, while for the new REG-AQ40-SXX this value is not present.

  • The humidity set point is the hysteresis (multiplied by a factor of 10) of threshold switching between Economy/OFF and Comfort/Economy

  • Comfort and Economy set point are thresholds, so if I exceed the Economy threshold the CMV starts at Economy speed, if i exceed Comfort it starts in Comfort, to switch to lower speed it must drop below the threshold – the hysteresis.

So, it is the ppm variation in CO2 that activates the Economy and Comfort speed above the thresholds and switches the speed back to OFF and Economy if the value drops below the threshold – the hysteresis:

The economy and comfort speeds are switched to the Dehumidifier page according to what is indicated in the integration column of the zone which has an associated VOC sensor (on the Zone – Configuration/1 page).

The configuration of the Dehumidifier page and the outputs (DO or AO) is the same as step 1, the only difference is that they are activated by threshold and not by timetable.

The ppb value is only for display in the HR% column of the zone, but has no effects on regulation.

3. Combination of timetable and VOC sensor

If both point 1 and point 2 are configured on the same CMV, the speed and ON/OFF is determined by the OR condition between the two, so the timetable may be in OFF, but if the VOC sensor exceeds the Economy threshold, the CMV activates at Economy speed.

It is different if the timetable is directly associated with the zone and not in the dehumidifiers page: in this case, the timetable and the threshold operate in AND, then if the timetable is in OFF and the VOC sensor exceeds the Economy threshold, the CMV will not be activated.