Access 4.x

Rotary exchanger defrosting (temperature monitoring)


Exhaust air (alternatively Defrosting) temperature is constantly measured.

The defrosting controller (PID) will take over control of sequence output (reduces rotation speed) if temperature falls below [-3] oC.

The temporary reduction of the exchanger's efficiency has a defrosting effect. The operation returns to normal once temperature and minimal defrosting time conditions are met.

The defrosting can also be triggered via digital input signal. In that case the defrosting is active while digital output signal is present.

It is also possible to combine both options: the defrosting will be active until at least one defrosting start condition is present.


Configuration of defrosting with temperature monitoring



Variable

Available options & Selection

Note


Sequence selection

Configuration > Functions > Function activation > Heating/Cooling sequence setup

Sequence for exchanger

...| SEQ-B Exchanger |...

Select sequence for exchanger


Sequence settings

Configuration > Functions > Function activation > Heating/Cooling sequence setup > Exchanger

Type of sequence

...| Exchanger |...


Type of exchanger

| Rotary | Plate | Liquid |


Type of defrosting

| None | Temperature monitoring |



Defrosting configuration

Configuration > Functions > Temperature control > Defrosting temperature monitoring

Temperature sensor

| Exhaust air | Defrosting |


Extract air fan speed when fan stop defrosting

|Auto | Low | Normal | High |

Operation level of the extract air fan when the supply air fan is stopped


Allocate analog input

Configuration > I/O allocation settings > Analog inputs

Exhaust air temperature

Any available I/O



Allocate digital input

Configuration > I/O allocation settings > Digital inputs

Defrosting guard exchanger

Any available I/O


PID Settings

Configuration > PID controllers > Defrosting

P-band

[16] oC

PID settings for the defrosting controller

I-time

[240] s

D-time

[0] s


Defrost operational settings

Data & Settings > Temperature control > Exchanger > Defrosting temperature monitoring

Setpoint min limit

[-3] oC

Defrosting starts when the exhaust (defrosting) temperature is < -3 oC and will continue until it becomes +1 oC (-3 oC + 4 oC), but not less than 15 minutes

Hysteresis to end defrosting

[4] oC

Min time

[15] min

Min output during defrosting

[40] %

Rotation of the exchanger will gradually slow down (PID regulated) but not less than minimal output limit

Stop supply air fan if outdoor temp <

[-100] oC