Heating; On/Off Heating Element Management; Post-Ventilation Function For The Electric Heaters - Mitsubishi Electric s-MEXT-G00 006 Technical Manual

TM_s-MEXT_ME28relC_00_12_19_EN
6

HEATING

6.1

ON/OFF HEATING ELEMENT MANAGEMENT

The parameter indicating the presence of on/off electric heaters is in the "Optional" menu, which can be accessed by entering the "Service" password
The heating elements, when present, are given by two loads having different power; they are, therefore, always managed according to three heat steps, as shown below.
The heat setting parameter is under the "Set point" menu.
The heat Differential parameter is under the "Regulations" menu, which can be accessed by entering the "Service" password.
For the default values, see the parameters table.
The association of the heaters with the steps reflects the "binary management":
•
Step 1: Heaters 1
•
Step 2: Heaters 2
•
Step 3: Heaters 1 + Heaters 2
Activating the heating elements is possible only when all the following conditions are met:
1. Adjustment consent is active.
2. The heating element overheating alarm is not present (from thermostat).
3. None of the compressors are in cooling mode.
6.2

POST-VENTILATION FUNCTION FOR THE ELECTRIC HEATERS

This function, available for all the units equipped with electric heaters, is for cooling the electric heaters when the unit is turned off and the electric heaters are still active.
When the OFF command is given (at the keyboard, by the supervisor, or remotely), the fan continues to run at nominal speed for a period of time set in the parameter
(P23.61).
The diagram below illustrates the function described above.
During the post-ventilation cycle, the icons of the electric heaters and fans flash on the main mask.
The parameters for enabling and configuring the Post-Ventilation function are in the "Fan" menu, which can be accessed by entering the "Service" password.
For the default values, see the parameters table.
Technical manual
Step 3
P50.02 +
2/3
P20.19
P20.19 Differential
Figure 6-1: Heat resources management graph
On
Unit Status
Off
P23.01
EC fan
MIN Speed
Off
On
Electric heaters
Off
P23.62 Heaters post-ventilation time
Figure 6-2: The chart illustrates the Post-Ventilation function for the electric heaters.
Step 2
Step 1
P50.02 +
P50.02 T
1/3
P20.19
T(s)
78
(°C)
ambient
Electric heaters post-ventilation
function enabled (P23.61)
Normal operation
TRANSLATION OF THE ORIGINAL INSTRUCTIONS