11-14
CONTROL SYSTEM
SM DUODCI 1-A.1 GB
11.22.3 Outdoor Unit NLOAD setting
The MSMP controller gets the NLOAD from each of the indoor units, and sends a combined
NLOAD to the outdoor unit control. The combined NLOAD is a weighted average of the
indoor units NLOAD.
The weight of the indoor units as a function of their nominal capacity:
Indoor Unit Capacity [KW] (KBtu/hr) Capacity Code
2.5 (9000) 1
3.5 (12000) 1.5
5.0 (18000) 2
7.2 (24000) 3
11.22.4 EEV (electronic Expansion valve) Control
EEV opening is defined as EEV = EEV
OL
+ EEV
CV
• EEV
OL
is the initial EEV opening as a function of the compressor frequency,
operation mode, unit model and capacity.
• EEV
CV
is a correction value for the EEV opening that is based in cooling mode on the
relevant indoor unit super heat and compressor temperature.
• During the first 10 minutes of compressor operation EEV
CV
= 0.
11.22.5 System Mode Setting and Reversing Valve (RV) Control
The first indoor unit that is causing the system to be turned ON sets the system mode.
11.22.6 Indoor Units Operation when Indoor Unit Mode is Different than
Outdoor Unit Mode
• Open louvers according to user selection.
• Indoor fan is forced to OFF.
11.23 Dry Contacts Control
Dry Contact Contact = Open Contact = Short
STBY No Limit System is Forced to STBY
Night No Limit Outdoor fan speed reduced to low in cooling mode
A dry contact output for Alarm will be shorted when any failure exists in the system.
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