MITSUBISHI ELECTRIC PAC-US444CN-1 Thermostat Interface User Manual
- June 17, 2024
- Mitsubishi Electric
Table of Contents
Application Note: 3039
Thermostat Interface Installation
with Zoning Systems
Introduction
This application note is to explain the wiring process between the Mitsubishi
Thermostat Interface (PAC-US444CN-1) and a third-party zone control panel.
This is only a reference guide for wiring the thermostat interface. Duct
sizing, bypass damper, static pressure settings, and local code requirements
must be followed and developed per application.
Important Note:
Local codes take precedence over recommendations contained in this document.
Wiring Information
The Thermostat Interface takes the incoming signals from an open/close switch to the air conditioner and outputs the on/off signals from the air conditioner to the back-up heater. The wires are polarity sensitive so it is necessary to double check the orientation before powering on the unit. See Figure 1 for the wiring diagram.
Dip Switches
The dip switches must be changed in order to allow for advanced functionality
to be supported. When received, the dip switches will be in the default off
position.
Static Pressure
To change the static pressure of the system, dip switches SW2-1, SW2-2, and SW2-3 on the Thermostat Interface will need to be set. Please refer to the applicable Indoor Unit Service Manual for more information. This may change depending on duct size, building insulation quality, and other reasons.
| DIP switch position on PAC-US444CN-1 | Indoor Unit Settings |
|---|---|
| SW2-1 | SW2-2 |
| OFF | OFF |
| OFF | OFF |
| OFF | ON |
| OFF | ON |
| ON | OFF |
| ON | OFF |
| ON | ON |
| ON | ON |
Table 1: External Static Pressure Settings
Two-stage Operation
To set the two stage indoor unit operation, SW2-6 will need to be set to on.
When the third party thermostat calls for 1st stage of heat, the thermostat
interface will change the indoor unit mode into heat and will optimize the
variable capacity. When the 2nd stage of heat is requested, the thermostat
interface will change the indoor unit mode into heat and ramp the indoor unit
to full capacity.
| SW2-6 | Operation during stage 1 |
|---|---|
| OFF (Single- stage) | Full capacity |
| ON (Two-stage) | The capacity is adjusted so that the room temperature is |
adjusted (heated or cooled) at a fixed rate.
Time Delay for Fan OFF
It is REQUIRED that both SW1-1 and SW1-2 be changed to ON in order to have the
time delay set to zero. If the time delay is set to a period of time other
than zero, the unit will continue to blow air with the dampers closed. See
Table 4 for the dip switch settings.
| SW1-1 | SW1-2 | Result |
|---|---|---|
| OFF | OFF | 5 minutes (Default) |
| ON | OFF | 10 minutes |
| OFF | ON | 30 minutes |
| ON | ON | 0 minutes |
Table 3: Time Delay for Fan OFF
Bypass Damper Information
Although many units supplied by Mitsubishi Electric do not require dampers, the air handlers (MVZ, PVA, and PEAD) can be combined with dampers in order to maintain the temperature in each zone. When wiring these products, please see the necessary wiring diagram in the bypass damper instruction manuals to verify installation with the Mitsubishi Electric system.
Specifications are subject to change without
notice.
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HVAC US LLC. All rights reserved.
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