Mitsubishi Electric PAC-IF081B-E

Questions and Answers

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jessicaleeNov 27, 2025
Why is LED2 on my Mitsubishi Electric Controller FTC (Main) off?
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  Catherine HowardNov 27, 2025
  When LED1 on FTC (Main) is also off, the possible causes are: * The outdoor unit is not supplied at the rated voltage. Check the voltage across the terminals L and N or L3 and N on the outdoor power board. When the voltage is not 220 to 240 V AC, check wiring of the outdoor unit and of the breaker. When the voltage is at 220 to 240 V AC, check the voltage across the outdoor unit terminals S1 and S2. * Defective outdoor controller circuit board. Check the voltage across the outdoor unit terminals S1 and S2. When the voltage is not 220 to 240 V AC, check the fuse on the outdoor control board and check for faulty wiring. When the voltage is 220 to 240 V AC, check the voltage across the indoor unit terminals S1 and S2. * FTC (Main) is not supplied with 220 to 240V AC. Check the voltage ...
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Emily BrownAug 25, 2025
Why is my Mitsubishi Electric PAC-IF081B-E noisy?
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  Patrick JordanAug 26, 2025
  A noisy water circulation pump in your Mitsubishi Electric Controller system is caused by air in the water circulation pump. Use manual and automatic air vents to remove air from the system. Top up water if necessary to achieve 1 bar on primary circuit.
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Scott RivasAug 29, 2025
What does it mean if LED4 on Mitsubishi Electric Controller FTC (Main) is blinking?
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  espinozapeterAug 29, 2025
  If LED4 on the FTC (Main) of your Mitsubishi Electric Controller is blinking, it indicates a problem with the SD memory card: * Full of data: Move or delete data, or replace microSD memory card with a new one. * Write-protected: Release the write-protect switch. * NOT formatted: Refer to "4.11 Using microSD memory card". * Formatted in NTFS file system: FTC is not compatible with NTFS flie system. Use a microSD memory card formatted in FAT file system.
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Christopher JamesAug 30, 2025
Why does my Mitsubishi Electric Controller have no hot water at the hot tap?
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  Julia EdwardsAug 30, 2025
  If there's no hot water at the tap with your Mitsubishi Electric Controller, the possible causes are: * Cold main off: Check and open stop cock. * Strainer (local supply) blocked: Isolate water supply and clean strainer.
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linda10Sep 19, 2025
Why doesn't the cooling system cool down to the set temperature with Mitsubishi Electric PAC-IF081B-E Controller?
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  Lauren PetersSep 22, 2025
  If the cooling system on your Mitsubishi Electric Controller isn't cooling down to the set temperature, it could be due to: * When the water in the circulation circuit is unduly hot, Cooling mode starts with a delay for the protection of the outdoor unit. Normal operation. * When the outdoor temperature is lower than the preset temperature below which the freeze stat. function is activated, Cooling mode does not start running. To run Cooling mode overriding the freeze stat. function, adjust the preset temperature below which the freeze stat. function is activated.
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allison60Sep 16, 2025
Why is FTC unit running in the DHW mode after power recovery with Mitsubishi Electric PAC-IF081B-E Controller?
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  Terry HicksSep 16, 2025
  The FTC unit is designed to run in an operation mode with a higher priority (i.e. DHW mode in this case) at power recovery. Normal operation. After the DHW max. operation time has elapsed or the DHW max. temperature has been reached, the DHW mode switches to the other mode (ex. heating mode).
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ashley08Sep 18, 2025
Why is cooling mode NOT available on my Mitsubishi Electric Controller?
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  Melissa FlemingSep 18, 2025
  If cooling mode is not available on your Mitsubishi Electric Controller, DIP SW2-4 is OFF. Turn DIP SW2-4 to ON. (Refer to “5.1 DIP switch functions” in this manual.)
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Kelly DyerSep 9, 2025
Why does water discharge from the pressure relief valve (Primary circuit) in Mitsubishi Electric PAC-IF081B-E Controller?
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  Jonathan CruzSep 9, 2025
  If water is discharging from the pressure relief valve (primary circuit) in your Mitsubishi Electric Controller, it could be due to: * If continual – pressure relief valve may be damaged. Turn the handle on the pressure relief valve to check for foreign objects in it. If the problem is not still solved, replace the pressure relief valve with a new one. * If intermittent – expansion vessel charge may have reduced/bladder perished. Check pressure in expansion vessel. Recharge to 1 bar if necessary. If bladder perished replace expansion vessel with a new one.
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Anthony TuckerSep 7, 2025
Why does only Zone 2 not reach the set temperature in Mitsubishi Electric PAC-IF081B-E Controller?
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  Steven YoungSep 7, 2025
  For a Mitsubishi Electric Controller with 2-zone temperature control, if only Zone 2 isn't reaching the set temperature, consider these factors: * When Zone 1 and Zone 2 are both in heating mode, the hot water temperature in Zone 2 does not exceed that in Zone 1. Normal operation no action necessary. * Faulty wiring of motorized mixing valve. Refer to "4.7 Wiring for 2-zone temperature control". * Faulty installation of motorized mixing valve. Check for correct installation. (Refer to the manual included with each motorized mixing valve.) * Incorrect setting of running time. Check for correct setting of running time. * Motorized mixing valve failure. Inspect the mixing valve.
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Jennifer ClineSep 8, 2025
Why does the room temperature rise during DHW operation with Mitsubishi Electric PAC-IF081B-E Controller?
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  Jeffrey BoydSep 8, 2025
  If the room temperature rises during DHW operation with your Mitsubishi Electric Controller, the 3-way valve may have failed. Check the 3-way valve.

Summary

Safety Precautions

1.1 Before Installation (Environment)

Precautions for installing the FTC unit in various environments.

1.2 Before Installation or Relocation

Precautions for moving the FTC unit.

1.3 Before Electric Work

Safety precautions before performing electrical work.

1.4 Before Starting Test Run

Precautions before performing the test run.

1.5 Electric Booster and Immersion Heaters

Requirements for electric heaters used on the water circuit.

Installing the FTC Unit

2.1 Check the Parts

List of parts supplied with the FTC unit.

2.2 Choosing the Installation Location

Guidelines for selecting an appropriate installation location.

2.3 Installing the FTC Unit

Step-by-step instructions for installing the FTC unit.

System

3.1 First Step (Electrical Work)

Initial electrical work for powering the FTC unit.

3.2 Second Step (Outdoor Unit Connection)

Connecting the FTC unit to the outdoor unit.

3.3 Third Step (Functions Setting)

Setting functions for different system configurations.

3.4 Fourth Step (Functions Setting)

Minimum requirements for safe FTC unit use and system design.

3.5 Local System

Diagrams for various local system configurations.

3.6 Minimum Water Amount

Required water volume for heating/cooling circuits.

3.7 Energy Monitor

Monitoring energy consumption and production.

Electrical Work

4.1 Electrical Connection

General guidelines for electrical connections.

4.2 Connecting the Main Remote Controller

Connecting the main remote controller cable to the FTC unit.

4.3 Main Remote Controller Options

Different options for connecting remote controllers or thermostats.

4.4 Connecting Thermistor Cables

Procedures for connecting various thermistor cables to the FTC unit.

4.5 Connecting Inputs;Outputs

Connecting external inputs and outputs to the FTC unit.

4.6 Wiring for Heater

Wiring instructions for booster and immersion heaters.

4.7 Wiring for 2-Zone Control

Wiring for 2-zone temperature control systems.

4.8 2-Zone Valve ON;OFF Control

Setting up 2-zone control using 2-way valves.

4.9 Smart Grid Ready

Using smart grid ready inputs for control.

4.10 DHW Tank Installation

Procedure for installing a DHW tank.

4.11 Forced Cooling Mode

How to use the forced cooling mode input.

4.12 Using microSD Memory Card

Instructions for using the microSD memory card.

DIP Switch Setting

5.1 DIP Switch Functions

Detailed explanation of each DIP switch function.

5.2 Outdoor Unit Type

Setting the DIP switch for outdoor unit type.

5.3 Functions Setting

Setting various system functions via DIP switches.

5.4 Operation Setting

Configuring operation settings using DIP switches.

5.5 Emergency Mode (Heater Only)

Setting up emergency mode for heater-only operation.

5.6 Emergency Mode (Boiler)

Setting up emergency mode for boiler operation.

5.7 Indoor Unit Only Operation

Using indoor unit heaters during installation.

Before Test Run

6.1 Check

Pre-operation checks for wiring and connections.

6.2 Self-Check

How to interpret and reset error codes.

Remote Controller

7.1 Safety Precautions

Safety precautions for users when operating the remote controller.

7.2 Menu Tree Overview

Navigation and structure of the remote controller menu.

7.3 Service Menu

Accessing service functions via the remote controller.

7.4 Password Protection

Procedures for setting and resetting the service menu password.

Service and Maintenance

Engineers Forms

Section for recording commissioning and field settings.

Commissioning;Field Settings Record Sheet

Record sheet for system settings and commissioning data.

Troubleshooting

Troubleshooting by Inferior Phenomena

Table of fault symptoms, causes, and solutions.

Multiple Outdoor Units Control

10.1 Wiring for Multiple Units

Wiring requirements for multi-unit systems.

10.2 Pipe Work

Pipework examples for multi-unit systems.

10.3 Electrical Connection

Electrical connection procedures for multi-unit systems.

10.4 Main Remote Controller Wiring

Wiring the main remote controller in multi-unit systems.

10.5 Connecting Thermistor Cables

Connecting thermistor cables to FTC sub controllers.

10.6 DIP Switch Functions

DIP switch settings for outdoor units and FTC sub units.

10.7 Connecting Inputs;Outputs

Connecting inputs/outputs for main and sub controllers.

Supplementary Information

11.1 Refrigerant Collecting

Procedure for refrigerant collection on split systems.

11.2 Back-up Operation of Boiler

How the boiler backs up heating operation.

Local Application Factors

Heat Exchanger

Requirements for heat exchanger performance and maintenance.

Thermistor Position

Notes on thermistor placement.