RC-100 / RC-100B Heat Pump Thermostat Installation Instructions

Description

The RC-100 is a precision digital thermostat designed for 24 VAC heat pump systems. It offers local and remote control, programmability, stand-alone operation, and robust, optically isolated communications with automation systems, utility control systems, and personal computers. The RC-100B features a "cool blue" backlight display.

• Electrical rating: 24 V; 3 A; 50/60 Hz
• Maximum current: 2 A on any circuit, 3 A total
• Thermostat operating current: less than 15 mA

The following requirements must be observed for installation in Europe: CE [European Conformity]

• This equipment must be installed in accordance with National wiring rules for the country in which it is installed.
• Fuses must be replaced only with IEC rated components.
• All product labels, instructions, and markings relating to safety must be translated to a language acceptable in the country where this equipment is installed.

Installation

Before installing this thermostat:

• Read all installation instructions carefully.
• Read the Owner's Manual carefully.
• Ensure this product is suitable for your application.
• Ensure wiring complies with all codes and ordinances.
• Disconnect power to the control transformer to prevent electrical shock and damage to equipment.
• Select an appropriate location for accurate temperature reading.

Location

When replacing an existing thermostat, install the RC-100 in the same location. If the existing location does not meet the following criteria, choose a new location.

When choosing a location for the thermostat:

• Ensure the thermostat is mounted 5 feet above the floor and at least 2 feet from an outdoor wall.
• Ensure the thermostat is located in an area with adequate air circulation.
• Do not mount in the path of direct sunlight or radiant heat generated by appliances.
• Do not mount behind an outdoor wall, near a fireplace, or in the path of any air ducts.

Removing an Existing Thermostat

• Disconnect the power to the control transformer.
• Remove the cover of the existing thermostat.
• Disconnect the wires going to each terminal on the thermostat. Label each wire with the letter or number at the terminal.
• Remove the existing plate or base from the wall.

Mounting

When mounting the RC-100, grasp the thermostat by the sides, avoiding the keys, and unsnap the base from the face.

Holding the base to the wall so that the word "TOP" is upright and facing you:

• Mark the two mounting holes on the wall using a pencil.
• Drill a hole using a 3/16" bit at each mounting hole marking.
• Install the two wall anchors supplied.
• Slide the system wires through the opening in the base.
• Mount the base to the wall using the two #6 x 1/2" self-tapping screws supplied. (See Figure 1)

Figure 1: Mounting illustration

Diagram showing the thermostat base being mounted to the wall with wires passing through the opening.

Wiring

Connect each wire to the terminal strip on the thermostat base per the wiring diagram for your system application (See Figures 4-5).

Form the thermostat wiring so that the cable lies flat between the terminal strip and the center of the base.

If a remote system is being used, connect the remote system wiring to the supplied cable using wire splices per the diagram for your remote system application (See Figures 7-8). Insert the cable into the connector on the thermostat circuit board marked "COMM".

Upon completion of wiring, push excess wiring into the hole in the wall. Plug the hole with the supplied insulating foam to ensure an accurate temperature reading.

Align the tabs of the thermostat face with the slots of the thermostat base. Gently push the thermostat face into the thermostat base, locking it into place (See Figure 2).

Figure 2: Connecting the thermostat face to the base

Diagram illustrating the alignment of tabs on the thermostat face with slots on the base for connection.

Figure 3: Thermostat temperature sensor

Note: Be sure that the thermostat temperature sensor is standing up and has not been damaged during installation.

Typical Wiring Diagrams

Caution:

Be sure to disconnect power to the control transformer before removing or installing the thermostat. Do not short compressor relay, fan relay, auxiliary heat relay, or reversing valve, even momentarily, as this will blow a non-replaceable fuse. Do not attempt to hook up to live circuits. An accidental connection to a component on the thermostat circuit board could cause damage.

Figure 4: Thermostat power-up for test or demonstration purposes

Diagram showing a typical wiring setup for thermostat power-up, illustrating connections from a 24VAC control transformer to thermostat terminals R, 24VAC, and COMMON, with other terminals like 1, 2, 3, 4, 5, 6, 7, 8 labeled.

Notes for Figure 4:

• 1. To cancel compressor start-up protection delay: Press Prog key 3 times ➡️, then press Fan key 2 times ➡️.
• 2. "O" Terminal is energized for cooling.
• 3. "B" Terminal is energized for heating. In most applications, the reversing valve is energized for cooling and should be connected to the "O" terminal. If the heat pump requires the reversing valve to be energized for heating, connect it to the "B" terminal.
• 4. "X1" and "X2" are connected to a 24VAC Red LED, often used to indicate a heat pump compressor fault.
• The Emergency Heat Relay (E Terminal) and outdoor thermostats are not used. The RC-100 automatically controls auxiliary heat efficiently.
• The RC-100 requires at least 1 stage of auxiliary heat enabled at all times. If the heat pump is equipped with an outdoor thermostat, it should be removed from the auxiliary heat circuit or reconfigured to disable only 2nd and 3rd stage auxiliary heat.

Figure 5: Heat Pump System Wiring Diagram

Diagram illustrating the wiring connections between the thermostat and a heat pump system, showing terminals like R1, G2, O3, B4, C5, Y6, W27, and X28, connected to components like Fault Relay, Fan Relay, Reversing Valve, Compressor Relay, Aux Heat Relay, and Transformer.

Configuring the Backlight on the RC-100B

The backlight can be configured to one of three modes: 1) on for 30 seconds when a key is pressed, 2) always on, or 3) always off.

• Timed Mode: Set the "JP2" (Select Backlight Mode) jumper to the "TIMED" position (between the top and middle pin) - See Figure 6.
• Always On Mode: Set the "JP2" jumper to the "ON" position (between the middle and bottom pin) - See Figure 6.
• Always Off Mode: Remove the "JP2" jumper from the connector - See Figure 6.

Figure 6: Jumper settings for backlight and disabling keys

Diagram showing jumper locations on the circuit board for "SELECT BACKLIGHT MODE" (JP2) and a location for soldering a wire jumper to disable keys (JP1).

Disable Keys

The thermostat keys can be disabled to prevent local control. To disable keys, solder a wire jumper across "JP1" (two holes on the circuit board) - See Figure 6.

Power Up

• Double-check wiring for stray wires or strands.
• Connecting the remote system (COMM) cable is not necessary at this time.
• Connect power to the transformer and system. The display will show all segments for approximately 5 seconds.
• Press the Fan key. The fan should turn on. Press the Fan key again. The fan should turn off.
• Set the Mode to "HEAT". Use the up arrow key (⬆️) to raise the desired temperature setting above the current temperature. Ensure the heat pump operates in heating mode. After a few minutes, set the mode to "EM HEAT". The heat pump should stop, and auxiliary heating should come on. Set the mode to "OFF". Ensure both heat pump and auxiliary heat turn off.
• Set the Mode to "COOL". Use the down arrow key (⬇️) to lower the desired temperature setting below the current temperature. Ensure the heat pump operates in cooling mode. Set the mode to "OFF". Ensure the cooling unit turns off.

If the thermostat or system does not perform as stated, recheck all wiring (See Troubleshooting Tips).

Installer Setup

This section describes items the installer must set up. Installer Setup mode configures general operating parameters.

When in Installer Setup mode:

• The small digits at the top of the display are the item number.
• The large blinking digits in the center are the value for the item number.
• Press the Prog (>) key to advance to the next item.
• Press the Hold (<) key to return to the previous item.
• Use the arrow keys (⬆️, ⬇️) to change the value of each item.
• Do not set values outside the specified range for each item.
• To exit Setup mode, press the Fan key. The thermostat will automatically exit Setup mode after 20 seconds of no key activity.

To enter Installer Setup mode, press the Prog key three times (day will flash), then press the Fan key.

The word "default" indicates the initial factory setting.

Installer Setup Items:

00 Address

If using Communications Mode 0 or 1 with multiple thermostats, each must have a consecutive address starting at 1. The default is 1. An address from 1-127 may be selected.

01 Communications mode

The thermostat can communicate with remote systems in 4 modes:

• 0: 300 baud, RS-232 mode (for personal computers)
• 1: 100 baud, System mode (OmniLT, Omni, Omni II, OmniPro, OmniPro II systems)
• 8: PESM mode (for Model 1503 automation systems)
• 24: Day/Night mode (for remote setback switch)

The default setting is 1.

02 System options

The thermostat can be configured with the following system options:

*Energy Efficient Control (EEC) of Auxiliary Heat: Select 0, 1, 4, and 5 to enable EEC, or 8, 9, 12, and 13 to disable EEC display. See Owner's Manual for description.

In most heat pump installations, auxiliary heat is electric resistance. EEC should be turned on (settings 0, 1, 4, 5). If auxiliary heat is more efficient (e.g., gas water heater), EEC can be turned off (settings 8, 9, 12, 13). The thermostat will then act as a conventional 2-stage thermostat.

The default setting is 1.

03 Display options

The thermostat can be configured to display the following attributes:

• 0: Celsius, am/pm time format, programmable
• 1: Fahrenheit, am/pm time format, programmable
• 2: Celsius, 24-hour time format, programmable
• 3: Fahrenheit, 24-hour time format, programmable
• 4: Celsius, am/pm time format, non-programmable
• 5: Fahrenheit, am/pm time format, non-programmable
• 6: Celsius, 24-hour time format, non-programmable
• 7: Fahrenheit, 24-hour time format, non-programmable

When connected to an HAI controller, configure as "non-programmable". To disable clock and filter reminder displays, add "16" to each value.

The default setting is 1.

04 Calibration offset

Adjusts the temperature reading by 1°F or 0.5°C. Setting 30 makes no change. Each digit below 30 lowers the temperature; each digit above 30 raises it. Range: 1 ("-29") to 59 ("+29") temperature units; 30 = No change.

The default setting is 30.

05 Cool setpoint limit

Limits the temperature setting in cool mode. The desired cool setting cannot be set below this value.

The default setting is 51.

06 Heat setpoint limit

Limits the temperature setting in heat mode. The desired heat setting cannot be set above this value.

The default setting is 91.

07-10 Not used

11 Cooling minimum on/off time (minutes)

Limits the on/off times for the cooling system. The system must remain on for the minimum set time and off for the minimum set time. The table shows cycles per hour for different settings.

The recommended setting is 8 minutes. Higher settings may be suitable for buildings with low heat loss/gain.

The default setting is 8.

12 Heating minimum on/off time (minutes)

Same as "Cooling minimum on/off time", but for the heating system.

The default setting is 8.

13 Stage 2 Differential

Specifies the temperature difference between stage 1 heating (heat pump) and stage 2 heating (auxiliary heat). The default setting of 2°F is recommended. Settings of 3 or 4 may be used for higher energy efficiency if precise temperature control is less critical. A setting of 1 or 0 is not recommended. The thermostat's automatic anticipator compensates for temperature droop.

14 Clock adjust

Allows the thermostat to automatically compensate for clock drift (±29 seconds per day). Range: 1 ("-29") to 59 ("+29") seconds per day; 30 = No change.

The default setting is 30.

Note: If an HAI automation system is used, the controller sends the time, making this adjustment ineffective.

15 Filter reminder

Logs system fan run time. When the setting reaches 0, a filter replacement reminder is displayed. The setting is the number of days (24 hours of system operation) before the reminder. Counting down from 10-0. The reminder can be disabled by setting this item to 60.

16 System runtime (This week)

Logs the total hours the heating and cooling system was in operation this week.

17 System runtime (Last week)

Logs the total hours the heating and cooling system was in operation last week.

Anticipation

RC-100 anticipation is electronic and independent of system components. It uses proportional, integral, and derivative control to maintain temperature within 1°F of the setting. Anticipation is not adjustable.

Owner's Manual

After Installer Setup, check the option boxes in the Owner's Manual according to the thermostat's configuration.

Quick-Reference Setup Guide

This table lists Installer Setup items and their default settings. The "CURRENT" column can be used to record changes.

Remote System Wiring Diagrams

This thermostat is preprogrammed with EPA Energy Star recommended energy-saving settings. For remote systems, HAI recommends configuring the thermostat as "non-programmable" (See Setup Item 03 - "Display Options").

HAI Automation Systems

The thermostat can connect to an HAI automation system. The controller can send commands to change mode, cool/heat settings, fan status, and hold. Run a 3 or 4 conductor wire from the HAI system to the thermostat location. For Omni, Omni II, OmniPro, OmniPro II controllers, thermostats connect to Zone 16 and Output 8. For OmniLT controllers, connect to GRN, BLK, and YEL terminals in the "TSTAT" section.

Connect the red COMM cable wire with the black COMM cable wire using supplied wire splices (See Figure 7).

Figure 7: Hookup to an HAI system

Diagram showing connections from a thermostat to a controller, including GRN, YELLOW, GREEN, RED, BLACK wires, and a COMM connection. Note: Do not connect the red COMM cable wire to 12V.

Additional thermostats connect in parallel, either home-run or daisy-chain.

Remote Day/Night Setback Switches

The thermostat can connect to a remote system or switch to change temperature settings between "DAY" and "NIGHT". Setup item 01 - "Communications mode" must be set to 24. Run a two-conductor wire from the remote system/switch to the thermostat location. Make connections using supplied wire splices (See Figure 8).

Figure 8: Hookup to remote Day/Night setback switch

Diagram showing connections from a thermostat to a remote Day/Night setback switch, using BLACK and GREEN wires. Note: Red and yellow wires are not used and should be insulated.

Other Systems

For connections to personal computers, utility management systems, and other automation systems, refer to connection diagrams provided with the respective software package or system.

Troubleshooting Tips

Symptom: Thermostat Dead

Action to Take:

• Check power to the thermostat.
• Check wiring diagrams.
• Check thermostat temperature sensor.

Thermostat will not operate with a damaged temperature sensor.

Symptom: Fan, Heat, Or Cool Inoperative

Action to Take:

• Check for a break in the G, W, or Y wire.
• Allow minimum off time to pass.
• Check system options for correct settings.
• Remote system is overriding thermostat: "REMOTE" is displayed. Disconnect the cable from the "COMM" connector to test.

Symptom: Can't Adjust Temperature

Action to Take:

• Mode is Off (Select Heat, Cool, or Auto).
• Check if thermostat keys are disabled. To enable keys for testing, remove the jumper.

Symptom: Control By Remote System Not Working

Action to Take:

• Check COMM connector and wiring.
• Check thermostat address setting.
• Check communications mode setting.
• Check setup of the remote system.
• Ensure all setup items for the thermostat and remote system are configured correctly for communication.

Symptom: Temperature Reading Incorrect

Action to Take:

• Allow 30 minutes for the thermostat to adjust to room temperature.
• Adjust calibration offset.
• Change setup option to display °F or °C.

After installation, allow up to 30 minutes for an accurate temperature reading.

Symptom: Display Problem

Action to Take:

• Disconnect power to the thermostat. Reconnect, then observe the display self-test. For 5 seconds after power reconnection, all display segments should light up, indicating all thermostat functions are operational.

Symptom: Aux Heat On Too Often

Action to Take:

• Heat Pump is not able to meet load due to cold weather.
• Thermostat is in EM Heat mode - Set thermostat to Heat or Auto mode. (In EM Heat mode, auxiliary heat is always on).

Symptom: Heat Pump Heats In Cool Mode & Cools In Heat Mode

Action to Take:

• Reversing valve is connected to the wrong terminal - move wire from B to O or from O to B. The wires connecting the reversing valve may be reversed (See Note 1 - Page 8).

Symptom: No Auxiliary OR Emergency Heat

Action to Take:

• Check if the heat pump is equipped with an outdoor thermostat. If so, disconnect it. The heat pump may be equipped with an outdoor thermostat that overrides Aux Heat when the outdoor temperature is above a certain level. Disconnect the outdoor thermostat; the RC-100 controls Aux Heat automatically.

Heat Pump Cross Reference Guide

This table cross-references thermostat terminals with common HVAC system wiring.

RC-100 Terminal Descriptions

• R (1): 24VAC "HOT"
• G (2): FAN
• O (3): REV VALVE (COOLING)
• B (4): REV VALVE (HEATING)
• C (5): 24VAC COMMON
• Y (6): COMPRESSOR
• W2 (7): AUXILIARY HEAT
• (8): NOT USED
• X2: FAULT LED

Note: X1 is jumped to C terminal in the RC-100, if X2 is in use.