HAI OMNISTAT RC-122 User manual

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RC-122 / RC-122B Two Stage Heat/Cool
2 Stage Heat / 2 Stage Cool
Thermostat Installation Instructions
DESCRIPTION
The RC-122 is a precision digital thermostat designed for 24 VAC two-stage heating and cooling systems. It
offers programmability, stand-alone operation, and robust, optically isolated communications with automation
systems, utility control systems, and personal computers. The RC-122B is equipped with 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 beobserved for installation in Europe: CE
1. This equipment must be installed in accordance with National wiring rules for the country in which it is
installed.
2. Fuses must be replaced only with IEC rated components.
3. All product labels, instructions and markings relating to safety must be translated to a language, which is
acceptable in the country in which this equipment is to be installed.
INSTALLATION
Before installing this thermostat:
1. Read all of the installation instructions carefully.
2. Read the Owner's Manual carefully.
3. Ensure that this product is suitable for your application.
4. Ensure that wiring complies with allcodes and ordinances.
5. Disconnect power to the control transformer to prevent electricalshock and damage to equipment.
6. Select an appropriate location to ensure an accurate temperature reading.
Location
When replacing an existing thermostat, install the RC-122 in the same location. If the existing location doesn't
meet the following criteria, choose a new location. When choosing a location for the thermostat:
1. Ensure that the thermostat is mounted 5 feet above the floor and is at least 2 feet from an outdoor wall.
2. Ensure that the thermostat is located in an area where there is adequate air circulation.
3. Do not mount in the pathof direct sunlight or of radiant heat generated by appliances.
4. Do not mount behind an outdoor wall, near a fireplace, or in the path of any air ducts.
Document Number 13I00-17 / Rev B / April, 2004
Copyright  1999-2004 Home Automation, Inc.
All Rights Reserved

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Removing an existing thermostat
1. Disconnect the power to the control transformer.
2. Remove the cover to the existing thermostat.
3. Disconnect the wires going to each terminal on the thermostat. Label each wire with the letter or number
at the terminal.
4. Remove the existing plate or base from the wall.
MOUNTING
When mounting the RC-122, grasp the thermostat by the sides, avoiding the keys, and unsnap the base from the
face.
Holding the base to the wallso that the word "TOP" is upright and facing you:
1. Mark the two mounting holes on the wallusing a pencil.
2. Drill a hole using a 3/16" bit at each mounting hole marking.
3. Install the two wall anchors supplied.
4. Slide the system wires through the opening in the base.
5. Mount the base to the wall using the two #6 x 1/2" self-tapping screws supplied - See Figure 1.
Figure 1

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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 with the thermostat, connect the remote system wiring to the supplied cable
using the 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 the thermostat, push all excess wiring into the hole in the wall. Plug the hole with
the supplied insulating foam to ensure an accurate temperature reading by the thermostat.
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 Figure 3
Note:
Be sure that the thermostat temperature sensor is standing up, and that it has not been damaged during
installation - See Figure 3.

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TYPICAL WIRING DIAGRAMS
CAUTION:
Be sure to disconnect the power to the controltransformer before removing or installing thermostat.
Do not short gas valve(s), fan, heat relay(s), or cool relay(s)... even momentarily. 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 to the thermostat.
Figure 4 - Thermostat power-up for test or demonstration purposes
NOTE: As a convenience to the installer, the compressor start up protection delay can be canceled. To cancel
the delay, press the Prog key 3 times, then press the Fan key 2 times.
POWER UP
1. Double check wiring, be sure that there are no stray wires or wire strands at the connections.
2. It is not necessary to connect the remote system (COMM) cable at this time.
3. Connect power to the transformer and system. The display willshow all segments for about 5 seconds.
4. Press the Fan key. The fan should comeon. Press the Fan key again. The fan should go off.
5. Press Hold to override Energy Efficient Control routines.
6. Set the Mode to "HEAT". Use the up arrow key to raise the desired temperature setting 1 degree above
the current temperature. Ensure that Stage 1 heat comes on. After a few minutes, raise the desired
temperature 3 degrees over the current temperature. Stage 2 heat should come on. Set the mode to
"OFF". Ensure that the heat unit goes off.
7. Set the Mode to "COOL". Use the down arrow key to lower the desired temperature setting 1 degree
below the current temperature. Ensure that Stage 1 cool comes on. After a few minutes, lower the
desired temperature 3 degrees below the current temperature. Stage 2 coolshould come on. Set themode
to "OFF". Ensure that the cooling unit goes off.
If the thermostat or system does not perform as stated above, recheck all wiring - See Troubleshooting Tips.

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Figure 5

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CONFIGURINGTHE BACKLIGHT ON THE RC-122B
The backlight on the RC-122B can be configured to one of three different modes: 1) on for 30 seconds when a
key is pressed, 2) always on, or 3) always off.
1) To configure the display backlight to turn on when a key is pressed, then back off 30 seconds later, set
the “JP2” (Select Backlight Mode) jumper to the “TIMED” position (between the top and middle pin on
the connector) - See Figure 6.
2) To configure the display backlight to always be on, set the “JP2” (Select Backlight Mode) jumper to the
“ON” position (between the middle and bottom pin on the connector) - See Figure 6.
3) To configure the display backlight to never come on (always off), remove the “JP2” (Select Backlight
Mode) jumper from the connector - See Figure 6.
DISABLE KEYS
The keys on the thermostat can be disabled to prevent anyone from controlling the thermostat locally. To
disable the keys, solder a wire jumper across “JP1” (two holes on the circuit board) - See Figure 6.
SOLDER WIRE JUMPER HERE SELECT BACKLIGHT
MODE (SET JUMPER)
TO DISABLE KEYS LOCALLY
Figure 6

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INSTALLER SETUP
This section describes the items that the installer must setup as part of the thermostat installation. The Installer
Setup mode is used to configure the general operating parameters of the thermostat.
When in Installer Setup mode:
1. The small digits on the top of the display are the item number.
2. The large blinking digits in the center of the display are the value of the item number.
3. Press the Prog (>) key to advance to the next item.
4. Press the Hold (<) key to return to the previous item.
5. Use the arrow keys (∧−∨) to change the value of each item.
6. Do not set the values to anything other than the specified range for each item.
7. To exit Setup mode, press the Fan key.
The thermostat will automatically exit Setup mode after 20 seconds of no key activity.
To enter the Installer Setup mode, press the Prog key three times (day willflash), then press the Fan key.
The word "default" indicates the initial setting when the thermostat is delivered from the factory.
00 Address
If you are using Communications Mode 0 or 1, and you are installing more than one thermostat, each must be
set to a consecutive address, starting at 1. The default address setting is 1.
An address from 1- 127 may be selected.

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01 Communications mode
The thermostat can communicate with remote systems in 4 different modes. These modes are:
0 300 baud, RS-232 mode (for use with personal computers)
1 100 baud, System mode (OmniLT, Omni, Omni II, OmniPro, and OmniPro II systems)
8 PESM mode, (use with Model 1503 automation systems)
24 Day/Night mode (for use with remote setback switch)
The default setting is 1.
02 System options
The thermostat can be configured with the following system options:
WITH NO
EEC EEC*
0 8 Auto changeover no fan with heat
1 9 Auto changeover fan on with heat
4 12 Manualchangeover no fan with heat
5 13 Manualchangeover fan on with heat
* Energy Efficient Control (EEC): In most two-stage installations, stage 2 is less efficient than stage 1. In this
case, Energy Efficient Control (EEC) should be turned on (settings 0, 1, 4, and 5). If the system is equipped
with a highly efficient second stage, you may want to turn EEC off (settings 8, 9, 12, and 13). The thermostat
will act like a conventional two- stage thermostat.
See Owner's Manual for description of EEC.
The default setting is 0.
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, the thermostat should be configured as "non-programmable". To disable
the clock and filter reminder displays, add “16” to each value.
The default setting is 1.

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04 Calibration offset
This item is used to raise or lower the current temperature reading by 1 degree Fahrenheit or 1/2 degree Celsius.
If this item is set to 30, no change will be made. Each digit below 30 will lower to temperature, and each digit
above 30 will raise the temperature.
(1 = “- 29” to 59 = “+ 29” temperature units; 30 = No change)
The default setting is 30.
05 Cool setpoint limit
This item is used to limit the temperature setting in cool mode. The desired cool setting can never be set below
this setting.
The default setting is 51.
06 Heat setpoint limit
This item is used to limit the temperature setting in heat mode. The desired heat setting can never be set above
this setting.
The default setting is 91.
07 Not used
08 Not used
09 Not used
10 Not used
11 Cooling minimum on/off time (minutes)
This item is used to limit the on and off times of the cooling system. When the cooling system starts, it must
remain on for the minimum time set by this item. When the cooling system turns off, it must remain off for a
minimum time set by this item.
Setting Cycles per hour (maximum)
5 6
6 5
7 4
8 3.7
10 3
The recommended setting is 8 minutes. A higher setting may be appropriate for buildings with low heat
loss/gain. The default setting is 8.

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12 Heating minimum on/off time (minutes)
This item is the same as the “Cooling minimum on/off time”, but for the heating system.
The default setting is 8.
13 Stage 2 Differential
This item specifies the temperature difference between stage 1 and stage 2. The default setting of 2 (degrees F)
is recommended for all applications. In special cases a setting of 3 or 4 may be used when precise controlof
temperature is not as important as highest energy efficiency, however, the thermostat will not be able to
maintain temperature within 1 degree of its setting under severe weather conditions. A setting of 1 or 0 is not
recommended. The default setting is 2.
In this thermostat, the automatic anticipator will compensate for the temperature "droop" caused by the stage 2
differential under cold weather conditions.
14 Clock adjust
If the clock on the thermostat is running faster or slower than the actual time, you can have the thermostat
automatically compensate up to 29 seconds per day. The thermostat will add or subtract the selected amount of
time daily.
(1 = “- 29” to 59 = “+ 29” seconds per day; 30 = No change)
The default setting is 30.
Note: If an HAI automation system is being used, the controller system time is sent to the thermostat every
minute. This adjustment willhave no effect.
15 Filter reminder
The thermostat logs the amount of time the system fan has been running. When this setting reaches 0, the
thermostat will display a reminder to replace the filter. The setting is the amount of days (24 hours of system
operation) before this reminder is displayed.
Days - Counting down from 10 - 0
The filter reminder can be disabled by setting this item to 60.
16 System runtime (This week)
This item logs the amount of time (hours) that theheating and cooling system was in operation this week.
17 System runtime (Last week)
This item logs the amount of time (hours) that theheating and cooling system was in operation last week.

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ANTICIPATION
Anticipation is performed electronically and is independent of the type and load of the components in the
heating and cooling equipment. This thermostat has electronic controlbased on proportional, integral and
derivative components and maintains temperature to within 1 degree F of the setting. Anticipation is not
adjustable.
OWNER'S MANUAL
Following Installer Setup, check the option boxes (  ) in the Owner's Manual according to the configuration of
the thermostat.
QUICK-REFERENCE SETUP GUIDE
This table displays each Installer Setup item with its default setting. The column labeled "CURRENT" can be
used to write down the current settings if any changes are made to the default settings.
Item Number Description Default Current
00 Address 1
01 Communication mode 1
02 System options 0
03 Display options 1
04 Calibration offset 30
05 Coolsetpoint limit 51
06 Heat setpoint limit 91
07 Not used -
08 Not used -
09 Not used -
10 Not used -
11 Cooling minimum on/off time 8
12 Heating minimum on/off time 8
13 Stage 2 differential 2
14 Clock adjust 30
15 Filter reminder 10
16 System runtime (This week) -
17 System runtime (Last week) -

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REMOTE SYSTEM WIRING DIAGRAMS
This thermostat has been preprogrammed with energy saving settings recommended under the EPA Energy Star
program. When used with remote systems, HAI recommends that the thermostat be configured as "non-
programmable" (See Setup Item 03 - "Display Options").
HAI AUTOMATION SYSTEMS
The thermostat can be connected to an HAI automation system. The controller can send commands to the
thermostat to change mode, cool setting, heat setting, status of fan and hold, and other items.
Run a 3 (or 4) conductor wire from the HAI system to the thermostat location. All thermostats on an Omni,
OmniII, OmniPro, or OmniPro II controller are connected to Zone 16 and Output 8.
All thermostats on an OmniLT controller are connected to the GRN (Green), BLK (Black), and YEL (Yellow)
terminals in the section marked "TSTAT".
Connect the red COMM cable wire with the black COMM cable wire. Make the connections (as shown in
Figure 7) using the supplied wire splices.

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Note: Do not connect the red COMM cable wire to 12V.
Figure 7 - Hookup to an HAI system
Additional thermostats are connected in parallel. They may be connected in home-run or daisy chain
configuration.
REMOTE DAY/NIGHT SETBACK SWITCHES
The thermostat can be connected to a remote system or remote switch. A signal can be sent from the remote
location to change the thermostat temperature settings from the "DAY" setting to the "NIGHT" setting. To use
this mode, setup item 01 - "Communications mode" must be set to 24.
Run a two-conductor wire from the remote system or remote switch to the thermostat location. Make the
connections using supplied wire splices - See Figure 8.

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* Red and yellow wires are not used.
Insulate each using a small piece of tape.
Figure 8 - Hookup to remote Day/Night setback switch
OTHER SYSTEMS
For connections to personal computers, utility management systems, and other automation systems, refer to
connection diagrams provided with personalcomputer software package or other system.

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TROUBLESHOOTING TIPS
SYMPTOM ACTION TO TAKE
1. Check power to the thermostat
2. Check wiring diagrams
Thermostat Dead
3. Check thermostat temperature sensor
Thermostat will not operate with a damaged temperature sensor
SYMPTOM ACTION TO TAKE
1. Check for break in G, W, or Y wire
2. Allow minimum off time to pass
3. Check system options for correct settings
Fan, Heat, Or Cool
Inoperative
4. Remote system is overriding thermostat
"REMOTE" is displayed when system is overriding thermostat. Disconnect the cable from
"COMM" connector to test
SYMPTOM ACTION TO TAKE
1. Mode is Off (Select Heat, Cool, or Auto)Can't Adjust Temperature 2. Check if thermostat keys are disabled
To enable thermostat keys for test, remove jumper
SYMPTOM ACTION TO TAKE
1. Check COMM connector and wiring
2. Check thermostat address setting
3. Check communications mode setting
Control By Remote System
Not Working
4. Check setup of the remote system
Ensure that all setup items for the thermostat and the remote system are set to the proper
configurations for communication
SYMPTOM ACTION TO TAKE
1. Allow 30 minutes for thermostat to adjust to room
temperature
2. Adjust calibration offset
Temperature Reading
Incorrect
3. Change setup option to display oF or oC
After installation, allow the thermostat up to 30 minutes for an accurate temperature reading
SYMPTOM ACTION TO TAKE
Display Problem 1. Disconnect power to the thermostat. Reconnect, then
observe display self-test
For a 5 second period after power is reconnected, allsegments of the display should light indicating
all thermostat functions

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SYMPTOM ACTION TO TAKE
1. Stage 1 is not able to meet the load due to severe weatherStage 2 On Too Often 2. EEC is disabled
SYMPTOM ACTION TO TAKE
1. System may be equipped with an outdoor thermostat which
is overriding Stage 2 the when outdoor temperature is mild
No Stage 2 Operation
2. Stage 1 is heating and cooling adequately