1. Two Stage Communicating System
Company Private

3. Model 2 Stage Communicating
R410A Air Conditioner (2-5 ton even sizes)
CCA9, HCA9, TCA9
CCA7, HCA7, TCA7
R410A Heat Pump (2-5 ton even sizes)
CCH9, HCH9, TCH9
CCH6, HCH6, TCH6
CCA724GKA100 HCA724GKA100 TCA724GKA100 CCA736GKA100 HCA736GKA100 TCA736GKA100 CCA748GKA100 HCA748GKA100 TCA748GKA100 CCA760GKA100 HCA760GKA100 TCA760GKA100 CCA024GKA100 HCA024GKA100 TCA024GKA100 CCA036GKA100 HCA036GKA100 TCA036GKA100 CCA048GKA100 HCA048GKA100 TCA048GKA100 CCA060GKA100 HCA060GKA100 TCA060GKA100 CCH624GKA100 HCH624GKA100 TCH624GKA100 CCH636GKA100 HCH636GKA100 TCH636GKA100 CCH648GKA100 HCH648GKA100 TCH648GKA100 CCH660GKA100 HCH660GKA100 TCH660GKA100 CCH924GKA100 HCH924GKA100 TCH924GKA100 CCH936GKA100 HCH936GKA100 TCH936GKA100 CCH948GKA100 HCH948GKA100 TCH948GKA100 CCH960GKA100 HCH960GKA100 TCH960GKA100

4. SAME WALL CONTROL AS SINGLE STAGE
Observer™ Wall Control

5. OD Control Board
P/N

6. What allows the communication:
Outdoor
Indoor fan coil
Observer™ Control

7. Communication or Standard Stat
Do not use both connections, either use the DX connections or the standard stat connections.
If you planning to use an Observer™ but need to use standard stat for emergency, make sure the communicating plugs are removed from equipment DX connectors.

8. Model Plug location Model Plug
Uses model plug to determine:
·  Unit capacity
·  Compressor type
·  Outdoor fan type
·  Type of the outdoor unit (AC/HP)
Model Plug
Doesn’t matter which way installed on pins
Replacement board will not come with model plug, must transfer plug to new board.
Model plug takes priority over factory model information input at the factory . If removed after initial power up the unit will operate according to the last valid model plug installed.
Pull insert of this model plug to other pic

9. Model Plug
On new units, the model and serial numbers are input into the boards memory at the factory.
Replacement boards have no model plug therefore the model plug must be saved from original board and transferred to new board.

10. System Communicating Concept
Input/Output logic communicating between variable speed indoor and outdoor units through the Observer™ wall control.
Allows system to adjust for maximum comfort and efficiency. (multiple stages of cooling and heat.)
Airflow for two stage outdoor requires two different indoor airflow settings for proper operation. Indoor blower must be set up per indoor instructions for 2 stage outdoor CFM requirements.

11. All have the communication bus in ID board
ID Fan Motor Types
9MAC Full Function ECM
9MVT PWM ECM
8MVL Full Function ECM
FCM4X PWM ECM
All have the communication bus in ID board

12. OD Fan Motor Type
(Single Stage OD) PSC Type: CCH6, HCH6, TCH6, CCA7, HCA7, TCA7
Fan relay on control board turns the fan on and off by opening and closing the high voltage circuit to the motor. It does not change speeds between low and high stage operation of the compressor.
(Two Stage OD) ECM Type: CCH9, HCH9, TCH9, CCA9, HCA9, TCA9
Motor is continuously powered with high voltage, speed determined by electrical pulses from the PWM outputs on the OD control board.
The motor adjust RPM to outdoor conditions. Table in the install manual explains.

13. High Voltage sensing and for FAN and CCH
PWM output for ECM fan
PWM1
PWM2
P/N

14. OD Fan Motor Troubleshoot
Test PWM output at OD board terminals with a voltmeter set to DC volts.

15. Compressor Staging
Basic scroll design modified with internal unloading mechanism. It opens a bypass port in first compression pocket and reduces the displacement of the scroll when unloading.
Operates approximately 67% capacity when the solenoid is not energized and 100% capacity when the solenoid is energized.
Loading and unloading is done “on the fly” without shutting off the motor between steps.

16. Scroll Compressor Unloading
Molded solenoid plug to compressor converts 24Vac to 24Vdc with an internal rectifier.
Plug output should read 24Vdc if calling for high stage.
Internal Protection
Internal Pressure Relief (IPR)-relieves pressure discharge gas into compressor shell if differential between suction and discharge exceeds psig.
Internal overload in motor windings.

17. Control Inputs Low pressure Switch input High pressure switch input
OCT
Compressor
Transformer input
OAT
P/N

18. Compressor Control VS and L2 function
Monitors high voltage to the compressor and for diagnostics.
Voltage should be present anytime compressor contactor is pulled in, no voltage if not pulled in.
Compressor always starts in Low for 5 seconds regardless of call
Easier starting
C-24VAC com rtn contactor
C-24VAC com rtn solenoid
Lo/on-run cap
Hi-compressor solenoid

19. Troubleshooting Compressor Staging
Suction pressure at the service valve should be reduced by 3-10% when switching from low to high capacity.
Note the liquid pressure will be very similar in high and low stage so do not use this to determine.
Compressor current should increase 20-45% when switching stages.
In high stage the compressor DC solenoid coil should be energized

20. Unloader Test Procedure
Check for amperage change at least 20 percent when cycling from high to low at wall control.
If not, remove the solenoid plug from compressor. With unit running and wall control calling for high stage, check voltage at the plug with a DC meter..should be 24volt DC.
If correct DC at control circuit molded plug, measure the compressor unloader coil resistance. Resistance should be ohms depending on compressor temp. If coil resistance is infinite, much lower than 32 ohms or is grounded, the compressor must be replaced.

21. HP DEFROST Quiet Shift can be enabled:
on the board (non communicating)
or with the observer™ wall control (comm)
Add purpose of quiet shift
Forced Defrost Pins
Defrost time and Quiet Shift switches

22. Defrost Reversing Valve Outdoor coil temperature
Outdoor air temperature
Control Board interval times

23. Quiet Shift
Field selectable defrost mode which may eliminate occasional noise that could be heard at the start and end of defrost cycles.
At start of defrost cycle the reversing valve will energize and compressor will turn off for 30 seconds, then turn back on to complete defrost.
At the end of defrost cycle the reversing valve de-energizes, compressor will turn off for another 30 seconds, then the fan will turn off for 40 seconds before starting in the heating mode.

24. Defrost Options and Operation
Interval Time options:
30, 60, 90, 120 or Auto (Observer™ Control overrides the dip switch settings (see next slide)
Defrost initiate temp: 32° F
Defrost terminate temp: 65° F or 10 min has passed.
Defrost will not occur if over 50° F outdoor temperature exist.
If OAT is >25*F defrost will occur in high or low stage as demanded by stat or observer.
If OAT is </= 25*F defrost will occur in high stage and terminate at 50*F coil temp with min 2.5 min defrost.

25. Auto Defrost:
Adjust the defrost interval time based on the last defrost time
DEFROST TIME
NEXT DEFROST INTERVAL
< 3 minutes
120 minutes
3 to 5 minutes
90 minutes
5 to 7 minutes
60 minutes
> 7 minutes
30 minutes

26. Forced Defrost Forced defrost pins provided on board
Short pins for 5 sec and release
If coil temp is below initiate and outdoor temp is below 50*F – full defrost cycle
If coil temp is above initiate temp OR outdoor temp is above 50 – 30*F second defrost cycle occurs

27. Defrost Termination Fan Operation
ODF will remain off for 20 seconds after defrost termination. Allows time for system to capture the heat from the od coil and reduce the steam cloud effect that may occur on transition of defrost to heating cycle

28. Defrost hold
On non-communicating system the thermostat becomes satisfied (Y1 or Y1 and Y2) before the defrost cycle is terminated, the control will “hold” in defrost mode and finish the cycle on the next call for heat.
On communicating systems the Observer™ doesn’t need hold because the system will complete the defrost cycle before shutting down the system.

29. Time Delays 20 second outdoor fan delay after defrost
Reduces fog effect
15 second aux heat hold after defrost termination (W1)
Prevent cold blow
1 minute delay in cooling mode before turning outdoor fan off if outdoor temp is 100 deg F or higher
For easier starting
30 second compressor delay and 40 second OD fan delay after defrost before starting in heat mode if Quiet Shift enabled.
The 2 wire control board does not give a status code when you defeat these time delays so with no way to tell if it is on or not we chose not to allow it to be defeated at this time. Next version of UI software may allow it.

30. Time Delays (cont.)
2 minute to return to standby from last valid communication (Observer™ Wall Control Only)
5-minute time guard between compressor cycles
Can be defeated by shorting forced defrost pins for 1 second and releasing
Or by pressing heat to or cool to button for 10 seconds.
5 minute compressor re-cycle delay on return from a brown-out condition.

31. Refrigerant Control ID all to have cooling TXV
OD Heat pumps will have heating pistons.

32. the system reverts to default operation
Outdoor Thermistors
Electronic devices that sense temperature, as temp increases, resistance decreases.
OD unit has two: OAT and OCT
Coil and Outdoor temp thermistors are compared to verify proper operating range
Sensor failure:
the system reverts to default operation
If OAT fails low ambient cooling will not be allowed and one minute outdoor fan off delay will not occur.
If OCT fails low ambient cooing will not be allowed.
COMPARISON OCCURS:
20 min after defrost termination, not during defrost
Ignored until unit as run for 5 consecutive minutes

33. Troubleshoot Thermistors
Sensors may be out of range if:
If OAT indicates 10*F warmer than the OCT
If the OAT indicates 20*F cooler than the OCT
OPEN if resistance is reads 500K Ohms or higher (-50ºF or below)
SHORTED if resistance reads 1K ohms Or lower (188ºF or higher)

34. Liquid Line Solenoid
Standard Stat: LLS is connected to the Y1 and C terminals. Energized anytime compressor is running.
Observer™: LLS output is at the Y1. The LLS coil is 24Vac. Y1 gives 24Vac signal anytime the compressor is energized.
LLS is required in HP long line applications to control refrigerant migration in the heating mode. Install near outdoor unit with the arrow facing the outdoor unit, this is direction of flow.

35. Utility Saver Operation Communicating Mode
Utility Curtailment is not available directly with the Observer™ Wall control.
To accomplish curtailment with the Observer a daughter board kit must be used to convert the control signals to standard thermostat signals.

36. Utility Saver Operation Non-Communicating Mode
The utility company provided relay should be wired in the Y2 thermostat lead. This allows a power utility to interrupt high stage compressor operations during peak load periods.
If the utility requires control of the low stage compressor operation a second utility curtailment relay should be wired in the Y1 lead.

37. Low Ambient Cooling Operation
Is not available for the 2 stage communicating or non communicating system at this time. Low ambient kits are not set up and not to be installed.
Consideration may be given in future Observer™ software to allow this to be done.
Single stage communicating and non communicating systems can apply low ambient cooling controls. See single stage training and literature. Considering if future may allow this in Observer software.
ECM motors are used in outdoor units (19 SEER) which is why the external low ambient pressure switch cannot be used. If the UI has low ambient in software it will allow the UI communicating low ambient for future.

38. Diagnostics

39. Status Codes

40. Diagnostics LED on OD Board
Green COMM LED1 will indicate successful communication
Off until communication is established
Amber STATUS LED2 to display operating mode or error conditions
If multiple errors exist, the highest priority error will be flashed on circuit board
Status (amber) light
is read by series of short and long flashes.
Example: code 74
7 short flashes followed by 4 long flashes.

41. High Voltage Monitoring Brown Out Detection (230V) Code 46
If line voltage drops below 187, a brown out condition is declared
Operation is not allowed until voltage is 190 or higher for at least 4 seconds
Unit is shipped with Brown Out Active
Can be defeated if needed. Defeat by shorting forced defrost pins from power up with both OAT and OCT sensors removed. Status Code 6 disabled. Code 5 is active. Install instructions detail.

42. Observer™
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