Symbio 700 Compressor Circuit(s) Troubleshooting
Summary:
This compressor circuit troubleshooting is for the Precedent and Odyssey with Symbio 700 unit controller. The following images illustrate the circuit's route for the auxiliary and safety components to the contactor to ensure that the compressor circuit is connected correctly and closed.
🛑 Important Notes:
- Recommend having needle leads for testing.
- On a call for first-stage cooling, LED 15 is on, and the Symbio 700 UC module should have 24Vac out of UC-P9-5 going to CC2 (the smaller compressor). Similarly, on a call for second-stage cooling, LED 5 is on the Symbio 700 UC module and should have 24Vac out of UC-P8-5 going to CC1 (the bigger compressor).
- If the contactor does not pull in and the LED is on for that stage, you have 5 seconds to verify 24Vac output from the unit controller or through the circuit.
- With the unit powered up, 24Vac is on the Yellow wire for (CC1) auxiliary one and similarly for the Red/Black wire for (CC2) auxiliary two.
💡 Note: Compressor Proving Alarms - Click Me
Precedent:
Circuit 1 Run Command Path
- Compressor 1 run command from UC P8-5 to Adapter Board J20-5.
- Then, to Adapter Board J13-1 by board trace.
- Out to the HPC1 and back to Adapter Board J13-2.
- Then, to Adapter Board J13-3 by board trace.
- Out to DTL1 and back to the Adapter Board J13-4.
- Then, to Adapter Board J5-9 by board trace, then out to CC1 coil.
Continuity Test:
- When the unit is powered off, disconnect the J8 plug from the Unit Controller. Leave all the other plugs plugged in. Place one of the leads on J8-5 (yellow wire) and the other on the Adapter Board J5-10 (yellow/brown wire).
- If the meter reads OL, work yourself back, verifying where it's open, and look at the drawing below and the unit drawings.
Notes:
- Between the adapter board and the CC1 coil, there are two plugs: PPF81/PPM81 and PPF/PPM23
- Between the adapter board and the CC1(AUX1) there is one plug: PPF81/PPM81
Circuit 1 Proving Circuit Path
- The Proving Circuit is UC P8-2 to J20-2.
- To Adapter Board J5-5 by board trace.
- Through the Aux switch to J5-6.
- To Adapter Board J20-3 by board trace.
- Then to UC P8-3
Continuity Test:
- When the unit is powered off, disconnect the J8 plug from the Unit Controller. Leave all the other plugs plugged in. Place the lead on J8-2 (red wire) and the other on J8-3 (blue wire).
- Your meter will read OL until the contactor is pressed in.
- If you still read OL, move the lead from J8-3 to the Adapter Board J20-3 (blue wire) and work yourself back to verify where it's open; look at the wiring below and the unit drawings.
Circuit 2 Run Command Path
- Compressor 2 run command from UC P9-5 to Adapter Board J20-11.
- Then, to Adapter Board J11-1 by board trace.
- Out to the HPC2 and back to Adapter Board J11-2.
- Then, to Adapter Board J11-3 by board trace.
- Out to DTL2 and back to the Adapter Board J11-4.
- Then, to Adapter Board J5-11 by board trace, then out to CC2 coil.
Continuity Test:
- When the unit is powered off, disconnect the J9 plug from the Unit Controller. Leave all the other plugs plugged in. Place one of the leads on J9-5 (brown/black wire) and the other on the Adapter Board J5-12 (black/red wire).
- If the meter reads OL, work yourself back, verifying where it's open, and look at the drawing below and the unit drawings.
Notes:
- Between the adapter board and the CC2 coil, there are two plugs: PPF81/PPM81 and PPF/PPM24
- Between the adapter board and the CC2(AUX1) there is one plug: PPF81/PPM81
Circuit 2 Proving Circuit Path
- The Proving Circuit is UC P9-2 to J20-8.
- To Adapter Board J5-7 by board trace.
- Through the Aux switch to J5-8.
- To Adapter Board J20-9 by board trace.
- Then, to UC P9-3
Continuity Test:
- When the unit is powered off, disconnect the J8 plug from the Unit Controller. Leave all the other plugs plugged in. Place the lead on J9-2 (blue/black wire) and the other on J9-3 (orange/black wire).
- Your meter will read OL until the contactor is pressed in.
- If you still read OL, move the lead from J9-3 to the Adapter Board J20-9 (orange/black wire) and work yourself back to verify where it's open; look at the wiring below and the unit drawings.
💡 Note: Symbio 700 UC Relay Contact Resistance Test - Click Me
Odyssey:
Circuit 1
- Compressor 1 run command from UC P8-5 to Adapter Board J20-5.
- Then, to Adapter Board J13-1 by board trace.
- Out to the HPC and back to Adapter Board J13-2.
- Then, to Adapter Board J13-3 by board trace.
- Out to DTL and back to the Adapter Board J13-4.
- Then, to Adapter Board J7-1 by board trace, then out to CC1 coil.
- The Proving Circuit is J5-1 to J22-1 through the Aux switch, to J22-2 to J20-3, then to UC P8-3.
Circuit 2
- Compressor 2 run command from UC P9-5 to Adapter Board J20-11.
- Then, to Adapter Board J11-1 by board trace.
- Out to the HPC and back to Adapter Board J11-2.
- Then, to Adapter Board J11-3 by board trace.
- Out to DTL and back to the Adapter Board J14-4.
- Then, to Adapter Board J7-3 by board trace, then out to CC2 coil.
- The Proving Circuit is J5-1 to J22-3 through the Aux switch, to J22 -4, to J20-9, then to UC P9-3.
Relay Contact Resistance Test
Symbio 700 UC P8 CC1 Relay contact resistance check steps
- Unplug the J8 harness from the Red P8 connection on the board. Pay attention to which connector pins the Orange and Yellow wires are connected too.
- Connect to the Symbio 700 UC board with the cell phone app and go to the Tools > Service Test Mode page.
- Click on Cool 1 to energize the compressor relay output on the Symbio 700 UC. LED 5 on the Symbio 700 UC board should be ON.
- Check the relay contact resistance across the connector pins where the Orange and Yellow wires were connected. You will only have about 5 seconds to check this before getting a proving fault.
The resistance should be less than 10 ohms. - Repeat this process a few times to see if the relay contact ohm reading changes. If the ohm reading goes above 10 ohms, the Symbio 700 UC board will need to be changed.
Symbio 700 UC P9 CC2 Relay contact resistance check steps
- Unplug the J9 harness from the White P9 connection on the board. Pay attention to which connector pins the Y/BK and BR/BK wires are connected too.
- Connect to the Symbio 700 UC board with the cell phone app and go to the Tools > Service Test Mode page.
- Click on Cool 2 to energize the compressor relay output on the Symbio 700 UC. LED 15 on the Symbio 700 UC board should be ON when compressor 2 is energized.
- Check the relay contact resistance across the connector pins where the Y/BK and BR/BK wires were connected. You will only have about 5 seconds to check this before getting a proving fault.
The resistance should be less than 10 ohms. - Repeat this process a few times to see if the relay contact ohm reading changes. If the ohm reading goes above 10 ohms, the Symbio 700 UC board will need to be changed.
Compressor Proving Alarms
Possible Alarms:
Alarm - Compressor Proving Trip Diagnostic – 15-minute lockout
- The HPC or DTL opens while the compressor is running, (after the circuit has proved) and the Compressor Contactor loses its 24 VAC, causing the Aux Switch to open
Alarm - Compressor Proving Lockout Diagnostic – INSTANT UNIT LOCKOUT!
- The Symbio Board calls for the Compressor Contactor, and the Contactor doesn’t pull in within 7 seconds.
Possible causes:
The HPC and or the DTL are open.
Contactor Coil open.
Wiring error.
Alarm - Compressor Proving Lockout Diagnostic – INSTANT UNIT LOCKOUT!
- The Symbio Board calls for the Compressor Contactor, it pulls in and drops back out after 7 seconds.
Possible causes:
No 24 VAC at black wire on the Aux Switch
Bad Aux Switch.
Aux Switch is not on the contactor correctly.
Alarm - Compressor Contactor Fail Diagnostic – INSTANT UNIT LOCKOUT!
- The Compressor Contactor Aux Switch closes before it is supposed to
Possible causes:
The technician pushes in the contactor manually.
The contactor welded shut.
💡 Note:
- A good way to determine whether the pressure switches or the board/wiring are the issue is to unwire the line voltage from the compressor in question and isolate it. Have the Symbio 700 Board turn on the circuit. If the circuit operates normally with the compressor line voltage unwired, you may have a refrigeration issue. If you still get a proving diagnostic, you may have a board/wiring issue.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.