Compressor Control Circuit Troubleshooting Tips - Derived From Bench Testing - Trane SYMBIO 700 Troubleshooting Manual

Compressor Control Circuit Troubleshooting Tips - derived from bench testing.

If either the HPC or DTL opens while the compressor is running, the Compressor Contactor will lose its
24 vac and the Aux Switch will open, causing the Symbio Board to generate a "Compressor Proving Trip
Diagnostic" – 15 minute lockout -
If the HPC and or the DTL are open when the Symbio Board energizes the Compressor Contactor and the
Contactor Aux switch doesn't close, the Symbio Board to generate a "Compressor Proving Lockout
Diagnostic" – INSTANT UNIT LOCKOUT! -
If the Aux Switch is bad (or is off the Contactor) the Compressor Contactor will pull in for 7 seconds and
drop back out, causing the Symbio Board to generate a "Compressor Proving Lockout Diagnostic" –
INSTANT UNIT LOCKOUT! –
If the Compressor Contactor Aux Switch closes before it is supposed to (for example if the technician
pushes in the contactor manually) the Symbio Board will generate a "Compressor Contactor Fail
Diagnostic" – INSTANT UNIT LOCKOUT! -
A good way to find out if the pressure switches or the board / wiring is the issue on a "Compressor
Proving Trip Diagnostic" unwire the line voltage from the compressor and then have the Symbio Board
turn on the circuit in question.
The LPC appears to follow Reliatel Logic.
If the outdoor temperature is less than 40ºF the LPC bypass delay will be set to 60 seconds.
When the outdoor temperature is between 40 to 49.9°F the delay will be set to 30 seconds.
For all outdoor temperatures 50°F and above, there will be no delay.
Refrigeration Circuit Management
Configured to Manifolded- both compressors disabled if protection device in either circuit opens
Configured to Independent- only the affected compressor is disabled if protection opens.
Below is the Official Sequence of Operation
30