What is VC-VH? Old capacitor voltage terminology. Terminals on capacitor

Transcription

1 What is VC-VH? Old capacitor voltage terminology Terminals on capacitor VC=Voltage common; VH= voltage hermetic

2 2-Stage Board Voltage constantly monitored at compressor run capacitor. Looks for voltage presence when contactor is closed. Should not sense voltage when contactor is open.

3 Input to Vc-Vh terminals

4 Normal Operation Contactor energized, contacts closed, compressor starts, voltage sensed at Vc-Vh.

5 What causes VC-VH Fault? (6-flash) 3 Conditions will cause this fault Condition #1: Voltage present when no call. Condition #2: Voltage remains absent 2 seconds after start up sequence. Condition #3: Voltage present at start up then disappears for 10 sec after compressor starts. Final result of condition #3: Compressor lockout

6 Condition #1: Voltage present when no call Causes: stuck contactor, mis-wire, manual manipulation of contactor. 2-Speed board action: De-energize contactor outputs. Energize fan. Communicate error and lock out. User Interface (if used) display in fault history VC STANDBY VOLTS Voltage present on run capacitor with no call

7 UI display of 2-Speed Error Codes Infinity User Interface displays errors in text Examples: VC START UP VOLTS VC VOLTS AT STANDBY RANGE ERROR

8 Condition #2 Voltage remains absent 2 seconds after start sequence Causes Disconnect pulled while indoor powered and calling. Contactor did not close. Faulty VC/VH sensing circuit. 2-Speed board action: Board continues in normal run sequence, communicates error. Infinity display in fault history VC STARTUP VOLTS No voltage on run capacitor when calling

9 No line voltage, compressor doesn t start. No voltage sensed at Vc-Vh. Bad contacts, compressor doesn t start. No voltage sensed at Vc-Vh. Bad coil, compressor doesn t start. No voltage sensed at Vc-Vh.

10 Condition #3 Voltage present at start then disappears for 10 seconds after compressor starts Causes Compressor thermal cut out caused by: Start gear not releasing. Low voltage; relay pickup voltage not achieved. Faulty start components. Faulty contactor. Marginal wire connection(s) in compressor circuit. High operating superheat.

11 Open Compressor Thermal, compressor stops running, voltage lost at Vc-Vh.

12 Condition #3 Thermal Cutout 2-Speed board actions: De energize contactor. Keep fan running to aid cooldown. Increment thermal cutout counter by 1. Wait 15 minutes and attempt restart. If restart is successful for 15 minutes, reset counter. Infinity display: LO THERMAL CUTOUT or HI THERMAL CUTOUT

13 Final Result of Condition #3 Compressor Lockout 2-Speed board Control Process: 3 consecutive thermal cut out errors on Y1 lock out Y1 and only respond to Y2 (Only high speed operation) Infinity error display LO COMP CUTOUT 3 consecutive Y2 or combination Y1 and Y2 Lock out both Y1 and Y2 Infinity error display HI COMP CUTOUT Control is reset by power cycle or User Interface reset command.

14 Start No LO Compressor Call? Yes No HI Compressor Call? No Yes VC Volts? Yes LO COMP CUTOUT? No Yes HI COMP CUTOUT? No Yes VC-VH Error Communicate VC STANDBY VOLTS to fault History Continue Normal Operation. Reset thermal cutout Counter in Yes 15 minutes Energize Lo contactor VC Volts after 2 seconds? No Continue with startup And run sequence As normal Communicate VC STARTUP VOLTS To fault history Energize HI contactor VC Volts after 2 seconds? No Continue with startup And run sequence As normal Communicate VC STARTUP Volts To fault history Lock out Y1+Y2 6 Flash Yes VC Volts? No De-energize LO contactor Energize Fan Communicate LO THERMAL CUTOUT to fault History Yes De-energize HI contactor Energize Fan Communicate HI THERMAL CUTOUT to fault History No Continue normal operation. Reset thermal cutout counter in 15 minutes VC Volts? Yes Yes Wait to be Reset Display 6 flash Wait 15 minutes Lo Thermal Cutout counter +1 Lock out Y1 Communicate LO COMP CUTOUT to fault History HI Thermal Cutout counter +1 Communicate HI COMP CUTOUT to fault history No LO counter =3? Yes No HI counter=3 Or LO+HI=3? Yes

15 2-Speed Start Circuit

16 2-speed Starting Circuit R and S windings switch roles for hi and lo Lead and lag windings switch Run winding voltage is similar in hi and lo Allows use of one capacitor and relay

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18 Hi speed start up

19 Hi speed after start up

20 Lo speed start up

21 Lo speed after start up

22 2-Speed Start Gear Compressor run capacitor voltage is sensed by start relay Calibration of start relay is very tight Use of proper start kit is critical Generic start gear will cause degradation of compressor life

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