WARNING
WARNING TO SERVICE PERSONS! Electric shock hazard. When electrical power to the internal control box components must be available for troubleshooting, a common practice is to construct a ass" of the door interlock switch. When such a by−pass is in place, a potential shock hazard is present which can cause injury or death. Make sure any door interlock switch by−pass has been removed after troubleshooting is complete and BEFORE attempting any re- pairs to the control box components!
Troubleshooting: Cooling Sequence of Operation
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Power On |
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Normal Operation LED: Steady Flash |
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Thermostat (S1) Provides 24 Volt Cooling Call to In- | NO |
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Check for 24 Volts Between Y and C at A15 Terminal Strip | |||
door Blower (B3) | |||
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| YES |
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NO | Blower (B3) Operates at the 2nd Stage | NO | Check for 24 Volts | |||||||||
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2 Stage Condensing Unit? | Cooling Speed Determined by COOL, | |||||||||||
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| Between Pins 14 and | |||||||||
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| DELAY and ADJUST Jumper Positions on |
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| YES |
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| the BDC3 Control (A52) |
| 3 on J49 | |||
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| YES |
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Blower (B3) Operates at the 1st Stage Cooling Speed |
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| CFM Light on A52 Indicates Blower CFM |
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Determined by COOL, DELAY and ADJUST Jumper |
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NO |
| Selection with 100CFM / Blink |
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Positions on the BDC3 Control (A52) |
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CFM Light on A52 Indicates Blower CFM Selection with |
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| YES |
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100CFM / Blink |
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| Thermostat (S1) Demand Satisfied |
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| YES |
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| YES |
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| Check for 24 Volts Between Y |
| Blower Shuts Off According to the DELAY |
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| Jumper Position on the BDC3 Control |
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| and C on A15 Terminal Strip |
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| Check for 24 Volts Between |
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| Pins 6 and 3 on J49 |
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| YES |
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| Demand for Cooling Satisfied |
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First Stage Demand for Cooling Satisfied?
YES 
Blower Shuts Off According to the DELAY Jumper Position on the BDC3 Control (A52)
YES 
Demand for Cooling Satisfied
NO | Thermostat (S1) Calls for |
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| 2nd Stage Cooling |
YES 
Blower Operates at the 2nd Stage Cooling Speed Deter- mined by COOL, DELAY and ADJUST Jumper Positions on the BDC3 Control (A52)
YES 
NO
NO
Check for 24 Volts Between Y2 on TB1 and C on A15 Terminal Strip
Check for 24 Volts Between Pins 14 and 3 on J49
CFM Light on A52 Indi- cates Blower CFM Selec- tion with 100CFM / Blink
YES 
2nd Stage Thermostat (S1) Demand Satisfied
YES 
Blower Returns to 1st Stage Cooling Speed
Page 19
CBWMV SERIES
