Bosch LM Series Installation, Operation And Maintenance Manual page 27

LM Series Heat Pump
UPM Board LED Indications
Indication
Color Blinks
GREEN Solid
RED 1
RED 2
RED 3
RED 4
RED 5
RED 6
Status LED
YELLOW "ALERT" Short Cycling
FLASH CODE 3 Compressor is
running only briefly
YELLOW "ALERT" Locked Rotor
FLASH CODE 4
Revised 09-13
Description
18-30 VAC Power is present
High pressure lockout
Low pressure lockout
Freeze sensor lockout
Condensate overflow
Brownout
Evaporator Freeze condition
Comfort Alert Module -Flash Codes
Status LED
Description
1. Thermostat demand signal is intermittent
2. Time delay relay or control board defective
3. If high pressure switch present go to Flash Code 2
4. If low pressure switch present go to Flash Code 1
1. Run capacitor has failed (may not be bad, verify)
2. Low line voltage (contact utility if voltage at disconnect
3. Excessive liquid refrigerant in compressor
4. Compressor bearings are seized
Status LED Troubleshooting Information Solution
information
information
is low)
• Check wiring connections
• Measure compressor oil level
Troubleshooting | 27
8 733 905 315 (2013/9)