Bosch SM024 Installation, Operation And Maintenance Manual page 54

54 | Troubleshooting
Status LED
YELLOW "ALERT" Open Start Circuit
FLASH CODE 6 Current only in run
circuit
YELLOW "ALERT" Open Run Circuit
FLASH CODE 7 Current only in start
circuit
YELLOW "ALERT" Welded Contactor
FLASH CODE 8 Compressor always
runs
YELLOW "ALERT" Low Voltage
FLASH CODE 9 Control circuit <
17VAC
Problem
NO FLOW
LOW FLOW
HIGH WATER
TEMPERATURE
LOW HEAT OUTPUT
6 720 220 406 (2015/02)
Comfort Alert Module -Flash Codes
Status LED
Description
1. Run capacitor has failed (may not be bad, verify)
2. Open circuit in compressor start wiring or connections
3. Compressor start winding is damaged
1. Open circuit in compressor run wiring or connections
2. Compressor run winding is damaged
1. Compressor contactor has failed closed
2. Thermostat demand signal not connected to module
1. Control circuit transformer is overloaded
2. Low line voltage (contact utility if voltage at disconnect
HRP Troubleshooting
Possible Cause
No Power
On/Off Switch Position
Compressor Contactor
Broken or loose wires
Air Lock
Stuck pump shaft/impeller
Defective pump
Kinked or under sized water piping
Water temp limit closed
Scaled or fouled heat exchanger
Subject to change without prior notice
Status LED Troubleshooting Information Solution
• Check wiring and connectors between supply and
the compressor "S'" terminal
• Check compressor motor winding resistance
• Check wiring and connectors between supply and
the compressor "R" terminal
• Check compressor motor winding resistance
is low)
• Check wiring connections Flash Code number
corresponds to a number of LED flashes, followed
by a pause and then repeated. TRIP and ALERT LEDs
flashing at same time means control circuit voltage
is too low for operation
Check power supply
Set switch to "ON" position
Engage heat pump contactor
Repair or tighten wires
Purge air from piping system
Remove pump cartridge and clean
Replace pump
Repair kink and check for proper line size
Stuck limit switch
Sensor not attached securely to line
Clean heat exchanger
SM Series Heat Pump
Checks and Corrections
SM Series Heat Pump