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Bosch Greensource SM024 Installation, Operation And Maintenance Manual page 51

Greensource cdi series sm model water-to-air heat pumps
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Greensource CDi Series SM Model
Problem
EWT LOW-LIMIT
TRIP
NOT COOLING
FAULT, LWT < EWT
NOT HEATING
FAULT, LWT > EWT
NO WATERFLOW
CONDITION
WATERFLOW LOW
CONDITION
POWER FAILURE
DETECTED
LOW LOOP WATER
FAULT
FAN ERROR FAULT
OVERVOLTAGE
UNDERVOLTAGE
Table 11 Unit Troubleshooting
Greensource CDi Series SM Model
Unit Troubleshooting
Check
Possible Cause
Low loop temperature
detected. Entering water
Compressor,
temperature falls below low
Loop Pump,
loop water protection
Auxiliary Heat
setpoint. EWT < LLWP
Setpoint.
Warning
LWT is less than EWT
Warning
LWT is greater than EWT
No water flow has been
Compressor,
detected. No difference
Loop Pump
between LWT and EWT.
Low water flow has been
detected. Minimal
Warning
difference between LWT
and EWT.
Controller has sensed
sudden power loss.
Appliance
Nominal voltage is lower
than 21 VAC.
LWT has fallen below LLWP
Compressor,
setpoint. Controller has
Loop Pump,
initiated Low Loop Water
Auxiliary Heat
Protection.
Fan motor is not running.
Blower,
Controller has attempted to
Compressor
start motor and is receiving
no feedback signal.
Overvoltage condition
detected. Power supply
Appliance
voltage is 10% above
nominal valve.
Brownout voltage condition
detected. Power supply
Appliance
voltage is 10% below
nominal valve.
Subject to change without prior notice
Unit Troubleshooting | 51
Action
Loop has reached a temperature
outside the unit operating range
compressor has been disabled, and
Auxiliary Heat is enabled for heating
operation. Loop pump will run to allow
loop temperature to recover.
Unit is operating in cooling mode, but
LWT is lower than EWT: Check RV.
Service/replace.
Unit is operating in heating mode, but
LWT is higher than EWT: Check RV.
Service/replace.
Verify water supply and associated
components. Verify recommended
factory water flow. Verify loop pump,
fuse, and operation. Service/replace.
Verify water supply and associated
components. Verify recommended
factory water flow. Verify loop pump,
fuse, and operation. Service/replace.
Check line voltage is between
208–240 VAC. Verify P1 — 1, 2 is
greater than 21 VAC. Verify continuity
of fuse F4. Service/replace.
Loop has reached a temperature
outside the unit operating range,
compressor has been disabled, and
Auxiliary Heat is enabled for heating
operation. Loop pump will run to allow
loop temperature to recover.
Verify blower line voltage. Verify ECM
motor is connected to P4.
Check line voltage is between
208–240 VAC. Verify P1 — 1, 2 is 24
VAC. Verify continuity of fuse F4,
Service/replace.
Check line voltage is between
208–240 VAC. Verify P1 — 1, 2 is 24
VAC. Verify continuity of fuse F4,
Service/replace.
8733819578 (2019/02)

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