Troubleshooting - Bosch LV Series Installation And Maintenance Manual

36 | Troubleshooting

TROUBLESHOOTING
Problem
No compressor
operation but fan runs
8 733 905 683 (2013/04)
UNIT TROUBLESHOOTING
Mode Check
Cooling Heating
X
Is fault LED Blinking
1 time?
X
X
Is fault LED Blinking
2 times?
X
Is fault LED Blinking
X
3 times?
Subject to change without prior notice
Possible Cause
Check water valves and/or pumps
High Pressure fault - no
for proper operation. Check for
or low water flow
High Pressure fault - high Check water temperature - is it in
water temperature
High Pressure fault - Check for proper flow rate and
fouled or scaled water water temperature, but low water
coil
High Pressure fault - no
or low air flow
Inspect air coil for dirt/debris
Check duct work - are dampers
Low Pressure fault - no
or low air flow
Inspect air coil for dirt/debris
Check duct work - are dampers
Low Pressure fault - low Check refrigerant pressure with
refrigerant
Check water valves and/or pumps
Low Pressure fault - no
for proper operation. Check for
or low water flow
Check for proper flow rate and
75Unit water temperature, but low water
Low Pressure fault - low Check refrigerant pressure with
refrigerant
Check water valves and/or pumps
Freeze fault, water coil -
for proper operation. Check for
no or low water flow
Check water temperature - is it
below 40 deg entering? If heat
pump is connected to a closed loop
Freeze fault - low water with antifreeze check that the
temperature "FREEZE 1" resistor on the UPM
board has been cut to set the unit
to antifreeze mode (see UPM
Freeze fault - low Check refrigerant pressure with
refrigerant
LV Heat PumpSeries
Action
water coil blockage.
range?
side temp rise in cooling
Check fan motor for proper
operation.
Check air filter
closed or blocked?
Check fan motor for proper
operation.
Check air filter
closed or blocked?
gauge set
water coil blockage.
side temp drop in heating.
gauge set
water coil blockage.
features on pages 15-17).
gauge set
LV Heat Pump Series