Bosch CL Series User Manual

Troubleshooting
No compressor
operation but fan runs
(Continued)
X X
Is the Fault LED
blinking five (5)
times?
Brown out fault—
Low voltage supply
Check primary voltage—Ensure it is between the
limits listed on the unit data plate.
Brown out fault—
Bad thermostat
connection
Check control voltage—if below 18V check
accessories connected to the unit and ensure they
do not exceed the VA draw shown in
Table 5 on
page #21.
Check that thermostat wiring is proper gauge and
length,
that it is not damaged and that all
connections at the thermostat and heat pump are
secure.
X
Is the Fault LED
blinking six (6)
times?
Freeze fault, air
coil—No or low air
flow
Check fan motor for proper operation.
Check the air filter.
Inspect the air coil for dirt/debris.
Check duct work—Are dampers closed or blocked?
Freezer fault,
air coil—Blocked
return air
Check that there is adequate space between the
return air opening and walls or other obstructions
on free return applications.
Freezer fault,
air coil—Low
refrigerant
Check refrigerant pressure with a gauge set.
X X
No Fault LED—
Contractor Not
Energized
Thermostat
not calling for
compressor
operation
Ensure that the thermostat is ON and calling for "Y."
Bad thermostat
connection
Check "Y" connection from thermostat—Ensure that
there is
24 VAC between "Y" and "C."
Loose wire to
contactor coil
Check wiring—Ensure that there is 24 VAC across
the contactor coil.
Burned out
contactor coil
Test contactor with 24 VAC (between "R" and "C").
Ohm cont
actor coil—an open circuit indicates a
burned coil.
No compressor
operation but fan runs
(Continued)
X X
No Fault LED—
Contractor
Energized
Open compressor
overload
Check for supply voltage at the load side of the
contactor. For three-phase models check phase
rotation and voltage at all three phases.
Poor wiring
connection
Look for signs of heat on the wiring insulation.
Check th
at all wiring connections are secure and
properly torqued.
Burned out
compressor
Does compressor hum when power is applied?
If not check the resistance of the compressor
windings using the values shown in the compressor
characteristics chart. Note that the compressor
must be cool (70° F) when checking the windings.
Unit Troubleshooting
Problem
Mode
Check Possible Cause Action
Cooling Heating
| 57
CL Series Heat Pumps — 8733838716 (2024/05)

Bosch CL Series Specifications

General

Brand	Bosch
Model	CL Series
Category	Heat Pump
Language	English