MODELESP-D FAN COIL UNIT TROUBLESHOOTING GUIDE ESPD8-301
MODELESP-D
FAN COIL UNIT
TROUBLESHOOTING GUIDE
Protected by one or more of the following U.S. Patents (3,507,354; 3,575,234; 3,596,936; 3,605,797; 3,685,329; 4,045,977;
4,698,982; 926,673 and Canadian Patents: 891,292; 923,935; 923,936) Systematic troubleshooting is a logical series of steps to
follow in analyzing a problem in the Space-Pak central air
conditioning system with a minimum amount of lost time
or call backs. Although the owners initial complaint, most
of the time, will be NO COOLING, INSUFFICIENT
COOLING or NOISE, there are certain visible and
audible symptoms which you can use to pinpoint the
problem. This troubleshooting guide provides you with
step-by-step procedures, written in the proper sequence
for each condition, for solving the situation which you may
observe. Depending on the situation involved, upon
arrival at the service call, we recommend checking these
three most obvious items first:
1. Check that thermostat is calling for cooling and fan
switch is in the AUTO position.
2. Check that thermostat is set below room temperature.
3. Check for tripped circuit breaker or blown fuse at main
fuse box and at condensing unit disconnect box.
In addition to the usual assortment of refrigeration
system service tools, Space-Pak troubleshooting also
requires the use of a volt-amp-ohmmeter and a U-tube
manometer.
SERVICE CALL CONDITIONS
Page
ESP-D Unit & Condensing Units Run, But Cooling Insufficient......................................................................................2
ESP-D Unit & Condensing Unit Will Not Start................................................................................................................ 3
ESP-D Unit Will Not Start, But Condensing Unit Runs...................................................................................................3
ESP-D Unit Runs, But Condensing Unit Will Not Start...................................................................................................4
ESP-D Unit Will Not Start, But Condensing Unit Cycles.................................................................................................4
ESP-D Unit Cycles, But Condensing Unit Cycles...........................................................................................................4
ESP-D Unit Runs, But Condensing Unit Cycles............................................................................................................. 5
Sweating At ESP-D Unit Supply Outlet...........................................................................................................................5
Excessive Air Noise At Terminator...................................................................................................................................5
Excessive Noise At Return Air Grill.................................................................................................................................6
Excessive Vibration At ESP-D Unit................................................................................................................................. 6
POSSIBLE CAUSE
VERIFICATION
SOLUTION
Low Suction Pressure
Check blower motor as described on
If defective, replace motor.
page 6 in this manual.
Check that filter in return air box is
Clean air filter.
clean.
Check system refrigerant charge.
Charge to proper subcooling accord-
ing to manufacturers instructions.
Check for dirty evaporator coil.
Clean evaporator coil.
High Suction Pressure
Check for air bubbles in system
Charge to proper subcooling accord-
refrigerant.
ing to condensing unit manufactur-
ers instructions. Install sight glass
near indoor unit and monitor.
Check calculated heat gain to be
Take necessary action.
sure that equipment is sized properly.
Check for obstructions near
Remove obstructions.
condensing unit which could cause
recirculation of air.
Low Head Pressure
Check system refrigerant charge.
Charge to proper subcooling
according to condensing unit
manufacturers instructions.
Check calculated heat gain to be sure
Take necessary action.
that equipment is sized properly.
CONDITION: ESP-D & CONDENSING UNITS RUN, BUT COOLING INSUFFICIENT
2 POSSIBLE CAUSE
VERIFICATION
SOLUTION
High Head Pressure
Check condenser fan motor accord-
If defective, replace fan motor.
ing to condensing unit manufacturers
instructions.
Check for dirty condensing unit coil.
Clean condensing unit coil.
Check system refrigerant charge.
Charge to proper subcooling
according to condensing unit
manufacturers instructions.
Check for dirty evaporator coil.
Clean evaporator coil.
Check for obstructions near
Remove obstructions.
condensing unit which could cause
recirculation of air.
Check for restricted liquid lines.
Remove restrictions and kinks from
lines.
Distribution System Air Leaks
Check all joints in air distribution
Make sure all joints are air tight.
system.
Verify static pressure as described
on page 6 in this manual.
ESP-D & CONDENSING UNITS RUN, BUT COOLING INSUFFICIENT (Continued)
POSSIBLE CAUSE
VERIFICATION
SOLUTION
Thermostat Not Level
Check level of thermostat
If necessary, level thermostat.
Defective Thermostat
With volt meter, check resistance of
If resistance, thermostat is O.K.
thermostat contacts.
If no resistance, replace thermostat.
Loose Low Voltage Wiring
Check all wiring connections for
Tighten all loose connections.
tightness.
Defective Blower Relay
Check relay as described on page 6 If defective, replace relay.
in this manual.
Defective Low Voltage Transformer
Check transformer as described on
If defective, replace transformer.
page 6 in this manual.
Inadequate Electrical Service
Check electrical service against
Replace electrical service with
minimum requirements.
adequately sized service.
CONDITION: ESP-D UNIT & CONDENSING UNIT WILL NOT START
POSSIBLE CAUSE
VERIFICATION
SOLUTION
Shorted Or Broken Wiring
Check wiring.
If necessary, repair or replace wiring.
Loose Low or High Voltage Wiring
Check all wiring connections for
Tighten all loose connections.
tightness.
Defective Blower Motor
Check motor as described on page 6
If defective, replace motor.
in this manual.
CONDITION: ESP-D UNIT WILL NOT START, BUT CONDENSING UNIT RUNS
3 POSSIBLE CAUSE
VERIFICATION
SOLUTION
Defective Thermostat
With volt meter, check resistance of
If resistance, thermostat is O.K.
thermostat contacts.
If no resistance, replace thermostat.
Loose Low Or High Voltage Wiring
Check all wiring connections for
Tighten all loose connections.
tightness.
Float Switch (If Used) And Anti-Frost
Thermostat fan ON. With volt meter,
If no voltage, fan relay is defective.
Switch (Switches are wired in series)
check for 24v across terminal 1 on
Replace it.
the fan relay and terminal 7 on low
If read 24v, relay is O.K.
voltage terminal strip.
With volt meter, check for 24v
If no voltage, check coil for ice
across terminals 1 and 7 on low
and drain pan for excessive water.
voltage terminal block.
If ice check air filter, return air duct
& blower motor for air flow. If
excessive water check and clean
condensate drain lines.
If no ice on coil and water level in
drain pan is normal, check each
switch for continuity. If switch has no
continuity, replace it.
If 24v, switches are O.K.
Shorted Or Broken Wiring
Check wiring.
If necessary, repair or replace wiring.
Condensing Unit
Check according to manufacturers
Repair or replace as directed by
instructions.
manufacturer.
CONDITION: ESP-D UNIT RUNS, BUT CONDENSING UNIT WILL NOT START
POSSIBLE CAUSE
VERIFICATION
SOLUTION
Incorrect Low Voltage Connections
Check low voltage connections
Correct low voltage connections.
against wiring diagram.
Loose Low Voltage Connections
Check all wiring connections for
Tighten all loose connections.
tightness.
Defective Blower Relay
Check relay as described on page 6 If defective, replace relay.
in this manual.
Defective Blower Relay
Check motor as described on page
If defective, replace motor.
6 in this manual.
CONDITION: ESP-D UNIT WILL NOT START, BUT CONDENSING UNIT CYCLES
POSSIBLE CAUSE
VERIFICATION
SOLUTION
Blower Motor
Check motor as described on page 6
If defective, replace motor.
in this manual.
Check motor amps and compare to
If excessive, the motor may be
nameplate ratings.
overloaded. Check supply duct for
breaks or leaks.
CONDITION: ESP-D UNIT CYCLES, BUT CONDENSING UNIT RUNS
4 POSSIBLE CAUSE
VERIFICATION
SO