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58
EconoMi$er IV Troubleshooting
Completion
This procedure is used to return the EconoMi$er IV to operation.
No troubleshooting or testing is done by performing the
following procedure.
1. Disconnect power at TR and TR1.
2. Set enthalpy potentiometer to previous setting.
3. Set DCV maximum position potentiometer to previous
setting.
4. Set minimum position, DCV set point, and exhaust
potentiometers to previous settings.
5. Remove 620-ohm resistor from terminals S
R
and +.
6. Remove 1.2 kilo-ohm checkout resistor from terminals S
O
and +. If used, reconnect sensor from terminals S
O
and +.
7. Remove jumper from TR to N.
8. Remove jumper from TR to 1.
9. Remove 5.6 kilo-ohm resistor from T and T1. Reconnect
wires at T and T1.
10. Remove jumper from P to P1. Reconnect device at P and
P1.
11. Apply power (24 vac) to terminals TR and TR1.
Table 35—Cooling Service Analysis
PROBLEM CAUSE REMEDY
Compressor and Condenser Fan
W
i
l
l
N
S
Power failure. Call powe r company.
C
o
m
p
r
e
s
s
o
r
a
n
d
C
o
n
d
e
n
s
e
r
F
a
n
Will Not Start.
Fuse bl own or circuit bre aker tripped. Replace fuse or reset circuit breaker.
Defective thermostat, contactor, transformer, or
control relay.
Replace component.
Insuffi cient line voltag e. Determine cause an d correct.
Incorre ct or faulty wiring. Check wiring diagram and rewire correctly.
Thermostat setting too high. Lower thermostat setting below room temperature.
Compressor Will Not Start
But Condenser Fan Runs.
Faulty wiring or loose connections in compres-
sor circuit.
Check wiring and repair or replace.
B
u
t
C
o
n
d
e
n
s
e
r
F
a
n
R
u
n
s
.
Compressor motor burned out, seized, or in-
ternal overload open.
Determine cause. Replace compressor.
Defective run/start capacitor, overload, start
relay.
Determine cause andreplace.
One leg of 3-phase power dead. Replace fuse or reset circuit breaker. Determine
cause.
CompressorCycles(OtherThan
Normally Satisfying Thermostat).
Refrigerant overcharge or undercharge. Recover refrigerant, evacuate system, and recharge
to nameplate.
N
o
r
m
a
l
l
y
S
a
t
i
s
f
y
i
n
g
T
h
e
r
m
o
s
t
a
t
)
.
Defective c ompressor. Replace and determine cause.
Insuffi cient line voltag e. Determine cause an d correct.
Blocked condenser. Determin e cause and correct.
Defective run/start capacitor, overload, or start
relay.
Determine cause andreplace.
Defective thermostat. Replace thermostat.
Faulty condenser-fan motor or capacitor. Replace.
Restriction in refrigerant system. Locate restriction and remo ve.
Compressor Operates Continuously.
Dirty a ir filter. Replace filter.
C
o
m
p
r
e
s
s
o
r
O
p
e
r
a
t
e
s
C
o
n
t
i
n
u
o
u
s
l
y
.
Unit undersized for load. Decrease load orincrease unit size.
Thermosta t set too low. Reset thermostat.
Low refrigerant charg e. Locate leak, repair, and recharge.
Leaking valves in compressor. Replace c ompressor.
Air in system. Recover refrigerant, evacuate system, and recharge.
Condenser coil dirty or restricted. Clean coil or remove restriction.
Excessive Head Pressure.
Dirty a ir filter. Replace filter.
E
x
c
e
s
s
i
v
e
H
e
a
d
P
r
e
s
s
u
r
e
.
Dirty condenser coil. Clean coil.
Refrigerant overcharged. Recover excess refrigerant.
Air in system. Recover refrigerant, evacuate system, and recharge.
Condense r air restricted or ai r short-cycling . Determine cause and correct.
Head Pressure Too Low.
Low refrigerant charg e. Check for leaks, repair, an d recharge.
H
e
a
d
P
r
e
s
s
u
r
e
T
o
o
L
o
w
.
Compressor valves leaking. Replace compressor.
Restrictioninliquidtube. Remove restriction.
Excessive Suction Pressure.
High heat load. Check for source and eliminate.
E
x
c
e
s
s
i
v
e
S
u
c
t
i
o
n
P
r
e
s
s
u
r
e
.
Compressor valves leaking. Replace compressor.
Refrigerant overcharged. Recover excess refrigerant.
Suction Pressure Too Low.
Dirty a ir filter. Replace filter.
S
u
c
t
i
o
n
P
r
e
s
s
u
r
e
T
o
o
L
o
w
.
Low refrigerant charg e. Check for leaks, repair, an d recharge.
Metering device or low side restricted. Remove source of restriction.
Insufficient evaporator airflow . Increase air quant ity. Ch eck filter andreplace if neces-
sary.
Temperature too low in conditioned area. Reset thermostat.
Outdoor ambient below 25 F. Install low-a mbient kit.
Evaporator Fan Will Not Shut Off.
Time off delay not finished. Wait for 30-second off delay.
551B,C