Bryant 551B Installation Instructions Manual page 58

Single-package rooftop electric cooling units with optional electric heat
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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
PROBLEM
Compressor and Condenser Fan
Compressor and Condenser Fan
Will Not Start.
Will N
S
Compressor Will Not Start
But Condenser Fan Runs.
But Condenser Fan Runs.
Compressor Cycles (Other Than
Normally Satisfying Thermostat).
Normally Satisfying Thermostat).
Compressor Operates Continuously.
Compressor Operates Continuously.
Excessive Head Pressure.
Excessive Head Pressure.
Head Pressure Too Low.
Head Pressure Too Low.
Excessive Suction Pressure.
Excessive Suction Pressure.
Suction Pressure Too Low.
Suction Pressure Too Low.
Evaporator Fan Will Not Shut Off.
and +.
R
Table 35—Cooling Service Analysis
CAUSE
Power failure.
Fuse blown or circuit breaker tripped.
Defective thermostat, contactor, transformer, or
control relay.
Insufficient line voltage.
Incorrect or faulty wiring.
Thermostat setting too high.
Faulty wiring or loose connections in compres-
sor circuit.
Compressor motor burned out, seized, or in-
ternal overload open.
Defective run/start capacitor, overload, start
relay.
One leg of 3-phase power dead.
Refrigerant overcharge or undercharge.
Defective compressor.
Insufficient line voltage.
Blocked condenser.
Defective run/start capacitor, overload, or start
relay.
Defective thermostat.
Faulty condenser-fan motor or capacitor.
Restriction in refrigerant system.
Dirty air filter.
Unit undersized for load.
Thermostat set too low.
Low refrigerant charge.
Leaking valves in compressor.
Air in system.
Condenser coil dirty or restricted.
Dirty air filter.
Dirty condenser coil.
Refrigerant overcharged.
Air in system.
Condenser air restricted or air short-cycling.
Low refrigerant charge.
Compressor valves leaking.
Restriction in liquid tube.
High heat load.
Compressor valves leaking.
Refrigerant overcharged.
Dirty air filter.
Low refrigerant charge.
Metering device or low side restricted.
Insufficient evaporator airflow.
Temperature too low in conditioned area.
Outdoor ambient below 25 F.
Time off delay not finished.
58
6. Remove 1.2 kilo-ohm checkout resistor from terminals S
and +. If used, reconnect sensor from terminals S
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.
Call power company.
Replace fuse or reset circuit breaker.
Replace component.
Determine cause and correct.
Check wiring diagram and rewire correctly.
Lower thermostat setting below room temperature.
Check wiring and repair or replace.
Determine cause. Replace compressor.
Determine cause and replace.
Replace fuse or reset circuit breaker. Determine
cause.
Recover refrigerant, evacuate system, and recharge
to nameplate.
Replace and determine cause.
Determine cause and correct.
Determine cause and correct.
Determine cause and replace.
Replace thermostat.
Replace.
Locate restriction and remove.
Replace filter.
Decrease load or increase unit size.
Reset thermostat.
Locate leak, repair, and recharge.
Replace compressor.
Recover refrigerant, evacuate system, and recharge.
Clean coil or remove restriction.
Replace filter.
Clean coil.
Recover excess refrigerant.
Recover refrigerant, evacuate system, and recharge.
Determine cause and correct.
Check for leaks, repair, and recharge.
Replace compressor.
Remove restriction.
Check for source and eliminate.
Replace compressor.
Recover excess refrigerant.
Replace filter.
Check for leaks, repair, and recharge.
Remove source of restriction.
Increase air quantity. Check filter and replace if neces-
sary.
Reset thermostat.
Install low-ambient kit.
Wait for 30-second off delay.
O
and +.
O
REMEDY

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