Bryant DURAPAC PLUS SERIES 542J, Installation, Start-Up And Service Instructions Manual

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TROUBLESHOOTING
I. UNIT TROUBLESHOOTING
Refer to Table 15 and Fig. 42-45, for assistance when trou-
bleshooting the 542J units.
A. Cooling Cycle
1. Hot gas from compressor flows through the 4-way
valve and is directed to the outdoor-coil header. At
the header it is condensed and subcooled through
converging circuits (7-2-1). Refrigerant leaves the
outdoor-coil by way of the check valve to the liquid
line.
2. The refrigerant then flows through the filter drier
and feeds the indoor coil by way of fixed orifice tubes
on each circuit.
3. Each circuit evaporates the refrigerant, and the cir-
cuits are combined in the indoor-coil header with
some of the circuits flowing through the check valve.
4. The refrigerant then flows through the 4-way valve,
accumulator and back to the compressor.
B. Heating Cycle
1. Hot gas from the compressor flows through the 4-way
valve and is directed to the indoor-coil header. At the
header it is condensed and directed through subcool-
ing circuits and out the indoor-coil check valve to the
liquid line.
2. The refrigerant then flows through a strainer and
feeds the outdoor-coil by way of fixed orifice tubes on
each circuit.
3. Each circuit evaporates the refrigerant, and the cir-
cuits are combined in the outdoor-coil header with
some of the circuits flowing through the check valve.
4. The refrigerant then flows through the 4-way valve,
accumulator and back to the compressor.
II. ECONOMI$ERIV TROUBLSHOOTING
See Table 16 for EconoMi$erIV logic.
A functional view of the EconoMi$erIV is shown in Fig. 46.
Typical settings, sensor ranges, and jumper positions are
also shown. An EconoMi$erIV simulator program is avail-
able from Bryant to help with EconoMi$erIV training and
troubleshooting.
A. EconoMi$erIV Preparation
This procedure is used to prepare the EconoMi$erIV for
troubleshooting. No troubleshooting or testing is done by
performing the following procedure.
NOTE: This procedure requires a 9-v battery, 1.2 kilo-ohm
resistor, and a 5.6 kilo-ohm resistor which are not supplied
with the EconoMi$erIV.
IMPORTANT: Be sure to record the positions of all potenti-
ometers before starting troubleshooting.
1. Disconnect power at TR and TR1. All LEDs should be
off. Exhaust fan contacts should be open.
2. Disconnect device at P and P1.
3. Jumper P to P1.
4. Disconnect wires at T and T1. Place 5.6 kilo-ohm
resistor across T and T1.
5. Jumper TR to 1.
6. Jumper TR to N.
7. If connected, remove sensor from terminals S
O
and +.
Connect 1.2 kilo-ohm 4074EJM checkout resistor
across terminals S
O
and +.
8. Put 620-ohm resistor across terminals S
R
and +.
9. Set minimum position, DCV set point, and exhaust
potentiometers fully CCW (counterclockwise).
10. Set DCV maximum position potentiometer fully CW
(clockwise).
11. Set enthalpy potentiometer to D.
12. Apply power (24 vac) to terminals TR and TR1.
B. Differential Enthalpy
To check differential enthalpy:
1. Make sure EconoMi$erIV preparation procedure has
been performed.
2. Place 620-ohm resistor across S
O
and +.
3. Place 1.2 kilo-ohm resistor across S
R
and +. The Free
Cool LED should be lit.
4. Remove 620-ohm resistor across S
O
and +. The Free
Cool LED should turn off.
5. Return EconoMi$erIV settings and wiring to normal
after completing troubleshooting.
C. Single Enthlapy
To check single enthalpy:
1. Make sure EconoMi$erIV preparation procedure has
been performed.
2. Set the enthalpy potentiometer to A (fully CCW). The
Free Cool LED should be lit.
3. Set the enthalpy potentiometer to D (fully CW). The
Free Cool LED should turn off.
4. Return EconoMi$erIV settings and wiring to normal
after completing troubleshooting.
D. DCV (Demand Controlled Ventilation) and Power
Exhaust
To check DCV and Power Exhaust:
1. Make sure EconoMi$erIV preparation procedure has
been performed.
2. Ensure terminals AQ and AQ1 are open. The LED for
both DCV and Exhaust should be off. The actuator
should be fully closed.
3. Connect a 9-v battery to AQ (positive node) and AQ1
(negative node). The LED for both DCV and Exhaust
should turn on. The actuator should drive to between
90 and 95% open.
4. Turn the Exhaust potentiometer CW until the
Exhaust LED turns off. The LED should turn off
when the potentiometer is approximately 90%. The
actuator should remain in position.
5. Turn the DCV set point potentiometer CW until the
DCV LED turns off. The DCV LED should turn off
when the potentiometer is approximately 9 v. The
actuator should drive fully closed.
6. Turn the DCV and Exhaust potentiometers CCW
until the Exhaust LED turns on. The exhaust con-
tacts will close 30 to 120 seconds after the Exhaust
LED turns on.
7. Return EconoMi$erIV settings and wiring to normal
after completing troubleshooting.