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After inspecting the electrical controls and wiring, replace all the
panels. Start the unit, and observe at least one complete cooling
cycle to ensure proper operation. If discrepancies are observed in
operating cycle, or if a suspected malfunction has occurred, check
each electrical component with the proper electrical instrumenta-
tion. Refer to the unit wiring label when making these checkouts.

NOTE:

Refer to the Sequence of Operation section, as an aid in

determining proper control operation.

Step 7—Refrigerant Circuit

Inspect all refrigerant tubing connections and the unit base for oil
accumulations annually. Detecting oil generally indicates a refrig-
erant leak.

If oil is detected or if low cooling performance is suspected,
leak-test all refrigerant tubing using an electronic leak-detector, or
liquid-soap solution. If a refrigerant leak is detected, refer to Check
for Refrigerant Leaks section. (See Table of Contents for page
number.)

If no refrigerant leaks are found and low cooling performance is
suspected, refer to Refrigerant Charge. (See Table of Contents for
page number.)

Step 8—Indoor Airflow

The cooling airflow does not require checking unless improper
performance is suspected.

If a problem exists, be sure that all

supply- and return-air grilles are open and free from obstructions,

and that the air filter is clean

. When necessary, refer to Indoor

Airflow and Airflow Adjustments section to check the system
airflow.

Step 9—Metering Devices

Refrigerant cooling metering device is an Accurator (024-042) or
TXV (048 and 060) located upstream of the indoor coil distributor
assembly. Refrigerant heating mode metering device is an Accu-
rater located upstrem of the outdoor coil distributor assembly.

Step 10—Lubrication

COMPRESSOR

—The compressor is charged with the correct

amount of oil at the factory.

FAN MOTOR BEARINGS

—Fan motor bearings are perma-

nently lubricated. No further lubrication of outdoor or indoor fan
motors is required.

Step 11—Liquid Line Strainer

The liquid line strainer (to protect metering device) is made of wire
mesh and is located in the liquid line on the inlet side of the
metering device.

Check valves are also located in the liquid lines near the strainers.
The Strainers are the larger of the two components.

Step 12—High Flow Valves

Located on the compressor hot gas and suction tubes are High
Flow Valves. Large black plastic caps distinguish these valves
with O-rings located inside the caps. These valves cannot be
accessed for service in the field. Ensure the plastic caps are in
place and tight or the possibility of refrigerant leakage could occur.

TROUBLESHOOTING

Use the Troubleshooting Cooling and Heating guide if problems
occur with these units.

START-UP CHECKLIST

Use the Start-Up checklist to ensure proper start-up procedures are
followed.

Fig. 13—Outdoor-Fan Adjustment (060 Size)

C02017

0.708in.

17

Summary of Contents for 50ZHA024-060

Page 1: ...AN 14 DEFROST 14 ELECTRIC RESISTANCE HEATING 14 MAINTENANCE 15 Air Filter 15 Unit Top Removal Outdoor Coil Side 15 Indoor Blower and Motor 15 Outdoor Coil Indoor Coil and Condensate Drain Pan 16 Outdoor Fan 16 Electrical Controls and Wiring 16 Refrigerant Circuit 17 Indoor Airflow 17 Metering Devices 17 Lubrication 17 Liquid Line Strainer 17 High Flow Valves 17 TROUBLESHOOTING 17 START UP CHECKLIS...

Page 2: ...n beyond the unit casing on the 2 sides The duct connection side and condensate drain connection sides should be flush with the edge of the flat surface A 6 in wide gravel apron should be used around the flat surface to prevent airflow blockage by grass or shrubs Do not secure the unit to the flat surface except where required by local codes The unit should be level to within 1 4 inch This is nece...

Page 3: ...Fig 2 Unit Base Dimensions 50ZHA024 060 A05201 3 ...

Page 4: ...in power to unit and install lockout tag Turn off accessory heater power switch if applicable Units are dedicated side supply products They are not convertible to vertical air supply A field supplied plenum must be used to convert to vertical air discharge Step 6 Provide for Condensate Disposal NOTE Be sure that condensate water disposal methods comply with local codes restrictions and practices U...

Page 5: ...er company for correction of improper voltage HIGH VOLTAGE CONNECTIONS The unit must have a separate electrical service with a field supplied waterproof disconnect switch mounted at or within sight from the unit Refer to the unit rating plate for maximum fuse circuit breaker size and minimum circuit amps ampacity for wire sizing See Table 6 for electrical data The field supplied disconnect may be ...

Page 6: ...hen checking or servicing refrigerant system 2 Do not operate compressor or provide any electric power to unit unless compressor terminal cover is in place and secured 3 Do not remove compressor terminal cover until all electri cal sources are disconnected and lockout tag is installed 4 Relieve all pressure from both high and low pressure sides of the system before touching or disturbing anything ...

Page 7: ...d Line Temperature REQUIRED LIQUID LINE TEMPERATURE FOR A SPECIFIC SUBCOOLING R 22 Pressure psig Required Subcooling F Pressure kPa Required Subcooling C 5 10 15 20 3 6 8 11 134 71 66 61 56 924 24 22 19 16 141 74 69 64 59 972 26 23 21 18 156 80 75 70 65 1075 30 27 24 21 163 83 78 73 68 1124 31 28 26 23 170 86 81 76 71 1172 33 30 27 24 177 89 84 79 74 1220 34 31 29 26 184 91 86 81 76 1268 36 33 30 ...

Page 8: ...ressor outdoor fan and indoor blower motors start and that reversing valve shifts Observe that cooling cycle shuts down when control setting is satisfied Reversing valve RV remains energized 3 Place system switch in HEAT position Observe that compres sor indoor fan and outdoor fan energize Reversing Valve is deenergized in heat pump heating mode Set control above room temperature Observe that heat...

Page 9: ...ubcooling 8 Add charge if the measured temperature is higher than the liquid line temperature value in the table 9 Add charge using the service connection on the suction line of the compressor HEATING MODE CHARGE Do not attempt to adjust charge by cooling methods while in heat pump heating mode Recover refrigerant and weigh in according to unit data plate refrigerant data Step 4 Indoor Airflow and...

Page 10: ...Fig 11A Typical Unit Electrical Diagram Sizes 024 042 A05199 10 ...

Page 11: ...A05200 Fig 11B Typical Unit Electrical Diagram Sizes 048 060 11 ...

Page 12: ...7 54 3 57 8 76 9 83 8 99 4 109 9 122 0 135 9 63 2 69 2 40 40 60 70 80 90 100 110 110 150 70 80 048 208 230 1 60 187 253 24 7 116 0 1 5 7 7 3 8 5 0 7 5 10 0 11 3 15 0 15 0 20 0 5 4 7 2 18 1 20 8 36 1 41 7 54 2 62 5 72 2 83 3 26 0 30 0 40 0 40 0 62 6 66 1 85 1 92 1 107 7 118 1 130 3 144 2 72 5 77 5 50 50 80 80 100 100 110 125 125 125 90 90 060 208 230 1 60 187 253 28 0 118 0 3 0 7 7 3 8 5 0 7 5 10 0...

Page 13: ...gized NOTE Some units are equipped with a time delay relay On these units the indoor fan remains on for 30 seconds after G or Y is deenergized Table 7 Dry Coil Air Delivery Horizontal Discharge Deduct 10 percent for 208 Volt Operation 50ZHA SPEED TAP WATTS C F M EXTERNAL STATIC PRESSURE 0 1 0 2 03 0 4 0 5 0 6 0 7 0 8 0 9 1 0 024 1 Watts 99 100 118 130 142 C F M 848 793 757 698 632 2 Watts 222 233 ...

Page 14: ... compressor and switching the indoor fan into high stage The auxiliary or backup heat is controlled by a third stage W2 If the demand is not met W3 is energized in case of staged heating When heating demand is satisfied W3 W2 and Y2 sequentially de energize switching the compressor and the indoor fan into low stage heating When the low stage heating demand is met Y1 de energizes shutting the compr...

Page 15: ...tdoor Coil Side NOTE When performing maintenance or service procedures that require removal of the unit top be sure to perform all of the routine maintenance procedures that require top removal including coil inspection and cleaning and condensate drain pan inspection and cleaning ELECTRICAL SHOCK HAZARD Failure to follow this warning could result in personal injury or death Disconnect and tag ele...

Page 16: ...r similar probe device Ensure that the auxiliary drain port above the drain tube is also clear Step 5 Outdoor Fan UNIT OPERATIONAL HAZARD Failure to follow this caution may result in damage to unit components Keep the Outdoor fan free from all obstructions to ensure proper cooling operation Never place articles on top of the unit 1 Shut off unit power supply and install lockout tag 2 Remove outdoo...

Page 17: ...is clean When necessary refer to Indoor Airflow and Airflow Adjustments section to check the system airflow Step 9 Metering Devices Refrigerant cooling metering device is an Accurator 024 042 or TXV 048 and 060 located upstream of the indoor coil distributor assembly Refrigerant heating mode metering device is an Accu rater located upstrem of the outdoor coil distributor assembly Step 10 Lubricati...

Page 18: ...erant then flows through the 4 way valve accumulator and back to the compressor Fig 15 Typical Heat Pump Operation Cooling Mode C95044 STRAINER ACCUMULATOR COMPRESSOR STRAINER LCS OUTDOOR COIL INDOOR COIL A B D C Check Valves A Closed B Open C Closed D Open LEGEND LCS Loss of Charge Switch Acutrol Metering Device Check Valve Arrow indicates direction of flow COOLING CYCLE 1 Hot gas from compressor...

Page 19: ...tes continuously Dirty air filter Replace filter Unit undersized for load Decrease load or increase unit size Thermostat set too low Reset thermostat Low refrigerant charge Locate leak repair and recharge Leaking valves in compressor Replace compressor Frosted outdoor coil with incorrect defrost operation heating Check defrost time settings Reset as necessary Check defrost temperature switch Repla...

Page 20: ...r Temperature __________ DB ____________WB Return Air Temperature __________ DB __________ WB Cooling Supply Air __________DB___________WB PRESSURES Cooling Mode Refrigerant Suction __________ psig Suction Line Temp ___________ Refrigerant Discharge __________ psig Discharge Temp __________ TEMPERATURE Heating Mode Outdoor Air Temperature __________ DB ____________WB Return Air Temperature _______...

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