Carrier 50TCA04-A07 User Manual

50TCA04---A07 Nominal 3 to 6 Tons Wit h Pu r on® (R410A) Refrigerant

Service and Maintenance Instructions

TABLE OF CONTENTS

SAFETY CONSIDERA TIONS 1....................

UNIT ARRANGEMENT AND ACCESS 2...........

SUPPLY FAN (BLOWER) SECTION 3..............

COOLING 5....................................

PURONR (R--410A) REFRIGERANT 7..............

COOLING CHARGING CHARTS 9.................

CONVENIENCE OUTLETS 13....................

SMOKE DETECTORS 13.........................

DETECTOR CLEANING 18.......................

INDICATORS 19................................

TROUBLESHOOTING 20.........................

PROTECTIVE DEVICES 20.......................

ELECTRIC HEATERS 21.........................

PREMIERLINKT CONTROL 23...................

ECONOMIZER SYSTEMS 32.....................

FASTENER TORQUE VALUES 50.................

WIRING DIAGRAMS 50.........................

APPENDIX I. MODEL NUMBER SIGNIFICANCE 52.

APPENDIX II. PHYSICAL DATA 53................

APPENDIX III. FAN PERFORMANCE 54...........

APPENDIX IV. ELECTRICAL DATA 63.............

APPENDIX V. WIRING DIAGRAM LIST 69.........

APPENDIX VI. MOTORMASTER SENSOR

LOCATIONS 70.................................

UNIT START-UP CHECKLIST 73..................

SAFETY CONSIDERATIONS

Installation and servicing of air-conditioning equipment can be hazardous due to system pressure and electrical components. Only trained and qualified service personnel should install, repair, or service air-conditioning equipment. Untra ined personnel can perform the basic maintenance functions of replacing filters. Trained service personnel should perform all other operations.

When working on air-conditioning equipment, observe precautions in the literature, tags and labels attached to the unit, and other safety precautions that may apply. Follow all safety codes. Wear safety glasses and work gloves. Use quenching cloth for unbrazing operations. Have fire extinguishers available for all brazing operations.

Follow all safety codes. Wear safety glasses and work gloves. Use quenching cloth for brazing operations. Have fire extinguisher available. Read these instructions thoroughly and follow all warnings or cautions attached to the unit. Consult local building codes and National Electrical Code (NEC) for special requirements.

Recognize safety information. This is the safety--alert symbol

instructions or manuals, be alert to the potential for personal injury.

Understand the signal words DANGER, WARNING, and CAUTION. These words are used with the safety--alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies a hazard which could result in personal injury or death. CAUTION is used to identify unsafe practices which may result in minor personal injury or product and property damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation.

. When you see this symbol on the unit and in

WARNING

ELECTRICAL OPERATION HAZARD

Failure to follow this warning could result in personal injury or death.

Before performing service or maintenance operations on unit, turn off main power switch to unit. Electrical shock and rota ting equipment could cause injury.

WARNING

ELECTRICAL OPERATION HAZARD

Failure to follow this warning could result in personal injury or death.

Units with convenience outlet circuits may use multiple disconnects. Check convenience outlet for power status before opening unit for service. Locate its disconnect switch, if appropriate, and open it. Tag--out this switch, if necessary.

WARNING

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this warning could cause personal injury, death and/or equipment damage.

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Puron (R--410A) refrigerant systems operate at higher pressures than standard R--22 systems. Do not use R--22 service equipment or components on Puron refrigerant equipment.

UNIT ARRANGEMENT AND ACCESS

General

Fig. 1 and 2 show general unit arrangement and access locations.

FILTER ACCESS PANEL

Routine Maintenance

These items should be part of a routine maintenance program, t o be checked every month or two, until a specific schedule for each can be identified for this installation:

Quarterly Inspection (and 30 days after initi al

start)

S Return air filter replacement

S Outdoor hood inlet filters cleaned

S Belt tension checked

S Belt condition checked

S Pulley alignment checked

S Fan shaft bearing locking collar tightness checked

S Condenser coil cleanliness checked

S Condensate drain checked

Seasonal Maintenance

These items should be checked at the beginning of each season (or more often if local conditions and usage patterns dictate):

Conditioning

Air

S Condenser fan motor mounting bolts tightness

S Compressor mounting bolts

S Condenser fan blade positioning

S Control box cleanliness and wiring condition

S Wire terminal tightness

S Refrigerant charge level

COMPRESSOR ACCESS PANEL

OUTDOOR-AIR OPENING AND INDOOR COIL ACCESS PANEL

Fig. 1 -- Typical Access Panel Locations

BLOWER ACCESS PANEL

Fig. 2 -- Blower Access Panel Location

C06023

C07081

S Evaporator coil cleaning

S Evaporator blower motor a mperage

Heating

S Power wire connections

S Fuses ready

S Manual--reset limit switch is closed

Economizer or Outside Air

Damper

S Inlet filters condition

S Check damper travel (economizer)

S Check gear and dampers for debris and dirt

Air Filters and Scr

eens

Each unit is equipped with return air filters. If the unit has an economizer, it will also have an outside air screen. If a manual outside air damper is added, an inlet air screen will also be present.

Each of these filters and screens will need to be periodically replaced or cleaned.

Return Air

Filters

Return air filters are disposable fiberglass media type. Access to the filters is through the small lift--out panel

located on the rear side of the unit, above the

evaporator/return air access panel. (See Fig. 1.)

To remove the filters:

1. Grasp the bottom flange of t he upper panel.

2. Lift up and swing the bottom out until the panel disengages and pulls out.

3. Reach inside and extract the filters from the filter rack.

4. Replace these filters as required with similar replacement filters of same size.

To re--install the access panel:

1. Slide the top of the panel up under the unit top panel.

2. Slide the bottom into the side channels.

3. Push the bottom flange down until it contacts the top of the lower panel (or economizer top).

IMPORTANT: DO NOT OPERATE THE UNIT WITHOUT THESE FILTERS!

Outside Air

Hood

Outside air hood inlet screens are permanent aluminum-- mesh type filters. Check these for cleanliness. Remove the screens when cleaning is required. Clean by washing with hot low--pressure water and soft detergent and replace all screens before restarting the unit. Observe the flow direction arrows on the side of each filter frame.

C07156

Fig. 4 -- Screens Installed on Outdoor--Air Hood

(Sizes 7--1/2 to 12--1/2 Tons Shown)

To remove the screen, loosen the screws in the top retainer and slip the retainer up until the filter can be removed. Re--install by placing the frame in its track, rotating the retainer back down and tighten all screws.

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Economizer Inlet Air Screen

This air screen is retained by spring c lips under the top edge of the hood. (See Fig. 3.)

17 1/4”

DIVIDER

OUTSIDE AIR

HOOD

CLEANABLE

BAROMETRIC RELIEF

ALUMINUM FILTER

FILTER

FILTE CLIP

C06027

Fig. 3 -- Filter Installation

To remove the filter, open the spring clips. Re--install the filter by placing the frame in its track, then closing the spring clips.

Manual Outside Air Hood Screen

This inlet screen is secured by a retainer angle across the top edge of the hood. (See Fig. 4.)

C07087

Fig. 5 -- Belt Drive Motor Mounting

SUPPLY F AN (BLOWER) SECTION

WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could cause personal injury or death.

Before performing service or maintenance operations on the fan system, shut off all unit power and tag--out the unit disconnect switch. Do not reach into the fan section with power still applied to unit.

Supply Fan (Belt--Drive)

The supply fan system consists of a forward--curved centrifugal blower wheel on a solid shaft with two concentric type bearings, one on each side of the blower housing. A fixed--pitch driven pulley is attached to the fan shaft and an adjustable--pitch driver pulley is on the motor. The pulleys are connected using a “V” type belt. (See Fig. 5.)

Belt

Check the belt condition and tension quarterly. Inspect the belt for signs of cracking, fraying or glazing along the

inside surfaces. Check belt tension by using a spring--force tool (such as Browning’s Part Number “Belt Tension Checker” or equivalent tool); tension should be 6--lbs at a 5/8--in. deflection when measured at the centerline of the belt span. This point is at the center of the belt when measuring the dista nce between the motor shaft and the blower shaft.

NOTE: Without the spring--tension tool, place a straight edge across the belt surface at the pulleys, then de f lect the belt at m id--span using one finger to a 1/2--in. deflection.

Adjust belt tension by loosening the motor mounting plate front bolts and rear bolt and sliding the plate toward the fan (to reduce tension) or away from fan (to increase tension). Ensure the blower shaft and the motor shaft are parallel to each other (pulleys aligned). Tighten all bolts when finished.

To replace the belt:

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1. Use a belt with same section type or similar size. Do not substitute a “FHP” type belt. When installing the new belt, do not use a tool (screwdriver or pry--bar) to force the belt over the pulley flanges, this will stress the belt and cause a reduction in belt life.

2. Loose n the motor mounting plate front bolts and rear bolts.

3. Push the motor and its mounting plate towards the blower housing as close as possible to reduce the center distance between fan shaft and motor shaft.

4. Re move the belt by gently lifting the old belt over one of the pulleys.

5. Install the new belt by gently sliding the belt over both pulleys and then sliding the motor and plate away from the fa n housing until prope r tension is achieved.

6. Check the alignment of the pulleys, adjust if necessary.

7. Tighte n all bolts.

8. Check the t ension after a few hours of runtime and re--adjust as required.

Adjustable--Pitch Pulley on

Motor

The motor pulley is an adjustable--pitch type that allows a servicer to implement changes in the fan wheel speed to match as--installed ductwork systems. The pulley consists of a fixed flange side that faces the motor (secured to the motor shaft) and a movable flange side that can be rotated around the fixed flange side that increases or reduces the pitch diameter of this driver pulley. (See Fig. 6.)

To change fan speed:

1. Shut off unit power supply.

2. Loose n belt by loosening fan motor mounting nuts. (See Fig. 5.)

3. Loose n movable pulley flange setscrew. (See Fig. 6.)

4. Screw movable flange toward fixed flange to increase speed and away from fixed flange to decrease speed. Increasing fan speed increases load on motor. Do not exceed maximum speed specified.

5. Set movable flange at nearest keyway of pulley hub and tighten setscrew to torque specifications.

To align fan and motor pulleys:

1. Loosen fan pulley setscrews.

2. Slide fan pulley along fan shaft. Make angular alignment by loosening motor from mounting.

3. Tighten fan pulley setscrews and motor mounting bolts to torque specifications.

4. Re check belt tension.

C07075

Fig. 6 -- Supply--Fan Pulley Adjustment

Bearings

This fan system uses bearings featuring concentric split locking collars. The collars are tightened through a cap screw bridging the split portion of the collar. The cap screw has a Torx T25 socket head. To tighten the locking collar: Hold the locking collar tightly against the inner race of the bearing and torque the cap screw to 65--70 in--lb (7.4--7.9 Nm). See Fig. 7.

As the pitch diameter is changed by adjusting the position of the movable flange, the centerline on this pulley shifts laterally (along the motor shaft). This creates a requirement for a realignment of the pulleys a fter any adjustment of the movable flange. Also reset the belt tension after each realignment.

Check the condition of the motor pulley for signs of wear. Glazing of the belt contact surfaces and erosion on these surfaces are signs of improper belt tension and/or belt slippage. Pulley replacement may be necessary.

C08121

Fig. 7 -- Tightening Locking Collar

Motor

When replacing the motor, also replace the external--tooth lock washer (star washer) under the motor mounting base; this is part of the motor grounding system. Ensure the teeth on the lock washer are in contact with the motor ’s painted base. Tighten motor mounting bolts to 120 +/ -- 12 in--lbs.

Changing fan wheel speed by changing pulleys: The horsepower rating of the belt is primarily dic tated by the pitch diameter of the smaller pulley in the drive system (typically the motor pulley in these units). Do not install a replacement motor pulley with a smaller pitch diameter than provided on the original factory pulley. Change fan wheel speed by changing the fan pulley (larger pitch diameter to reduce wheel speed, smaller pitch diameter to increase wheel speed) or select a new system (both pulleys and matching belt(s)).

Before changing pulleys to increase fan wheel speed, check the fan performance at the target speed and airflow rate to dete rmine new motor loading (bhp). Use the fan performance tables or use the Packaged Rooftop Builder software program. Confirm that the motor in this unit is capable of operating a t the new operating condition. Fan shaft loading increases dramatically as wheel speed is increased.

To reduce vibration, replace the motor’s adjustable pitch pulley with a fixed pitch pulley (after the final airflow balance adjustment). This will reduce the amount of vibration generated by the motor/belt--drive system.

COOLING

WARNING

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this warning could cause personal injury, death and/or equipment damage.

This system uses PuronR refrigerant which has higher pressures than R--22 and other refrigerants. No other refrigerant may be used in this system. Gauge set, hoses, and recovery system m ust be designed to handle Puron refrigerant. If unsure about equipment, consult the equipment manufacturer.

Condenser Coil

The condenser coil is fabricated with round tube copper hairpins and plate fins of various materials and/or coatings (see Model Number Format in the Appendix to identify the materials provided in this unit). The coil may be one--row or composite--type two--row. Composite two--row coils are two single--row coils fabricated with a single return bend end tubesheet.

Condenser Coil Maintenance and Cleaning Recommendation

Routine cleaning of coil surfaces is essential to maintain proper operation of the unit. Elimination of contamination and removal of harmful residues will greatly increase the

life of the coil and extend the life of the unit. The following maintenance and cleaning procedures are recommended as part of the routine maintenance activities to extend the life of the coil.

Remove Surface Loaded

Surface loaded fibers or dirt should be removed with a vacuum cleaner. If a vacuum cleaner is not available, a soft non--metallic bristle brush may be used. In either case, the tool should be applie d in the direction of the fins. Coil surfaces can be easily damaged (fin edges can be easily bent over and damage to the coating of a protected coil) if the tool is applied across the fins.

NOTE: Use of a water stream, such as a garden hose, against a surface loaded coil will drive the fibers and dirt into the coil. This will make cleaning efforts more difficult. Surface loaded fibers must be completely removed prior to using low velocity clean water rinse.

Periodic Clean Water

A periodic clean water rinse is very beneficial for coils that are applied in coastal or industrial environments. However, it is very important that the water rinse is made with a very low velocity water stream to avoid damaging the fin edges. Monthly cleaning as described below is recommended.

Routine Cleaning of Coil

Periodic cleaning with TotalineR environmentally sound coil cleaner is essential to extend the life of coils. This cleaner is available from Carrier Replacement Components Division as part number P902--0301 for a one gallon container, and part number P902--0305 for a 5 gallon container. It is recommended that all coils, including standard a luminum, pre--coated, copper/copper or E--coated coils be cleaned with the Totaline environmentally sound coil cleaner as describe d below. Coil cleaning should be part of the unit’s regularly scheduled maintenance procedures to ensure long life of the coil. Failure to clean the coils may result in reduced durability in the environment.

Avoid use of:

S coil brighteners

S acid cleaning prior to painting

S hi gh pressure washers

S poor quality water for cleaning

Totaline environmenta lly sound coil cleane r is nonflammable, hypo allergenic, non bacteri al, and a USDA accepted biodegradable agent that will not harm the coil or surrounding components such as electrical wiring, painted metal surfaces, or insulation. Use of non--recomm ended coil cleaners is strongly discouraged since coil and unit durability could be affected.

One--Row Coil

Wash coil with commercial coil cleaner. It is not necessary to remove top panel.

Fibers

Rinse

Surfaces

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Two--Row Coils

Clean coil as follows:

1. Turn off unit power, tag disconnect.

2. Re move top panel screws on condenser end of unit.

3. Re move condenser coil corner post. See Fig. 8. To hold top panel open, place coil corner post between top panel and center post. See Fig. 9.

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Fig. 8 -- Cleaning Condenser Coil

C08205

6. Use a water hose or other suitable equipment to flush down between the 2 coil sections to remove dirt and debris. Clean the outer surfaces with a stiff brush in the normal manner.

7. Secure inner and outer coil rows together with a field--supplied fastener.

8. Reposition the outer coil section and remove the coil corner post from between the top panel and center post. Reinstall the coil corner post and replace all screws.

Totaline Environmentally Sound Coil Cleaner Application Equipment

S 2--1/2 gallon garden sprayer

S Water rinse with low velocity spray nozzle

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in accelerated corrosion of unit parts.

Harsh chemicals, household bleach or acid or basic cleaners should not be used to clean outdoor or indoor coils of any kind. These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion at the fin/tube interface where dissimilar materials are in contact. If there is dirt below the surface of the coil, use the Totaline e nvironmentally sound coil cleaner.

C08206

Fig. 9 -- Propping Up T op Panel

4. Remove screws securing coil to compressor plate and compressor access panel.

5. Re move fastener holding coil sections together at return end of condenser coil. Carefully separate the outer coil section 3 to 4 in. from the inner coil section. See Fig. 10.

C08207

Fig. 10 -- Separating Coil Sections

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in reduced unit performance or unit shutdown.

High velocity water from a pressure washer, garden hose, or compressed air should never be used to clean a coil. The force of the water or air jet will bend the fin edges and increase airside pressure drop.

Totaline Environmentally Sound Coil Cleaner Application Instructions

1. Proper eye protection such as safety glasses is recommended during mixing and application.

2. Remove all surface loaded fibers and dirt with a vacuum cleaner as described above.

3. Thoroughly wet finned surfaces with clean water and a low velocity garden hose, being careful not t o bend fins.

4. Mix Totaline environmentally sound coil cleaner in a 2--1/2 gallon garden sprayer according to the instructions included with the cleaner. The optimum solution temperature is 100_F.

NOTE: Do NOT USE water in excess of 130_F, a s t he enzymatic activity will be destroyed.

5. Thoroughly apply Totaline environmentally sound coil cleaner solution to all coil surfaces including finned area, tube sheets and coil headers.

6. Hold garden sprayer nozzle close to finned areas and apply cleaner with a vertical, up--and--down mot ion. Avoid spraying in horizontal pattern to minimize potential for fin damage.

7. Ensure cleaner thoroughly penetrates deep into finned areas.

8. Interior and exterior finned areas must be thoroughly cleaned.

9. Finned surfaces should remain wet with cleaning solution for 10 minutes.

10. Ensure surfaces are not allowed to dry before rinsing. Reapplying cleaner as needed to ensure 10--minute saturation is achieved.

11. Thoroughly rinse all surfaces with low velocity clean water using downward rinsing motion of water spray nozzle. Protect fins from damage from the spray nozzle.

Evaporator Coil

Cleaning the Evaporator Coil

1. Turn unit power off. Install lockout tag. Remove evaporator coil access panel.

2. If economizer or two--position damper is installed, remove economizer by disconnecting Molex plug and removing mounting screws.

3. Slide filters out of unit.

4. Clean coil using a commercial coil cleaner or dishwasher detergent in a pressurized spray canister. Wash both sides of coil and flush with clean water. For best results, back--flush toward return--air section to remove foreign material. Flush condensate pan after completion.

5. Reinstall economizer and filters.

6. Re connect wiring.

7. Replace access panels.

Evaporator Coil M etering

The metering devices are multiple fixed--bore devices (Acutrolt) wedged into the horizontal outlet tubes from the liquid header, located at the entrance to each evaporator coil circuit path. These are non--adjustable. Service requires replacing the entire liquid header assembly.

To check for possible blockage of one or more of these metering devices, disconnect the supply fan contactor (IFC) coil, then start the compressor and observe the frosting pattern on the face of the evaporator coil. A frost pattern should develop uniformly across the face of the coil starting at each horizontal header tube. Failure to develop frost at an outle t tube can indicate a plugged or a missing orifice.

Devices

Refrigerant System Pressure Access Ports

There are two access ports in the system -- on the suction tube near the compressor and on the discharge tube near the compressor. These are brass fittings with black plastic caps. The hose connection fittings are standard 1/4 SAE Male Flare couplings.

The brass fittings are two--piece High Flow valves, with a receptacle base brazed to the tubing and an integral spring--closed check valve core screwed into the base. (See Fig. 11.) This check valve is permanently assembled into this core body and cannot be serviced separately; replace the entire core body if necessary. Service tools are available from RCD that allow the replacement of the check valve core without having to re cover the entire system refrigerant charge. Apply compressor refrigera nt oil to the check valve core’s bottom o--ring. Install the fitting body with 96 +/ --10 in -- lbs of t orque; do not overtighten.

PURONR (R--410A) REFRIGERANT

This unit is designed for use with Puron (R--410A) refrigerant. Do not use any other refrigerant in this system.

Puron (R--410A) is provided in pink (rose) colored cylinders. These cylinders are available with and without dip tubes; cylinders wit h dip tubes will have a label indicating this feature. For a cylinder with a dip tube, place the cylinder in the upright position (access valve at the top) when removing liquid refrigerant for charging. For a cylinder without a dip tube, invert the cylinder (access valve on the bottom) when removing liquid refrigerant.

Because Puron (R--410A) is a blend, it is strongly recommended t hat refrigerant always be removed from the cylinder as a liquid. Admit liquid refrigerant into the system in the discharge line. If adding refrigerant into the suction line, use a commercial metering/expansion device at the gauge manifold; remove liquid from the cylinder, pass it t hrough the metering device at the gauge set and then pass it into the suction line as a vapor. Do not remove Puron (R--410A) from the cylinder as a vapor.

Refrigerant Charge

Amount of refrigerant charge is listed on the unit’s nameplate. Refer to Carrier GTAC2--5 Charging, Recovery, Recycling and Reclamation training manual and the following procedures.

Unit panels must be in place when unit is operating during the charging procedure.

Charge

Use standard evacuating techniques. After evacuating system, weigh in the specified amount of refrigerant.

Low--Charge

Using Cooling Charging Charts, Fig. 12, vary refrigerant until the conditions of the appropriate chart are met. Note the charging charts are different from type normally used. Charts are based on charging the units to the correct superheat for t he various operating conditions. Accurate pressure gauge and temperature sensing device are required. Connect the pressure gauge to the service port on the suction line. Mount t he temperature sensing de vice on the suction line and insulate it so that outdoor ambient temperature does not affect the reading. Indoor--ai r cfm must be within the normal operating range of the unit.

Cooling

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To Use Cooling Charging Charts

Take the outdoor ambient temperature and read the suction pressure gauge. Refer to chart to determine what suction temperature should be. If suction temperature is high, add refrigerant. If suction temperature is low, carefully recover some of the charge. Recheck the suction pressure as charge is adjusted.

1/2-20 UNF RH

EXAMPLE:

Model 50TC*A06

Outdoor Temperature 85_F(29_C)..................

Suction Pressure 130 psig (896 kPa).................

Suction Temperature should be 63_F (17.2_C).........

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5/8” HEX

.47

SEAT

0.596

WASHER

O-RING

This surface provides a metal to metal seal when torqued into the seat. Appropriate handling is required to not scratch or dent the surface.

Fig. 11 -- CoreMax Access Port Assembly

1/2" HEX

CORE

DEPRESSOR PER ARI 720 +.01/-.035 FROM FACE OF BODY

7/16-20 UNF RH

C07150

COOLING CHARGING CHARTS

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C08203

Fig. 12 -- Cooling Charging Charts

C08204

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COOLING CHARGING CHARTS (cont)

C08228

Fig. 12 -- Cooling Charging Charts (cont.)

C08229

Compressor

Lubrication

The compressor is charged with t he correct amount of oil at the factory.

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in damage to components.

The compressor is in a PuronR refrigerant system and uses a polyolester (POE) oil. This oil is extremely hygroscopic, meaning it absorbs water readily. POE oils can absorb 15 times as much water as other oils designed for HCFC and CFC refri gerants. Avoid exposure of the oil to the atmosphere.

Replacing Compressor

The compressor used with Puron refrigerant c ontains a POE oil. This oil has a high affinity for moisture. Do not remove the compressor’s tube plugs until ready to insert the unit suction and discharge tube ends.

Compressor mounting bolt torque is 65--75 ft--lbs.

The suction and discharge pressure levels should now move to their normal start--up levels.

NOTE: When the compressor is rotating in the wrong direction, the unit makes an elevated level of noise and does not provide cooling.

Filter Drier

Replace whenever refrigerant system is exposed to atmosphere. Only use factory specified liquid--line filter driers with working pressures no less than 650 psig. Do not install a suction--line filter drier in liquid line. A liquid--line filter drier designed for use with Puron refrigerant is re quired on every unit.

Condenser--Fan Location

See Fig. 13.

1. Shut off unit power supply. Install lockout tag.

2. Remove condenser--fan assembly (grille, motor, and fan).

3. Loosen fan hub setscrews.

4. Adjust fan height as shown in Fig. 13.

5. Tighten setscrews.

6. Re place condenser--fan assembly.

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Compressor

On 3--phase units with scroll compressors, it is important to be certain compressor is rotating in the proper direction. To dete rmine whether or not compressor is rotating in t he proper direction:

1. Conne ct service gauges to suction and discharge pressure fittings.

2. Energize the compressor.

3. The suction pressure should drop and the discharge pressure should rise, as is normal on any start--up.

NOTE: If t he suction pressure does not drop and the discharge pressure does not rise to normal levels:

4. Note that the evaporator fan is probably also rotating in the wrong direction.

5. Turn off power to the unit.

6. Re verse any two of the unit power leads.

7. Re apply power to the compressor.

Rotation

C07091

Fig. 13 -- Condenser Fan Adjustment

(except with Motormaster)

Troubleshooting Cooling System

Refer to Table 1 for additional troubleshooting topics.

Table 1 – Cooling Service Analysis

PROBLEM CAUSE REMEDY

Power failure. Call power company. Fuse blown or circuit breaker tripped. Replace fuse or reset circuit breaker.

Compressor and Condenser Fan Will Not Start.

Compressor Will Not Start But Condenser Fan Runs.

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Compressor Cycles (other than normally satisfying thermostat).

Compressor Operates Continuously.

Excessive Head Pressure.

Head Pressure Too Low.

Excessive Suction Pressure.

Suction Pressure Too Low.

Evaporator Fan Will Not Shut Off.

Compressor Makes Excessive Noise.

Defective thermostat, contactor, transformer, or control relay.

Insufficient line voltage. Determine cause and correct. Incorrect or faulty wiring. Check wiring diagram and rewire correctly. Thermostat setting too high. Lower thermostat setting below room temperature. Faulty wiring or loose connections in compres-

sor circuit.

Compressor motor burned out, seized, or internal overload open.

Defective run/start capacitor, overload, start relay.

Onelegofthree---phasepowerdead.

Refrigerant overcharge or undercharge.

Defective compressor. Replace and determine cause. Insufficient line voltage. Determine cause and correct. Blocked condenser. Determine cause and correct. Defective run/start capacitor, overload, or start

relay.

Defective thermostat. Replace thermostat. Faulty condenser--- fan motor or capacitor. Replace. Restriction in refrigerant system. Locate restriction and remove. 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. Air in system. Recover refrigerant, evacuate system, and recharge. Condenser coil dirty or restricted. Clean coil or remove restriction. Dirty air filter. Replace filter. Dirty condenser coil. Clean coil. Refrigerant overcharged. Recover excess refrigerant. Air in system. Recover refrigerant, evacuate system, and recharge. Condenser air restricted or air short --- cycling. Determine cause and correct. Low refrigerant charge. Check for leaks; repair and recharge. Compressor valves leaking. Replace compressor. Restrictioninliquidtube. Remove restriction. High head load. Check for source and eliminate. Compressor valves leaking. Replace compressor. Refrigerant overcharged. Recover excess refrigerant. Dirty air filter. Replace filter. Low refrigerant charge. Check for leaks; repair and recharge. Metering device or low side restricted. Remove source of restriction.

Insufficient evaporator airflow.

Temperature too low in conditioned area. Reset thermostat. Outdoor ambient below 25˚F. Install low---ambient kit.

Time off delay not finished. W a i t f o r 3 0 --- s e con d o f f delay.

Compressor rotating in wrong direction. Reversethe3---phasepowerleads.

Replace component.

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.

Determine cause and replace.

Increase air quantity. Check filter and replace if necessary.

CONVENIENCE OUTLETS

WARNING

ELECTRICAL OPERATION HAZARD

Failure to follow this warning could result in personal injury or death.

Two types of convenience outlets are offered on 50TC models: Non--powered and unit--powered. Both types provide a 125--volt GFCI (ground--fault circuit--interrupter) duplex receptacle rated at 15--A behind a hinged waterproof access cover, located on the end panel of the unit. See Fig. 14.

Pwd-CO Transformer

Conv Outlet GFCI

or HACR switch is open. Other connection methods will result in the convenience outlet circuit being de--energized when the unit disconnect or HACR switch is open. See Fig. 15.

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CO8283

Fig. 15 -- Powered Convenience Outlet Wiring

Pwd-CO Fuse Switch

C08128

Fig. 14 -- Convenience Outlet Location

Non--powered type: This type requires the field

installation of a general--purpose 125--volt 15--A circuit powered from a source elsewhere in the building. Observe national and loca l codes when selecting wire size, fuse or breaker requirements and disconnect switch size and location. Route 125--v power supply conductors into the bottom of the utility box containing the duplex receptacle.

Unit--powered type: A unit--mounted transformer is factory--i nstalled to stepdown the main power supply voltage to the unit to 115--v at the duplex receptacle. This option also includes a manual switch with fuse, located in a utility box and m ounted on a bracket behind the convenience outlet; access is through the unit’s control box access panel. See Fig. 14.

The primary leads to the convenience outlet transformer are not factory--connected. Selection of primary power source is a customer--option. If local codes permit, the transformer primary leads can be connected at the line--side terminals on a unit--mounted non--fused disconnect or HACR breaker switch; this will provide service power to the unit when the unit disconnect switch

Duty Cycle: The unit--powered convenience outlet has a duty cycle limitation. The transformer is intended to provide power on an intermittent basis for service tools, lamps, etc; it is not intended to provide 15 --amps loading for continuous duty loads (such as electric heaters for overnight use). Observe a 50% limit on circuit loading above 8--amps (i.e., limit loads exceeding 8--amps to 30 minutes of operation every hour).

Maintenance: Periodically test the GFCI receptacle by pressing the TEST button on the face of the receptacle. This should cause the internal circuit of the receptacle to trip and open the receptacle. Check for proper grounding wires and power line phasing if the GFCI receptacle does not trip as re quired. Press the RESET button to clear the tripped condition.

Fuse on powered type: The factory fuse is a Bussman “Fusetron” T--15, non-- renewable screw--in (Edison base) type plug fuse.

Using unit--mounted convenience outlets: Units with unit--mounted convenience outlet circuits will often require that two disconnects be opened to de--energize all power to the unit. Treat all units as electrically energized until the convenience outlet power is also checked and de--energization is confirmed. Observe National Electrical Code Article 210, Branch Circuits, for use of c onvenience outlets.

SMOKE DETECTORS

Smoke detectors are available as factory--installed opt ions on 50TC models. Smoke detectors may be specified for Supply Air only or for Return Air without or with economizer or in combination of Supply Air and Return Air. Return Air smoke detectors are arranged for vertical return configurations only. All components necessary for

operation are factory--provided and mounted. The unit is factory-- configured for immediate smoke detector shutdown operation; additional wiring or modifications t o unit terminal board may be necessary to complete the unit and smoke detector configuration to meet project requirements.

System

The smoke detector system consists of a four--wire controller and one or two sensors. Its primary function is to shut down the rooftop unit in order to prevent smoke from circulating throughout the building. It is not to be used as a life saving device.

Controller

The controller (see Fig. 16) includes a controller housing, a printed circuit board, and a clear plastic cover. The controller can be connected to one or two compatible duct

50TC

smoke sensors. The clear plastic cover is secured to the housing with a single captive screw for easy access to the wiring terminals. The controller has three LEDs (for Power, Trouble and Alarm) and a manual test/reset button (on the cover face).

inspections without having to disassemble the sensor. The cover attaches to the sensor housing using four captive screws and forms an airtight chamber around the sensing electronics. Each sensor includes a harness with an RJ45 terminal for connecting to the controller. Each sensor has four LEDs (for Power, Trouble, Alarm and Dirty) and a manual test/reset button (on the left--side of the housing).

Duct smoke sensor

Exhaust tube

See

Detail A

Intake

gasket

Plug

TSD-CO2

(ordering option)

Sampling tube

(ordered separately)

Exhaust gasket

Sensor housing and electronics

Cover gasket

(ordering option)

Sensor cover

Duct smoke sensor

controller

Conduit nuts

(supplie d by installer)

Conduit s upport plate

Controll er housing

and electronics

Conduit c ouplings

(supplie d by installer)

Alarm

Fastener

(2X)

Terminal block cover

Troub le

Power

Tes t / r e s e t switch

Cover gasket

(ordering option)

Controll er cover

C08208

Fig. 16 -- Controller Assembly

Sensor

The sensor (see Fig. 17) includes a plastic housing, a printed circuit board, a clear plastic cover, a sampling tube inlet and an exhaust tube. The sampling tube (when used) and exhaust tube are attached during installation. The sampling tube varies in length depending on the size of the rooftop unit. The clear plastic cover permits visual

Magnetic test/reset

switch

Coupling

Alarm

Troub le

Power Dirty

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Detail A

Fig. 17 -- Smoke Detector Sensor

Air is introduced to the duct smoke detector sensor’s sensing chamber through a sampling tube that extends into the HVAC duct and is directed back into the ventilation system through a (shorter) exhaust tube. The difference in air pressure between the two tubes pulls the sampled air through the sensing chamber. When a sufficient amount of smoke is detected in the sensing chamber, the sensor signals an alarm state and the controller automatically takes the appropriate action to shut down fans and blowers, change over air handling systems, noti fy the fire alarm control panel, etc.

The sensor uses a process called differential sensing to prevent gradual environmental changes from triggering false alarms. A rapid change in environmental c onditions, such as smoke from a fire, causes the sensor to signal an alarm state but dust and debris accumulated over time does not.

For installations using two sensors, the duct smoke detector does not differentiate which sensor signals an alarm or trouble condition.

Smoke Detector Locations

Supply Air — The Supply Air smoke detector sensor is located to the left of the unit’s indoor (supply) fan. See Fig. 18. Access i s through the fan access panel. There is no sampling tube used at this location. The sampling tube inlet exte nds through the side plate of the fan housing (into a high pressure area). The controller is located on a bracket to the right of the return filter, accessed through the lift--off filter panel.

Smoke Detector Sensor

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Fig. 18 -- Typical Supply Air Smoke Detector Sensor

Location

Return Air without Economize r — The sampling tube is located across the return air opening on the unit basepan. See Fig. 19. The holes in the sampling tube fa ce downward, into the return air stream. The sampling tube is connected via tubing to the return a ir sensor that is mounted on a bracket high on the partition between return filter and controller location. (This sensor is shipped in a flat--mounting location. Installation requires that this sensor be relocated to its operating location and the tubing to the sampling tube be connected. See installation steps below.)

Return Air Detector module (shipping position shown)*

Return Air with Economizer — The sampling tube is inserted through the side plates of the economizer housing, placing it across the return air opening on the unit basepan. See Fig. 20. The holes in the sampling tube face downward, into the return air stream. The sampling tube is connected via tubing to the return air sensor that is mounted on a bracket high on the partition between return filter and controller location. (This sensor is shipped in a flat--mounting location. Installation requires that this sensor be relocated to its operating location and the tubing to the sampling tube be connected. See installation steps below.)

50TC

Return Air Sampling Tube

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Fig. 20 -- Return Air Sampling Tube Location

Completing Installation of Return Air Smoke Sensor:

Screws

Flexible Exhaust Tubes

Controller module

Return Air Detector Sampling Tube

*RA detector must be moved from shipping position to operating position by installer

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Fig. 19 -- Typical Return Air Detector Location

Sample Tube

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Fig. 21 -- Return Air Detector Shipping Position

1. Unscrew the two screws holding the Return Air Sensor detector plate. See Fig 21. Save the screws.

2. Re move the Return Air Sensor and its detector plate.

3. Rotate the detector plate so the sensor is facing outwards and the sampling tube connection is on the bottom. See Fig 22.

4. Screw the sensor and det ector plate into its operating position using screws from Step 1. Make sure the sampling tube connection is on the bottom and the exhaust tube is on the top. See Fig 22.

5. Conne ct the flexible tube on the sam pling inlet t o the sampling tube on the basepan.

6. For units with an economizer, the sampling tube is integrated into the economizer housing but the connection of the flexible tubing to the sampling tube is the same.

50TC

Fig. 22 -- Return Air Sensor Operating Position

FIOP Smoke Detector Wiring and Response

All units: FIOP smoke detector is configured to automatically shut down all unit operations when smoke condition is detected. See Fig. 23, Smoke Detector Wiring.

Highlight A: JMP 3 is fac tory--cut, transferring unit control to smoke detector.

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Highlight B: Smoke detector NC contact set will open on smoke al arm condition, de--energizing the ORN conductor.

Highlight C: 24--v power signal via ORN lead is removed at Smoke Detector input on LCTB; all unit operations cease immediately.

PremierLink Control: Unit operating functions (fan, cooling and heating) are terminated as described above. In addition:

Highlight D: On smoke alarm condition, the smoke detector NO Alarm contact will close, supplying 24--v power to GRA conductor.

Highlight E: GRA lead at Smoke Alarm input on LCTB provides 24--v signal. This signal is conveyed to PremierLink FIOP’s TB1 at terminal TB1--6 (BLU lead). This signal initiates the FSD sequence by the PremierLink control.

Using Remote Logic: Five conductors are provided for field use (see Highlight F) for additional annunciation functions.

Additional Application Data — Refer to Catalog No. HKRNKA--1XA for discussions on additional control features of these smoke detectors including multiple unit coordination. See Fig. 23.

Fig. 23 -- Typical Smoke Detector System Wiring

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Sensor and Controller Tests

Sensor Alarm Test

The sensor alarm test checks a sensor’s ability to signal an alarm state. This test requires that you use a field provided SD-- MAG test magnet.

CAUTION

OPERATIONAL TEST HAZARD

Failure to follow t his caution may result in personnel and authority concern.

This test places the duct detector into the alarm state. Unless part of the test, disconnect all auxiliary equipment from the controller before performing the test. If the duct detector is connected to a fire alarm system, notify the proper authorities before performing the test.

Sensor Alarm Test Procedure

1. Hold the test magnet where indicated on the side of the sensor housing for seven seconds.

2. Verify that the sensor’s Alarm LED turns on.

3. Re set the sensor by holding the test magnet against the sensor housing for two seconds.

4. Verify that the sensor’s Alarm LED turns off.

CAUTION

OPERATIONAL TEST HAZARD

Failure to follow t his caution may result in personnel and authority concern.

Pressing the controller’s test/re set switch for longer than seven seconds will put the duct detector into the alarm state and activate all automatic alarm responses.

Dirty Controller Test Procedure

1. Press the controller’s test/reset switch for two seconds.

2. Verify that the controller’s Trouble LED flashes.

Dirty Sensor Test

The dirty sensor test provides an indication of the sensor’s ability to compensate for gradual environmental changes. A sensor that can no longer compensate for environmental changes is considered 100% dirty and requires cleaning or replacing. You must use a field provided SD--MAG test magnet to initiate a sensor dirty test. The sensor’s Dirty LED indicates the results of the dirty test as shown in Table 2.

CAUTION

50TC

Controller Alarm Test

The controller alarm test checks the controller ’s ability to initiate and indicate an alarm state.

CAUTION

OPERATIONAL TEST HAZARD

Failure to follow t his caution may result in personnel and authority concern.

This test places the duct detector into the alarm state. Disconnect all auxiliary equipment from the controller before performing the test. If the duct detector is connected to a fire alarm system, notify the proper authorities before performing the test.

Controller Alarm Test Procedure

1. Press the controller’s test/reset switch for seven seconds.

2. Verify that the controller’s Alarm LED turns on.

3. Re set the sensor by pressing the test/reset switch for two seconds.

4. Verify that the controller’s Alarm LED turns off.

Dirty Controller Test

The dirty controller test checks the controller ’s ability to initiate a dirty sensor test and indicate its results.

OPERATIONAL TEST HAZARD

Failure to follow t his caution may result in personnel and authority concern.

Holding the test magnet agai nst the sensor housing for more than seven seconds will put the duct detector into the alarm state and activate all automatic alarm responses.

Tabl e 2 – Di r ty L ED Te st

FLASHES DESCRIPTION

1 0---25% dirty. (Typical of a newly installed detector)

2 25---50% dirty

3 51---75% dirty

4 76---99% dirty

Dirty Sensor Test Procedure

1. Hold the test magnet where indicated on the side of the sensor housing for two seconds.

2. Verify that the sensor’s Dirty LED flashes.

CAUTION

OPERATIONAL TEST HAZARD

Failure to follow t his caution may result in personnel and authority concern.

Changing the dirty sensor test operation will put the detector into the alarm state and activate all automatic alarm responses. Before changing dirty sensor test operation, disconnect all auxiliary equipment from the controller and notify the proper authorities if connected to a fire alarm system.

Changing the Dirt Sensor Test

By default, sensor dirty test results are indicated by:

S The sensor’s Dirty LED flashing. S The controller’s Trouble LED flashing. S The controller’s supervision re lay contacts toggle.

The operation of a sensor’s dirty test can be changed so that the controller ’s supervision relay is not used to indicate test results. When two detectors a re connected to a controller, sensor dirty test operation on both sensors must be configured to operate in the same manner.

To Configure the Dirty Sensor Test

Operation

1. Hold the test magnet where indicated on the side of the sensor housing until the sensor’s Alarm LED turns on and its Dirty LED flashes twice (approximat ely 60 seconds).

2. Re set t he sensor by removing the test magnet then

50TC

holding it against the sensor housing again until the sensor’s Alarm LED turns off (approximately 2 seconds).

Remote Station Test

The remote station a larm test checks a test/reset station’s ability to initiate and indicate an alarm state.

upe

contacts [3]

ire must be

added by installer

ision relay

TB3

Smoke Detector Controller

−

18 Vdc ( )

−

Auxiliary

equipment

SD-TRK4

Trouble

ower

Alarm

Reset/Test

Fig. 24 -- Remote Test/Reset Station Connections

CAUTION

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CAUTION

OPERATIONAL TEST HAZARD

Failure to follow t his caution may result in personnel and authority concern.

SD--TRK4 Remote Alarm Test Procedure

1. Turn the key switch to the RESET/TEST position for seven seconds.

2. Verify that the test/reset station’s Alarm LED turns on.

3. Re set the sensor by turning the key switch to the RESET/TEST position for two seconds.

4. Verify that the test/reset station’s Alarm LED turns off.

Remote Test/Reset Station Dirty Sensor Test

The test/reset station dirty sensor test checks the test/reset station’s ability to initiate a sensor dirty test and indicate the results. It must be wired to the controller as shown in Fig. 24 and configured to operate the controller’s supervision relay. For more information, see “Changing sensor dirty test operation.”

OPERATIONAL TEST HAZARD

Failure to follow t his caution may result in personnel and authority concern.

If the test/reset station’s key switch is left in the RESET/TEST position for l onger than seven seconds, the detector will automatically go into the alarm state and activate all automatic alarm responses.

CAUTION

OPERATIONAL TEST HAZARD

Failure to follow t his caution may result in personnel and authority concern.

Holding the test magnet to the target area for longer than seven seconds will put the detector into the alarm state and activate all automatic alarm responses.

Dirty Sensor Test Using an SD--TRK4

1. Turn the key switch to the RESET/TEST position for two seconds.

2. Verify that t he test/rese t station’s Trouble LED flashes.

DETECTOR CLEANING

Cleaning the Smoke Detector

Clean the duct smoke sensor when the Dirty LED is flashing continuously or sooner i f conditions warrant.

Table 3 – Detector Indicators

CONTROL OR INDICATOR DESCRIPTION

Magnetic test/reset switch Resets the sensor when it is in the alarm or trouble state. Activates or tests the sensor when it is in

Alarm LED Indicates the sensor is in the alarm state.

Troubl e LED Indicates the sensor is in the trouble state.

Dirty LED Indicates the amount of environmental compensation used by the sensor

Power LED Indicates the sensor is energized.

the normal state.

(flashing continuously = 100%)

CAUTION

OPERATIONAL TEST HAZARD

Failure to follow t his caution may result in personnel and authority concern.

If the smoke detector is connected to a fire alarm system, first notify the proper authorities that the detector is undergoing maintenance then disable the relevant circuit to avoid generating a false alarm.

1. Disconnect power from the duct detector then remove the sensor’s cover. (See Fig. 25.)

2. Using a vacuum cleaner, clean compressed air, or a soft bristle brush, remove loose dirt and debris from inside the sensor housing and cover. Use isopropyl alcohol and a l int--free cloth to remove dirt and other contaminants from the gasket on the sensor’s cover.

3. Squeeze the retainer clips on both sides of the optic housing then lift the housing away from the printed circuit board.

4. Gently remove dirt and debris from around the optic plate and inside the optic housing.

5. Re place the optic housing and sensor cover.

6. Conne ct power to the duct detector then perform a sensor alarm test.

Sampling

tube

Airow

HVAC duct

Sensor housing

Optic plate

Retainer clip

Optic housing

C07305

Fig. 25 -- Sensor Cleaning Diagram

INDICATORS

Normal State

The smoke detector operates in the norm al state in the absence of any trouble conditions and when its sensing chamber is free of smoke. In the normal state, the Power LED on both the sensor and the controll er are on and all other LEDs are off.

Alarm State

The smoke detector enters the alarm state when the amount of smoke particulat e in the sensor’s sensing chamber exceeds the alarm threshold value. (See Table 3.) Upon entering the alarm state:

S The sensor’s Alarm LED and the controller’s Alarm LED

turn on.

S The contacts on the controller ’s two auxiliary relays

switch positions.

S The contacts on the controller’s alarm initiation relay

close.

S The controller’s remote alarm LED output is activated

(turned on).

S The controller ’s high impedance multiple fan shutdown

control line is pulled to ground Trouble state.

The SuperDuct duct smoke detector enters the trouble state under the following conditions:

S A sensor’s cover is removed and 20 minut es pass before

it is properly secured.

S A sensor’s environmental compensation limit is reached

(100% dirty).

S A wiring fault between a sensor and the controller is

detected.

An internal sensor fault is detected upon entering the trouble state:

S The contacts on the controller’s supervisory relay switch

positions. (See Fig. 26.)

S If a sensor trouble, the sensor ’s Trouble LED the

controller’s Trouble LED turn on.

S If 100% dirty, the sensor’s Dirty LE D turns on a nd the

controller’s Trouble LED flashes continuously.

50TC

S If a wiring fault between a sensor and the controller, the

controller’s Trouble LED turns on but not the sensor’s.

Alarm

Fig. 26 -- Controller Assembly

NOTE: All troubles are latched by the duct smoke

detector. The trouble condition must be cleared and then the duct smoke detector must be reset in order to restore it

50TC

to the normal state.

Resetting Alarm and Trouble Condition Trips:

Manual reset is required to restore smoke detector systems to Normal operation. For installations using two sensors, the duct smoke detector does not differentiate which sensor signals an alarm or trouble condition. Check each sensor for Alarm or Trouble status (indicated by LED). Clear the condition that has generated the trip at this sensor. Then reset the sensor by pressing and holdi ng the reset button (on the side) for 2 seconds. Verify that the sensor’s Alarm and Trouble LEDs are now off. At the controller, clear its Alarm or Trouble state by pressing and holding the manual reset button (on the front cover) for 2 seconds. Verify that the controller’s Alarm and Trouble LEDs are now off. Replace all panels.

Tro uble

Power

Test/reset switch

C07298

2. Check the wiring between the sensor and the controller. If wiring is loose or missing, repair or replace as required.

Controller’s Power LED is Off

1. Make sure the circuit supplying power to the controller is operational. If not, make sure JP2 and JP3 are set correctly on the controller before applying power.

2. Verify that power is applied to the controller’s supply input terminals. If power is not present, replace or repair wiring as required.

Remote Test/Reset Station’s Trouble LED Does Not flash When Performing a Dirty Test, But the Controller’s Trouble LED Does

1. Verify that the remote test/station is wired as shown in Fig. 23. Repair or replace loose or missing wiring.

2. Configure the sensor dirty te st to activate the controller’s supervision relay. See “Changing sensor dirty test operation.”

Sensor’s Trouble LED is On, But the Controller’s Trouble LED is OFF

Remove JP1 on the controller.

PROTECTIVE DEVICES

Compressor Protection

Overcurrent

The compressor has internal linebreak motor protection.

Overtemperatur

The compressor has an internal protector to protect it against excessively high discharge gas temperatures.

TROUBLESHOOTING

Controller’s Trouble LED is On

1. Check the Trouble LED on each sensor connected to the controller. If a sensor’s Trouble LED is on, determine the cause and make the necessary repairs.

2. Check the wiring between the sensor and the controller. If wiring is loose or missing, repair or replace as required.

Controller’s Trouble LED is Flashing

1. One or both of the sensors is 100% dirty.

2. Determine which Dirty LED is flashing then clean that sensor assembly as described in the detector cleaning section.

Sensor’s Trouble LED is On

1. Check the sensor’s Dirty LED. If it is flashing, the sensor is dirty and must be cleaned.

2. Che ck the sensor’s cover. If it is loose or missing, secure the cover to the sensor housing.

3. Re place sensor assembly.

Sensor’s Power LED is Off

1. Che ck the controller’s Power LED. If it is off, determine why the controller does not ha ve power and make the necessary repairs.

High Pressure

Switch

The system is provided with a high pressure switch mounted on the discharge line. The switch is stem--mounted and brazed into the discharge tube. Trip setting is 630 psig +/-- 10 psig (4344 +/-- 69 kPa) when hot. Reset is automatic at 505 psig (3482 kPa).

Low Pressure

Switch

The system is protected against a loss of charge and low evaporator coil loading condition by a low pressure switch located on the suction line near the compressor. The switch is stem--mounted. Trip setting is 54 psig +/-- 5 psig (372 +/-- 34 kPa). Reset is automatic at 117 +/-- 5 psig (807 +/-- 34 kPa).

Evaporator Freeze Pr

otection

The system is protected against evaporator coil frosting and low temperature conditions by a temperature switch mounted on the evaporator coil hairpin. Trip setting is 30_F+/--5_F(--1_C+/--3_C). Reset is automatic at 45_F (7_C).

Supply (Indoor) Fan Motor Protection

Disconnect and lockout power when servicing fan motor.

The standard supply fan motor is equipped with internal overcurrent and overtem perature protection. Protection devices reset automatically.

The High Static option supply fan motor is equipped with a pilot--circuit Thermix combination overtemperature/overcurrent protection device. This device resets automatically. Do not bypass this switch to correct trouble. Determine the cause and correct it.

Condenser Fan Motor Protection

The condenser fan motor is internally protected against overtemperature.

Relief Device

A soft solder joint at the suction service access port provides pressure relief under abnormal temperature and pressure conditions (i.e., fire in building). Protect this joint during brazing operations near this joint.

Control Circuit, 24--V

DISCONNECT MOUNTING LOCATION

MAIN CONTROL BOX

BRACKET AND CONDUIT DRIP BOOT

EMT OR RIGID CONDUIT (FIELD-SUPPLIED)

SINGLE POINT BOX MOUNTING SCREW

CONTROL WIRE TERMINAL BLOCK

SINGLE POINT BOX

HEATER MODULE (LOCATION 1)

CENTER POST

HEATER MODULE (LOCATION 2)

MANUAL RESET LIMIT SWITCH

Fig. 28 -- Typical Component Location

HEATER COVERS

HEATER MOUNTING BRACKET

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The control circuit is protected against overcurrent conditions by a circuit breaker mounted on control transformer TRAN. Reset is manual.

ELECTRIC HEATERS

50TC units may be equipped with field--installed accessory electric heaters. The heaters a re modular in design, with heater frames holding open coil resistance wires strung through ceramic insulators, line--break limit switches and a control contactor. One or two heater modules may be used in a unit.

Heater modules are installed in the compartment below the i ndoor (supply) fan outlet. Access is through the indoor access panel. Heater modules slide into the compartment on tracks along the bottom of the heater opening. See Figs 27 -- 29.

DISCONNECT MOUNTING LOCATION

UNIT BLOCK-OFF PAN EL

OUTDOOR ACCESS PANEL

Fig. 27 -- Typical Access Panel Location (3--6 Ton)

INDOOR ACCESS PAN EL

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50TC

TRACK

FLANGE

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Fig. 29 -- Typical Module Installation

Not all available heater modules may be used in every unit. Use only those heater modules that are UL listed for use in a specific size unit. Refer to the label on the unit cabinet re approved heaters.

Unit heaters are marked with Heater Model Numbers. But heaters are ordered as and shipped in cartons marked with a corresponding heater Sales Package part number. See Table 4 for correlation between heater Model Number and Sales Package part number.

NOTE: The value in position 9 of the part number differs between the sales package part number (value is 1) and a bare heater model number (value is 0).

Bare Heater Model

Number

Heater Sales Package PNO Includes: Bare Heater Carton and packing materials Installation sheet

Table 4 – Heater Model Number

C R H E A T E R 0 0 1 A 0 0

C R H E A T E R 1 0 1 A 0 0

Single Point Boxes and Supplementary Fuses — When the unit MOCP device value exceeds 60--A, unit--mounted supplementary fuses are required for each heater circuit. These fuses are included in accessory Single Point Boxes, with power distribution and fuse blocks. The single point box will be installed directly under the unit control box, just to the left of the partition separating the indoor section (with electric heaters) from the outdoor section. The Single Point Box has a hinged access cover. See Fig

30.

50TC

CONTROL BOX

BUSHING

SINGLE POINT BOX MOUNTING SCREWS

DRIP BOOT BRACKET MOUNTING SCREWS

POWER WIRES

FOAM BUSHING

HEATER RELAYS

HEATER MOUNTING SCREWS

A L LIE

P A

O R

P .

M O

L N

O .

ERI

L N

O .

2 2

. 2

ISTED

AIR

NDITIONING

1 2 3

UIP

ACCESS

346N

/ N

5 6

REV

Fig. 30 -- Typical Single Point Installation

On 50TC units, all fuses are 60--A. Single point boxes containing fuses for 208/230--V applications use UL Cl ass RK5 250--V fuses (Bussman FRNR 60 or Shawmut TR 60R). Single point boxes for 460--V and 575--V applications use UL Class T 600--V fuses (Bussman JJS 60 or Shawmut A6T 60). (Note that all heaters are qualified for use with a 60--A fuse, regardless of actual heater ampacity, so only 60--A fuses are necessary.)

Unit heater applications not requiring supplemental fuses do not require a Single Point Box. Connect power supply conductors to heater conductors and field--supplied base unit power tap leads (see text below re: “Completing Heater Installation”) below the unit’s main control box using UL--approved connectors.

Safety Devices — Electric heater applications use a combination of line--break/auto--reset limit switches and a pilot--circuit/manual reset limit switch to protect the unit against over--temperature situations.

Line--break/auto--reset limit switches are mounted on the base plate of each heater module. See Fig. 31. These a re accessed through the indoor access panel. Remove the switch by removing two screws into the base plate and extracting the existing switch.

Pilot-- c ircuit/manual reset limit switch is located in the side plate of the indoor (supply) fan housing. See Fig. 28.

Completing Heater Installation

Field Power Connections — Field--supplied tap

conductors must be insta lled between the base unit’s field power connection lugs and the splice connection between field power supply conductors and the conductors to the electric heater(s). Refer to unit wiring schematic. Use

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copper wire only. Size these conduct ors based on the MCA (Minimum Circuit Ampacity) value marked on the 50TC unit’s info plate for the base unit less electric heater load. Use UL--approved pressure connectors (field--supplied) for these splice joints.

Line-Break Limit Switches

ALLIED P

MODE

NO.

ERIAL

NO.

ISTED

AIR

NDITIONING

ACCESS

/ N

5610-4

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Fig. 31 -- Typical Location of Heater Limit Switches

(3--phase heater shown)

Low--Voltage Control Connections — Pull the

low--voltage control leads from the heater module(s) -VIO and BRN (two of each if two modules are installed; identify for Module #1) -- to the 4--pole terminal board TB4 located on the heater bulkhead to the left of Heater #1. Connect the VIO lead from Heater #1 to terminal TB4--1. Connect the VIO lead from Heater #2 to terminal TB4--2. Connect both BRN leads to terminal TB4--3. See Fig. 32.

LCTB

CONTL BOARD

Field

VIO

ORN

BRN

ORN

TB4

VIO

Connections

Elec Htr

HR2

HR1

BRN

VIO

HR1: On Heater 1 in Position #1 HR2: On Heater 2 in Position #2 (if installed)

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Fig. 32 -- Accessory Electric Heater Control

Connections

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