Page 1: Table Of Contents
........A99338 Fig. 1 - - Unit 48SD Use of Rigging Bracket .
Page 2: Introduction
INTRODUCTION C99096 Fig. 2 - - Slab Mounting Details The 48SD unit (see Fig. 1) is a fully self- -contained, combination Category I gas heating/electric cooling unit designed for outdoor GROUND MOUNT installation (See Fig. 3 and 4 for unit dimensions). All unit sizes...
Page 3 A07555 Fig. 3 - - 48SD018- -036 Unit Dimensions...
Page 4 A07556 Fig. 4 - - 48SD042- -060 Unit Dimensions...
Page 5 HVAC unit HVAC unit base base Gask eting inner flange* Scre w Gask eting Scre w (NO TE A) (NO TE A) inner flange* *Gask eting *Gask eting outer flange outer flange Wood nailer* Wood nailer* Flashing field Flashing field supplied supplied Roof curb*...
Page 6: Provide Clearances
Step 4—Provide Clearances WARNING The required minimum operating and service clearances are shown in Fig. 3 and 4. Adequate combustion, ventilation and condenser air PROPERTY DAMAGE HAZARD must be provided in accordance with section 5.3, Air for Combustion and Ventilation, of the National Fuel Gas Code ANSI Failure to follow this warning could result in personal (American National Standards Institute) Z223.1 or applicable injury/death or property damage.
Page 7 Table 1—Physical Data - - Unit 48SD UNIT SIZE 48SD 018040 024040 024060 030040 030060 036060 036090 042060 042090 NOMINAL CAPACITY (ton) 2- -1/2 2- -1/2 3- -1/2 3- -1/2 OPERATING WEIGHT (lb) (kg) COMPRESSORS Scroll Scroll REFRIGERANT (R- - 22)
Page 8: Connect Condensate Drain
Shipping Shipping Weight Weight Fig. 6 - - 48SD Unit Corner Weights and Suggested Rigging Step 6—Connect Condensate Drain These models meet the California maximum oxides of nitrogen (NOx) emissions requirements of 40 nanograms/joule or less as NOTE: When installing condensate drain connection be sure to shipped from the factory.
Page 9: Install Gas Piping
Step 8—Install Gas Piping The gas supply pipe enters the unit through the access hole provided. The gas connection to the unit is made to the 1/2- -in. FPT gas inlet on the gas valve. Install a gas supply line that runs to the heating section. Refer to Table 2 and the NFGC for gas pipe sizing.
Page 10 Table 2—Maximum Gas Flow Capacity* NOMINAL INTERNAL LENGTH OF PIPE (FT)† IRON PIPE DIAMETER SIZE (IN.) (IN.) .622 — — .824 1.049 1- - 1/4 1.380 1400 1- - 1/2 1.610 2100 1460 1180 *Capacity of pipe in cu ft of gas per hr for gas pressure of 0.5 psig or less. Pressure drop of 0.5- -in. wc (based on a 0.60 specific gravity gas). Refer to Table, National Fire Protec- tion Association NFPA 54.
Page 11: Install Electrical Connections
Step 10—Install Electrical Connections 3. Locate the black and yellow wires connected to the line side of the contactor. WARNING 4. Connect field L1 to black wire connected to 11 terminal of the compressor contactor. ELECTRICAL SHOCK HAZARD 5. Connect field wire L2 to yellow wire connected to 23 terminal of the compressor contactor.
Page 12: Heat Anticipator Setting
Run the low- -voltage leads from the thermostat, through the inlet b. Inspect for oil at all refrigerant tubing connections and on hole, and into unit low- -voltage splice box (see Fig. 13). unit base. Detecting oil generally indicates a refrigerant leak.
Page 13: Start- -Up Heating & Make Adjustments
NOTE: Install a filter drier whenever the system has been opened CHECK HEATING CONTROL for repair. Start and check the unit for proper heating control operation as follows (see furnace lighting instructions located inside burner or 3. Add a small charge of R- -22 refrigerant vapor to system and blower access panel): leak- -test unit.
Page 14: Check Burner Flame
Table 3—Heating Inputs GAS SUPPLY PRESSURE (IN. WC) HEATING INPUT NUMBER OF NUMBER OF MANIFOLD PRESSURE (IN WC) MANIFOLD PRESSURE (IN. WC) Natural{ Propane*{ (BTUH) ORIFICES ORIFICES Natural{ Propane*† 40,000 13.0 13.0 60,000 13.0 13.0 90,000 13.0 13.0 115,000 13.0 13.0 130,000 13.0...
Page 15 A07439 Fig. 15 - - 208/230- -1- -60 Wiring Diagram...
Page 16 A07569 Fig. 16 - - 208/230- -3- -60 Wiring Diagram...
Page 17 A07570 Fig. 17 - - 460- -3- -60 Wiring Diagram...
Page 18: Limit Switches
LIMIT SWITCHES temperature) and operates in Cooling mode when temperature control is set to call for cooling (below room Normally closed limit switch (LS) completes the control circuit. temperature). Should the leaving- -air temperature rise above the maximum IMPORTANT: Three- -phase, scroll compressors are direction allowable temperature, the limit switch opens and the control circuit “breaks.”...
Page 19: Indoor Airflow And Airflow Adjustments
2. Using hoses with valve core depressors, attach low- - and blower motor. high- -pressure gauge hoses to low- - and high- -pressure All 48SD units are factor wired for low speed except the 030 service fittings, respectively. through the 048 size.
Page 20 Table 6—Cooling Charging Chart - - 018 only Required Subcooling Required Liquid Line Temperature for a Specific Subcooling (R --- 22) Model Outdoor Ambient Temperature Required Subcooling ( Required Subcooling ( Size Pressure Pressure 75 (24) 85 (29) 95 (35) 105 (41) 115 (46) (psig)
Page 21 Speed Watts --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Heating Rise 48SD(--- ,N)018040 30 --- 60 Watts --- --- --- --- --- --- High 1064 --- --- --- --- --- ---...
Page 22 “NA” = Not allowed for heating speed Note: Deduct field- -supplied air filter pressure drop and wet coil pressure drop to obtain external static pressure available for ducting. Table 9—48SD Wet Coil Pressure Drop (in. wc) STANDARD CFM (S.C.F.M.) UNIT...
Page 23: Maintenance
MAINTENANCE AIR FILTER To ensure continuing high performance and to minimize the IMPORTANT: Never operate the unit without a suitable air filter possibility of premature equipment failure, periodic maintenance in the return- -air duct system. Always replace the filter with the same must be performed on this equipment.
Page 24: Induced Draft (Combustion Air) Blower
1. Remove the induced- -draft blower assembly according to OUTDOOR COIL, INDOOR COIL, AND CONDENSATE directions below. DRAIN PAN 2. Remove the flue collector box cover (See Fig. 18) from the Inspect the condenser coil, evaporator coil, and condensate drain heat exchanger assembly.
Page 25: Outdoor Fan
ELECTRICAL CONTROLS AND WIRING Inspect and check the electrical controls and wiring annually. Be BLOWER sure to turn off the electrical power to the unit. HOUSING Remove access panel to locate all the electrical controls and wiring. Check all electrical connections for tightness. Tighten all screw connections.
Page 26 Table 10—Troubleshooting Chart SYMPTOM CAUSE REMEDY Power failure Call power company Fuse blown or circuit breaker tripped Replace fuse or reset circuit breaker Defective contactor, transformer, or high--pressure, Replace component loss--of--charge or low--pressure switch Compressor and condenser fan will not start. Insufficient line voltage Determine cause and correct Incorrect or faulty wiring...
Page 27 Table 11—Troubleshooting Guide–Heating SYMPTOM CAUSE REMEDY Water in gas line Drain. Install drip leg. No power to furnace Check power supply fuses, wiring or circuit breaker. Check transformer. No 20--v power supply to control circuit NOTE: Some transformers have internal over--current protection that requires a cool--down period to reset.
Page 28 Catalog No: 48SD---7SI Printed in U.S.A. Edition Date: 07/07 Copyright 2007 Carrier Corp. S 7310 W. Morris St. S Indianapolis, IN 46231 Replaces: 48SD- -6SI Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.

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