Technical Guide: PG3 Ultra-Low NOx Series - 208 V/230 V - 1 Phase

Model Number Nomenclature

The model number indicates various specifications of the unit. Below is a breakdown of the nomenclature:

Model Number Nomenclature Example:

The PG3E24U05S21A model is a packaged air conditioner with gas heat. It has a 13.4 SEER2 efficiency rating and uses R-454B refrigerant. It has a nominal capacity of 24,000 Btu/h or 2 ton for cooling. It produces <14ng/J Low NOx emissions and has a gas heating input of 50,000 Btu/h. It uses a standard control strategy and voltage of 208 V/230 V, single phase, 60 Hz. It is a first generation, style A model.

Unit Components

The following diagrams illustrate the components of the PG3 ULN units:

Figure 1: Unit Components - PG3E24 and PG3E36 ULN units with rotary compressor

This diagram shows an isometric view of the unit with internal components labeled. Key components include: Fan motor, Outdoor fan, Coil guard panel, Outdoor coil (behind panel), Gas heat exchanger, Dual run capacitor, Transformer, High-voltage contactor, Burner assembly, Transducer, Gas valve, Removable base rails, Draft inducer blower, Blower motor, TXV, Indoor coil, Compressor, Indoor blower, ULN control board, and Thermostat connections (without refrigerant detection system).

Figure 2: Unit Components - PG3E48 and PG3E60 ULN units with scroll compressor and RDS

This diagram is similar to Figure 1 but represents units with a scroll compressor and RDS (Refrigerant Detection System). Components labeled include: Fan motor, Outdoor fan, Coil guard panel, Outdoor coil (behind panel), Gas heat exchanger, Dual run capacitor, Transformer, High-voltage contactor, Burner assembly, Transducer, Gas valve, Removable base rails, Draft inducer blower, Blower motor, TXV, Indoor coil, Compressor, Indoor blower, ULN control board, Thermostat connections, and A2L mitigation control board.

Unit Limitations

The following tables detail unit limitations:

Table 3: Unit Limitations

Table 4: Application Limitations

Accessories

Various accessories are available to enhance the functionality and installation of the units:

• Anchor bracket kit (S1-1HK0601): Anchors units to pads or structures; approved for ground/roof mounting and wind load certified.
• Flue exhaust extension kit (S1-1FE0422): Diverts flue gas away from walkways or intakes.
• Economizer for downflow applications (S1-2EE04720024, S1-2EE04720124): Modulating integrated economizer with independent blade design, hood, mesh bird screen filter, dry bulb sensor, and barometric relief damper.
• Economizer for horizontal applications (S1-2EE04720224, S1-2EE04720324): Similar to downflow economizer but for horizontal applications.
• Barometric relief hood (S1-1RD1201): Used with horizontal economizers to equalize building pressure.
• Single or dual enthalpy sensor (S1-HE-69630NS-2D): Replaces standard dry bulb sensor to sense enthalpy for improved economizer operation.
• Duct or unit mount CO₂ kit (S1-2AQ04700924): Detects CO₂ levels and overrides economizer when levels rise.
• Wall mount CO₂ kit (S1-2AQ04701024): Similar to duct/unit mount CO₂ kit.
• Supply air temperature sensor kit (S1-TE-63616E-2D): Used with economizers.
• Air filter frame kit (S1-1FF0602, S1-1FF0601): For field installation of 1 in. or 2 in. air filters.
• Air filter (S1-02647812000): Permanent 1 in. air filter.
• Motorized fresh air damper (S1-2MD04706224, S1-2MD04706124): Provides 0% to 50% outdoor air, closes on power loss.
• Rectangle to round (horizontal) adapter (S1-1AK0110, S1-1AK0111): Adapts horizontal duct openings to round.
• Rectangle to round (downflow) adapter (S1-1AK0108, S1-1AK0109): Adapts downflow duct openings to round.
• Roof curbs (S1-1RC0503, S1-1RC0501): 8 in. high NRCA approved curbs for rooftop installations.
• Roof curbs (S1-1RC0504, S1-1RC0502): 14 in. high NRCA approved curbs for rooftop installations.
• Transition curb kits (S1-1TC01*): Adapter kits for compatibility with existing roof curbs.
• Manual outdoor damper (S1-1FA1202, S1-1FA1201): Provides 0% to 50% outdoor air capability.
• Transformer kit (S1-2EC06700124): Increases transformer capacity to 75 VA for economizer or damper installations.
• Loss of charge switch (S1-2LC00024): Provides safe compressor shutdown if refrigerant is lost.
• Low ambient kit (S1-2LA06701024): Allows cooling operation down to 0°F.
• Base rail hole cover kit (S1-1HC0101): Closes openings in base rails.
• Thermostat: Compatible thermostats available, including the Hx™ Touch Screen Thermostat via Source 1 (www.simplygettingthejobdone.com).
• Wall thermostat: Compatible with standard 24 V electronic thermostats.

Guide Specifications

Units are designed for outdoor installation, compliant with SCAQMD Rule 1111 for NOx reduction. They feature a single-stage gas-fired heating section with a stainless steel tubular gas heat exchanger and spark-to-burner ignition.

Description

Factory-assembled, single-packaged, electric cooling/gas heating units. Rated per DOE and AHRI procedures. CSA listed and classified to CSA/ANSI Z21.47:21/CSA 2.3:21 and UL 60335-2-40 (4th edition)/CAN/CSA-C22.2 No. 60335-2-40:22 standards. Units are factory wired, piped, charged with R-454B, and tested.

Unit Cabinet

Features a single-piece design with drip edges for water integrity. Includes a rigid outdoor coil guard. Indoor blower section is insulated. Cabinet panels are easily removable for servicing. Built on a formed base pan with embossments for strength and sound reduction. Full perimeter base rails facilitate transit and rigging. Filters are field-installed and accessible via a removable door. Vertical discharge and return duct configuration fits standard 24 in. O.C. beams.

• Durable Finish: G90 galvanized steel with powder paint coating; 1,000 hr salt spray tested.
• On-site Flexibility: Compact cabinet design in two footprints for easy placement. Field convertible duct connections.
• Attractive Appearance: Single-piece top cover with top-discharge fan, rounded corners, and water drip edges.
• Convertible Airflow Design: Bottom duct openings can be converted from side to bottom supply/return.
• Utility Connections Made Easy: Easy access for gas and electric connections; requires field-supplied disconnect switch.

Easy Service Access

Individual access panels allow easy access to major components for servicing and troubleshooting.

Top Discharge

Outdoor fan directs warm air upwards and away from the unit, minimizing impact on surroundings.

Outdoor Coil Grille

Stamped slotted design offers superior impact protection.

Indoor Blower Assembly

Direct drive design with forward-curved blades, dynamically balanced. Features sealed, permanently lubricated bearings. Slide-out design for easy removal and cleaning. Equipped with a standard high-efficiency brushless DC motor (ECM).

Outdoor Fan Assembly

Direct driven propeller type, discharges air vertically. Aluminum blades riveted to a corrosion-resistant steel spider bracket, statically balanced. Motor is totally enclosed with permanently lubricated bearings and overload protection.

Refrigerant Components

• Protected Compressor: Fully hermetic, direct drive, internally protected against high pressure and temperature. Suction gas cooled with ±10% voltage tolerance. Features internal isolation and sound muffling.
• Indoor Coil: Direct expansion, draw-through design with aluminum plate fins bonded to seamless internally enhanced aluminum tubes.
• Condensate Pan: Corrosion-resistant, watertight pan below the indoor coil. Conforms to ASHRAE 62-19.
• Condensate Drain: 3/4 in. NPT female connection, rigidly mounted.
• Outdoor Coils: Aluminum louvered fins bonded to seamless internally enhanced aluminum microchannel tubes.
• Refrigerant Circuit Components: Thermal expansion valve (TXV) and filter drier/strainer.

Gas Heating Section

Constructed of corrosion-resistant materials with induced draft combustion, post-purge logic, and a redundant main gas valve. The gas heat exchanger is a tubular type made of stainless steel. The premix burner is designed for minimum NOx emissions and quiet operation. All gas piping enters the unit at a single location. An integrated control board manages blower and burner ignition. Minimum protection includes primary high-temperature limit switch, induced draft pressure switch, blocked burner inlet pressure switch, and flame proving controls. All models meet SCAQMD Rule 1111 for emissions of less than 14ng/J.

Physical Data

The following table provides physical data for the various models:

Table 5: Physical Data

Note: Field-supplied external filters should not exceed 300 fpm air velocity. An air filter frame kit is available for internal filters. Filter size A is 20 in. x 20 in.; Filter size B is 20 in. x 30 in.

Cooling Performance Data

The following tables provide cooling performance data for different models under various conditions:

Table 6: Cooling Performance Data for PG3E24U05S2 unit - 2 ton

Table 7: Cooling Performance Data for PG3E36U05S2 unit - 3 ton

Table 8: Cooling Performance Data for PG3E48U06S2 unit - 4 ton

Table 9: Cooling Performance Data for PG3E60U06S2 unit - 5 ton

Table 10: Sound Performance Data

Note: Sound ratings are in accordance with AHRI Standard 270.

Unit Dimensions and Access Locations

Figure 3: Unit Dimensions and Access Locations

This diagram shows an isometric view of the unit, illustrating external dimensions and access points. Key labels include: Unit top panel, Corner post, Outdoor coil guard, Indoor coil (behind panel), Combustion air intake, High voltage opening (7/8 in.), High voltage opening (1 3/32 in.), Heat exchanger access panel, Compressor access panel, Flue exhaust hood, Condensate drain, Blower access panel, Control/heat access panel, Low voltage opening (7/8 in.), and Gas supply hole (1 5/8 in. with grommet opening of 7/8 in.).

Table 11: Unit Dimensions

Weights and Dimensions

Figure 4: Center of Gravity

This diagram illustrates the unit from above, indicating the front of the unit, the compressor location, and the center of gravity with X and Y dimensions.

Table 12: Weights and Dimensions

Unit Clearances

Table 13: Unit Clearances

Notes:
- Maintain 1 in. clearance between combustible material and supply air ductwork.
- Ensure products of combustion do not accumulate in confined spaces.
- Install units outdoors, ensuring overhanging structures do not obstruct the outdoor air discharge.
- Units can be installed on combustible materials (wood, Class A, B, or C roof covering) if factory base rails remain installed.

Electrical Data

Table 14: Electrical Data for 208/230-1-60

Notes:
- 208/230-1-60 indicates 208 V/230 V, single phase, 60 Hz.
- MCA: Minimum Circuit Ampacity.
- MOP: Maximum Overcurrent Protection device (HACR breaker or time delay fuse), must comply with UL 60335-2-40 standard.

Indoor Blower Specifications

Table 15: Indoor Blower Specifications

Airflow Performance Data for Side Duct Application

Table 16: Airflow Performance Data for Side Duct Application

Notes:
- Airflow tested with dry coil conditions, without air filters, at 230 V.
- Applications above 0.8 in. W.C. external static pressure are not recommended.
- Brushless DC high-efficiency ECM blower motor used.
- Minimal variations for 208 V operation.
- Heating applications tested at 0.50 in. W.C. external static pressure. Cooling applications tested per AHRI Standard 210/240.
- Side and bottom duct airflow differences are insignificant.

Additional Static Resistance Data

Table 17: Additional Static Resistance Data

Notes:
- Pressure drop through the economizer is greater for 100% outdoor air. If return air duct resistance is less than 0.25 IWG, CFM may be reduced during full economizer operation.
- Filter pressure drop is based on standard filter media tested at velocities not exceeding 300 ft/min.

Bottom Duct Dimensions

Figure 5: Bottom Duct Dimensions (in.)

This diagram shows the bottom view of the unit, detailing duct connections and openings with dimensions.

Table 18: Bottom Duct Dimensions

Rear Duct Dimensions

Figure 6: Rear Duct Dimensions (in.)

This diagram shows the rear view of the unit, detailing duct connections with dimensions.

Table 19: Rear Duct Dimensions

Note: See Figure 3 for side hole sizes of electrical and gas lines.

Typical Applications

The following figures illustrate typical installation scenarios:

Figure 7: Typical Duct Applications for Unit

This diagram shows typical duct applications for units installed via roof curb (rear duct and bottom duct) and on a slab.

Figure 8: Typical Ground Installation on Slab for Unit

This diagram illustrates a typical ground installation on a slab, showing the unit, condensate drain, manual gas shutoff valve, gas supply line, power supply, control wiring to indoor thermostat, return air duct, and supply air duct, along with a field-supplied disconnect switch.

Figure 9: Typical Installation on Roof Curb for Unit

This diagram shows a typical installation on a roof curb, detailing the unit, condensate drain, manual gas shutoff valve, gas supply line, power supply, control wiring to indoor thermostat, roof curb, field-supplied disconnect switch, return air duct, and supply air duct.

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Subject to change without notice. Published in U.S.A. Copyright © 2025 by Johnson Controls. All rights reserved.