York DHUC 048 - User Manual

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GENERAL

Model DUC units are single package air conditioners with gas

heat designed for outdoor installation on a rooftop or a slab.

The units are completely assembled on rigid, permanently

attached base rails. All piping, refrigerant charge, and electrical

wiring is factory-installed and tested. The units require only electric

power, gas piping and duct connections at the point of installation.

The gas-fired heaters have aluminized steel tubular heat

exchangers and spark ignition with intermittent pilot.

This appliance is not to be used for temporary heating of

buildings or structures under construction.

INSPECTION

As soon as a unit is received, it should be inspected for possible

damage during transit. If damage is evident, the extent of the

damage should be noted on the carrier’s freight bill. A separate

request for inspection by the carrier’s agent should be made in

writing.

REFERENCE

Additional information on the design, installation, operation and

service of this equipment is available in the following reference forms:

•

530.18-N1.2V -Economizer Accessory

•

530.18-N1.13V -Man. Outdoor Air Damper Accy 0-35%

•

530.18-N1.14V -Man. Outdoor Air Damper Accy 0-100%

•

530.18-N1.12V -Motorized Outdoor Air Damper Accy.y

•

530.18-N1.8V -Coil Guard

•

530.18-N2.11V -Low NOx Accessory

•

530.18-N8.2V -High Altitude Accy. (Natural Gas)

•

530.18-N8.3V -High Altitude Accy. (Propane)

•

530.18-N8.4V -Gas Piping Accessory

•

530.18-N8.12V -Propane Conversion Accessor

•

690.15-N25V -Low Ambient Accessory

Renewal Parts:

•

Refer to Parts Manual for complete listing of replacement

parts on this equipment.

All forms referenced in this instruction may be ordered from:

Publications Distribution Center

Unitary Products Group

P.O. Box 1592, York, PA 17405

APPROVALS

Design certified by CGA and UL listed as follows:

1. For use as a forced air furnace with cooling unit.

2. For outdoor installation only.

3. For installation directly on combustible flooring or, in the U.S.A.,

on wood flooring or Class A, B, or C roof covering material.

4. For use with natural gas and/or propane (LP) gas.

Not suitable for use with conventional venting systems.

Installer should pay particular attention to the words:

NOTE, CAUTION

and

WARNING

. Notes are intended to clarify or make

the installation easier. Cautions are given to prevent equipment damage. Warnings are given to alert installer that personal injury

and/or equipment damage may result if installation procedure is not handled properly.

CAUTION

THIS PRODUCT MUST BE INSTALLED IN STRICT COMPLIANCE WITH THE ENCLOSED INSTALLATION INSTRUCTIONS

AND ANY APPLICABLE LOCAL, STATE, AND NATIONAL CODES INCLUDING, BUT NOT LIMITED TO, BUILDING, ELECTRI-

CAL, AND MECHANICAL CODES

WARNING

INCORRECT INSTALLATION MAY CREATE A CONDITION WHERE THE OPERATION OF THE PRODUCT COULD CAUSE

PERSONAL INJURY, PROPERTY DAMAGE AND/OR DEATH.

WARNING

DE-ENERGIZE THE ELECTRICAL POWER AND TURN OFF THE GAS SUPPLY TO THE UNIT BEFORE ATTEMPTING TO

INSPECT, REPAIR OR PERFORM MAINTENANCE TO THE UNIT.

CAUTION

SCROLL COMPRESSORS

OPERATE IN ONLY ONE

DIRECTION.

If the compressor is

experiencing:

- low amperage draw

- similar discharge and

suction pressure

- increased noise level

It is operating in reverse.

Switch two line voltage

connections to correct.

FOR YOUR SAFETY

Do not store or use gasoline or

other flammable vapors or liquids

in the vicinity of this or any other

appliance

If you smell gas:

1. Open windows

2. Don’t touch electrical switches.

3. Extinguish any open flame.

4. Immediately call your gas supplier.

035-14839

MODELS DHUC 036, 048 & 060 (10 SEER)

MODEL DBUC 072 (9 EER)

(STYLE A & Belt-Drive Option)

INSTALLATION

INSTRUCTION

GAS / ELECTRIC

SINGLE PACKAGE AIR CONDITIONERS

Supersedes: 530.18-N8W (295)

530.18-N8W (1096)

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Summary

General Unit Information

Inspection Procedures

Check for damage during transit and document any issues with the carrier.

Reference Documents

List of available documentation for design, installation, operation, and service.

Approvals and Certifications

Certification details from recognized safety organizations like UL and CGA.

Installation Guidelines

Installation Limitations

Codes and standards that must be followed during installation.

Location Selection

Guidelines for selecting a suitable outdoor installation site.

Rigging and Handling

Safe procedures for moving and lifting the unit.

Power and Control Wiring

Guidelines for safe and compliant electrical connections.

Operation Sequence

Cooling System Overview

Overview of the air-cooled condenser and refrigerant system.

Cooling Sequence of Operation

Step-by-step process of the unit's cooling cycle.

Safety Controls (Cooling)

Safety devices protecting the refrigerant system during cooling operation.

Heating Sequence of Operation

Describes the operational steps for the gas heating cycle.

Start-Up Procedures

Operating Instructions

Procedures for initial unit operation and testing.

Post-Start Check List (Gas)

Checks to perform after initial heating operation to ensure safety and performance.

Manifold Gas Pressure Adjustment

How to adjust gas pressure for optimal burner performance.

Pilot Checkout

Verifying pilot flame appearance and adjustment for proper ignition.

Maintenance and Troubleshooting

Normal Maintenance Tasks

Routine tasks including filter inspection and burner checks.

Cleaning Flue Passages and Heating Elements

Procedures for cleaning the heat exchanger and associated components.

Troubleshooting Common Issues

Diagnosing and resolving operational issues with the unit.

This document provides installation and operation instructions for Gas/Electric Single Package Air Conditioners, specifically models DHUC 036, 048 & 060 (10 SEER) and DBUC 072 (9 EER), available in Style A with an optional Belt-Drive. These units are designed for outdoor installation on a rooftop or a slab and come completely assembled with factory-installed and tested piping, refrigerant charge, and electrical wiring. They require only external electric power, gas piping, and duct connections at the installation site. The gas-fired heaters feature aluminized steel tubular heat exchangers and spark ignition with an intermittent pilot.

Function Description

These units provide both cooling and heating for forced air systems. For cooling, they utilize an air-cooled condenser and are factory-charged with Refrigerant-22. The scroll compressor is hermetically sealed and internally sprung, with inherent internal protection against abnormal temperature rise. For heating, gas-fired heaters with aluminized steel tubular heat exchangers provide warmth, controlled by a spark ignition with an intermittent pilot. The system is designed for outdoor installation only and is not suitable for temporary heating of buildings or structures under construction.

Important Technical Specifications

Unit Sizes:
- DHUC: 036 (3 Ton), 048 (4 Ton), 060 (5 Ton)
- DBUC: 072 (6 Ton)
SEER/EER: 10 SEER for DHUC models, 9 EER for DBUC 072.
Voltage Variations:
- 208/230V (Min./Max. 187/253V)
- 460V (Min./Max. 414/504V)
- 575V (Min./Max. 518/630V)
Supply Air CFM, Nominal:
- 036: 1200 CFM
- 048: 1600 CFM
- 060: 2000 CFM
- 072: 2400 CFM
Evaporator Coil Wet Bulb Temperature: 57/72°F (Min./Max.)
Condenser Coil Dry Bulb Temperature: 45/120°F (Min./Max.) (A low ambient accessory is available for operation down to 0°F).
Gas Heating Input Capacity (Mbh): 50, 75, 100, 125.
Gas Heating Output Capacity (Mbh): 40, 60, 79, 99.
Temperature Rise at Full Input: Ranges from 15-45°F (50 Mbh) to 45/35/35-75/65/65°F (125 Mbh), depending on the model.
Blower Motors:
- Direct-Drive: 1/2 HP (036), 3/4 HP (048), 1 HP (060, 072).
- Belt-Drive (Optional): 1-1/2 HP for all models.
Refrigerant Charge (R-22): 5/8 lbs./oz. (036), 6/8 lbs./oz. (048, 060), 10/0 lbs./oz. (072).
Electrical Data (Direct-Drive):
- 036 (208/230-1-60): RLA 18.0, LRA 105.0, Min. Circuit Ampacity 28.2, Max. Fuse/HACR Breaker 45 Amps.
- 072 (460-3-60): RLA 10.2, LRA 73.0, Min. Circuit Ampacity 17.2, Max. Fuse/HACR Breaker 25 Amps.
Electrical Data (Belt-Drive):
- 036 (208/230-1-60): RLA 18.0, LRA 105.0, Min. Circuit Ampacity 29.1, Max. Fuse/HACR Breaker 45 Amps.
- 072 (460-3-60): RLA 10.2, LRA 73.0, Min. Circuit Ampacity 17.3, Max. Fuse/HACR Breaker 25 Amps.
Safety Controls (Cooling): Suction Line Freezestat, High Pressure Cutout Switch, Low Pressure Switch.
Safety Controls (Heating): Limit Control (LS), Centrifugal Switch (CS-36), Redundant Gas Valve, Flame Sensor Rod, Rollout Switch, Auxiliary Limit Switch.

Usage Features

Outdoor Installation: Designed for rooftop or slab mounting.
Ductwork: Supply and return air duct connections should be made with flexible joints to minimize noise. Ductwork should be insulated and waterproofed.
Filters: 1" filters are supplied, 2" replacement filters can be used. Filters must be kept clean to maintain unit capacity and prevent frosted coils or safety shutdown.
Condensate Drain: A 3/4" PVC female connection is provided for the condensate drain line, which must be trapped for proper drainage.
Thermostat Control: A 24-volt room thermostat is used for operation. Two-stage cooling is supported with an economizer, where the economizer provides first-stage cooling and the scroll compressor provides second-stage cooling. Continuous blower operation is possible.
Gas Connection: Gas supply can be routed through knockouts on the front or through the unit's base. A drip leg and ground joint union must be installed. Special pipe compound is required for LP/propane gas due to its solvent properties.
Low NOx Application: Accessory model 1LN0404 is available for natural gas heat installations requiring low Nitrous Oxide emissions.
Blower Speed Selection: Direct-drive units have three blower motor speeds (HIGH, MED, LOW) selectable by wiring. Belt-drive units have an adjustable motor pulley for CFM adjustment.
Start-Up Procedure: Includes checks for gas type, vent and combustion air hood installation, and a detailed sequence for lighting the pilot and main burners.
Manifold Gas Pressure Adjustment: Small adjustments to high-fire gas flow can be made via the pressure regulator adjusting screw on the automatic gas valve.
Pilot Checkout: The pilot flame should envelop 3/8 inches of the flame sensor. Adjustment is made via a screw on the gas valve.
Burner Air Shutter Adjustment: Shutters can be adjusted to obtain a distinct, sharp, blue flame.
Supply Air Blower and Temperature Rise Adjustments: Blower speed is adjusted based on required CFM, unit accessories, and static resistances. For belt-drive units, the variable pitch pulley is adjusted. Temperature rise must be within the range specified on the rating plate.
Checking Gas Input: Involves measuring the time for one revolution of the smallest dial on the gas meter and using a provided table to determine cubic feet per hour. Input should be within 5% of the furnace rating.

Maintenance Features

Periodic Maintenance: Normally involves changing or cleaning filters and, under certain conditions, cleaning the main burners.
Filter Inspection: Inspect monthly, replace disposable filters or clean permanent ones.
Motor Lubrication: Indoor fan and outdoor fan motors are permanently lubricated and require no maintenance. The ventor motor is factory lubricated for an estimated 10-year life.
Outdoor Coil Cleaning: Clean as necessary with a brush, vacuum, or water (with power off).
Burner & Pilot Inspection: Annually, visually check pilot and main burner flame. Adjust primary air shutters if needed. Clean burners with hot water if necessary.
Combustion Air Discharge Inspection: Periodically inspect for soot and dirt buildup.
Cleaning Flue Passages and Heating Elements: If sooted, elements can be cleaned by removing the burner assembly, roof over the gas heat section, flue collector box, and flue diverter baffle, then brushing out the heat exchangers and flue components.
Troubleshooting Guide: Provides detailed steps for diagnosing common issues such as draft motor operation, furnace ignition, sparker function, pilot ignition, main burner ignition, and erratic flame characteristics. Includes checks for electrical connections, voltage, relays, switches, and gas supply.
Safety Precautions: Emphasizes de-energizing electrical power and turning off gas supply before inspection, repair, or maintenance. Warnings are provided for working with live circuits during troubleshooting.
Owner's Approval: After proper system function is confirmed, the installer should secure the owner's approval, demonstrate disconnect switch locations and thermostat operation.