Carrier Comprehensive Guide to 48SS Gas Heater Operating Characteristics and Features

I.Operating Characteristics:

1.Unit shall be capable of starting and running at 125 F ambient outdoor temperature per maxi- mum load criteria of ARI Standard 210/240.

2.Compressor with standard controls shall be ca- pable of operation in cooling down to 40 F am- bient outdoor temperature.

3.Unit provided with fan time delay to prevent cold air delivery before heat exchanger warms up.

4.Unit provided with fan time-delay after the ther- mostat is satis®ed.

J.Electrical Requirements:

All unit power wiring shall enter unit cabinet at a single location.

K.Motors:

1.Compressor motors shall be of the refrigerant- cooled type with line break thermal and current overload protection.

2.All fan motors shall have permanently lubricated- bearings and inherent automatic reset thermal overload protection.

3.Condenser-fan motor shall be totally enclosed.

L.Special Features:

1.Roof Curb:

Curb shall have seal strip and a wood nailer for ¯ashing and shall be installed per manufacturer's instructions.

2.25% Open Manual Outdoor-Air Damper:

Manual damper package shall consist of damper, birdscreen, and rainhood which can be preset to admit outdoor air for year-round ventilation.

3.Thermostat and Subbase:

To provide for one-stage heating and cooling in addition to manual or automatic changeover and fan control.

4.Electronic Programmable Thermostat:

Thermostat provides 2-stage heating and 2-stage cooling control with remote communication ability.

5.Natural-to-Propane Conversion Kit:

Kit shall be complete with burner ori®ce(s).

6.Low Ambient Package:

Package shall consist of a solid-state control and condenser coil temperature sensor for control- ling outdoor-fan motor operation, which shall al- low unit to operate down to 0° F outdoor ambi- ent temperature.

7.Compressor Short-Cycle Protection:

Solid-state control shall protect compressor by preventing short cycling.

8.Lifting Bracket Kit:

Kit shall provide attachment points for rigging straps. (Not required with optional base rail or down¯ow option applications.)

9.High- and Low-Pressure Switch Kits:

Switches provide additional safety features and protect the unit from running at unsuitable pressures.

10.Filter Rack:

Rack provides mounting location for ®lters when unit is in down¯ow application.

11.Crankcase Heater:

Heater warms crankcase oil to reduce refriger- ant migration (recommended on 208/230-v, single- phase units in sizes 024-042).

12.Base Rail:

Base rail provides holes for rigging and handling, and an elevated base for horizontal applications.

13.Down¯ow Option:

Option provides for vertical ductwork connec- tions. Unit shall be equipped with base rail.

14.High Altitude Kit:

Kit shall have new burner ori®ces for use in ap- plications from 2001 to 5000 feet.

15.Low NOx Kit:

Kit shall provide low NOx emissions for units be- ing installed in California Air Quality Manage-

ment Districts which require NOx emissions of 40 nanograms/joule or less.

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