Trane RT-PRC031-EN manual Heating System

Mechanical Specifications

Economizer Control with Comparative Enthalpy

Used with the fresh air economizer, two enthalpy sensors are provided to compare total heat content of the indoor air and outdoor air to determine the most efficient air source when economizing.

Economizer Control with Reference Enthalpy

Used with the fresh air economizer, an outdoor enthalpy sensor is provided to compare the total heat content of outdoor air to a locally adjustable setpoint. The setpoint is programmed at the human interface, or remote human interface, to determine if the outdoor enthalpy condition is suitable for economizer operation.

Economizer Control with Dry Bulb

Used with the fresh air economizer, an outdoor temperature sensor is included for comparing the outdoor dry bulb temperature to a locally adjustable temperature setpoint. The setpoint is programmed at the human interface, or remote human interface, to determine if outdoor air temperature is suitable for economizer operation.

Heating System

Electric Heating Option

All electric heat models shall be completely assembled and have wired electric heating system integral within the air handler. Heavy duty nickel chromium elements internally wired with a maximum density of 40 watts per square inch shall be provided.

Heater circuits shall be 48 amps or less, each individually fused. Automatic reset high limit control shall operate through heater backup contactors. The units shall have optional factory mounted non-fused disconnect switch located in the main control panel to serve the entire unit.

Gas Fired Heating Option

All gas fired units shall be completely assembled and have a wired gas fired heating system integral within

unit. Units shall be UL/CSA approved specifically for outdoor applications downstream from chilled water coils. All gas piping shall be threaded connection with a pipe cap provided. Gas supply connection shall be provided through the side on horizontal discharge units, and through the bottom and side for downflow discharge units. All units shall be fire tested prior to shipment.

•Heat Exchanger shall be tubular two pass design with stainless steel primary and secondary surfaces. Free floating design shall eliminate expansion and contraction stresses and noises. Gasketed cleanout plate shall be provided for cleaning of tubes/ turbulators. Heat exchanger shall be factory pressure and leak tested.

•Burner shall be a stainless steel industrial type with an air proving switch to prevent burner operation if the burner is open for maintenance or inspection. Ceramic cone shall be provided to shape the flame to prevent impingement on sides of heat exchanger drum. Burner assembly shall house ignition and monitoring electrode.

•Combustion Blower shall be centrifugal type fan to provide air required for combustion. Fan motor shall have built-in thermal overload protection.

•Gas Safety Controls shall include electronic flame safety controls to require proving of combustion air prior to ignition sequence which shall include a 60 second pre-purge cycle. Pilot ignition shall be provided on 850, 1100 and 1800 MBH heat exchanger units. Sixty second delay shall be provided between first and second stage gas valve operation on two-stage heaters. Continuous electronic flame supervision shall be provided as standard.

•Full Modulation Gas Heaters shall be made from grades of stainless steel suitable for condensing conditions. The heater shall have a turn down ratio of at least 10 to 1 on the 850 and 20 to 1 on the 1100 and 1800

MBH

Steam Heating Option

Steam coils shall be Type NS with non-freeze steam distribution circuits. Distributor tubes shall be located concentrically within condensing tubes to assure even steam distribution. Coils shall be pitched to provide complete drainage. Steam modulating valve with actuator shall be provided.

Hot water Heating Option

Hot water coils shall be Type 5W and factory mounted in the air handling unit to provide complete drainage of coil. Hot water modulating valve with actuator shall be provided.

Accessories

Roof Mounting Curb

Roof mounting curb shall be heavy gauge zinc coated steel with nominal two-inch by four-inch nailer setup. Piping enclosure and supply/return air opening gasketing shall be provided. Curb shall ship knocked down for easy assembly. Channel shall be provided to allow for adjustment of return air opening location. Curb shall be manufactured to National Roofing Contractors Association guidelines.

Electronic Zone Sensors

•Zone Sensors shall provide two temperature setpoint levers, Heat, Auto, Off, or Cool system switch, Fan Auto or Fan On switch. Optional status indication LED lights, System On, Heat, Cool, and Service shall be available. These sensors shall be used with CV units.

•Programmable Night Setback Sensors shall be electronic programmable sensors with auto or manual changeover with 7 day programming. Keyboard shall provide selection of Heat, Cool, Fan Auto or On. All programmable sensors shall have System On, Heat, Cool, Service LED/indicators as standard. Night setback sensors shall have (1) Occupied, (1) Unoccupied and (2) Override programs per day. Sensors shall be available for CV zone

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