Section Cover Page
Section 15732
Packaged Roof Top
2000-06-01Heating/Cooling Units

This Master Specification Section contains:

.1This Cover Sheet

.2Specification Section Text:

1.General

1.1Quality Assurance

2.Products

2.1Type

2.2Construction

2.3Burner

2.4Electric Heater

2.5Evaporator Coil

2.6Compressor

2.7Condenser

2.8Supply/Return Casing

2.9Operating Controls

2.10Remote Panel

3.Execution

3.1Installation

3.2Performance

3.3Packaged Roof Top Heating Cooling Units Schedule

BMS Basic Master Specification
Alberta Infrastructure
Master Specification System / Page 0
Section 15732
Packaged Roof Top
Plan No:Heating/Cooling Units
Project ID:Page 1

1.General

1.1QUALITY ASSURANCE

.1Meet the requirements of CSA, Provincial and Municipal Codes and be CSAlisted.

.2Units shall be products of manufacturers who provide local service personnel from factory representative, franchised dealer or certified maintenance service shop.

2.Products

2.1TYPE

.1Provide roof mounted type units with [gas burner] [oil burner] [electric heating elements] [and electric refrigeration].

.2Units shall be selfcontained, packaged, factory assembled and prewired consisting of a cabinet and frame, supply fan, [return fan,] [heat exchanger and burner,] [electric heating elements,] control, air filer [,refrigerant cooling coil] [and compressor, condenser coil and fan].

2.2CONSTRUCTION

.1Cabinet:Heavy gauge steel with baked enamel finish, easily removed access doors or panels with quick fasteners [,locking door handle type] [,screwdriver operated flush cam type. Structural members shall be minimum 1.3mm, with removable panels minimum 1.0mm.

.2Insulation:Neoprene coated glass fiber on surfaces where conditioned air is handled. Protect edges from erosion.

.3Heat Exchangers:[Aluminized] [Stainless] steel of welded construction.

.4Supply [and Return] Fan:Centrifugal type rubber mounted Vbelt drive, [adjustable variable pitch motor pulley,] rubber isolated hinge mounted motor. [Complete fan assembly shall be isolated].

.5Air Filters:50mm thick glass fiber disposable media in metal frames arranged for easy replacement.

2.3BURNER

.1Oil Burner:High pressure atomizing type with combustion air blower, fuel pump, hinged flame inspection port, cadmium sulphide flame sensor, electrodes, ignition transformer and oil nozzle.

.2Oil Burner Safety Controls:Energize burner motor and electric ignition, limit time for establishment of main flame, monitor flame continuously during burner operation and stop burner on flame failure with manual reset necessary. Solenoid oil delay valve opens as burner motor is energized and closes instantly when burner motor is deenergized.

.3Gas Burner:Forced or induced draft [or atmospheric] type burner with adjustable combustion air supply, pressure regulator, gas valves, manual shutoff, intermittent spark or glow coil ignition, flame sensing device and automatic 100% shutoff.

.4Gas Burner Safety Controls:Energize ignition, limit time for establishment of flame, prevent opening of gas valve until pilot flame is proven. Stop gas flow on ignition failure. Energize blower motor. After air flow proven and slight delay, gas valve is allowed to open.

.5High Limit Control:With fixed stop at maximum permissible setting, deenergizes burner on excessive bonnet temperature and energized burner when temperature drops to lower safe value.

.6Control supply fan in accordance with bonnet temperatures and independent of burner controls. Include switch for continuous fan operation.

2.4ELECTRIC HEATER

.1Finned tube, helical coil or expanded strip heating elements shall be easily accessible with protection against no flow or low air flows, shorts and grounds and failure of protection devices.

.2High limit temperature control shall deenergize heating elements to protect against overheating.

.3Start supply fan before electric elements are energized and continue operating until bonnet temperature reaches minimum setting. Include switch for continuous fan operation.

2.5EVAPORATOR COIL

.1Provide copper tube aluminum fin coil assembly with galvanized drain pan and connection, capillary tubes and expansion valve.

2.6COMPRESSOR

.1Provide hermetic or semihermetic compressor, 3600r/min maximum, resiliently mounted with positive lubrication, crankcase heater, high and low pressure safety controls, motor overload protection, service valves and filter drier.

.2Timed offcircuit shall limit number of compressor starts to 12perhour.

.3Outdoor thermostat shall energize compressor above 14°C ambient.

.4Provide stop capacity control by [hot gas bypass setup] [cycling the compressors] [cylinder unloading].

2.7CONDENSER

.1Provide copper tube aluminum fin coil assembly with subcooling rows.

.2Provide direct drive axial fans, resiliently mounted with fan guard, motor overload protection, wired to operate with compressor.

.3Provide refrigerant pressure switch to cycle condenser fans.

2.8SUPPLY/RETURN CASING

.1Provide manual outside [and return] air dampers for fixed outside air quantity.

.2Provide remote controlled outside [and return] air dampers with damper operator and remote rheostat package for adjusting outside air quantity.

.3Provide outside, return and relief dampers with damper operator and control package to automatically vary outside air quantity. Outside air damper shall fall to closed position. [Relief dampers may be gravity balanced.]

.4Provide tight fitting dampers with neoprene or suitable edge gaskets.

.5Damper Operator:24V, spring return with motor and gear train sealed in oil.

.6Mixed Air Controls:Maintain selected mixed air [temperature] [enthalpy], lock out compressor below approximately 14°C ambient, return dampers to minimum position above approximately [14°C] [24°C] ambient.

2.9OPERATING CONTROLS

.1Low voltage, adjustable thermostat shall control [burneroperation] [heater stages in sequence with delay between stages] [compressor and condenser fan] and supply fan to maintain temperature setting.

.2Thermostat shall include system selector switch [heatcooloff] [and fan control switch [onauto].

.3Double acting thermostat shall have minimum [] stage heating and [] stage cooling.

.4Single acting thermostat shall have minimum [] stage cooling.

.5Provide remote mounted fan control switch [onauto].

.6Provide in supply air low limit thermostat to [close outside air damper and] stop supply fan.

.7Locate thermostat in [room as shown] [supply air return air].

.8Provide night control energized by central time clock to [maintain lower thermostat setting,] [maintain night thermostat setting,] [lock out refrigeration,] [close outside air damper and open air return air damper,] [stop supply air fan,] [set fan control switch to auto position,] for night and unoccupied operation].

2.10REMOTE PANEL

.1Provide remote readout panels containing:signal lights indicating system status [,heating system failure] [,cooling system failure] and dirty filters; check switches proving signal light operation; system onoff switch [,cooling system onoff switch].

.2Provide in panel [,manual 12 hour timer to override night control] [,remote damper control] [,low limit manual reset] [,remote thermostat temperature set point].

.3Provide gauges in remote panel to indicate supply and mixed air temperature.

3.Execution

3.1INSTALLATION

.1Mount units on curbs to provide watertight enclosure to protect ductwork and utility services.

3.2PERFORMANCE

.1[]kW rated heating output when heated by []kW [L/s, gph, No.2 oil] [kW, natural gas] [kW electric heating elements].

.2[]kW rated cooling output with []°C DB and []°C WB air entering the evaporator []°C condenser ambient air and []kW input.

.3[]L/s supply air at []kPa external static pressure with []kW motor.

.4[]L/s return air at []kPa external static pressure with []kW motor.

.5Unit shall be [] Model [].

.6Refer to Roof Top Unit Schedule.

.7Rated cooling capacity is based on []°C condenser ambient air.

.8Supply [and return] air is corrected to []m altitude.

3.3PACKAGED ROOF TOP HEATING COOLING UNITS SCHEDULE

RT1 / RT2 / RT3
Location
Manufacturer
Model
Supply Fan L/s
Supply Ext. S.P. kPa
Supply Fan kW
Return Fan L/s
Return Ext. S.P. kPa
Return Fan kW
Sensible Cooling kW
Total Cooling kW
Coil Entr. °C DB/WB
Coil lvg. °C DB/WB
Cooling kW
Heating output kW

END OF SECTION