Installation & Maintenance Data IM 178-6 Group: Applied Systems Part Number: 347673Y-01 Date: January 1997 ® RoofPak Applied Rooftop Systems Air Handler RDS 800C & 802C LISTED ® C LISTED ® ® ©1997 McQuay International
Table of Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Receiving Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Unit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Typical Component Locations . . . . . . . . . . . . . . . . . . . Control Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control Panel Locations . . . .
Introduction This manual provides general information about the “C” vintage McQuay RoofPak applied rooftop unit, Model RDS. In addition to an overall description of the unit, it includes mechanical and electrical installation procedures, commissioning procedures, sequence of operation information, and maintenance instructions. For further information on the optional forced draft gas-fired furnace, refer to Bulletin No. IM 684 or 685.
Unit Description Typical Component Locations Figure 1 shows a typical RDS unit with the location of the major components and also lists some major dimensions. These figures are for reference only. See the certified submittals for actual specific dimensions. Figure 1. Typical component locations Plan View Bottom Discharge Air Opening Bottom Return Air Opening 94.
Control Locations Figure 2 shows the locations of the various control components mounted throughout the unit. See “Control Panel Locations” for the locations of control components mounted in control panels. Additional information is included in Table 2, “Controls, Settings, and Functions,” and the wiring diagram legend which is included in the “Wiring Diagrams” section of this manual. Figure 2.
Control Panel Locations ration. Specific unit configurations may differ slightly from these figures depending on the particular unit options. The unit control panels and their locations are shown in the following figures.
Electric heat control panel FB31 FB32 SR2 FB33 M31 HL4 M32 M33 SR3 FB41 FB42 FB43 M41 T5 M42 M43 HL14 SR1 TB12 IM 178 / Page 7
Page 8 / IM 178 SPS5 SPS2 SB1, 2 SD1 SD2 SPS1 SAT RAT FUNCTION Sensors pressure drop across first filter bank and sends signal to MicroTech controller. Converts static pressure signals to voltage signals and sends them to MicroTech controller. Building static pressure sensor Used to compare return air enthalpy to outside air enthalpy (used with OAE). Senses return air temperature; sends signal to MicroTech controller. Senses discharge air temperature; sends signal to MicroTech controller.
IM 178 / Page 9 FUNCTION RESET High pressure regulator High gas pressure switch Low gas pressure switch HPR HP5 LP5 Shuts off burner if pressure goes below set point. Shuts off burner if pressure goes above set point. Regulates pressure to main regulator. Opens furnace control circuit on temperature rise. Switch (toggle), electric heat Shuts off electric control circuit manually. Final filter high limit control HL23 Opens furnace control circuit on temperature rise.
Mechanical Installation The installation of this equipment shall be in accordance with the regulations of authorities having jurisdiction and all applicable codes. It is the responsibility of the installer to determine and follow the applicable codes. ! CAUTION Sharp edges are inherent to sheet metal parts, screws, clips, and similar items. Can cause personal injury. This equipment is to be installed and operated only by an experienced installation company and fully trained personnel.
Ventilation clearance Following are minimum ventilation clearance recommendations. The system designer must consider each application and assure adequate ventilation. If this is not done, the unit will not perform properly. Unit(s) surrounded by a screen or a fence: 1. The bottom of the screen or fence should be at least 1 ft. (305 mm) above the roof surface. 2. The distance between the unit and the screen or fence should be as described in “Service clearance.” 3.
Figure 5a. RDS roof curb assembly instructions “X” IN. MM 24.0 610 24.0 610 30.0 762 36.0 914 RETURN FAN NONE (2) 15" FC 30" AF 40" AF “Y” IN. MM 82.0 2083 82.0 2083 76.0 1930 78.0 1981 “XX” IN. MM 6.8 173 6.8 173 6.8 173 14.8 376 “YY” IN. MM 1.5 38 1.5 38 4.5 114 3.5 89 6.8 (173) 1.5 (38) 20 (508) Inside 76 (1930) Inside 7.5 (191) Supply Air 2 (51) “X” Inside 38.8 (984) “XX” Return Air “YY” See Detail “A” “Y” Inside 85 (2159) 62.8 (1594) Figure 5b.
Post and Rail Mounting When mounting by post and rail, the structural support should be run the full length of the unit. The structural member should be located at the base of the unit as shown in Figure 6 assuring the shaded area is well supported by the structural member. ! Figure 6. Post and rail mounting 94" (2388 mm) *5" (127 mm) CAUTION To assure proper system operation, it is important that the unit is mounted level.
Lifting points To determine the required lifting cable lengths and whether four- or six-point lifting is required, use Tables 3 and 4 below and Figure 8. Referring to Figure 8, note that dimension A is the distance between the outer lifting points. The four outer rigging cables must be equal to or longer than dimension A. Dimension B shows the minimum distance between the outer and the inner lifting points for six-point lifting.
Installing Ductwork For bottom discharge and return units not provided with a McQuay roof curb, the installing contractor should make an airtight connection by attaching field fabricated duct collars to the bottom surface of either the roof curb’s duct flange or the unit’s duct opening. Do not support the total weight of the ductwork fromhe unit or these flanges. Refer to Figure 9. Units with optional back return, side discharge, or front discharge all have duct collars provided.
back wall of the discharge plenum. Sensing tubes should enter the unit discharge plenum through the main supply duct trunk. Make sure that duct penetrations are sealed Figure 10. Duct static pressure tap installation and that tubing is protected by rubber grommets. Carefully connect the HI and LO tubes to the appropriate sensor fittings. Figure 11.
Condensate Drain Connection The unit is provided with a 1.5" male NPT condensate drain connection. Refer to certified drawings for the exact location. The unit and drain pan must be level side to side and a P-trap must be installed for proper drainage. RDS units may have positive or negative pressure sections. It is recommended that traps be used in both cases with care given to negative pressure sections. In Figure 12, dimension A should be a minimum of 8" (203 mm).
Piping recommendations 1. Use type K or L clean copper tubing. All joints should be thoroughly cleaned or brazed with high temperature solder. 2. Piping sizes should be based on temperature/pressure limitations as recommended in the following paragraphs. Under no circumstances should pipe size be based strictly upon coil or condensing unit piping connection size. 3. Suction line piping pressure drop should not exceed the pressure equivalent of 2°F (1°C), 3 psi (20.7 kPa) per 100 feet (30.
Charging the system 1. After all refrigerant piping is complete and the system has been evacuated, it can be charged as described in the paragraphs following. Connect the refrigerant drum to the gauge port on the liquid shutoff valve, and purge the charging line between the refrigerant cylinder and the valve. Then open the valve to the midposition. 2. If the system is under a vacuum, stand the refrigerant drum with the connection up, open the drum and break the vacuum with refrigerant gas. 3.
Unit coil piping Chilled water Unit chilled water coils have a fin height of 48" (1219 mm). A factory installed three-way valve, piping and motor actuator is available for chilled water coils provided in a cooling only section (see Figure 13). When no factory piping or valve is included, coil connections are 2.50" male NPT copper. With the factory valve package, field connections are the same NPT as the valve with female threading.
2. Do not reduce pipe size at the coil return connection. Carry return connection size through the dirt pocket, making the reduction at the branch leading to the trap. 3. It is recommended that vacuum breakers be installed on all applications to prevent retaining condensate in the coil. Generally, the vacuum breaker is to be connected between the coil inlet and the return main.
Step 2 Step 4 Remove gasketing around door flange and save for use on vestibule. See Step 4. Remove door and save for Step 4. 1. Reassemble access door to vestibule by screwing hinges into side panel using screws saved from Step 1. (Access door must be attached to the vestibule in the same opening direction as it was on the unit.) Figure 16b. 2. Remove and discard latch handle locking screws and retaining washer. Fasten door latch assembly to side panel using screws and bushing saved from Step 1.
Damper Assemblies The optional damper assemblies described in this section are provided with manually adjustable linkages, or may be shipped with factory installed actuators and linkages. Economizer dampers Outside air intake is provided on both sides of the unit, and the return air path is at the center of the damper set. As the single actuator modulates the outside air dampers open, the return air dampers close.
Intake hood damper (0 to 100% outside air) Units requiring 100% outside air are provided with a rain hood and dampers which may be controlled by a single actuator. The actuator provides two-position control for opening the dampers fully during unit operation and closing the dampers during the off cycle. No unit mounted exhaust dampers are provided. Figure 18b. Figure 18a. Shaft, .500 Dia. x 1.50 Long OA Open 90° Stroke OA Closed .25 3.00 .
Face and bypass dampers Face and bypass dampers are available for use with contractor heating an cooling coils. The damper sets are linked through a jack shaft for connection to a factory or field in– stalled actuator. Figure 20. Optional Contractor Coil Face and Bypass Damper Extended Shaft Face and Bypass Dampers Cabinet Weatherproofing This unit ships from the factory with fully gasketed access doors and cabinet caulking to assure weatherproof operation.
Electrical Installation Field Power Wiring Wiring must comply with all applicable codes and ordinances. The warranty is voided if wiring is not in accordance with these specifications. An open fuse indicates a short, ground, or overload. Before replacing a fuse or restarting a fan motor, the trouble must be found and corrected. According to the National Electrical Code, a disconnecting means shall be located within sight of and readily accessible from the air conditioning equipment.
With optional electrical power package ! RDS units are provided with internal power wiring for single point power connection. The single power block or an optional disconnect switch is located within the main control panel. Field power leads are brought into the unit through 3" knockouts in the bottom of the main control panel. Refer to Figure 22a. Note: Refer to certified drawings for dimensions to wire entry points.
Field Control Wiring RoofPak applied rooftop units are available with several control arrangements which may require low voltage field wiring. Detailed descriptions of various field control wiring options and requirements are included in the “Field Wiring” section of Bulletin No. IM 483, “MicroTech Applied Rooftop Unit Controller.” Refer to the unit wiring diagrams for additional installation information. Wiring must comply with applicable codes and ordinances.
Preparing Unit for Operation ! WARNING Moving machinery hazard. May cause severe injury or death. Disconnect power and lock off before servicing equipment. More than one disconnect may be required to de-energize unit. Relief Damper Tie-Down Economizer sections with a 30" or 40" return fan have a relief damper that is tied down for shipping. Two brackets and two screws must be removed before operation to allow free movement of dampers. Access is from inside the economizer section.
Adjustment of Scroll Dampers Two sets of scroll dampers are provided in the housing of the twin 15" x 6" supply fan to allow control of air volume to each fan wheel. At the factory, these dampers are fully closed unrestricting airflow. If fan paralleling occurs, correction can be made by loosening the adjustment screw on top of the fan housing (see Figure 26) and slightly lowering the rod until air distribution between the fans is even. Figure 26.
Adjustment of Seismic Restraints Spring mounted supply air and return air fans may be ordered with factory installed seismic restraints. The system consists of four snubbers, one located next to each spring isolator. These snubbers will allow free movement of the fan assemblies during normal operation because normal operation will not cause fan movements that exceed .25" (6 mm). However, they will restrain the fan assembly and limit movement to .
Sequences of Operation The following sequences of operation are for a typical “C” vintage applied rooftop unit that is equipped with an economizer, a return air fan, a MicroTech controller, an external time clock, and a Remote Monitor Panel. These sequences describe the ladder wiring diagram logic in detail; refer to the schematics in the “Wiring Diagrams” section as you read them. Note that your unit’s sequences of operation may vary from those described here.
Cooling Operation Chilled water coil, modulating valve Refer to the “Typical Actuator Control Circuit ” schematic in the following section, “Wiring Diagrams,” as you read this sequence of operation. If cooling is required, the valve motor VM5 modulates to maintain the discharge air set point. When terminal 4 and 1 are energized, output relay OBA2 opens the chilled water valve (line 332). When terminals 4 and 2 are energized, output relay OBA1 closes the chilled water valve (line 332).
Wiring Diagrams Legend Designation Description ACT1 .................. Actuator Motor, Supply Fan Vanes ............................ ACT2 .................. Actuator Motor, Return Fan Vanes ............................ ACT3, 4 .............. Actuator Motors, Economizer Dampers .................... ACT5 .................. Actuator Motor, Discharge Isolation Damper ........... ACT6 .................. Actuator Motor, Return Air Isolation Damper ........... ACT7, 8 ..............
Typical Power Circuit Typical Compressor Staging Outputs IM 178 / Page 35
Typical Main Control Circuit (VAV Units) Page 36 / IM 178
Typical Main Control Circuit (CAV-ZTC Units) IM 178 / Page 37
Typical Main Control Circuit (CAV-DTC Units) Page 38 / IM 178
Typical Actuator Control Circuit Typical Supply/Return Fan Control Circuit IM 178 / Page 39
Typical Gas Furnace Control Circuit (Modulating Burner, Mixed Air Intake) Sequence of Operation: When the rooftop unit is energized, 120 volt power is supplied through the system on-off switch S1 to OBA3 contacts. Upon a call for heat, the control system will close OBA3, thus energizing relay R20.
Typical Electric Heat Control Circuit (Multistage) IM 178 / Page 41
Unit Options Enthalpy Control Figure 29. Enthalpy control settings 100 105 (38) (40.5) 95 (35) 90 85 (29.5) (32) R HU ELA MI TIV DI E TY 0.6 0.5 0 32 PO UN 30 R PE 70 (21) 0 0.4 Y EN 0. 30 20 18 55 B (13) 16 (23°C) (21°C) (19°C) (17°C) 50 (10) 14 73°F 70°F 67°F 63°F 60 (15.5) A 12 A B C D 22 CONTROL POINT TEMP. AT 50% RH 65 (18.5) 24 TH A LP Table 12. Enthalpy control settings CONTROL CURVE 26 — BT U 0 36 AI R 34 75 (24) D DR Y 0.70 38 40 80 (26.5) 0.90 0.
External Time Clock An external time clock can be used as an alternative to (or in addition to) the MicroTech controller’s internal scheduling function. The external timing mechanism is set up to open and close the circuit between field terminals 101 and 102. When the circuit is open, power is not supplied to digital input D1 (terminal DH1-1) on the ADI board. This is the normal condition in which the programmable internal schedule is followed. When the circuit is closed, power is fed to DH1-1.
Variable Inlet Vanes Variable inlet vanes are installed on the supply and return fans of VAV units. They are also installed on the return fans of constant volume units that have direct building static pressure control capability. The inlet vane assemblies consist of airfoil type inlet funnels with integral sets of lever-actuated radial vanes. Supply fans have one assembly on each side of the fan. Return fans have one assembly on the inlet side of the fan only.
Figure 31. Supply fan vane assembly Open 180° CW To Open B X Closed 24° A X = 3.00" — 20" Wheel (800C) 2.80" — 24" Wheel (802C) Adjustable [11/8" (28 mm) slot] Floating Link Figure 32. Return fan vane assembly Closed Open View #1 30" Wheel (800C & 802C) 2.80" B 180° CCW To Open Closed A 60° 180° CW To Open Closed Open View #2 40" Wheel (802C) 20° Open 2.
Check, Test, and Start Procedures ! WARNING Electric shock and moving machinery hazard. Can cause severe equipment damage, personal injury, or death. All start-up and service work must be performed by qualified technicians who are familiar with the hazards of working on this type of equipment. Do not attempt to operate or service this equipment without first reading and understanding this manual, the “MicroTech Applied Rooftop Unit Controller” manual (Bulletin No.
3. If the fans are equipped with optional spring isolators, check the fan spring mount adjustment. When the fans are running they should be level. Refer to “Spring Isolated Fans” in the “Preparing Unit for Operation” section of this manual for information. Note: The supply and return fan drives are usually selected for operation in the drive’s midspeed range.
Air Balancing Air balancing should be performed by a qualified air balancing technician. Note that the supply fan motors are usually shipped with variable pitch sheaves which are typically set at the low end of the drive’s fan rpm range. See “Mounting and Adjusting Motor Sheaves” below for more information. The return fan motors are usually shipped with fixed pitch sheaves. Figure 33. VM and VP variable pitch sheaves A B B B E ! E WARNING Moving machinery hazard.
Figure 34. LVP variable pitch sheaves A A E E E C C A F F D D A D B Section A-A Section A-A 9. Be sure that all keys are in place and that all setscrews and all capscrews are tight before starting the drive. Check and retighten all screws and retension the belts after approximately 24 hours of operation. MVP variable pitch sheaves Adjusting: 1. Slack off belt tension by moving the motor toward the driven shaft until the belts are free from the grooves. For easiest adjustment, remove the belts.
Final Control Settings When all start-up procedures have been completed, set the controls and program the MicroTech controller for normal operation. Use the following list as a guide; some items may not apply to your unit. 1. Turn system switch S1 to “on.” 2. Turn gas furnace switch S3 to “auto” or turn electric heat switch HS1 to “on.” 3. Set the electromechanical (Honeywell H205) enthalpy control (OAE) as required (A, B, C, or D).
Control parameter record (cont’d) MENU 13 MENU NAME Clg Control (VAV & CAV-DTC) Programs: ART1, ART2, ART3, ART4, ART6 and ART8 13 Clg Control (CAV & ZTC) Programs: ART5 and ART7 14 Htg Control (VAV & CAV-DTC) Programs: ART1, ART2, ART3, ART4, ART6 and ART8 14 Htg Control (CAV-ZTC) Programs: ART5 and ART7 15 Alarm Limits 17 Unocc Htg/Clg MENU ITEM = Set Point = ____ °F Min OAT = ____ °F Min Spt = ____ °F Max Spt = ____ °F Reset = No Reset Space Return OAT Network External Airflow Min Spt @ = ___
Control parameter record (cont’d) MENU 18 MENU NAME Duct Pressure (VAV) Programs: ART1, ART2, ART3 and ART4 19 Ret Fan Cntl (VAV with fan tracking control) Programs: ART1 and ART3 19 Bldg Pressure Programs: ART2, ART4, ART5 and ART6 20 Fan Balance (VAV with fan tracking control) Programs: ART1 and ART3 21 Outdr Damper (VAV) Programs: ART1, ART2, ART3 and ART4 MENU ITEM = Duct Spt = ____ "WC Max Spt = ____ "WC Reset = No Reset Network Position Deadband = ____ "WC Mod Lim = ____ "WC Wait Time = ____
Control parameter record (cont’d) MENU 21 MENU NAME Outdr Damper (CAV) Programs: ART5, ART6, ART7 and ART8 22 Dirty Filter 23 24 Timers Programs: ART1, ART2, ART3, ART4, ART5 and ART6 Timers Programs: ART7 and ART8 Set Date/Time 25 Schedule 26 Holiday Date 23 MENU ITEM = Min Airflow = ____ % Min Type = None External ____ % @ 5V Ext Enthalpy = Yes No Changeover = ____ °F Chngovr Diff = ____ °F Max Purge = ____ Min Deadband = ____ °F Mod Limit = ____ °F Wait Time = ____ Sec Max Step = ____ Sec PA
Control parameter record (cont’d) MENU 27 28 MENU NAME Optimal Start Service MENU ITEM = Opt Start = On Off Auto Update =Yes No Ht Rate = ____ °F/Min Heat OAT = ____ °F Ht Factor = ____ Min Cl Rate = ____ °F/Min Cool OAT = ____ °F Cl Factor = ____ Min Mode = Normal Shutdown Timers = Normal Fast Space Sensor = No Yes OAT = Local Remote ➀ Duct Sensor 2 = No Yes Alarm Out = Blink Off Port A Baud = 1200 2400 9600 19200 IDENT = ____ FINAL SETTING ___________ ___________ ___________ ___________ ___________
Maintenance Installation and maintenance are to be performed only by qualified personnel who are experienced with this type of equipment and familiar with local codes and regulations. WARNING ! ! CAUTION Moving machinery and electrical power hazards. May cause severe personal injury or death. Sharp edges are inherent to sheet metal parts, screws, clips, and similar items. May cause personal injury. Disconnect and lock off power before servicing equipment. Exercise caution when servicing equipment.
3. Run the motor for five minutes before replacing the plugs. Note: Specific greasing instructions may be found on a tag attached to the motor. If special lubrication instructions are on the motor, they will supersede all other instructions. Fan shaft bearings Fan shaft bearings should be relubricated periodically. Relubricate according to the schedule shown in Table 15.
Supply Fan Wheel-to-Funnel Alignment If the unit is equipped with an airfoil or backward curved supply fan, the fan wheel-to-funnel alignment must be as shown in Figure 37 or 38 to obtain proper air delivery and operating clearance. If necessary, adjustments are made as follows: 1. Verify that the fan shaft has not moved in its bearings. 2. Loosen the fan hub setscrews and move the wheel(s) along the shaft as necessary to obtain the correct dimension shown in Figure 37 or 38. 3.
Service and Warranty Procedure In-Warranty Return Material Procedure Material other than compressors may not be returned except by permission of authorized factory service personnel of McQuay International at Minneapolis, Minnesota. A “return goods” tag will be sent to be included with the returned material. Enter the information as called for on the tag in order to expedite handling at out factories and issuance of credits.
Product Warranty McQuay International, hereinafter referred to as the “Company,” warrants that it will provide, at the Company’s option, either free replacement parts or free repair of component parts in the event any product manufactured by the Company and used in the United States proves defective in material or workmanship within twelve (12) months from initial start-up or eighteen (18) months from the date shipped by the Company, whichever comes first.
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