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Part #470654
VSU Make-Up Air Unit
®®
with Direct-Fired Gas Heater
Installation, Operation and Maintenance Manual Installation, Operation and Maintenance Manual
Please r Please read and save these instructions. Read car ead and save these instructions. Read carefully befor efully before attempting to assemble, install, operate or maintain the e attempting to assemble, install, operate or maintain the
pr product described. Pr oduct described. Protect yourself and others by observing all safety in
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Receiving Inspection and Maintenance during Storage Upon receiving the product check to make sure all items While in storage, inspect fans once per month. Keep a are accounted for by referencing the bill of lading to record of inspection and maintenance performed. ensure all items were received. Inspect each crate for If moisture or dirt accumulations are found on parts, shipping damage before accepting delivery. Notify the the source should be located and eliminated. At each carrier if any
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Table of Contents General Safety Information ....................1 Receiving, Handling and Storage ...............2 Product Overview ............................4 Subassembly Overview: Filter Section / Vertical Mounting Stand ..........4 Optional Service Platform .....................4 Burner, Blower and Control Center Overview ......5 Burner Subassembly .......................6 Control Center ............................6 Dampers ...................................6 Installation Concre
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Product Overview Subassemblies The model is a vertically-configured make-up air unit Filter Section / Vertical Mounting Stand designed for outdoor installations. It contains a highly The filter section of the unit is factory installed in the efficient direct-fired gas burner to provide a heat source mounting stand and shipped ready for installation on for the building or to simply temper the air. The unit is the concrete mounting pad. Each filter unit has a large designed to provide suffic
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Burner, Blower and Control Center Section The blower section of the unit consists of one motor and The burner section, blower section and control center either one or two forward curved blowers. It is the top- of the unit are all combined into one assembly which most assembly in the unit. If two blowers are used, their is installed in the field on top of the filter and stand drive shafts are connected and driven by a single motor. section. The burner section is the lowest part of the Supp
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Dampers There are four locations where optional dampers may be found. An optional motorized intake damper may be located horizontally on the bottom of the burner section. A patented passive control damper may be found adjacent to the burner opening plates if a VAV is ordered and a motorized damper may be installed vertically on the side of the burner section if recirculating air mode is chosen. In addition, an outlet damper may be shipped with the unit for field installation. Optional Fi
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Installation Concrete Slab Burner/Blower Section The first step in unit installation is to pour a concrete Use a crane and a spreader bar hooked to the factory slab capable of holding the unit weight as a base. The lifting lugs (shown below) to lift and center the unit onto slab should have a proper gravel drainage bed. the filter stand section. The sections should be caulked together. Spreader Bar Concrete Slab Dimensions Housing Size A B C D E 20 64 64 42 40 40 30 77 76 42 52 53 40 78 135
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Complete Installation Installation of Optional Service Platform A typical horizontal discharge installation is shown. Gas and/or electrical lines can be connected at this time. For upblast units, a duct elbow may be needed to turn the ductwork into the building. Follow proper ductwork methods recommended by AMCA to make this elbow to minimize duct losses. TOOLS REQUIRED • (2) 9/16 in. sockets or wrenches • Drill with 7/16 in. drill bit and 5/16 in. drill bit • A crane or forklift is recommen
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Assembly 6. Facing the control panel side of the unit, find the center of the housing and drill a (7/16 in.) hole 1. Position platform base as shown below in Figure A through the housing and support stand (3/8 in.) with the grate side up. above the form line as shown in Figure C. 2. Attach the left and right handrails to the platform base with (3/8 in. x 3/4 in.) hex head bolts and (3/8 in.) hex nuts as shown in Figure A. Use six bolts and 3/8 inch nuts on each rail. 3. Raise the platfo
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Installation of Electrical Wiring must be compatible with the ratings on the nameplate, IMPORTANT supply power voltage, phase and amperage. Consult Before connecting power to the unit, read and ANSI/NFPA 70 and CSA C22.1 for proper conductor understand the following instructions and wiring sizing. diagrams. Complete wiring diagrams are attached on Connect the Main Power the inside of the control center door(s). Connect the main power lines to the disconnect switch IMPORTANT and main groun
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Installation of Direct Gas Piping Determine the Supply Gas Requirements IMPORTANT The unit’s direct gas nameplate states the requirements All gas piping must be installed in accordance for the gas being supplied to the unit. The direct gas with the latest edition of the National Fuel Gas nameplate is located on the outside of the unit on the Code ANSI/Z223.1 and any local codes that may control center side. apply. In Canada, the equipment shall be installed Minimum gas pressure for in ac
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Connect the Supply Gas Line Installation of Building Pressure A manual shut off valve (gas cock), 1/8 in. plugged test Control (optional) port and 6 in. drip leg must be installed prior to the gas Mount Pressure Tap train. The valve and the test port must be accessible for the connection of a test gauge. Supply gas connections Using the factory provided bracket, mount the pressure must be made by a qualified installer and are not tap to the outside of the furnished by manufacturer. unit.
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Start-Up - Checklist Unit Model Number _______________________________ Start-Up Direct Gas (Pilot Ignition) – refer to (e.g. VSU-H20) Start-Up - Direct Gas section for further detail. o Check supply gas pressure Unit Serial Number _______________________________ (e.g. 10111000) ________ Maximum ________ Minimum Start-Up Date _______________________________ ________ Actual Start-Up Personnel Name __________________________ o Check Pilot Gas Pressure Start-Up Company _____________
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Start-Up - Blower Check for Vibration WARNING Check for unusual noise, vibration or overheating of the Check the housing, blower, and ductwork for any bearings. Reference the Troubleshooting section for foreign objects before running the blower. corrective actions. WARNING IMPORTANT Disconnect and lock-out all power and gas before Excessive vibration may be experienced during performing any maintenance or service to the unit. the initial start-up. Left unchecked, it can cause a Failure to
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Start-Up - Direct Gas Set-Up Optional Components IMPORTANT Adjust the settings on the optional components. See For proper unit function and safety, follow the start-up the unit’s specific wiring diagram located on the access procedure in the exact order that it is presented. door or the unit. IMPORTANT • Heating Inlet Air Sensor This start-up should begin after all of the installation Typical setting: 60-70ºF procedures and the blower start-up have been • Building Freeze Protection compl
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Set the Burner Air Pressure Differential NOTE With the fan running and discharging 70ºF (21ºC) air, The pressure drop was set at the factory and may not connect a U-Tube manometer to the outer sensing need adjustment. probes (see below) and measure the static pressure across the burner. NOTE When required pressure is obtained, be sure to 9 Outer Sensing Probes reconnect the outer sensing probes. 8 IMPORTANT This process may need to be repeated until the proper 7 pressure is achieved. This
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Set the Minimum Firing Rate IMPORTANT Disconnect and isolate one of the wires running to the Setting the maximum firing rate during mild weather modulating valve to send the unit to its minimum firing conditions may cause the high limit to trip out during rate. Set the minimum firing rate by adjusting the needle extreme conditions requiring manual resetting. valve indicated. NOTE After setting the minimum firing rate, shut off the pilot Gas trains are equipped with either separate to ensu
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Set the Unit’s Operating Temperature Set the operating temperature. The operating Maxitrol SC25S: The SC25S is an analog signal temperature setting depends on which Maxitrol converter that will change a 0-10 VDC or a 4-20 mA controller is used. control signal provided by an owner supplied Building Management System into an output level capable of driving one or more modulating gas valves. The SC25S Maxitrol Series 14 – 8 Terminals: The Maxitrol also limits the minimum and maximum disch
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Building Pressure Control — BLOWER Operation - VAV Units (optional) EXHAUST (OPTIONAL) a variable frequency drive is SUPPLY MAIN VALVES HEAT controlled according to input from NOTE a pressure sensing device. Blower Start-Up, as shown on page 14, should be DIRTY FILTERS Turn both knobs to the upper 70 performed before the blower is run. 75 65 80 (OPTIONAL) 60 85 90 55 most pressure setting. You may NOTE have to remove the outdoor pressure tap tubing. VAV systems For maintenance issues ass
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Building Pressure Control — a Operation - Recirculating Units BLOWER EXHAUST (OPTIONAL) modulating spring return actuator SUPPLY (optional) MAIN VALVES is used to control the return air HEAT amounts. The return air damper NOTE modulates from fully open to fully DIRTY FILTERS 75 70 65 80 (OPTIONAL) 60 closed based on a signal from a 85 Blower Start-Up, as shown on page 14, should be 55 90 remote pressure sensing device. performed before the blower is run. Turn both knobs to the upper most PH
