Greenheck VSU Installation, Operation And Maintenance Manual
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Greenheck VSU Installation, Operation And Maintenance Manual

Greenheck VSU Installation, Operation And Maintenance Manual

Vsu make-up air unit with direct-fired gas heater
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Installation, Operation and Maintenance Manual
Installation, Operation and Maintenance Manual
Please read and save these instructions. Read carefully before attempting to assemble, install, operate or maintain the
Please read and save these instructions. Read carefully before attempting to assemble, install, operate or maintain the
product described. Protect yourself and others by observing all safety information. Failure to comply with instructions could
product described. Protect yourself and others by observing all safety information. Failure to comply with instructions could
result in personal injury and/or property damage! Retain instructions for future reference.
result in personal injury and/or property damage! Retain instructions for future reference.
Model VSU

General Safety Information

Only qualified personnel should install this unit.
Personnel should have a clear understanding of these
instructions and should be aware of general safety
precautions. Improper installation can result in electric
shock, possible injury due to coming in contact with
moving parts, as well as other potential hazards. Other
considerations may be required if high winds or seismic
activity are present. If more information is needed,
contact a licensed professional engineer before moving
forward.
1. Follow all local electrical and safety codes, as well
as the National Electrical Code (NEC), the National
Fire Protection Agency (NFPA), where applicable.
Follow the Canadian Electric Code (CEC) in
Canada.
2. The rotation of the wheel is critical. It must be free
to rotate without striking or rubbing any stationary
objects.
1
Model VSU Make-Up Air Unit
with Direct-Fired Gas Heater
3. Motor must be securely and adequately grounded.
4. Do not spin fan wheel faster than the maximum
cataloged fan rpm. Adjustments to fan speed
significantly affects motor load. If the fan RPM is
changed, the motor current should be checked to
make sure it is not exceeding the motor nameplate
amps.
5. Do not allow the power cable to kink or come in
contact with oil, grease, hot surfaces, or chemicals.
Replace cord immediately if damaged.
6. Verify that the power source is compatible with the
equipment.
7. Never open blower access doors while the fan is
running.
DANGER
Always disconnect power before working on or near a
unit. Lock and tag the disconnect switch or breaker to
prevent accidental power up.
CAUTION
When servicing the unit, motor may be hot enough
to cause pain or injury. Allow motor to cool before
servicing.
FOR YOUR SAFETY
If you smell gas:
1. Open windows.
2. Do not touch electrical switches.
3. Extinguish any open flame.
4. Immediately call your gas supplier.
FOR YOUR SAFETY
The use and storage of gasoline or other flammable
vapors and liquids in open containers in the vicinity
of this appliance is hazardous.
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage,
injury or death. Read the installation, operating
and maintenance instructions thoroughly before
installing or servicing this equipment.
Document 470654
VSU Make-Up Air Unit

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  • Page 1: General Safety Information

    Document 470654 VSU Make-Up Air Unit with Direct-Fired Gas Heater ® ® Installation, Operation and Maintenance Manual Installation, Operation and Maintenance Manual Please read and save these instructions. Read carefully before attempting to assemble, install, operate or maintain the Please read and save these instructions. Read carefully before attempting to assemble, install, operate or maintain the product described.

  • Page 2: Receiving, Handling And Storage

    Immediately remove the original rust preventive Greenheck Fan Corporation. coating with petroleum solvent and clean with lint-free Unpacking cloths. Polish any remaining rust from surface with crocus cloth or fine emery paper and oil.

  • Page 3: Table Of Contents

    Table of Contents General Safety Information ....1 Receiving, Handling and Storage ....2 Product Overview .

  • Page 4: Product Overview

    Product Overview Subassemblies Filter Section / Vertical Mounting Stand The model is a vertically-configured make-up air unit 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.

  • Page 5: Burner, Blower And Control Center Overview

    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.

  • Page 6: Burner Subassembly

    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.

  • Page 7: Installation Concrete Slab

    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.

  • Page 8: Complete Installation

    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.
  • Page 9 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.

  • Page 10: Electrical Wiring

    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.

  • Page 11: Direct Gas Piping

    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.

  • Page 12: Building Pressure Control, Optional

    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.

  • Page 13: Start-Up Checklist

    Start-Up - Checklist Unit Model Number _______________________________ Start-Up Direct Gas (Pilot Ignition) – refer to Start-Up - Direct Gas section for further detail. (e.g. VSU-H20) Check supply gas pressure Unit Serial Number _______________________________ (e.g. 10111000) ________ Maximum Start-Up Date _______________________________ ________ Minimum ________...

  • Page 14: Blower

    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.

  • Page 15: Blower

    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.
  • Page 16 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 NOTE across the burner.
  • Page 17 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.
  • Page 18 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.

  • Page 19: Operation Optional Vav Units

    Operation - VAV Units (optional) Building Pressure Control — BLOWER EXHAUST a variable frequency drive is (OPTIONAL) SUPPLY controlled according to input from MAIN VALVES NOTE HEAT a pressure sensing device. Blower Start-Up, as shown on page 14, should be Turn both knobs to the upper DIRTY FILTERS performed before the blower is run.

  • Page 20: Optional Recirculating Units

    Operation - Recirculating Units Building Pressure Control — a BLOWER modulating spring return actuator EXHAUST (OPTIONAL) (optional) SUPPLY is used to control the return air MAIN VALVES HEAT amounts. The return air damper NOTE modulates from fully open to fully DIRTY FILTERS closed based on a signal from a Blower Start-Up, as shown on page 14, should be...

  • Page 21: Direct Gas

    • Power passes to N.C. supply overload contact • Power passes to optional N.O. and N.C. high and (ST1 OL) low gas pressure contacts (PS4 and PS3), which are both closed if gas pressure is within the set • Power passes through N.C. contact on optional range freeze protection timer (RT4) which remains closed if the temperature has remained above the...

  • Page 22: Troubleshooting

    Troubleshooting Blower Does Not Operate Proper supply power at main disconnect Check main voltage. Reference: Start-Up - Blower, Check the Voltage, pg. 14 Main disconnect (DS1) off. Turn main disconnect (DS1) on. Primary fuses blown. Replace fuses. 24 VAC between terminals R and X? Main transformer (TR1) defective.

  • Page 23: Motor Overamps

    Troubleshooting Motor Overamps Air volume too high? Adjust drives or increase external static pressure as needed. Reference: Start-Up - Blower, Air Volume Measurement and Check, pg. 14 Actual static pressure lower than design? Adjust drives to reduce blower RPM. Reference: Start-Up - Blower, Air Volume Measurement and Check, pg. 14 Blower rotation correct? Reverse blower rotation.

  • Page 24: Insufficient Airflow

    Troubleshooting Insufficient Airflow Damper(s) not fully opened? Adjust damper linkage(s), or replace faulty actuator(s). Damper actuators may take a few minutes to open. System static losses too high? Reduce losses by improving ductwork. Blower speed too low? Adjust drives as needed. Reference: Start-Up - Blower, Air Volume Measurement and Check, pg.

  • Page 25: Excessive Noise Or Vibration

    Troubleshooting Excessive Noise or Vibration Belts worn or loose? Replace worn belts or tighten loose belts. Reference: Maintenance - Routine, V-Belt Drives, pg. 31 Sheaves aligned? Align sheaves. Reference: Maintenance - Routine, V-Belt Drives, pg. 31 Wheel unbalanced? Clean and/or balance wheel(s). Bearings worn or need lubrication? Replace worn bearings or lubricate bearings as needed.

  • Page 26: Heater Does Not Operate (Pilot Ignition)

    Troubleshooting Heater Does Not Operate (Pilot Ignition) Does not attempt to light (No visible spark) 24 VAC between terminals W1 and X? Heat switch (S4) off. Turn heat switch (S4) on. Heat switch not wired. Wire heat switch (S4). 115 VAC between terminals 102 and 101? Primary fuses blown.
  • Page 27 Troubleshooting Heater Does Not Operate (Pilot Ignition) Attempts to light, but no pilot (visible spark) Check inlet gas pressure. Reference: Start-Up - Direct Gas, Note: The minimum and maximum gas pressures Check the Supply Gas Pressure, pg. 27 for your unit are shown on the direct gas label. Reference: Start-Up - Direct Gas, Check the Supply Gas Pressure, pg.

  • Page 28: Maintenance

    Troubleshooting Heater Does Not Operate (Pilot Ignition) Visible pilot Measure the flame signal Note: The flame signal should be steady and when there is a visible pilot above 1.25 VDC with a visible pilot. Reference: Start-Up - Direct Gas, Flame Signal Check - Pilot Ignition, pg. 18 Flame signal greater than 1.25 VDC Unit is not grounded.

  • Page 29: Heater Does Not Operate (Direct Spark)

    Troubleshooting Heater Does Not Operate (Direct Spark) Does not attempt to light (No visible spark) 24 VAC between terminals W1 and X? Heat switch (S4) off. Turn heat switch (S4) on. Heat switch not wired. Wire heat switch (S4). 24 VAC between terminals 22 and 21? Main transformer (TR2) defective.

  • Page 30: Heater Does Not Operate (Direct Spark)

    Troubleshooting Heater Does Not Operate (Direct Spark) Attempts to light, but no flame (Visible spark) Is the low fire set properly? Reference: Start-Up - Direct Gas, Adjust the low fire setting. Set the Minimum Firing Rate, pg. 17 Reference: Start-Up - Direct Gas, Set the Minimum Firing Rate, pg.

  • Page 31: Maintenance Routine

    Maintenance - Routine Motors CAUTION Motor maintenance is generally limited to cleaning and Lock-out the gas and the electrical power to the lubrication (where applicable). unit before performing any maintenance or service Cleaning should be limited to exterior surfaces only. operations to this unit.

  • Page 32: Bearings

    Bearings Maintenance - Fall The bearings for the fans are carefully selected to Start-Up match the maximum load and operating conditions Repeat the information as outlined in: of the specific class, arrangement and fan size. The instructions provided in this manual and those provided •...

  • Page 33: Reference

    Reference Typical Gas Train Layout with Modulating Valve (Pilot Ignition) Burner Differential Pilot Solenoid Pressure Sensor Pilot Gas Pressure Pilot Regulator Test Port Airflow Modulating Manual Pilot Valve Shut-Off Valve Low Gas Pressure Burner Manual Switch (optional) Shut-Off Valve High Gas Pressure Switch (optional) Burner Gas Safety Shut-Off Valves...
  • Page 34 Reference Typical Gas Train Layout with Direct Spark Ignition This is a typical gas train. The gas train in your unit may be different. Burner Differential Pressure Sensor (Airflow Switch) to Burner Modulating Combination Shut-Off Low Gas Pressure Valve Valve/Regulator Switch (optional) Burner Manual Shut-Off Valve...

  • Page 35: Control Center Layout

    Reference Control Center Layout 1. Supply Motor Starter — 24 volt magnetic 18. Flame Safeguard/Spark Generator (Direct contacts for starting supply motor. Spark) — monitors flame, shuts down unit when unsafe conditions are detected. 2. Supply Overload — provides electronic overload protection to supply motor.

  • Page 36: Maintenance Log

    This publication can be obtained from AMCA International, Inc. at: www.amca.org. ® Phone: 715.359.6171 • Fax: 715.355.2399 • Parts: 800.355.5354 • E-mail: gfcinfo@greenheck.com • Website: www.greenheck.com 470654 • VSU, Rev. 2, April 2013 Copyright 2013 © Greenheck Fan Corporation...

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