Greenheck 470654 - Manual

5 Model VSU Make-Up Air ® Burner, Blower and Control Center Section The burner section, blower section and control center of the unit are all combined into one assembly which is installed in the field on top of the filter and stand section. The burner section is the lowest part of the burner / blowe...

6 Model VSU Make-Up Air ® Burner Subassembly The burner subassembly consists of the gas train with its controls, valves, pressure regulator, burner(s), and combustion chamber. The primary gas connection to the gas train is made through the side wall grommet into the factory-supplied female pipe fitt...

7 Model VSU Make-Up Air ® Burner/Blower Section Use a crane and a spreader bar hooked to the factory lifting lugs (shown below) to lift and center the unit onto the filter stand section. The sections should be caulked together. Install Ductwork This table shows the duct sizes and straight lengths re...

8 Model VSU Make-Up Air ® Complete Installation 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 ...

9 Model VSU Make-Up Air ® 5. Fasten three (3/8 in. x 1-1/2 in.) hex head bolts into the side of the platform base. Secure each bolt with two (3/8 in.) hex head nuts placed back to back on each bolt as shown in Figure B. These bolts will be used to attach the platform base to the unit. 6. Facing the ...

10 Model VSU Make-Up Air ® Installation of Electrical Wiring IMPORTANT Before connecting power to the unit, read and understand the following instructions and wiring diagrams. Complete wiring diagrams are attached on the inside of the control center door(s). IMPORTANT All wiring should be done in ac...

11 Model VSU Make-Up Air ® Installation of Direct Gas Piping Determine the Supply Gas Requirements The unit’s direct gas nameplate states the requirements for the gas being supplied to the unit. The direct gas nameplate is located on the outside of the unit on the control center side. Type of gas “ ...

12 Model VSU Make-Up Air ® Vent Line Solenoid To Burner Vent Line To Outdoors From Supply Safety Shut-off Valves Optional Vent Line WARNING NEVER test for a gas leak with an open flame. NOTE The factory piping has been checked for leaks, but should be rechecked due to shipping and installation. Conn...

13 Model VSU Make-Up Air ® Unit Model Number _______________________________ (e.g. VSU-H20) Unit Serial Number _______________________________ (e.g. 10111000) Start-Up Date _______________________________ Start-Up Personnel Name __________________________Start-Up Company ____________________________...

14 Model VSU Make-Up Air ® NOTE The most accurate way to measure the air volume is by using a pitot traverse method downstream of the blower. Other methods can be used, but should be proven and accurate. IMPORTANT Changing the air volume can significantly increase the motor’s amps. If the air volume...

15 Model VSU Make-Up Air ® Set-Up Optional Components Adjust the settings on the optional components. See the unit’s specific wiring diagram located on the access door or the unit. • Heating Inlet Air Sensor Typical setting: 60-70ºF • Building Freeze Protection Typical setting: 5 minutes; 45ºF • Dir...

16 Model VSU Make-Up Air ® IMPORTANT Proper air velocity over the burner is critical on direct- fired gas units. If the air velocity is not within the unit specifications, the unit will not operate efficiently, may have sporadic shutdowns, and may produce excessive carbon monoxide (CO) or other gase...

17 Model VSU Make-Up Air ® IMPORTANT Setting the maximum firing rate during mild weather conditions may cause the high limit to trip out during extreme conditions requiring manual resetting. NOTE Gas trains are equipped with either separate regulators and modulating valves or with a combined modulat...

18 Model VSU Make-Up Air ® IMPORTANT If the flame signal is not above 1.25 VDC and steady, consult the troubleshooting section. Flame Signal Check - Pilot Ignition To measure the flame signal connect a standard DC voltmeter to the flame amplifier test jacks + and - (com) as shown to the right. The f...

19 Model VSU Make-Up Air ® Building Pressure Control — a variable frequency drive is controlled according to input from a pressure sensing device.Turn both knobs to the upper most pressure setting. You may have to remove the outdoor pressure tap tubing. VAV systems should go to maximum speed. Set bo...

20 Model VSU Make-Up Air ® Operation - Recirculating Units (optional) NOTE Blower Start-Up, as shown on page 14, should be performed before the blower is run. Recirculation Operation The recirculation operation option is recommended when the ventilation equipment provides the primary source of heati...

21 Model VSU Make-Up Air ® Direct Gas Burner Sequence - Pilot Ignition1. Supply Fan Contact Closed • Power passes to the supply fan and heat switch 2. Heat Contact Closed • Power passes to the heat relay then to the Flame Safeguard 3. Flame Safeguard (FSG) Sequence • Checks for proper airflow• Verif...

22 Model VSU Make-Up Air ® Blower Does Not Operate Troubleshooting 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...

23 Model VSU Make-Up Air ® Motor Overamps Troubleshooting Air volume too high? Adjust drives or increase external static pressure as needed. Reference: Start-Up - Blower, Air Volume Measurement and Check, pg. 14 Motor horsepower too low? Resize motor. Motor voltage correct? Provide proper power supp...

24 Model VSU Make-Up Air ® Insufficient Airflow Troubleshooting Damper(s) not fully opened? Adjust damper linkage(s), or replace faulty actuator(s). Damper actuators may take a few minutes to open. Filters dirty or clogged Clean or replace filters. Reference: Maintenance - Routine, Filters, pg. 31 B...

25 Model VSU Make-Up Air ® Excessive Noise or Vibration Troubleshooting Sheaves aligned? Align sheaves. Reference: Maintenance - Routine, V-Belt Drives, pg. 31 Wheel unbalanced? Clean and/or balance wheel(s). Belts worn or loose? Replace worn belts or tighten loose belts. Reference: Maintenance - Ro...

26 Model VSU Make-Up Air ® Heater Does Not Operate (Pilot Ignition) Does not attempt to light (No visible spark) Troubleshooting 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? Pri...

27 Model VSU Make-Up Air ® Heater Does Not Operate (Pilot Ignition) Attempts to light, but no pilot (visible spark) Troubleshooting Gas pressure between the minimum and maximum shown on the direct gas label? Check inlet gas pressure. Reference: Start-Up - Direct Gas, Check the Supply Gas Pressure, p...

28 Model VSU Make-Up Air ® Heater Does Not Operate (Pilot Ignition) Visible pilot Troubleshooting Flame signal greater than 1.25 VDC Measure the flame signal when there is a visible pilot Pressure drop across the burner between 0.625 and 0.675 in. WC? Check for proper airflow Reference: Start-Up - D...

29 Model VSU Make-Up Air ® Heater Does Not Operate (Direct Spark) Does not attempt to light (No visible spark) Troubleshooting 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 tra...

30 Model VSU Make-Up Air ® Heater Does Not Operate (Direct Spark) Attempts to light, but no flame (Visible spark) Troubleshooting Check inlet gas pressure. Reference: Start-Up - Direct Gas, Check the Supply Gas Pressure, pg. 15 Is the low fire set properly? Reference: Start-Up - Direct Gas, Set the ...

31 Model VSU Make-Up Air ® Maintenance - Routine CAUTION Lock-out the gas and the electrical power to the unit before performing any maintenance or service operations to this unit. V-Belt Drives V-belt drives must be checked on a regular basis for wear, tension, alignment, and dirt accumulation.Chec...

32 Model VSU Make-Up Air ® Bearings The bearings for the fans are carefully selected to match the maximum load and operating conditions of the specific class, arrangement and fan size. The instructions provided in this manual and those provided by the bearing manufacturer will minimize any bearing p...

33 Model VSU Make-Up Air ® Reference Typical Gas Train Layout with Modulating Valve (Pilot Ignition) High Gas Pressure Switch (optional) Low Gas Pressure Switch (optional) Manual Pilot Shut-Off Valve Pilot Regulator Pilot Solenoid Burner Gas Pressure Test Port Burner Differential Pressure Sensor Pil...

34 Model VSU Make-Up Air ® Burner Differential Pressure Sensor (Airflow Switch) Burner Manual Shut-Off Valve High Gas Pressure Test Port High Gas Pressure Switch (Optional) Modulating Valve To Burner Combination Shut-Off Valve/ Regulator Low Gas Pressure Test Port Low Gas Pressure Switch (Optional) ...

35 Model VSU Make-Up Air ® Control Center Layout Dirty Filter Switch Reference 13 22 26 28 27 20 15 21 4 1 7 8 2 9 3 5 16 23 17 18 19 14 25 10 12 11 6 24 1. Supply Motor Starter — 24 volt magnetic contacts for starting supply motor. 2. Supply Overload — provides electronic overload protection to sup...

36 Greenheck warrants this equipment to be free from defects in material and workmanship for a period of one year from the shipment date. Any units or parts which prove defective during the warranty period will be replaced at our option when returned to our factory, transportation prepaid. Motors ar...