Reznor CAUA Installation, Operation And Maintenance Manual
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Reznor CAUA Installation, Operation And Maintenance Manual

Reznor CAUA Installation, Operation And Maintenance Manual

Indoor upflow
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INDOOR UPFLOW HEATER INSTALLATION, OPERATION,
AND MAINTENANCE
• Failure to follow safety warnings exactly could result in serious injury, death, or property
damage.
• Improper installation, adjustment, alteration, service, or maintenance can cause serious injury,
death, or property damage.
• Installation and service must be performed by a qualified installer, service agency, or the gas
supplier.
• Be sure to read and understand the installation, operation, and service instructions in this
manual.
• Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or
any other appliance.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your building.
• Leave the building immediately.
• Immediately call your gas supplier from a phone remote from the building. Follow the gas
supplier's instructions.
• If you cannot reach your gas supplier, call the fire department.
DO NOT DESTROY. PLEASE READ CAREFULLY. KEEP IN A SAFE PLACE FOR FUTURE REFERENCE.
MODEL CAUA
 ⚠ DANGER ⚠ 
FIRE OR EXPLOSION HAZARD
WHAT TO DO IF YOU SMELL GAS
Revision: CAUA-IOM (05-22) 164771-B
Supersedes: I-CAUA (06-21) 164771-A
Shown with model ACU
cased cooling coil.

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  • Page 1 Revision: CAUA-IOM (05-22) 164771-B Supersedes: I-CAUA (06-21) 164771-A INDOOR UPFLOW HEATER INSTALLATION, OPERATION, AND MAINTENANCE MODEL CAUA Shown with model ACU cased cooling coil.  ⚠ DANGER ⚠  FIRE OR EXPLOSION HAZARD • Failure to follow safety warnings exactly could result in serious injury, death, or property damage.

  • Page 2: Table Of Contents

    Enthalpy Sensors for Modulating Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 CAUA-IOM (05-22) 164771-B...
  • Page 3 INSTALLATION RECORD (TO BE COMPLETED BY INSTALLER)..........64 CAUA-IOM (05-22) 164771-B...

  • Page 4: General Information

    . The type of fuel, the firing rate, and the electrical characteristics are on the unit rating plate . • A model CAUA heater requires installation of an inlet air duct or an optional inlet air base and a supply duct or an optional discharge plenum .

  • Page 5: Installation Codes

    Refer to the limited warranty information on the warranty card in the owner’s envelope . Warranty is void if: a . Wiring is not in accordance with the diagram furnished with the heater . b . Unit is installed without proper clearance to combustible materials . CAUA-IOM (05-22) 164771-B...

  • Page 6: Dimensions

    GENERAL INFORMATION—CONTINUED Dimensions Figure 1 Table Dimensions are shown in and listed in Right Side View View Rear View Front View Bottom View Figure 1. Dimensions (Refer to Table CAUA-IOM (05-22) 164771-B...

  • Page 7: Weights

    300 grade stainless steel . Care should be taken to separate these vapors from the combustion process . This may be done by wise location of the unit vent terminal and combustion air inlet with regard to exhausters or prevailing wind directions . CAUA-IOM (05-22) 164771-B...

  • Page 8: Installation

    Duct Connections ⚠ CAUTION ⚠ To prevent possible motor overloading, ensure that the external duct system static pressure is within the limits shown on the rating plate and that the motor pulley and belt are properly adjusted CAUA-IOM (05-22) 164771-B...

  • Page 9: Requirements And Suggestions For Connecting And Installing Ducts

    (618 × 813) (953 × 813) (953 × 1168) With optional mixing box (duct opening 22 × 19-1/2 36-1/2 × 19-1/2 Attached to heater rear in top, bottom, or rear of cabinet) (578 × 495) (927 × 495) CAUA-IOM (05-22) 164771-B...

  • Page 10: Discharge Air Ductwork

    • Inlet air mounting base (option AVA2): The optional inlet air mounting base is designed to support a model CAUA 350 or 400 heater while providing an inlet for return air . The mounting base is designed to be used with an optional discharge plenum to create packaged stand-alone heating or heating/cooling upflow system which can be used in an air turnover application .
  • Page 11 Figure 2. Discharge Duct Connection (Refer to Table Table 7. Discharge Duct Dimensions Unit Size Dimension (See Figure 150, 200 250, 300 350, 400 Dimensions (Inches (mm)) 36 (914) 48 (1219) 48 (1219) 21 (533) 21 (533) 34 (864) CAUA-IOM (05-22) 164771-B...

  • Page 12: Venting/Combustion Air Connections

    • The venting or venting/combustion air systems illustrated in this manual are the only ones approved for a model CAUA heater. DECIDE WHICH VENTING SYSTEM TO INSTALL: • Power-vented: a power-vented installation uses a power venter to draw combustion air from the indoor space and exhaust flue products to the outdoors.
  • Page 13 9) before installing an elbow in the vent system . An elbow should never be attached directly to the venter . An elbow attached to the straight pipe can be in any position at or above horizontal (see Figure 4, DETAIL A) . CAUA-IOM (05-22) 164771-B...
  • Page 14 Figure 4. Vent Pipe for Power-Vented Installations NOTES: • Do not install dampers or any other type of flue restrictor device. • If installing a double-wall vent run (allowed if half of the vent length is vertical), see Figure DETAIL B. CAUA-IOM (05-22) 164771-B...
  • Page 15 Perform STEP 2 immediately fol- Do not overtighten screws. lowing STEP 1. Single-wall or Category Double- III vent pipe Wall Pipe or taper-type reducer Figure 5. Joining Double-Wall (Type B) Pipe to Single-Wall or Category III Vent Pipe CAUA-IOM (05-22) 164771-B...
  • Page 16 (vertical vent configurations) and (horizontal vent configurations) . Refer to horizontal vent terminal clearances . NOTE: A vent cap is required. Maintain a clearance of 12” (305mm) from the wall to the vent terminal cap for stability under wind conditions. CAUA-IOM (05-22) 164771-B...
  • Page 17 SINGLE-WALL VENT RUN AND SINGLE-WALL TERMINAL SINGLE-WALL VENT RUN AND DOUBLE-WALL TERMINAL Figure 7. Vertical Vent Terminal—Power-Vented Installations CAUA-IOM (05-22) 164771-B...
  • Page 18 INSTALLATION—CONTINUED Venting/Combustion Air Connections—Continued Venting/Combustion Air Requirements for Power-Vented Installations—Continued SINGLE-WALL VENT RUN AND SINGLE-WALL TERMINAL SINGLE-WALL VENT RUN AND DOUBLE-WALL TERMINAL Figure 8. Horizontal Vent Terminal—Power-Vented Installations CAUA-IOM (05-22) 164771-B...

  • Page 19: Venting/Combustion Air Requirements For Separated-Combustion Installations

    Diameter (Inches (mm)) Venter outlet 5 (127) 5 (127) 6 (152) Combustion air inlet 6 (152) CUT OUT HOLE FOR VENTER OUTLET COLLAR COMBUSTION AIR PIPE COMBUSTION AIR INLET COLLAR Figure 9. Venter Outlet and Combustion Air Pipe Collars CAUA-IOM (05-22) 164771-B...
  • Page 20 6 inches (152 mm) from the concentric adapter box . e . To seal the joint between the terminal section of double-wall vent pipe and the vent cap: Follow the Figure 10 . illustrated step-by-step instructions in CAUA-IOM (05-22) 164771-B...
  • Page 21 • Concentric adapter box: The concentric adapter box is included in the vent/combustion air kit . Installation instructions depend on whether the vent system is horizontal (option CC6) or vertical (option CC2) . All separated- Figure 11 . combustion installations require a concentric adapter box as shown in CAUA-IOM (05-22) 164771-B...
  • Page 22 Adapter Box Figure 11. Concentric Adapter Box • Concentric adapter box pipe connections: When pipe diameters differ, depending on direction of airflow, join Figure 12 . the pipes with either a tapered reducer or enlarger as shown in CAUA-IOM (05-22) 164771-B...
  • Page 23 The connection requirements are the same for both vertical and horizontal systems, but pipe length requirements vary. Unit Sizes 150 and 200 • CAUA Sizes 150 and 200 always require a 5” to 4” (127 to 102 mm) reducer in the vent pipe.

  • Page 24: Vertical Vent Terminal For Separated-Combustion Installations (Option Cc2)

    110052 Exhaust vent terminal assembly (see 155635 53330 Combustion air inlet assembly (see Figure 207232 Concentric adapter box bracket 53335 High-temperature silicone sealant, tube EXHAUST VENT TERMINAL ASSEMBLY COMBUSTION AIR INLET ASSEMBLY Figure 14. Option CC2 Components CAUA-IOM (05-22) 164771-B...
  • Page 25 . Extend piping runs close to roof at location selected in step 1 and support piping . NOTE: The vent pipe will extend through the roof after the concentric adapter box is installed. The indoor combustion air pipe will end at the box. CAUA-IOM (05-22) 164771-B...
  • Page 26 . Position concentric adapter box to match pipe runs and secure short angles of concentric adapter brackets Figure 16) to underside of roof using field-supplied hardware . (see c . Install field-supplied flashing around combustion air pipe on roof outside . CAUA-IOM (05-22) 164771-B...
  • Page 27 Figure 17. Combustion Air Pipe Installation Figure 18. Combustion Air Pipe Through Roof CAUA-IOM (05-22) 164771-B...
  • Page 28 Be sure not to penetrate the vent pipe. 3) At the top, completely seal the space between the vent pipe and the air inlet with silicone. Single-wall Combustion Air Pipe Figure 19. Combustion Air Inlet and Vent Terminal Installation CAUA-IOM (05-22) 164771-B...

  • Page 29: Horizontal Vent Terminal For Separated-Combustion Installations (Option Cc6)

    • In climates with below freezing temperatures, condensate may form icicles on the vent terminal. Locate the terminal where falling icicles do not present a hazard. • Consider local snow depth conditions. The vent must be at least 6 inches (152 mm) above the anticipated snow depth. CAUA-IOM (05-22) 164771-B...
  • Page 30 (2) Plus wall thickness (3) Plus 2 inches (51 mm) beyond wall b . Secure inlet air pipe to collar of concentric adapter box using sheet metal screws . Seal joint and seam using tape or sealant . CAUA-IOM (05-22) 164771-B...
  • Page 31 . Secure short angles (see Figure 21) of concentric adapter box brackets to wall . c . Seal or flash inlet air pipe on outside using sealant and/or field-supplied flashing . Top View Side View Figure 21. Option CC6 Installation CAUA-IOM (05-22) 164771-B...

  • Page 32: Piping Connections

    • Test pressures above 1/2 psi—disconnect the heater and manual valve from the gas supply line to be tested. Cap or plug the supply line. • Test pressures below 1/2 psi—before testing, close the manual valve on the heater. CAUA-IOM (05-22) 164771-B...

  • Page 33: Gas Supply Piping

    22) . typically 6-inch (see • Seal the opening for the gas supply pipe with the grommet provided . • Bleed the system of all air and leak test all connections by brushing on a soap solution . CAUA-IOM (05-22) 164771-B...

  • Page 34: Condensate Drain Installation

    • Burner condensate drain: If the packaged unit includes a cased cooling coil, the installation of a burner condensate drain line is required . The parts to install the drain line are packaged and shipped with all Model CAUA heaters .

  • Page 35: Electrical Connections

    1) and connect to the supply voltage The electrical supply and control wiring enter at the top of the heater (see terminal strip located above the contactor(s) or starter(s) . Consult the wiring diagram provided with the heater . CAUA-IOM (05-22) 164771-B...

  • Page 36: Thermostat Wiring

    STRIP STRIP TERMINAL CL33 STRIP Figure 24. Wiring Connections for Options CL1, CL22, CL52, and CL33 CONTROLS NOTE: Refer to the TROUBLESHOOTING section for probable causes and reset instructions for the following controls. Figure 25. Control Locations CAUA-IOM (05-22) 164771-B...

  • Page 37: Thermostat

    . The main burners will remain off until the system has cooled and/or the flue system resistance is reduced . Refer to Table 18 for approximate water column negative pressure readings and combustion air proving switch setpoints for sea level operating conditions (standard settings apply to 0–4000 feet elevation (US) or 0–2000 feet elevation (Canada)) . CAUA-IOM (05-22) 164771-B...

  • Page 38: Flame Rollout Switch

    . Ignition System • A model CAUA heater is equipped with a direct-spark integrated-control system . The system monitors the safety devices and controls the operation of the blower and venter motors and the gas valve .

  • Page 39: Dirty Filter Switch

    Belts, Blowers, and Drives • Model CAUA units are equipped with either direct-drive motor(s) and blower(s) or adjustable belt-drive blower(s) and motor . All direct-drive blower motors are 1 Horsepower (HP) . Unit sizes 150–200 have a single motor, unit size 150 has a 12-9 blower, and unit size 200 has a 12-12 blower .

  • Page 40: Inlet Air Dampers

    . When in the heating mode, the temperature of the mixed return and outside air entering a standard model CAUA heater must always be 35°F or above . Only when the heater is factory-equipped with makeup air option AD4 can the entering air temperature be below 35°F .

  • Page 41: Startup

    • Do not use this appliance if any part has been under water. Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control which has been under water. CAUA-IOM (05-22) 164771-B...
  • Page 42 . If service is to be performed, turn OFF electric power to appliance . c . Open access door . d . Turn gas control knob to OFF (refer to step 4) . Do not force control knob . e . Close access door . CAUA-IOM (05-22) 164771-B...

  • Page 43: Operating Sequences

    . When the limit switch re-closes or the call for heat is lost, the control runs the induced draft motor through post purge and runs the blower through the selected fan off delay . CAUA-IOM (05-22) 164771-B...

  • Page 44: Ignition System Operating Sequence

    . If the gas valve was sensed as closed when it should be open, and has not de-energized after the venter motor was shutoff for 15 seconds, then the venter motor is re-energized to vent the unburned gas . CAUA-IOM (05-22) 164771-B...

  • Page 45: Vent System Testing

    . Follow instructions on envelope . ‰ IMPORTANT: After at least 8 hours but no longer than 1 week of operation, recheck blower wheel, all setscrews, blower pulley, motor pulley, and belt tension . Make any required adjustments . CAUA-IOM (05-22) 164771-B...

  • Page 46: Adjustments

    No change should be made to the starter setting unless the original motor is replaced. Starters are equipped with a manual reset. If an overload condition is experienced, the condition must be corrected and the starter must be manually-reset. CAUA-IOM (05-22) 164771-B...
  • Page 47 3/4 inch (see Figure 28) . Re-tighten the lock nut on the adjusting screw . Ensure that the belts are aligned in the pulley grooves properly and are not angled from pulley to pulley . CAUA-IOM (05-22) 164771-B...

  • Page 48: Ductstat Adjustment (Two-Stage, Makeup Air, Option Ag3)

    • Due to different CFM settings and outside air temperatures, the average downstream outlet temperature may not match the ductstat setting exactly . After the installation is complete, adjust the setpoint of the ductstat to achieve the desired average outlet air temperature . CAUA-IOM (05-22) 164771-B...

  • Page 49: Measure And Adjust Manifold (Outlet) Gas Pressure

    3 . Normally, adjustments to the factory-preset regulator should not be necessary . If adjustment is necessary, set pressure to correct settings by turning the regulator screw IN (clockwise) to increase pressure or OUT (counterclockwise) to decrease pressure . CAUA-IOM (05-22) 164771-B...

  • Page 50: High Elevation (>2,000 Feet/609 Meters) Installations

    Failure to use the proper conversion kit can cause fire, explosion, property damage, carbon monoxide poisoning, personal injury, or death. If LP (propane) conversion is required, convert the unit in accordance with form CAUA-GC listed in Table 1 .
  • Page 51 84437 61652 1 .45 mm 39651 63922 1 .15 mm 39658 84583 63922 1 .15 mm 7001–8000 39658 84437 11834 39651 63922 1 .15 mm 39658 40414 63922 1 .15 mm 8001–9000 39658 84437 11830 11828 11834 CAUA-IOM (05-22) 164771-B...

  • Page 52: Dirty Filter Switch Adjustment

    ‰ Check filters ‰ Check ignitor ‰ Clean venter ‰ If equipped with cooling coil, check drain lines and clean as necessary Electrical Connections ‰ Check wiring for any damaged wire—replace damaged wiring (refer to section for wiring requirements) CAUA-IOM (05-22) 164771-B...

  • Page 53: Maintenance Procedures

    . Observe gas pressure on manometer . There should be no loss of gas pressure . If manometer indicates loss of gas pressure, replace combination gas valve before placing heater in operation . CAUA-IOM (05-22) 164771-B...

  • Page 54: Burner Rack And Manifold Maintenance

    . If two, right and left sections extend over front . If three, there will be right, left, and separate front section . b . Remove screws (see Figure 31) that secure manifold to burner rack . Slide manifold from burner rack . Figure 31. Burner Rack Removal CAUA-IOM (05-22) 164771-B...

  • Page 55: Cleaning Heat Exchanger

    . If the unit is equipped with a belt drive, check the belt for signs of wear . Replace if needed . If belt adjustment is required, refer to the Checking and Adjusting Belt Tension section . If blower speed adjustment is Adjusting Blower Speed required, refer to the section . CAUA-IOM (05-22) 164771-B...

  • Page 56: Filter Maintenance

    Do not attempt to disassemble ignition control module . However, each heating season lead wires should be checked for insulation deterioration and good connections . NOTE: Proper operation of the direct spark ignition system requires a minimum flame signal of 1.0 microamps as measured by a microampmeter. CAUA-IOM (05-22) 164771-B...

  • Page 57: Venter Motor And Wheel Maintenance

    (6) Check for proper balance . If wheel is damaged or does not turn properly, replace it . g . Install assembled venter motor and wheel . Follow wiring diagram to connect venter wires . h . Close access panel . CAUA-IOM (05-22) 164771-B...

  • Page 58: Transformer Maintenance

    There is no service required on this motor other than external cleaning . If the motor requires replacement, replace with an identical damper motor . Modulating Damper Motor with Logic Module Maintenance There is no service required other than external cleaning . If the motor or module requires replacement, replace with identical parts . CAUA-IOM (05-22) 164771-B...

  • Page 59: Potentiometer Maintenence

    . Cracked ceramic at sensor Replace sensor 10 . Flame rollout switch open a . Air blockage through unit Check for heat exchanger or vent pipe blockage b . Defective flame rollout switch Replace flame rollout switch CAUA-IOM (05-22) 164771-B...
  • Page 60 1 . Low or high supply voltage Correct electric supply motor cuts 2 . Defective blower motor Replace blower motor out on 3 . Static pressure incompatibility Adjust blower speed or ductwork overload 4 . Defective bearing Replace blower motor CAUA-IOM (05-22) 164771-B...

  • Page 61: Unit Troubleshooting Using Ignition Control Module

    Pressure switch is closed before venter motor is energized Steady OFF Blown fuse, no power, or defective board Steady ON Flame is sensed Yellow Slow flash Weak flame—current below 1 .0 (±50%) microamps Fast flash Undesired flame—valve open and no call for heat CAUA-IOM (05-22) 164771-B...
  • Page 62 TROUBLESHOOTING—CONTINUED Unit Troubleshooting Using Ignition Control Module—Continued Figure 35. Ignition Control Module Troubleshooting Flowchart CAUA-IOM (05-22) 164771-B...
  • Page 63 NOTES CAUA-IOM (05-22) 164771-B...

  • Page 64: Installation Record (To Be Completed By Installer)

    For more information, contact your Factory Representative. Specifications and illustrations subject to change without notice or incurring obligations . Latest version of this manual is available at www.reznorhvac.com . ©2022 Nortek Global HVAC LLC, O’Fallon, MO . All rights reserved . CAUA-IOM (05-22) 164771-B...

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