REZNOR EUH Electric Unit Heater Installation Guide
- June 15, 2024
- Reznor
Table of Contents
REZNOR EUH Electric Unit Heater Installation Guide
DANGER
- Read all instructions before using the heater.
- 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 technician.
- Be sure to read and understand the installation, operation, and service instructions in this manual.
- This heater has hot parts inside. Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.
- This heater is hot when in use. To avoid burns, do not let bare skin touch hot surfaces.
- Do not operate any heater after it malfunctions. Disconnect power at the service panel and have the heater inspected by a reputable electrician before reusing.
- Do not use outdoors.
- Do not insert or allow foreign objects to enter any heater opening as this may cause electrical shock, fire, or damage to the heater.
- To prevent a possible fire, do not block air intakes or exhaust in any way whatsoever.
- Use this heater only as recommended by the manufacturer. Any other use may cause electrical shock, fire, or damage to the heater.
IMPORTANT INSTRUCTIONS
SAVE THESE INSTRUCTIONS
GENERAL INFORMATION
- This unit heater has been tested for capacity and efficiency so as to provide many years of safe and dependable comfort providing it is properly installed and maintained. With regular maintenance, this unit will operate satisfactorily year after year. Abuse, improper use, and/or improper maintenance can shorten the life of the appliance and create unsafe hazards.
- To achieve optimum performance and minimize equipment failure, it is recommended that periodic maintenance be performed on this unit. The ability to properly perform maintenance on this equipment requires certain tools and mechanical skills.
References
Important Safety Information
Please read all information in this manual thoroughly and become familiar with
the capabilities and use of your appliance before attempting to operate or
maintain this unit. Pay attention to all dangers, warnings, cautions, and
notes highlighted in this manual. Safety markings should not be ignored and
are used frequently throughout to designate a degree or level of seriousness.
DANGER: A danger statement describes a potentially hazardous situation that if
not avoided, will result in severe personal injury or death and/or property
damage.
WARNING: A warning statement describes a potentially hazardous situation that
if not avoided, can result in severe personal injury and/or property damage.
CAUTION: A caution statement describes a potentially hazardous situation that
if not avoided, can result in minor or moderate personal injury and/or
property damage.
NOTE: A note provides important information that should not be ignored.
DANGER
Read these instructions carefully before installation and operation of the
heater. Failure to adhere to the instructions could result in fire, electric
shock, serious personal injury, death, or property damage. Review frequently
for continuing safe operation and instruction of future users, if necessary.
WARNING
- Installation should be done by a qualified agency in accordance with these instructions. The qualified service agency installing this heater is responsible for the installation.
- This appliance is not intended for use by persons with reduced physical, sensory, or mental capabilities or lack of experience and knowledge, unless they have been given supervision or instruction concerning use of the appliance by a person responsible for their safety.
- Children should be supervised to ensure that they do not play with the appliance.
**CAUTION**
- The thermostat should not be considered an infallible device in cases where maintaining a temperature is considered critical. In these particular cases, it is imperative to add a monitoring system to avoid the consequences of a thermostat failure.
- This heater is not approved for use in corrosive atmospheres, wet or very humid locations such as marine green house, or chemical storage areas.
- To prevent damage to the unit or to its internal components, it is recommended that two wrenches be used when loosening or tightening nuts. Do not over tighten!
Warranty
Refer to the limited warranty form in the literature bag provided with the
unit. The warranty is void if:
- Wiring is not in accordance with the diagram furnished with the heater.
- The unit is installed without proper clearance to combustible materials.
- The air delivery system is modified.
Certification
These electric unit heaters are listed by Intertek to UL 2021 and CSA C22.2
46 for use in the US and Canada.
Installation Codes
These units must be installed in accordance with local building codes. Local
authorities having jurisdiction should be consulted before installation is
made to verify local codes and installation procedure requirements.
Heater Location
CAUTION
Do not locate the heater where it may be exposed to water spray, rain, or
dripping water.
For best results, the heater should be located with certain rules in mind:
- Units should always be arranged to blow toward or along exposed wall surfaces, if possible. Where two or more units are installed in the same room, a general scheme of air circulation should be maintained for best results.
- Suspended heaters are most effective when located as close to the working zone as possible, and this fact should be kept in mind when determining the mounting heights to be used. However, care should be exercised to avoid directing the discharged air directly on the room occupants.
- Partitions, columns, counters, or other obstructions should be taken into consideration when locating the unit heater so that a minimum quantity of airflow will be deflected by such obstacles.
- When units are located in the center of the space to be heated, the air should be discharged toward the exposed walls. In large areas, units should be located to discharge air along exposed walls with extra units provided to discharge air in toward the center of the area.
Mounting Height
WARNING
If touched, the internal heater surfaces that are accessible from outside the
heater will cause burns. Suspend the heater a minimum of 6 feet (1.8 meters)
above the floor.
In general, a unit should be located 6–14 feet (1.8–4.3 meters) above the
floor. At those points where infiltration of cold air is excessive, such as at
entrance doors and shipping doors, it is desirable to locate the unit so that
it will discharge directly toward the source of cold air from a distance of
15–20 feet (4.6–6.1 meters).
Heater Throw
Figure 1 shows throw patterns and Table 2 lists throw distances for heaters
suspended at varying mounting heights. The louver angles listed are relative
to the top of the heater.
Figure 1. Heater Throw Patterns (Refer to Table 2)
Dimensions
Figure 2. Dimensions (Refer to Table 3)
Weights
Clearances
DANGER
Keep combustible materials like furniture, pillows, bedding, papers, clothes,
and curtains at least 36 inches (915 mm) away from the front of the heater.
The unit must be located so that the clearances listed in Table 5 are provided
for with regards to inspection and service and for proper spacing from
combustible construction. Clearance to combustibles is defined as the minimum
distance from the heater to a surface or object for which it is necessary to
ensure that a surface temperature of 90°F (50°C) above the surrounding ambient
temperature is not exceeded. Refer to the dimensions listed in Table 3 and
shown in Figure 2 when determining clearances to combustibles.
INSTALLATION
Unpacking and Inspection
The unit was test-operated and inspected at the factory prior to crating and
was in operating condition. If, upon removing it from its crate, the unit has
been found to have incurred any damage in shipment, document the damage with
the transporting agency and contact an authorized Factory Distributor. If you
are an authorized Distributor, follow the FOB freight policy procedures.
Pre-Installation Checklist
- Check the rating plate for the electrical characteristics of the heater to ensure that they are compatible with the electric supply at the installation site.
- Read this manual and become familiar with the installation requirements of your particular heater.
- If you do not have knowledge of local requirements, check with the local agencies who might have requirements concerning this installation.
- Before beginning, make preparations for necessary supplies, tools, and manpower.
- Check to see if there are any field-installed options (refer to Table 6) that need to be assembled/installed prior to unit installation. Ensure that all options ordered are at the installation site. Instructions are in this manual or in the shipped-separate option package.
- The wall-mounting bracket is shipped with the unit. If the unit is to be mounted on a wall, ensure that the required field-supplied hardware is available (refer to Suspension of Heater Using Wall-Mounting Bracket section).
Heater Suspension
**** WARNING
- Before suspending the unit, check the supporting structure to be used to verify that it has sufficient load-carrying capacity to support the weight of the unit (refer to Weights section).
- DO NOT add additional weight to a suspended unit.
**** CAUTION
When the heater is lifted for suspension, support the bottom of the heater
with plywood or other appropriately placed material. If the bottom is not
supported, damage could occur.
The heater is designed to be suspended using two-point suspension. A 3/8-16 threaded nut retainer is located at each suspension point. The heater may be suspended using either 3/8-inch threaded rods, a hanger kit option package, or the wall-mounting bracket shipped with the unit.
Suspension of Heater Using Option CK8 Two-Point Suspension Kit
Option CK8 allows the heater to be suspended using two swivel connectors connected to 1-inch pipe. Attach the swivel connectors at the 3/8-16 threaded nut retainers. Ensure that the swivel connectors are locked to the heater as shown in Figure 3.
Figure 3. Option CK8 Two-Point Suspension Kit
Suspension of Heater Using Field-Supplied Threaded Rods
The heater may be suspended from 3/8-inch threaded rods using two-point
suspension. The recommended maximum rod length is 6 feet (1.8 meters). The
length of the threaded rod extending into the heater MUST NOT exceed 1/2 inch
(13 mm). Ensure that the threaded rods are locked to the heater as shown in
Figure 4.
Figure 4. Heater Suspension Using Field-Supplied Threaded Rods
Suspension of Heater Using Wall-Mounting Bracket
Secure the wall-mounting bracket shipped with the heater as shown in Figure 5.
The bracket is secured to the heater at the 3/8-16 threaded nut retainers
using 1- to 2-inch-long 3/8-16 bolts. Secure the mounting bracket to the wall
using field-supplied hardware.
Figure 5. Heater Suspension Using Wall-Mounting Bracket
Suspension of Heater Using Option CK22 Ceiling Suspension Kit
Option CK22 allows the heater to be installed 1 inch from the ceiling without
hanger rods. Refer to the installation instructions provided with the kit.
Electrical Connections
****CAUTION
Ensure that all wiring is in accordance with the wiring diagram (refer to
APPENDIX: WIRING DIAGRAMS) provided with the unit.
- All electrical wiring and connections, including electrical grounding MUST be made in accordance with the National Electric Code ANSI/NFPA No. 70 (latest edition) or, in Canada, the Canadian Electric Code, Part 1 (CSA C.22.1). In addition, the installer should be aware of any local ordinances that might apply.
- Check the rating plate on the heater for the supply voltage and current requirements. A dedicated line voltage supply with a disconnect switch should be run directly from the main electrical panel to the heater.
- All external wiring must be within approved conduit and have a minimum temperature rise rating of 60°C. Conduit must be run so as not to interfere with the heater access panel.
Supply Wiring Connection
Check the rating plate on the unit for the supply voltage and current requirements.
NOTE: IMPORTANT (BEFORE CONNECTING THE SUPPLY WIRING): Determine if units with option AK6 or AK44 require field-modification of the transformer or contactor wiring.
If required, modify the transformer or contactor wiring as follows:
a. Units with voltage option AK6 are factory-wired for 240V supply. Field-
modification to the unit wiring is required for 208V applications. Refer to
the wiring diagram to change the white transformer wire from the 240 terminal
to the 208 terminal.
b. Units with voltage option AK44 are factory-wired for 208V/240V/1Ph supply.
Field-modification to the unit wiring is required for 3Ph applications. Refer
to the wiring diagram to change the black contactor wires as follows:
(1) Loosen terminal screws T1, T2, and T3 on 3-pole contactor (see Figure 6)
terminals.
(2) Disconnect black wires from T1 and T2 terminals and connect them to T3
terminal.
(3) Tighten all terminal screws.
Figure 6. Typical Control Panels
The supply wiring enters as shown in Figure 7 and connects to the terminal block on the control panel shown in Figure 6).
Figure 7. Supply Wiring Entrance and Control Connection Terminal Strip
Control Connections
- The terminal strip for 24V control connections is located on the outside of the cabinet at the back of the unit, as shown in Figure 7. The strip has five terminals: C, R, G, W1, and W2.
- The thermostat connections are the C (optional), R, G, W1, and W2 (optional) terminals.
- If the installation features a heater and an H series HuracanTM destratification fan controlled by a single two-stage thermostat, ensure that the wiring is in accordance with the wiring diagram shown in Figure 8.
Figure 8. Heater and Destratification Fan Wiring Diagram
CONTROLS
Disconnect Switch
A disconnect switch is available as optional equipment (refer to Table 6) or
it may be field-supplied. When installing the disconnect switch on the back of
the unit, allow at least 4 feet (1.2 meters) of service room between the
switch and any service panels and ensure that conduit and the switch housing
are clear of all service doors.
Fan Motor
The fan motor is equipped with automatic-reset thermal overload protection. If
the motor does not run, the cause may be due to improper voltage. Ensure that
the correct voltage is available at the motor.
Thermostat
The unit may be controlled by a thermostat—either an optional thermostat
(refer to Table 6) or a field-supplied 24V thermostat that must be field-
installed in accordance with the thermostat manufacturer’s instructions. Pay
particular attention to the requirements regarding the location of the
thermostat. In accordance with the wiring diagram provided with the unit,
connect the thermostat at the 24V control wiring terminal strip on the back of
the unit (refer to Control Connections section).
Air Proving Pressure Switch
WARNING
The automatic-reset air proving pressure switch will continue to shut down the
heater until the cause is corrected. Never bypass this switch as hazardous
conditions could result.
All units are equipped with an automatic-reset air proving pressure switch (see Figure 6) that senses air pressure provided by fan operation. The switch is factory-set and is non-adjustable. If the setpoint is reached, the switch interrupts the electric supply to the heating elements. This safety device provides protection in the case of fan motor failure or lack of airflow due to a restriction at the inlet or outlet.
High Temperature Limit Switch
WARNING
The automatic-reset high temperature limit switch will continue to shut down
the heater until the cause is corrected. Never bypass this switch as hazardous
conditions could result.
All units are equipped with a temperature-activated, automatic-reset high
temperature limit switch (see Figure 6). The switch is factory-set and is non-
adjustable. If the setpoint is reached, the switch interrupts the electric
supply to the heating elements. This safety device provides protection in the
case of fan motor failure or lack of airflow due to a restriction at the inlet
or outlet.
Multiple Heater Control
If the unit was ordered with a multiple heater control option, one thermostat
can be used to control up to five heaters. This option includes a relay
assembly that attaches to each additional unit. Option CL31 provides for
control of two heaters. If control of additional heaters is desired (up to
five total), option CL32, which is the relay assembly only, must be added to
each additional heater. The option packages are shipped separately and include
complete instructions on installation and wiring.
OPERATION
Pre-Startup Checklist
Check the following before startup:
- Check to ensure that all screws used to secure shipping brackets have been re-installed in heater cabinet.
- Check suspension—unit must be secure and level.
- Check to ensure that clearances from combustibles are in accordance with Table 5.
- Check electrical wiring—ensure that all wire gauges are as recommended—service disconnect switch should be used—verify that fusing or circuit breakers are adequate for load use.
- Check polarity—verify that line voltage exists between all power wires and earth ground.
- Place literature bag that contains limited warranty form, this manual, and any control or optional information in accessible location near unit.
Startup
Start up the heater as follows:
- Set thermostat to desired setting.
- Turn ON electric power to heater.
- Observe startup sequence (refer to Table 7).
MAINTENANCE
**WARNING**
- Ensure that the disconnect switch is OFF before servicing the unit.
- Wait until the housing and heating elements cool before performing maintenance.
- Eye protection is recommended when cleaning unit.
**CAUTION**
- When any service is completed, ensure that the unit is reassembled correctly so that no unsafe conditions are created.
- If any of the original wire supplied with the unit must be replaced, the wiring material must have a temperature rating of at least 105°C.
- Ensure that all wiring is in accordance with the wiring diagram provided with the unit.
- If replacement parts are required, use only factory-authorized parts.
NOTE: To ensure long life and satisfactory performance, a unit that is operated under normal conditions should be inspected and cleaned at the start of each heating season. If the unit is operating in an area where an unusual amount of dust or soot or other impurities are present in the air, more frequent maintenance is recommended.
The unit is designed to operate with a minimum of maintenance. However, to ensure long life and satisfactory performance, routine service is recommended. When servicing, follow standard safety procedures and the specific instructions and warnings in this manual.
Service Checklist
The following section is designed to aid a qualified service person in
maintaining and servicing this equipment. At a minimum, perform the following
annually:
- Clean all dirt, lint, and grease from fan blade, fan guard, and motor.
- Replace any parts that do not appear sound.
- Check for any damaged wiring and replace as necessary.
Maintenance Procedures
Electrical Component Replacement
Use a voltmeter to verify that there is 24V output from the transformer. If
the transformer is not functioning, it must be replaced. If it is determined
that an electrical component needs replacing, use only the factory-authorized
replacement part that is designed for the unit.
Fan and Motor Assembly Maintenance
Inspect and clean the motor, fan guard, and blades. Remove any dirt and
grease. Take care when cleaning the fan blades so as not to cause misalignment
or imbalance. Check to ensure that the hub of the fan blades is secure to the
shaft. If necessary, replace the assembly as follows:
- Turn OFF electric power to unit.
- Remove access panel and disconnect fan motor wires, capacitor wires at capacitor, and ground screw.
- Remove assembled parts (fan guard, motor, and fan blade).
- Disassemble and replace part(s) as needed.
- Reassemble using replacement part(s) as needed and original parts.
- Ensure that fan is in proper position on shaft (see Figure 9) and setscrew is tightened in accordance with torque listed in Table 8.
- Position assembly on unit and secure fan guard.
- Rotate fan blade to check for adequate clearance. If adjustment is required, loosen mounting screws, reposition fan guard, and tighten screws to 30 inch-pounds. Repeat until assembly is positioned properly.
- Reconnect fan motor wires in accordance with wiring diagram.
- Install access panel.
- Turn ON electric power to unit and check for proper operation.
Figure 9. Fan and Motor Spacing (Refer to Table 8)
TROUBLESHOOTING
APPENDIX: WIRING DIAGRAMS
Wiring Diagram—3kW, 5kW, 7kW, 10kW, AK7
APPENDIX:
WIRING DIAGRAMS—CONTINUED
Wiring Diagram—15kW, 20kW, 25kW, 30kW, AK7
INSTALLATION RECORD (TO BE COMPLETED BY INSTALLER)
For service or repair, contact the installer. For additional assistance,
contact the distributor. For more information, contact your local Reznor
representative.
For more information on Reznor HVAC products:
• Contact your local Reznor representative at
1-800-695-1901
• Refer to the technical specifications, manuals, and consumer materials found
at www.reznorhvac.com
Specifications and illustrations subject to change without notice or incurring
obligations.
Latest version of this manual is available at
www.reznorhvac.com.
©2023 Nortek Global HVAC LLC, O’Fallon, MO. All rights reserved.
EUH-IOM (09-23) 1042454-0
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