General Information
This unit heater is designed for safe and dependable comfort, providing many years of service when properly installed and maintained. Regular maintenance ensures satisfactory operation year after year. Abuse, improper use, or improper maintenance can shorten the appliance's life and create unsafe hazards. Periodic maintenance is recommended for optimal performance and to minimize equipment failure. This requires specific tools and mechanical skills.
References
| Type | Form | PN* |
|---|---|---|
| Replacement parts | EUH-RPL | 1042456 |
| Ceiling suspension kit installation | EUH-CK22 | 1042758 |
| Relay kit for multiple unit control | OPT-CL31,32 | 1042699 |
*Also available at www.reznorhvac.com.
Important Safety Information
Read all information thoroughly and familiarize yourself with the unit's capabilities and use before operating or maintaining it. Pay close attention to all dangers, warnings, cautions, and notes. Safety markings are crucial:
- DANGER: Describes a potentially hazardous situation that, if not avoided, will result in severe personal injury or death and/or property damage.
- WARNING: Describes a potentially hazardous situation that, if not avoided, can result in severe personal injury and/or property damage.
- CAUTION: Describes a potentially hazardous situation that, if not avoided, can result in minor or moderate personal injury and/or property damage.
- NOTE: Provides important information that should not be ignored.
Warranty
Refer to the limited warranty form provided with the unit. The warranty is void if:
- Wiring is not in accordance with the furnished diagram.
- 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
Units must be installed according to local building codes. Consult local authorities for specific requirements.
Heater Location
For best results, locate the heater considering the following:
- Arrange units to blow toward or along exposed wall surfaces. Maintain a general scheme of air circulation for multiple units.
- Suspended heaters are most effective when close to the working zone. Avoid directing discharged air directly on occupants.
- Consider partitions, columns, or obstructions that might deflect airflow.
- In large areas, discharge air toward exposed walls, using extra units to direct air toward the center.
Mounting Height
Generally, locate units 6–14 feet (1.8–4.3 meters) above the floor. For areas with excessive cold air infiltration (e.g., entrance doors), locate the unit to discharge directly toward the cold air source from 15–20 feet (4.6–6.1 meters).
Heater Throw
Figure 1 illustrates heater throw patterns, and Table 2 lists throw distances based on mounting heights and louver angles. 'X' is the distance from the heater to the floor coverage, 'Y' is the distance from the heater to the start of floor coverage, and 'Z' is the distance where air velocity drops below 50 feet per minute.
| H* (Feet (Meters)) | Distance* or Angle | Unit Size (kW) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 3 | 5 | 7 | 10 | 15 | 20 | 25 | 30 | ||
| 0 (1.8) | X | 4 (1.2) | 5 (1.5) | 7 (2.1) | 6 (1.8) | 13 (4.0) | 11 (3.4) | 10 (3.0) | |
| Y | 8 (2.4) | 13 (4.0) | 15 (4.6) | 14 (4.3) | 19 (5.8) | 23 (7.0) | 28 (8.5) | 27 (8.2) | |
| Z | 18 (5.5) | 22 (6.7) | 36 (11.0) | 37 (11.3) | 42 (12.8) | 41 (12.5) | |||
| Downward louver angle | 36° | 27° | 22° | ||||||
| 8 (2.4) | X | — | 5 (1.5) | 9 (2.7) | 6 (1.8) | 14 (4.3) | 11 (3.4) | 9 (2.7) | 8 (2.4) |
| Y | 10 (3.0) | 15 (4.6) | 14 (4.3) | 19 (5.8) | 28 (8.5) | ||||
| Z | 16 (4.9) | 32 (9.8) | 36 (11.0) | 37 (11.3) | 39 (11.9) | ||||
| Downward louver angle | 36° | 34° | 30° | 27° | |||||
| 10 (3.0) | X | — | 6 (1.8) | 6 (1.8) | 13 (4.0) | 12 (3.7) | 8 (2.4) | 9 (2.7) | |
| Y | 15 (4.6) | 14 (4.3) | 18 (5.5) | 28 (8.5) | 27 (8.2) | 25 (7.6) | |||
| Z | 26 (7.9) | 34 (10.4) | 38 (11.6) | 36 (11.0) | |||||
| Downward louver angle | 36° | 32° | |||||||
| 12 (3.7) | X | — | 12 (3.7) | 10 (3.0) | 11 (3.4) | 10 (3.0) | 12 (3.7) | 10 (3.0) | |
| Y | 14 (4.3) | 15 (4.6) | 16 (4.9) | 22 (6.7) | 24 (7.3) | 22 (6.7) | |||
| Z | 20 (6.1) | 33 (10.0) | 27 (8.2) | 31 (9.4) | 34 (10.4) | ||||
| Downward louver angle | 36° | 45° | 36° | ||||||
| 14 (4.3) | X | — | 12 (3.7) | ||||||
| Y | 18 (5.5) | 16 (4.9) | |||||||
| Z | 25 (7.6) | ||||||||
| Downward louver angle | 45° | ||||||||
*See Figure 1.
Dimensions
Figure 2 shows the top, rear, front, and side views of the unit, illustrating dimensions A through J. Table 3 provides specific measurements in inches and millimeters for different cabinet sizes and unit kW ratings. Heater suspension points are 3/8-16 FEM.
| Cabinet Size | Unit Size (kW) | Dimension (See Figure 2) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| A | B | C | D | E | F | G* | H | J* | ||
| 1 | 3, 5, 7, 10 | 15-1/4 (388) | 23-11/32 (593) | 13-5/8 (347) | 14-11/32 (365) | 27-31/32 (711) | 20-7/8 (531) | 8-1/2 (216) | 25/32 (20) | 16-5/32 (411) |
| 2 | 15, 20, 25, 30 | 21-1/8 (537) | 28-5/32 (716) | 19-1/2 (496) | 19-11/32 (492) | 33-13/32 (849) | 24-3/4 (629) | 10-1/2 (267) | 21-7/32 (539) | |
*Heater suspension points (3/8-16 FEM).
Weights
Table 4 lists the weights of the unit heaters in pounds (kg) for various kW sizes.
| Unit Size (kW) | 3 | 5 | 7 | 10 | 15 | 20 | 25 | 30 |
|---|---|---|---|---|---|---|---|---|
| Pounds (kg) | 49 (23) | 50 (23.5) | 51 (24) | 53 (25) | 82 (38) | 92 (42) | 97 (44) | 101 (46) |
Clearances
The unit must be located to provide the clearances listed in Table 5 for inspection, service, and spacing from combustible construction. Clearance to combustibles is the minimum distance to ensure a surface temperature of 90°F (50°C) above ambient. Refer to dimensions in Table 3 and Figure 2 for determining clearances.
| Heater Surface | Minimum Clearance (Inches (mm)) |
|---|---|
| Top | 1 (25) |
| Access panel | 21 (533) |
| Non-access side | 1 (25) |
| Bottom* | 1 (25) |
| Rear (from fan motor) | 18 (457) |
*Suspend the heater so that the bottom is a minimum of 6 feet (1.8 meters) above the floor.
Installation
Unpacking and Inspection
The unit was test-operated and inspected at the factory. If damage occurred during shipment, document it with the transporting agency and contact an authorized Factory Distributor. Follow FOB freight policy procedures if you are a distributor.
Pre-Installation Checklist
Before installation:
- Check the rating plate for electrical compatibility with the site's supply.
- Read this manual and familiarize yourself with installation requirements. Consult local agencies if unfamiliar with local requirements.
- Prepare necessary supplies, tools, and manpower.
- Check for any field-installed options (Table 6) that need assembly/installation. Ensure all ordered options are present. Instructions are in this manual or shipped separately.
- If wall-mounting, ensure required field-supplied hardware is available (refer to Suspension of Heater Using Wall-Mounting Bracket section).
Heater Suspension
The heater is designed for two-point suspension using 3/8-16 threaded nut retainers. Suspension can be via 3/8-inch threaded rods, a hanger kit option, or the supplied wall-mounting bracket.
Suspension of Heater Using Option CK8 Two-Point Suspension Kit
Option CK8 uses two swivel connectors attached to 1-inch pipe. Attach swivel connectors to the 3/8-16 threaded nut retainers, ensuring they are locked to the heater as shown in Figure 3.
Suspension of Heater Using Field-Supplied Threaded Rods
Suspend the heater using 3/8-inch threaded rods. The maximum recommended rod length is 6 feet (1.8 meters). The threaded rod extending into the heater must not exceed 1/2 inch (13 mm). Lock rods as shown in Figure 4.
Suspension of Heater Using Wall-Mounting Bracket
Secure the supplied wall-mounting bracket to the heater at the 3/8-16 threaded nut retainers using 1- to 2-inch-long 3/8-16 bolts. Secure the bracket to the wall using field-supplied hardware, as shown in Figure 5.
Suspension of Heater Using Option CK22 Ceiling Suspension Kit
Option CK22 allows installation 1 inch from the ceiling without hanger rods. Refer to the kit's instructions.
Electrical Connections
- All electrical wiring and connections, including grounding, must comply with the National Electric Code (ANSI/NFPA No. 70) or the Canadian Electric Code (CSA C.22.1). Be aware of local ordinances.
- Check the heater's rating plate for supply voltage and current requirements. A dedicated line voltage supply with a disconnect switch should run from the main electrical panel.
- External wiring must be in approved conduit with a minimum 60°C temperature rise rating. Conduit placement should not interfere with the heater access panel.
Supply Wiring Connection
Check the unit's rating plate for supply voltage and current requirements. NOTE: Before connecting supply wiring, determine if units with option AK6 or AK44 require field-modification of the transformer or contactor wiring.
If required, modify wiring:
- AK6 units: Factory-wired for 240V. For 208V, change the white transformer wire from the 240 terminal to the 208 terminal, following the wiring diagram.
- AK44 units: Factory-wired for 208V/240V/1Ph. For 3Ph applications, change black contactor wires: Loosen terminal screws T1, T2, T3 on the 3-pole contactor. Disconnect black wires from T1 and T2, connect them to T3. Tighten screws.
Control Connections
The 24V control connection terminal strip is on the back of the unit (Figure 7). It has terminals C, R, G, W1, and W2. Thermostat connections use C (optional), R, G, W1, and W2 (optional). If installing with an H series Huracan™ destratification fan controlled by a two-stage thermostat, follow the wiring diagram in Figure 8.
Controls
Disconnect Switch
A disconnect switch is optional or field-supplied. Allow 4 feet (1.2 meters) of service room around the switch and ensure conduit/housing clear service doors.
Fan Motor
The fan motor has automatic-reset thermal overload protection. If the motor doesn't run, check voltage. Ensure correct voltage is supplied.
Thermostat
The unit can be controlled by an optional or field-supplied 24V thermostat. Follow the thermostat manufacturer's instructions for installation and location. Connect the thermostat to the 24V control wiring terminal strip.
Air Proving Pressure Switch
This switch senses fan operation pressure. It's factory-set and non-adjustable. If the setpoint is reached, it interrupts power to heating elements, protecting against fan motor failure or airflow restrictions.
High Temperature Limit Switch
This temperature-activated, automatic-reset switch is factory-set and non-adjustable. If the setpoint is reached, it interrupts power to heating elements, protecting against fan motor failure or airflow restrictions.
Multiple Heater Control
An optional multiple heater control allows one thermostat to control up to five heaters. Option CL31 controls two heaters. For more than two, add option CL32 (relay assembly only) to each additional heater. Option packages include installation and wiring instructions.
Operation
Pre-Startup Checklist
Before startup:
- Ensure all shipping bracket screws are re-installed in the heater cabinet.
- Verify the unit is secure and level.
- Confirm clearances from combustibles meet Table 5 requirements.
- Check electrical wiring for proper gauge and ensure the service disconnect switch, fusing, or circuit breakers are adequate.
- Verify line voltage polarity between power wires and earth ground.
- Place the literature bag (warranty, manual, options) in an accessible location.
Startup
To start the heater:
- Set the thermostat to the desired setting.
- Turn ON electric power to the heater.
- Observe the startup sequence (Table 7).
| Condition | Action |
|---|---|
| Thermostat calls for heat | Terminal W energized; Fan energized; Air proving pressure switch closes; Heating elements energized. |
| Steady heat | Heating elements and fan remain energized. |
| Thermostat is satisfied | Heating elements de-energized; Fan de-energized when time delay is satisfied. |
Maintenance
For long life and satisfactory performance, inspect and clean the unit at the start of each heating season. More frequent maintenance may be needed in dusty or contaminated environments. Routine service is recommended.
Service Checklist
Perform the following annually:
- Clean dirt, lint, and grease from the fan blade, guard, and motor.
- Replace any parts that appear unsound.
- Check for and replace any damaged wiring.
Maintenance Procedures
Electrical Component Replacement
Use a voltmeter to check for 24V output from the transformer. Replace the transformer if it's not functioning. Use only factory-authorized replacement parts for any component replacement.
Fan and Motor Assembly Maintenance
Inspect and clean the motor, fan guard, and blades. Remove dirt and grease carefully to avoid misalignment or imbalance. Ensure the fan blade hub is secure to the shaft. If necessary, replace the assembly:
- Turn OFF electric power.
- Remove the access panel. Disconnect fan motor wires, capacitor wires, and ground screw.
- Remove the fan guard, motor, and fan blade assembly.
- Disassemble and replace parts as needed.
- Reassemble using replacement and original parts.
- Ensure the fan is correctly positioned on the shaft (Figure 9) and the setscrew is tightened per Table 8.
- Position the assembly on the unit and secure the fan guard.
- Rotate the fan blade to check clearance. Adjust fan guard mounting screws if needed (tighten to 30 inch-pounds).
- Reconnect fan motor wires per the wiring diagram.
- Install the access panel.
- Turn ON electric power and check for proper operation.
Troubleshooting
Table 9 provides common symptoms, probable causes, and remedies for unit issues.
| Symptom | Probable Cause | Remedy |
|---|---|---|
| A. Unit will not start | 1. No power to unit | Turn ON power and check supply fuses or circuit breaker. |
| 2. No 24V power to thermostat | Turn up thermostat. | |
| 3. No power to fan motor | Check control transformer output. | |
| 4. Defective fan motor | Tighten connections at motor terminals. Replace fan motor. | |
| 5. Improper thermostat location or adjustment | Refer to thermostat manufacturer's instructions. | |
| B. No heat (fan operating) | 1. Defective heating element | Replace heating element. |
| 2. Improper thermostat location or adjustment | Refer to thermostat manufacturer's instructions. | |
| C. Fan motor will not run | 1. Circuit open | Check wiring and connections. |
| 2. Defective capacitor | Replace capacitor. | |
| 3. Defective fan motor | Replace fan motor. | |
| D. Fan motor cuts out on overload | 1. Low or high voltage supply | Correct electric supply. |
| 2. Defective capacitor | Replace capacitor. | |
| 3. Defective fan motor | Replace fan motor. | |
| 4. Poor airflow | Clean motor, fan, and fan guard. Adjust louvers. |
Appendix: Wiring Diagrams
This section contains wiring diagrams for various configurations of the Reznor EUH electric unit heater, including diagrams for 3kW, 5kW, 7kW, 10kW (AK7 and AK44), 15kW, 20kW, 25kW, 30kW (AK7), 15kW (AK20), and 20kW (AK6). These diagrams illustrate the electrical connections for components such as contactors, relays, transformers, switches, and the fan motor.
Installation Record
This section is for the installer to complete, recording details such as model, serial number, date of installation, installer, and distributor information. This record is important for service and warranty purposes.
