REZNOR UWS Hydronic Unit Heater Installation Guide
- September 11, 2024
- Reznor
Table of Contents
REZNOR UWS Hydronic Unit Heater
WARNING
- Be sure to read and understand the installation, operation, and maintenance instructions in this manual.
- Installation should be done by a qualified agency by 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 the 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.
- Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.
- Do not remove safety labels. If they are unreadable, contact an authorized distributor for replacement labels.
- The heat exchanger coils must be protected against freezing. DO NOT DESTROY. PLEASE READ CAREFULLY. KEEP IN A SAFE PLACE FOR FUTURE REFERENCE.
GENERAL INFORMATION
- This unit heater has been tested for capacity and efficiency 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.
- This unit heater is operated with hot water produced by a boiler that flows through the heat exchanger.
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.
CAUTION
To prevent damage to the unit or its internal components, it is recommended
that two wrenches be used when loosening or tightening nuts. Do not over-
tighten!
Warranty
NOTE: The standard unit heater warranty covers only original defects and does not cover the repairs resulting from a water condition such as corrosion or scale. It is up to you and is your sole responsibility to ensure that a proper water treatment and maintenance program is correctly followed at all times.
Refer to the limited warranty form in the literature bag provided with the unit. The warranty is void if:
- The wiring is not by the diagram furnished with the heater.
- The air delivery system is modified.
- Improper water conditions result in excessive corrosion or leaks.
Certification
These unit heaters are listed by Intertek for use in the US and Canada at
elevations up to 10,000 feet (3,000 meters).
Installation Codes
These units must be installed by local building codes. Local authorities
having jurisdiction should be consulted before installation is made to verify
local codes and installation procedure requirements.
Unit 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:
- Heaters should always be arranged to blow toward or along exposed wall surfaces, if possible. Where two or more heaters 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 heater so that a minimum quantity of airflow will be deflected by such obstacles.
- When heaters are located in the center of the space to be heated, the air should be discharged toward the exposed walls. In large areas, heaters should be located to discharge air along exposed walls with extra units provided to discharge air 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 5 feet (1.6
meters)—for unit sizes 10/15–44/62—or 8 feet (2.5 meters)—for unit sizes
62/77–159/191—above the floor. In general, the heater 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 heater so that it will discharge directly toward the
source of cold air from a distance of 15–20 feet (4.6–6.1 meters).
Table 1. Minimum Mounting Height
Unit Size (MBTUh)
10/15, 15/21, 22/31, 32/45, 44/62| 62/77, 83/104, 110/137, 159/191
Accessibility to the General Public
Accessible| Nonaccessible
Feet (Meters)
5 (1 .6)| 8 (2 .5)
Weights
Table 2. Weights
Unit Size (MBTUh)
10/15| 15/21| 22/31| 32/45| 44/62| 62/77|
83/104| 110/137| 159/191
Pounds (kg)
30 (14)| 39 (18)| 43 (20)| 52 (24)| 66 (30)| 88 (40)| 91 (42)| 117 (54)| 142
(65)
Clearances
The unit must be located so that the clearances listed in Table 3 are provided
with 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.
Table 3. Clearances to Combustibles
Heater Surface| Minimum Clearance (Inches (mm))
Top, bottom, sides| 0 (0)
Rear (from fan motor)| 18 (457)
Dimensions
Dimensions—Continued
Table 4. Dimensions
Dimension (See Figure 1 )
| Unit Size (MBTUh)
10/15| 15/21| 22/31| 32/45| 44/62| 62/77|
83/104| 110/137| 159/191
Inches (mm)
A| 19-1/4 (489)| 23-3/4 (603)| 24-3/4 (629)| 28-3/4 (730)| 32-3/4 (832)| 38
(965)
| 41-1/2 (1054)
B| 19-15/16 (506)| 17-1/16 (433)| 20 15/16
(532)
| 23-7/16 (595)| 27-7/16 (697)| 29-7/16 (748)| 35-7/16 (900)
C| 12
(305)
| 15
(381)
| ****
20
(508)
| 22
(559)
| 24-1/8 (613)| 28
(711)
| 32
(813)
D| 10
(254)
| 12-7/8 (327)| 17
(432)
| 23-7/8 (606)| 24
(610)
| 26
(660)
| 31-13/16 (808)
E | 3-5/16 (84)| 4-1/16 (103)| 4-9/16 (116)| 3-9/16 (90)| 4-9/16 (116)|
7-9/16 (192)
F | 8-1/2 (216)| 10
(254)
| 11
(279)
| 16
(406)
| 18
(457)
| 22
(559)
| 20
(508)
G| 5-1/4 (133)| 5-15/16 (151)| 6-1/8 (156)| 8
(203)
H| 9-1/2 (241)| 11-5/8 (295)
J| 1/2 (13)| 3/4 (19)| 11/16 (17)| 13/16 (21)| 11/16 (17)
K *****| 12-1/4 (311)| 15-5/8 (397)| 9-5/16 (237)| 22
(559)
| 26
(660)
| 28
(711)
| 34
(864)
L **| 3-1/2 (89)| 2-5/8 (67)| 5-5/8 (143)| 3-7/8 (98)| 3-15/16 (100)|
3-15/16 (100)
| 3-15/16 (100)| 4-15/16 (125)
M **| 1-5/32 (29)| 3
(76)
| 1-7/8 (48)| 1-7/8 (48)| 3-1/16 (78)| 2-15/16 (75)
N **| 4-5/16 (110)| 8-3/4 (222)| 7-1/16 (179)| 6-7/8 (175)| 3-7/16 (87)|
4-15/16 (125)| 3-15/16 (100)| 5-15/16 (151)
P| 4
(102)
| 5
(127)
| 4-5/8 (117)| 5-1/2 (140)| 5-3/4 (146)| 6-1/2 (165)| 5-3/4 (146)
Q| 6-1/8 (156)| 3-1/2 (89)| 2-1/4 (57)| 11-1/16 (281)| 9-1/4 (235)| 11-1/4
(286)| 12-1/4 (311)| 15-1/4 (387)
R| 7-15/16 (202)| 5-3/4 (146)| 4-1/2 (114)| 13-5/16 (338)| 14-1/4 (362)|
16-1/4 (413)| 17-1/4 (438)| 20-1/4 (514)
S| 14
(356)
| 16-11/16 (424)| 16-9/16 (421)| 18-5/8 (473)| 17-5/8 (448)| 19-13/16 (503)|
20-5/8 (524)| 20-13/16 (529)
T **| 3-1/2 (89)| 5-3/8 (137)| 5
(127)
| 1-13/16 (46)| 5-1/16 (129)| 7-1/16 (179)| 5
(127)
| 6-1/4 (159)| 2-3/4 (70)
* Heater suspension points (3/8-16 FEM) .
** Piping entrance points.
INSTALLATION
Unpacking and Inspection
The unit was test-operated and inspected at the factory before 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 water and electrical requirements of the heater to ensure that they are compatible with the water and electric supplies at the installation site.
- Read this manual and become familiar with the installation requirements of your particular heater.
- If you do not know local requirements, check with 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 5) that need to be assembled/installed before unit installation. Ensure that all options ordered are at the installation site. Instructions are in this manual or the shipped-separate option package.
Table 5. Field-Installed Options
Option| Description
CD1| Vertical louvers, direct discharge air to provide a wider throw pattern
CD2| Downturn nozzle, 25- to 65-degree variable air deflection range
CD3| Downturn nozzle, 50- to 90-degree variable air deflection range
CD4| Downturn nozzle, 25- to 65-degree variable air deflection range with
vertical louvers
CD5| Downturn nozzle, 50- to 90-degree variable air deflection range with
vertical louvers
CL5| Single-stage thermostat
CM1| Locking cover for CL1 thermostat
CM3| Bracket assembly for mounting thermostat on unit
CN3F| Remote ON/OFF switch in 2 × 4 box
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 the 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 for horizontal discharge using two-
point suspension or downward discharge using four-point suspension. A 3/8-16
threaded nut retainer is located at each suspension point to suspend the
heater using 3/8-16 threaded rods. 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 2.
Piping Connections
WARNING
- Maximum operating pressure is 150 psi (10 bar, 1,034 kPa). Maximum water temperature is 180°F (82°C). Minimum water temperature is 40°F (4.4°C).
- Flange seals must not be made with rubber or other material that melts easily. In the event of overheated water, rubber seals may melt.
- Mount a thermostatic air vent if the distribution ring of the water or steam is in a lower position than the heater.
Connect inlet and outlet piping using a three-part joint union and ball valve
sealed with pipe sealant. Recommended piping configurations are shown in
Figure 3.
Electrical Connections
CAUTION
- Ensure that all wiring is by the wiring diagram provided with the unit.
- All electrical wiring and connections, including electrical grounding, MUST BE made by 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.
- All external wiring must be within the approved conduit and have a minimum temperature rise rating of 140°F (60°C). The conduit must be run so as not to interfere with the heater access panel.
Route the 115V supply wiring and any 115V control wiring through the wiring entrance shown in Figure 1 and make connections inside the electrical compartment. Be sure to close and secure the electrical compartment door.
CONTROLS
Fan Speed Control
The fan speed control (see Figure 4) is shipped with unit sizes 10/15–83/104
(not used on unit sizes 110/137 and 159/191), but its use and where to mount
it is optional. It may be mounted remotely or on the unit using the thermostat
bracket kit (option CM3). Ensure that the control is wired per the wiring
diagram provided with the unit.
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 5) or a field-supplied thermostat that must be field-installed
per the thermostat manufacturer’s instructions. Pay particular attention to
the requirements regarding the location of the thermostat. Connect the
thermostat per the wiring diagram provided with the unit (refer to the
Electrical Connections section).
OPERATION
Pre-Startup Checklist
Check the following before starting:
- Check suspension—the unit must be secure and level.
- Check to ensure that clearances from combustibles are by Table 3.
- Check piping for leaks.
- 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 the literature bag that contains the limited warranty form, this manual, and any control or optional information in an accessible location near the unit.
Startup
Start up the heater as follows:
- Ensure that the water supply and return valves are open.
- Set the thermostat to the desired setting.
- Turn ON the electric power to the heater.
- Observe startup sequence: The fan is energized until the thermostat’s call for heat is satisfied.
MAINTENANCE
WARNING
- Ensure that the electric power is OFF and the water supply and return valves are closed before servicing the unit.
- Wait until the housing and piping cool before performing maintenance.
- Eye protection is recommended when cleaning the 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 wires supplied with the unit must be replaced, the wiring material must have a temperature rating of at least 220°F (105°C).
- Ensure that all wiring is by 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 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 a 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 the fan blade, fan guard, and motor.
- Replace any parts that do not appear sound.
- Check for any damaged wiring and replace it as necessary.
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 the electric power to the unit.
- Remove the access panel and disconnect the fan motor wires, capacitor wires at the 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 the fan is in the proper position on the shaft (see Figure 5) and setscrew is tightened by the torque listed in Table 6.
- Position assembly on the unit and secure the fan guard.
- Rotate the fan blade to check for adequate clearance. If adjustment is required, loosen mounting screws, reposition the fan guard, and tighten screws to 30-inch pounds. Repeat until the assembly is positioned properly.
- Reconnect fan motor wires by the wiring diagram.
- Install access panel.
- Turn ON the electric power to the unit and check for proper operation.
Figure 5. Fan and Motor Spacing (Refer to Table 6)
Table 6. Fan and Motor Assembly Specifications
Setscrew Torque (Inch-Pounds ±10)
80| 120| 130
Unit Size (MBTUh)
10/15| 15/21| 22/31| 32/45| 44/62| 62/77|
83/104| 110/137| 159/191
Dimension A ( Inches (mm))
1 (25)| 9/16 (14 .3)| 1-1/2 (38)| 2-3/8 (60 .3)| 2-5/16 (59)| 2 (51)| 1-3/8
(35)
See Figure 5.
TROUBLESHOOTING
Table 7. Troubleshooting
Symptom| Probable Cause| Remedy
A . The unit will not start| 1 . No power to unit| Turn ON the power and check
supply fuses or circuit breaker
2 . No power to thermostat| Turn up thermostat
Check the control transformer output
3 . No power to the fan motor| Tighten connections at motor terminals
4 . Defective fan motor| Replace fan motor
5 . Improper thermostat location or adjustment| Refer to the thermostat
manufacturer’s instructions
B . No heat (fan operating)| 1 . Defective hydronic coil| Replace hydronic
coil
2 . Improper thermostat location or adjustment| Refer to the thermostat
manufacturer’s instructions
C . The 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
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 are subject to change without notice or incurring obligations. The latest version of this manual is available at www.reznorhvac.com. ©2024 Nortek Global HVAC LLC, O’Fallon, MO. All rights reserved. UWS-IOM (06-24) 1042971-0
References
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