Rheem RTE 3 User manual

Water Heaters
Electric Tankless
The purpose of this manual is twofold:
one, to provide the installer with the basic
directions and recommendations for the proper
installation and adjustment of the water heater;
and two, for the owner–operator, to explain
the features, operation, safety precautions,
maintenance and troubleshooting of the water
heater. This manual also includes a parts list.
It is imperative that all persons who are
expected to install, operate or adjust this
water heater read the instructions carefully
so they may understand how to perform
these operations. If you do not understand
these instructions or any terms within it, seek
professional advice.
Any questions regarding the operation,
maintenance, service or warranty of this
water heater should be directed to the seller
from whom it was purchased. If additional
information is required, refer to the section on
“If you need service.”
Do not destroy this manual. Please read
carefully and keep in a safe place for future
reference.
!
Recognize this symbol as an
indication of Important Safety
Information!
!
California Proposition 65 Warning:
This product contains chemicals
known to the State of California to
cause cancer, birth defects or other
reproductive harm.
AP15447 (10/10)
Printed in USA.
Use & Care Manual
With Installation Instructions for the Installer
US
MET ®
Complies with UL 499.

Care and Cleaning
Maintenance . . . . . . . . . . . . . 12
Safety Information
Safety Precautions . . . . 3, 4
Installation Instructions
Location ............... 5
Heater Installation . . . . . . . 6
Mounting the Heater . . . . . 7
Water Connections . . . . . . 8
Electrical Connections. . . . 9
Operating Instructions
Preparing for Operation . . . 11
Water Temperature . . . . . . . .11
Troubleshooting Tips
Before You Call
For Service . . . . . . . . . . . . . . 14
If You Need Service . . . . 16
2
FOR YOUR RECORDS
Write the model and serial numbers here:
#
#
You can find them on a label on the appliance.
Staple sales slip or cancelled check here.
Proof of the original purchase date is needed to obtain
service under the warranty.
Inside you will find many helpful hints on how to use
and maintain your water heater properly. Just a little
preventive care on your part can save you a great deal of
time and money over the life of your water heater.
You’ll find many answers to common problems in the
Before You Call For Service section. If you review our
chart of Troubleshooting Tips first, you may not need to
call for service at all.
READ THIS MANUAL
Your safety and the safety of others are very important. There
are many important safety messages in this manual and on your
appliance. Always read and obey all safety messages.
!This is the safety alert symbol. Recognize this symbol
as an indication of Important Safety Information!
This symbol alerts you to potential hazards that can
kill or hurt you and others.
All safety messages will follow the safety alert symbol and
either the word “DANGER”, “WARNING”, “CAUTION” or
“NOTICE”.
These words mean:
!DANGER An imminently hazardous situation
that will result in death or serious
injury.
!
WARNING A potentially hazardous situation that
could result in death or serious injury
and/or damage to property.
!CAUTION A potentially hazardous situation that
may result in minor or moderate
injury.
Notice: Attention is called to observe a
specified procedure or maintain
a specific condition.
READ THE SAFETY INFORMATION

Time/Temperature Relationship in Scalds
Temperature Time To Produce a Serious Burn
120°F More than 5 minutes
125°F 1½ to 2 minutes
130°F About 30 seconds
135°F About 10 seconds
140°F Less than 5 seconds
145°F Less than 3 seconds
150°F About 1½ seconds
155°F About 1 second
Table courtesy of Shriners Burn Institute
The chart shown above may be used as a guide
in determining the proper water temperature for your
home.
!DANGER: Households with small children,
disabled,
or elderly persons may require a 120°F or lower
thermostat setting to prevent contact with
“HOT” water.
The temperature of the water in the heater is
regulated by the electronic control on the front of
the water heater. To comply with safety regulations
the thermostat was set at the lowest factory setting
before the water heater was shipped from the
factory.
The illustration below shows the temperature
adjustment dial used for setting the water
temperature.
Refer to the
Operating
Instructions
in this manual
for detailed
instructions in
how to adjust the
thermostat(s).
! DANGER: Hotter water increases the potential
for Hot Water SCALDS.
DANGER
!
HOT
Water temperature over 125°F can
cause severe burns instantly or
death from scalds.
Children, disabled and elderly are
at highest risk of being scalded.
See instruction manual before
setting temperature at water
heater.
Feel water before bathing or
showering.
Temperature limiting valves are
available, see manual.
BURN
IMPORTANT SAFETY INFORMATION.
READ ALL INSTRUCTIONS BEFORE USING.
3
DANGER!
WATER TEMPERATURE SETTING
Safety and energy conservation are factors to be considered when selecting the water
temperature setting of water heater’s thermostat. Water temperatures above 125°F
can cause severe burns or death from scalding. Be sure to read and follow the warnings
outlined on the label pictured below. This label is also located on the water heater near
the thermostat access panel.
NOTICE: Mixing valves are available for reducing point
of use water temperature by mixing hot and cold water
in branch water lines. Contact a licensed plumber or the
local plumbing authority for further information.
Thermostat dial
pointer

4
IMPORTANT SAFETY INFORMATION.
READ ALL INSTRUCTIONS BEFORE USING.
WARNING!
For your safety, the information in this manual must be followed to minimize the risk of
fire or explosion, electric shock, or to prevent property damage, personal injury, or loss of
life.
Be sure to read and understand the entire Use and Care Manual before attempting
to install or operate this water heater. It may save you time and cost. Pay particular
attention to the Safety Instructions. Failure to follow these warnings could result in
serious bodily injury or death. Should you have problems understanding the instructions
in this manual, or have any questions, STOP, and get help from a qualified service
technician, or the local electric utility.
FOR INSTALLATIONS IN THE STATE OF CALIFORNIA
California Law requires that residential water heaters must be braced, anchored or
strapped to resist falling or horizontal displacement due to earthquake motions. For
residential water heaters up to 52 gallon capacity, a brochure with generic earthquake
bracing instructions can be obtained from: Office of the State Architect, 1102 Q Street,
Suite 5100, Sacramento, CA 95814 or you may call 916-445-8100 or ask a water heater
dealer.
However, applicable local codes shall govern installation. For residential water heaters
of a capacity greater than 52 gallons, consult the local building jurisdiction for acceptable
bracing procedures.
READ AND FOLLOW THIS SAFETY INFORMATION
CAREFULLY.
SAVE THESE INSTRUCTIONS
Have the installer show you the location of the circuit breaker and how to shut it off if
necessary. Turn off the circuit breaker if the water heater has been subjected to overheating,
fire, flood, physical damage or if the ECO fails to shut off.
● Read this manual entirely before installing
or operating the water heater.
● Use this appliance only for its intended
purpose as described in this Use and Care
Manual.
● Be sure your appliance is properly installed
in accordance with local codes and the
provided installation instructions.
● Do not attempt to repair or replace any part
of your water heater unless it is specifically
recommended in this manual. All other
servicing should be referred to a qualified
technician.
SAFETY PRECAUTIONS

Installing the water heater.
The location chosen for the water heater must take into consideration the following:
Local Installation Regulations
This water heater must be
installed in accordance with
these instructions, local codes,
utility codes, utility company
requirements or, in the absence
of local codes, the latest edition
of the National Electrical Code.
It is available from some local
libraries or can be purchased
from the National Fire Protection
Association, Batterymarch park,
Quincy, MA 02269 as booklet
ANSI/NFPA 70.
Location
Locate the water heater in a clean
dry area as near as practical to
the area of greatest heated water
demand. Long uninsulated hot water
lines can waste energy and water.
The water heater and water
lines should be protected from
freezing temperatures. Do not
install the water heater in outdoor,
unprotected areas.
5
Inspect Shipment
Inspect the water heater for
possible damage.
Check the markings on the
rating plate of the water heater
to be certain the power supply
corresponds to the water heater
requirements.

Installing the water heater.
6
1. Thank you for your purchase
of the Electric Tankless
Water Heater. This is a quick
reference guide to installation.
Remember you must consult a
licensed electrician and plumber
for guidance.
2. Remove the unit from the
box before continuing.
Please check to make sure
all mounting hardware and
instruction manuals are present.
DO NOT continue until you
have all these items.
3. Shut off all water supply lines
to the existing water heater. (If
this is a new installation, make
sure the water is completely
shut off.)
4. Remove the water heater to
expose pipes. Locate and mark
the spot where you plan to
install the tankless water heater.
5. Mount unit to wall at selected
location.(See Figure 1)
6. Install the water lines to the
tankless water heater using
supplied compression fittings.
(See Figure 2.)
7. Open the main water valve and
let the water run for 2 minutes
through the unit to remove all
air in the line. Close water tap
after 2 minutes and check for
leaks.
8. Check existing electrical code
for appropriate wire gauge
and breaker size. (This step
should be done by a qualified
electrician to avoid electrical
problems.)
9. Once the electrical connection
is complete, turn on breaker
and verify the green "Stand-By"
light is on.
10. Electrical connections may be
completed without accessing
inside components of the water
heater.
11. Turn on hot water tap and
check that the red "Activation"
lights come on.
12. Set the temperature knob to the
desired water temperature. (See
Figure 3.)

7
Location of Unit
NOTICE: Unit must be installed in
a vertical position ONLY with the
water fittings pointing horizontally,
Do not install the unit where it
would routinely be splashed with
water. Electric shock may result.
1. Install the tankless water heater
as close as possible to the
hot water draw-off point, for
example, directly beneath the
sink or next to the shower stall.
2. Install the tankless water heater
in a frost free area. If frost may
occur, remove the unit before
freezing temperatures set in.
3. Leave a minimum of 12" of
clearance on top and bottom of
the unit for servicing.
Mounting The Water Heater
Mounting kit contains sheet metal
screws and supporting brackets in a
plastic bag.
These brackets can be attached to
the back of the heater and allows
the installer to secure the heater to
the wall without the need to open
the front cover.
Make sure to use only the brackets
and screws that are provided in the
mounting kit. The use of longer
screws may damage the unit and
void your warranty.
WALL
MOUNT
BRACKET
LOWER
MOUNT
HOLE
UPPER
MOUNT
HOLE
BACK PANEL
Figure 1

8
Installing the water heater.
1. All plumbing work must
comply with national applicable
state and local plumbing codes.
2. Make certain that the cold water
supply line has been flushed to
remove any scale and dirt.
3. Install isolating valve in cold
water line to allow the unit to
be isolated for maintenance
purposes.
4. Cold water connection (inlet) is
on the right side of the unit, hot
water connection (outlet) is on
the left side of unit.
NOTICE: Excessive heat from
soldering on copper pipes near the
tankless water heater may cause
damage.
5. Tankless water heaters are not
required to be equipped with
a Pressure and Temperature
Relief Valve (PTRV). If the
local inspector will not pass the
installation without a PTRV, it
should be installed on the hot
water outlet side of unit.
6. When all plumbing work is
completed, check for leaks and
take corrective action before
proceeding.
Very Important
Use only the compression fitting
ring and nut provided with each
unit as shown in drawing.
Important
Test the installation for leaks
before connecting the electrical
supply. Check with a professional
electrician for required breaker and
wire gauge.
Compression fittings are designed
exclusively for this unit. Do not
use a different type of threaded
coupling.
Water Connections
HOT
WATER
OUT
COLD
WATER
IN
COMPRESSION FITTING RINGS
COMPRESSION FITTING NUTS
Figure 2

After the unit is installed, open the
shut-off valve in the cold water
supply line.
Open each hot water faucet slowly
to allow the air to vent from the
water heater and piping.
A steady flow of water from the
hot water faucet(s) indicates a full
water heater.
Electrical Connections
A separate branch circuit with
copper conductors, overcurrent
protective device and suitable
disconnecting means must be
provided by a qualified electrician.
All wiring must conform to local
codes or latest edition of National
Electrical Code ANSI/NFPA 70.
The voltage requirements and
wattage load for the water heater
are specified on the rating plate on
the front of the water heater.
The branch circuit wiring should
include either:
Metallic conduit or metallic
sheathed cable approved for use
as a grounding conductor and
installed with fittings approved
for the purpose.
Non-metallic sheathed cable,
metallic conduit or metallic
sheathed cable not approved for
use as a ground conductor shall
include a separate conductor for
grounding. It should be attached
to the ground terminals of the
water heater and the electrical
distribution box.
9
NOTICE: This guide recommends minimum branch circuit sizing and
wire size based on National Electric Code. Refer to wiring diagrams in this
manual for field wiring connections.
WARNING: The heater
chamber must be full of water
before the water heater is
turned on. The water heater
warranty does not cover
damage or failure resulting
from operation with an empty
or partially empty heater
chamber.
!
Purge Air From System
CAUTION: The presence
of water in the piping
and water heater does
not provide sufficient
conduction for a ground.
Non-metallic piping,
dielectric unions, flexible
connectors etc. can cause
the water heater to be
electrically isolated.
!
WARNING: Before
beginning any work on the
electric installation, be sure that
main breaker panel switch is
“OFF” to avoid any danger of
electric shock. All mounting and
plumbing must be completed
before proceeding with electrical
hook-up. Where required by
local, state or national electrical
codes the circuit should be
equipped with a “Ground fault
interrupter”.
1. All electrical work must comply
with national and applicable state
and local electrical codes.
2. The tankless heater should be
connected to a properly grounded
dedicated branch circuit of proper
voltage rating. In installations with
several tankless units, each unit
requires an independent circuit.
Please refer to th technical data
table for the correct wire and
circuit breaker size.
Warning: As with any electric
appliance, failure to electrically
ground unit may result in serious
injury or death.

10
Installation Checklist
A. Water Heater Location
B. Water Supply
D. Wiring
❑ Close to area of heated water demand.
❑ Indoors and protected from freezing
temperatures.
❑ Area free of flammable vapors.
❑ Sufficient room to service heater.
❑ Water heater completely filled with
water.
❑ Air purged from water heater and
piping.
❑ Water connections tight and free of
leaks.
❑ Power Supply voltage agrees with
water heater rating plate.
❑ Branch circuit wire and fusing or
circuit breaker of proper size.
❑ Electrical connections tight and unit
properly grounded.
Operating the water heater.
Safety Precautions
Do turn off power to water heater
if it has been subjected to over
heating, fire, flood, physical
damage.
Do Not turn on water heater
unless it is filled with water.
Do Not turn on water heater if
cold water supply shut-off valve
is closed.
If there is any difficulty in
understanding or following the
Operating Instructions or the
Care and Cleaning section, it is
recommended that a qualified
person or serviceman perform the
work.

11
!DANGER: There is a
hot water scald potential
if the thermostat is set
too high. Households with
small children, disabled,
or elderly persons may
require a 120°F or lower
thermostat setting to
prevent contact with
HOT water.
Water Temperature Setting
The temperature of the water in the
water heater can be regulated by
setting the temperature dial.
Safety and energy conservation
are factors to be considered when
selecting the water temperature
setting of the water heater’s
thermostat(s). The lower the
temperature setting, the greater the
savings in energy and operating
costs.
Water temperatures above 125°F
can cause severe burns or death
from scalding. Be sure to read and
follow the warnings outlined in
this manual and on the label on the
water heater.
Mixing valves for reducing point
of use water temperature by mixing
hot and cold water in branch
water lines are available. Contact
a licensed plumber or the local
plumbing authority for further
information.
The chart on top of the next
page may be used as a guide in
determining the proper water
temperature for your home.
Operating the water heater.
Preparing the Water Heater for Operation
Warning: Open hot water
faucet for a few minutes until
water flows in continuous and all
air is purged from water pipes.
1. Turn temperature knob to
lowest setting.
2. Turn on circuit breaker to bring
electrical power to the unit.
3. Open hot water faucet to a
degree so that water flow is
“typical” i.e. until the water
flow is the same as that
encountered during normal use.
4. Wait twenty seconds until
temperature has stabilized. Then
check water temperature. If
temperature is too low, increase
temperature setting on heater
thermostat.
WARNING: If the
water heater has been
subjected to flood, fire,
or physical damage, turn
off power and water to
the water heater.
Do not operate the
water heater again until
it has been thoroughly
checked by qualified
service personnel.
Temperature Adjustment
!
Thermostat dial
pointer
When the "System Active"
is illuminated, there is a call for
hot water and the elements are
energized.
When "Standby Mode"
is illuminated, the unit is not
active and the elements are not
energized.

12
Time/Temperature Relationship in Scalds
Temperature Time To Produce a Serious Burn
120°F More than 5 minutes
125°F 11/2 to 2 minutes
130°F About 30 seconds
135°F About 10 seconds
140°F Less than 5 seconds
145°F Less than 3 seconds
150°F About 11/2 seconds
155°F About 1 second
Table courtesy of Shriners Burn Institute
Routine Preventative Maintenance
Properly maintained, your water
heater will provide years of
dependable trouble-free service.
It is suggested that a routine
preventive maintenance program
be established and followed by the
user.
Normal Maintenance
Tankless water heaters are designed
for a very long service life.
Actual life expectancy will vary
with water quality and use. The
unit itself does not require any
regular maintenance.
However, to ensure consistent
water flow, it is recommended to
periodically remove scale and dirt
that may build up at the aerator of
the faucet or in the shower head.

13
Notes:

14
Before You Call For Service…
Troubleshooting Tips
Save time and money! Review the chart on this page first and you may not need to call for
service.
Problem Possible Causes What To Do
Not enough or A fuse is blown or a circuit ● Replace fuse or reset circuit breaker.
no hot water breaker tripped.
Electric supply may be off. ● Make sure electric supply to water heater and
disconnect switch, if used, are in the ON position.
The thermostat may ● See the Temperature regulation of the water heater
be set set too low. section of this manual.
Leaking or open hot ● Make sure all faucets are closed.
water faucets.
Electric service to your ● Contact the local electric utility.
home may be interrupted.
Improper wiring. ● See the Installing the water heater section of this
manual.
Manual reset limit (ECO). ● See the Temperature regulation of the water heater
section of this manual.
Cold water inlet ● This is normal. The colder inlet water takes longer
temperature may be to heat.
colder during the
winter months.
Water is too hot The thermostat ● See the Temperature regulation of the water heater
is set too high. section of this manual.
!CAUTION: For your safety DO NOT attempt repair of electrical wiring, thermostats, heating
elements or other safety devices. Refer repairs to qualified service personnel.

15
Specifications:
DIMENSIONS (inches / pounds)
LENGTH WIDTH WEIGHT
10-1/4 5-3/8 6
10-1/4 5-3/8 6
10
10 7-1/4 8
10-1/2 11-1/4 12
10-1/2 11-1/4 12
•Plumbing connections: 1/2 NPT •Minimum flow rate: 1/2 gal. min.
REQ. MAX POWER AWG
KW VOLTS BREAKER (AMP) WIRE
3 110 30 29 10
7 240 30 29 10
9 240 40 38 8
3 240 60 54 6
18 240 (2) 40 75 (2) 8
27 240 (2) 60 112 (2) 6
ELECTRICAL SPECIFICATIONS
MINIMUM MAX.
ACTIVATION FLOW KW
FLOW RATE RATE @
(GPM) (GPM) 240V 20° 30° 40° 50° 60° 70° 80° 90° 100°
0.4 1.5 – 1.5 1.0 0.7 0.5
0.4 2.5 7 2.5 2.4 1.6 1.1 0.8 0.5
0.4 3 9 3.0 3.0 2.2 1.5 1.0 0.7 0.5
0.4 4 13 4.0 4.0 3.0 2.1 1.4 1.0 0.7 0.4
0.4 5 18 5.0 5.0 3.9 2.6 1.8 1.2 0.8 0.6
0.4 5 27 5.0 5.0 5.0 4.0 2.7 1.8 1.2 0.9 0.6
TEMPERATURE RISE AND GPM FLOW
TEMPERATURE RISE CHART (F°)
AND FLOW RATES BY MODEL
KW
3
7
9
3
18
27
7-1/4 8
1
1

49-50009-1 AP121168
16
IF YOU NEED SERVICE
1. Should you have any questions about your new water heater, or if
it requires adjustment, repair, or routine maintenance, it is suggested
that you first contact your installer, plumbing contractor or previously
agreed upon service agency. In the event the firm has moved, or is
unavailable, refer to the telephone directory, commercial listings or
local utility for qualified service assistance.
2. Should your problem not be solved to your complete satisfaction,
you should then contact the Manufacturer’s National Service
Department at the following address:
1241 Carwood Court
Montgomery, Alabama 36117
Phone: [phone].
When contacting the manufacturer, the following information will
be requested:
a. Model and serial number of the water heater as shown on the rating
plate attached to the jacket of the heater.
b. Address where the water heater is located and physical location.
c. Name and address of installer and any service agency who
performed service on the water heater.
d. Date of original installation and dates any service work was
performed.
e. Details of the problems as you can best describe them.
f. List of people, with dates, who have been contacted regarding your
problem.