Rheem MHD85245 User manual

Water Heaters
Light Duty Commercial Electric
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 warranty.
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!
Double Element Models,
75, 85, 105 Gallon
AP17946-3 Rev. 4
Use & Care Manual
With Installation Instructions for the Installer

2
Care and Cleaning
Draining ................ 16
Maintenance............. 16
Extended Shut-Down ..... 16
Safety Information
Safety Precautions ....... 3, 4
Installation Instructions
Location ................. 5
Water Connections ........ 8
Electrical Connections. . . . . 10
Wiring Diagram......... 11
Operating Instructions
Safety Controls .......... 14
Water Temperature ........14
Troubleshooting Tips
Before You Call
For Service.............. 17
Customer Service
Parts List................ 18
Replacement Parts .........19
Element Replacement ..... 20
Warranty ..............21-23
How To Register .......23-24
If You Need Service .......28
FOR YOUR RECORDS
Write the model, serial numbers, and installation details on the
back cover of the manual.
This information is located on the rating plate (silver label) on the
unit.
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

3
Time/Temperature Relationship in Scalds
Temperature Time To Produce a Serious Burn
120°F (49°C) More than 5 minutes
125°F (51°C) 1½ to 2 minutes
130°F (54°C) About 30 seconds
135°F (57°C) About 10 seconds
140°F (60°C) Less than 5 seconds
145°F (63°C) Less than 3 seconds
150°F (66°C) About 1½ seconds
155°F (68°C) 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
location.
!
DANGER: Locations with small children, disabled,
or elderly persons may require a 120°F (49°C) or
lower thermostat setting to prevent contact with
“HOT” water.
The temperature of the water in the heater is
regulated by the adjustable surface mounted
thermostat(s) located behind the jacket access
panel(s). Dual element heaters have two thermostats.
To comply with safety regulations the thermostat(s)
were set at 120°F before the water heater was
shipped from the factory. Canadian models are set
to 140°F (60°C).
The illustration at the left
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.
Reset button
Thermostat
protective
cover
Thermostat dial
pointer
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 (51°C)
can cause severe burns or death from scalding. This water heater is capable of supplying
outlet water temperature greater than 180° F (82° C). 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 recommended for reducing
point of use water temperature by mixing hot and
cold water in branch water lines. It is recommended
that a mixing valve complying with the Standard for
Temperature Actuated Mixing Valves for Hot Water
Distribution Systems, ASSE 1017 be installed. See page
14 for more details and contact a licensed plumber or the
local plumbing authority for further information.

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 95811 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 (Emergency Cut Off) on the thermostat 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.
●All replacement parts used on this
product must be manufacturer authorized
components.
●DO NOT turn on the electrical supply
or operate this water heater unless it is
completely full of water.
SAFETY PRECAUTIONS

5
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.
If the water heater is to be installed in a
restaurant, or other location where NSF
International listing is required, it must
be weather sealed to the floor, a raised
base, or on a shelf so that seepage cannot
accumulate under it; or elevated to provide
at least (6) inches of clearance from the
floor.
In order to meet NSF International
requirements for Standard 5, the base
of the water heater must be sealed to
the floor to prevent seepage underneath.
Apply a 3/8" bead of RTV Silicone
completely around the floor edge of the
base of the tank.
Location
Locate the water heater in a clean dry area
as near as practical to the area of greatest
heated water demand. Long un-insulated
hot water lines can waste energy and
water.
Place the water heater in such a manner
that the thermostat and element access
panels can be removed to permit inspection
and servicing such as removal of elements
or checking controls.
The water heater and water lines should
be protected from freezing temperatures.
DO NOT install the water heater in
outdoor, unprotected areas or near any
other appliances where high temperatures
are present, such as wood burning stoves,
boilers, or furnaces. High temperatures
can warp or otherwise damage the non-
metallic construction of this water heater.
Make certain the floor underneath
the water heater is strong enough to
sufficiently support the weight of the
water heater once it is filled with water.
Unit
Capacity
(Gallons)
Unit
Capacity
(Imperial Gallons)
Dimensions (Inches) Shipping
Weight
(lbs)
Approximate
Full Weight
(lbs)
Height 1Diameter
75 63 62 5/8 28 1/4 122 748
85 71 70 1/4 28 1/4 134 843
105 88 70 3/4 30 1/4 152 1,028
1Height includes factory installed Temperature and Pressure Relief Valve.
NOTICE: DO NOT use
fittings on top of the unit
as handles or lift points.