Rheem Tankless Water Heater User Manual

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Time/Temperature Relationship in Scalds
Water Temperature
Time To Produce a Serious Burn
120°F (49°C)
More than 5 minutes
125°F (52°C)
1
1
/
2
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 1
1
/
2
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 home.
DANGER: Households with small children, disabled or
elderly persons may require a 120°F (49°C) or lower
temperature setting to prevent contact with “HOT” water.
Maximum water temperature occurs while burner is on.
To find water temperature being delivered, turn on a hot
water faucet and place a thermometer in the water stream
and read the thermometer. (See page 27 & 28 for more
details.)
The temperature of the water at the outlet of the water
heater can be  regulated by setting the temperature on
Remote Control. The remote control was set at 100°F
(38°C) before it was shipped from the factory.
The diagram to the bottom left illustrates the Remote
Control and how to adjust the water temperature.
Notice: The factory setting allows operating temperatures
between 100°F (38°C) and 120°F (49°C). Temperatures 
of up to 140°F (60°C) for Light duty models and up to
180°F (82°C) for Heavy Duty models can be achieved
with the MAIN (UMC-117) remote control and a dip
switch adjustment. Only qualified service personnel
should perform this adjustment.  Only factory authorized
remote control(s) should be used.
Notice: When this water heater is supplying general
purpose hot water requirements for use by individuals, 
a thermostatically controlled mixing valve for reducing
point of use water temperature is recommended to reduce
the risk of scald injury. Contact a licensed plumber or the
local plumbing authority for further information.
D A N G E R
!
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
DANGER!
WATER TEMPERATURE SETTING
!
Safety and energy conservation are factors to be considered when selecting the water
temperature setting of a water heater’s remote control. Water temperatures above
125°F (52°C) can cause severe burns or death from scalding. Be sure to read and follow
the warnings outlined on the label pictured below.
IMPORTANT SAFETY INFORMATION
READ ALL INSTRUCTIONS BEFORE USING.
!
°F
PRIORITY 
POWER 
ON/OFF
100 102 104 106 108 110 112 114 116 118 120*   125 130 135 140 150 160 170 180  
°F
Higher (Hotter) 
Lower (Cooler) 
  38   39   40   41   42   43   44   46  47   48   49*     52   54   57   60   66   71   77   82   
°C
Notice:  Only heavy duty water heaters can achieve
temperatures up to 180°F (82°C).
*  Temperatures above 120°F (49°C) can be achieved
by adjusting the dip switch. See page 35 for dip
switch adjustment.
Notice:
Display
shows
°F only.
4