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INS

TALLA

TION

14     •        Electric Tankless Water Heater

model. (See “Wiring Diagrams” on 
page 29.)  

If you marked the board and con-
nector during earlier steps, align 
the marks when plugging the con-
nector in.  

NOTICE:

  The plug must be ori-

ented correctly.  If you plug it in 
backwards, it will not cause dam-
age, but the display will not work.   
If the display does not work a  er 
you have completed installa  on, 
follow these steps: 

A.)  Disconnect power at all 

branch circuits. 

B.)  Disconnect the plug. 

C.)  Rotate the plug 180 degrees, 

then plug it back in.

8.  Reinstall the water heater’s cover.

 

WARNING!  Be sure the cover is 

secured to reduce the risk of 

fi

 re 

and electric shock.

 

9.  Turn on power to the water heater.

10.  Verify proper operation.  

(ampacity) and circuit breaker 
ra  ng/type are correct for this 
water heater. 

NOTICE:

 The electrical 

requirements for your model are 
listed in “Electrical Requirements” 
which starts on page 8.

4.  Connect the electrical service 

as described in “Electrical 
Requirements” (starting on page 
8).  

There is a wiring diagram label on 
the inside of your water heater’s 
protective cover.  See also “Wiring 
Diagrams” on page 29 of this 
manual.  

5.  Do the following:

 

Check all electrical 
connections to make sure that 
they are correct and secure.

 

Make sure that the 
supply voltage, wiring 
size (ampacity), circuit 
breaker rating and type are 
correct.  (Refer to “Electrical 
Requirements” which starts 
on page 8).    

 

Label all breakers/connections 
to the water heater.

6.  Ensure that all air has been 

purged from the water lines by 
opening several hot water fixtures 
near the water heater.  Run water 
through the water heater until all 
air is purged from the lines.  

 

  

7. 

Two- and four-chamber models 
only:

 Plug the connector end 

of the cover’s ribbon cable into 
the control board. 

 See Figure 5.

  

(Plug it in where you see two rows 
of header pins close together, five 
pins in each row.)  If necessary, 
refer to the “DISPLAY” callout 
in the wiring diagram for your 

Operating instructions are listed 
on page 15.

5

Test Water 
Heater Operation

1.  At nearby hot water faucets, turn 

water on medium-low.

 

You should hear a “click” as 
the heater’s relays engage.

 

You may hear a hissing or 
crackling noise from the heat 
exchanger after the unit begins 
to heat water.  This is normal.  

2.  Check water at the fixtures to 

make sure that the water is being 
heated.  

NOTICE:

Your water heater includes on-board 
self diagnos  cs.  If an error occurs, the 
system’s feedback will help you iden  fy 
the issue.  See “Troubleshoo  ng” for 
more informa  on (page 17 or 19).

  

Ribbon Cable

Red Band

“TX” Label 
 on Board

NOTICE:
When plugging the display 
(User Interface Module) 
into the control board, 
orient it as shown in this 
graphic. 

Ribbon Cable 
Connector

Control Board

Figure  5.

Two- and four-chamber models only:

Summary of Contents for RPV series

Page 1: ...e you install operate or service it If you have di culty following the direc ons or aren t sure you can safely and properly do any of this work yourself Call our Technical Support Hotline United State...

Page 2: ...t remove any permanent instruc ons labels or the data plate from either the outside of the water heater or on the inside of the access panels Keep this manual near the water heater DANGER Read and fol...

Page 3: ...he tap Mixing valves are available at your local hardware store or from your plumbing supplier Follow the manufacturer s instructions for installation and adjustment of the valves For all models the t...

Page 4: ...r heater s cover is in place This cover keeps debris from entering and potentially being ignited and helps keep any internal fires from spreading Keep the water heater from becom ing wet Immediately s...

Page 5: ...emperature and pressure relief valve T P valve However some local codes do require the installation of a T P Valve If a T P valve must be installed install it on the hot outlet pipe according to the v...

Page 6: ...Figure 7 page 16 Component Identification Four Chamber Models R4L C4L R4M C4M Inlet Thermistor connects to TH IN INLET L1 L2 TH 1 TH 3 TH 4 Intermediate Thermistor connects to TH 1 TH 2 TH IN L1 L2 TH...

Page 7: ...es the distance from the bottom of the heater to the highest point of the inlet outlet Width dimension includes the mounting tabs on the left hand and right hand sides two and four chamber models NOTE...

Page 8: ...sorted by Voltage then by Wattage per Element Model Recommended Breaker Size Amps Voltage Number of Elements Wattage per Element KW Current per Breaker Amps Recommended Wire Size AWG Element Type P 2...

Page 9: ...AWG This model may used with a 208 VAC supply Use of 208 VAC may require different breaker and or wire sizes Follow all code requirements Two Chamber Models For potable water heating only Not for spac...

Page 10: ...Breaker Amps Recommended Wire Size AWG Element Type 4 280 X5 70 amps each 2 cirucits 208 4 7 67 31 6 Single 4 180 E5 40 amps each 2 circuits 240 4 4 5 37 50 8 Single 4 220 E5 50 amps each 2 circuits...

Page 11: ...lumbing heating and air conditioning codes during installation 1 Choose a Location Your water heater is designed to be installed indoors only Locate your water heater in a clean dry area that is as cl...

Page 12: ...the four mounting holes in the back plate If you have a two or four chamber model there are two mounting tabs on each side of your water heater 6 Two or four chamber water heaters only Apply one stand...

Page 13: ...ape NOTICE Failure to purge air from the water lines can leave air pockets causing damage to the heating elements when power is applied 4 Install Electrical Service WARNING Failure to observe these wa...

Page 14: ...tage wiring size ampacity circuit breaker rating and type are correct Refer to Electrical Requirements which starts on page 8 Label all breakers connections to the water heater 6 Ensure that all air h...

Page 15: ...erature turn the knob to the right clockwise Use a small flat blade screwdriver to turn the knob The water temperature set point can be adjusted within a range of 90 F 32C and 140 F 60 C Two or four c...

Page 16: ...d Celsius 1 Press and hold the DOWN button for five seconds See Figure 7 2 The F or C LED will illuminate and the 7 segment LED will display the temperature set point in the appropriate units F C ENTE...

Page 17: ...ensor Failure The 22 code would be displayed like this 2 2 2 red flashes pause two red flashes pause green flash A er you iden fy the code locate its descrip on and solu on in the table Flash Code Seq...

Page 18: ...ature rise water is not being heated su ciently Check elements Check temperature sensors Check wiring and circuit breakers Verify proper heater sizing If necessary reduce the unit tem perature from ma...

Page 19: ...n water runs uninterrupted from the hot water fixture turn on power to the water heater E04 Moisture leak detected in heater Turn o power and water supply to the water heater Contact Technical Support...

Page 20: ...Temperature Sensor Replacement on page 25 E20 Inlet thermistor shorted Replace the temperature sensor that is listed in the le hand column See Thermistor Temperature Sensor Replacement on page 25 E21...

Page 21: ...is cold Flow is too high Reduce flow High temperature limit switch may be tripped Verify if limit switch is tripped Reset if tripped The circuit breaker s may be tripped Check power panel Reset break...

Page 22: ...ff Some models are connected to more than one branch circuit Disconnect all branch circuits before servicing unit Check wires with a non contact circuit tester to make sure power is o When you are fin...

Page 23: ...ter use C Disconnect the green ground wire from the heating element See Figure 14 It is secured with a spade connector Pull it straight up from the element to slide it off the terminal Figure 14 Eleme...

Page 24: ...sing See above Grommets Outlet Inlet Flat 7 Two or four chamber water heaters only 7 1 Drain the two or four chamber water heater A Remove all six screws that secure the access plate beneath the eleme...

Page 25: ...r and pipes If a T P valve is installed operate it manually several times to allow any trapped air to escape 10 Check for water leaks Correct any leaks that are found NOTICE Do not restore power until...

Page 26: ...nlet thermistor TH 1 Intermediate thermistor TH 2 Outlet thermistor Thermistor Connections Often referred to as a temperature sensor L1 L2 TH 1 TH 2 TH IN Intermediate Thermistor connects to TH 1 Outl...

Page 27: ...s cool WARNING Be sure the water runs cool before draining the water heater to reduce the risk of scalding 3 Close the inlet valve to the water heater but leave the hot water faucet open to relieve pr...

Page 28: ...estore power until the circuit board and components are completely dry If water has dripped anywhere inside the heater dry it with a hair dryer or compressed air Be sure to dry behind the circuit boar...

Page 29: ...S ONLY WHEN CONNECTING TO ELECTRICAL SERVICE GRND L2 L1 Ground G R N GRN RED BLK GRN Power Supply RED BLK GRN RED BLK The wiring diagrams for various models are listed in this sec on Locate the one th...

Page 30: ...t RED BLK RED BLK Element RED BLK GRN BLK RED GRN RED BLK USE COPPER CONDUCTORS ONLY WHEN CONNECTING TO ELECTRICAL SERVICE BLK RED GRN Relay 1 Relay 2 GRND L2 TH IN TH AUX TH OUT Moisture Sense Level...

Page 31: ...ement 2 Element 1 L2 L1 BLK BLK BLK BLK RED RED RED RED RED BLK BLK BLK RED RED BLK RED BLK RED RED RED BLK BLK BLK RED USE COPPER CONDUCTORS ONLY WHEN CONNECTING TO ELECTRICAL SERVICE NOTICE 16 kW an...

Page 32: ...K RED RED RED RED RED BLK BLK BLK RED RED BLK RED BLK RED RED RED BLK BLK BLK RED USE COPPER CONDUCTORS ONLY WHEN CONNECTING TO ELECTRICAL SERVICE L2 L1 BLK RED BLK BLK CIRCUIT BREAKER A CIRCUIT BREAK...

Page 33: ...y 3 Relay 5 Relay 7 Display Ground RED BLK GRN Element 1 Element 3 Element 4 Element 2 Element 4 Element 2 Element 1 Element 3 L2 L1 L2 L1 BLK BLK BLK BLK BLK BLK BLK BLK RED RED RED RED RED RED RED R...

Page 34: ...Your Water Heater page 12 NOTICE Read Minimum Clearances Figure 2 page 11 before you start 1 Complete the installa on steps on pages 11 and 12 Stop when you have completed step 7 on page 12 2 Secure b...

Page 35: ...e toward the right as shown in Figure 27 page 34 4 Return to page 12 to complete the water heater installation Internal water heater components are represented by hidden lines D Surface Water Heater C...

Page 36: ...Copyright 2018 A O Smith Corpora on All rights reserved...

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