GENERAL INFORMATION. A.O. Smith RPVR-80E, *2**-120-E5 series, *P**-80-E5 series, R2VR-180E, R4MR-320E, *P**-55-E5 series, *4**-280-E5 series, RPVR-30K, *4**-280-X5 series, *4**-320-E5 series

GENERAL INFORMATION

Introduction

• This manual provides information necessary for the installation, operation, and maintenance of the water heater.

• The model description is listed on the rating plate which is attached to the side panel of the water heater.

• Please read all installation instructions completely before installing this product.

• If you have any problems or questions regarding this equipment, consult the manufacturer or its local representative.

This appliance is an on-demand, electric tankless water heater. It is designed to efficiently supply endless hot water for your needs.

A built-in alarm is included. If water leaks inside your electric water heater, an alarm will sound to provide warning. Simply turn off power to the water heater at the circuit breakers, turn off the water supply, then correct the leak.

Your water heater also includes on-board self diagnostics. If the system produces an error code, see

“Troubleshooting” on one of the following pages:

• Point-of-use models: page 17.

• Two- or four-chamber models: page 19.

Component

Descriptions

Temperature and Pressure

Relief Valve

In most cases, you are not required to install a temperature 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 valve manufacturer’s instructions and local code.

If you install a T&P valve, turn on the water supply to ensure that no water drips from it. Next, operate the valve manually two or three times to purge the trapped air from the top of the heater’s chamber, then close the valve. Verify that water has stopped flowing completely before connecting the discharge pipe to the valve.

NOTICE: If a temperature and pressure relief valve is installed, it must be piped by minimum 1 inch pipe to a suitable drain capable of discharging 10 GPM. A splash cover must be included to protect the area of attachment to the wall. The manufacturer will not be responsible for any water damage that may occur.

WARNING! Do not cap or plug the

T&P relief valve or discharge pipe.

Component Identification: Point-of-Use Models (RPV, CPV)

OUTLET INLET

Heating Element

(Behind inlet/outlet)

Thermistor* Connections

T-Aux Auxiliary thermistor

T-In Inlet thermistor

T-Out Outlet thermistor

T-Aux

T-In

T-Out

Outlet Thermistor *

(Connects to T-Out)

Auxiliary Thermistor *

(Connects to T-Aux)

Inlet Thermistor *

(Connects to T-In)

TERMINAL

BLOCK

POWER

SUPPLY

* Often referred to as a temperature sensor.

Continued on the next page...

Electric Tankless Water Heater • 5

Component Identification: Two-Chamber Models (R2V, C2V)

OUTLET INLET

HEATING ELEMENTS

NOTICE:

The user interface is described in Figure 7, page 16.

Intermediate

Thermistor *

(connects to

TH-1)

TH-1

TH-2

TH-IN

Thermistor* Connections

TH-IN Inlet thermistor

TH-1 Intermediate thermistor

TH-2 Outlet thermistor

Access Plate

(for draining)

L1

L2

* Often referred to as a temperature sensor.

Outlet Thermistor *

(connects to TH-2)

Inlet Thermistor *

(connects to TH-IN)

Component Identification: Four-Chamber Models (R4L, C4L, R4M, C4M)

OUTLET Intermediate

Thermistor *

(connects to

TH-2)

Element Element

Intermediate

Thermistor *

(connects to

TH-1)

Element Element

NOTICE:

The user interface is described in Figure 7, page 16.

INLET

TH-1

TH-2

TH-3

TH-4

TH-IN

Thermistor* Connections

TH-IN Inlet thermistor.

TH-1 Intermediate thermistor

TH-2 Intermediate thermistor

TH-3 Intermediate thermistor

TH-4 Outlet thermistor

* Often referred to as a temperature sensor.

Outlet Thermistor *

May be located on outlet elbow.

(connects to TH-4)

L1

L2

L1

L2

Access Plates

(for draining)

Intermediate Thermistor *

(connects to TH-3)

Inlet Thermistor *

(connects to TH-IN)

6 • Electric Tankless Water Heater

General Specifications

Models

Point-of-Use:

RPV, CPV

Two Chamber:

R2V, C2V

Four Chamber:

R4L, C4L, R4M, C4M

Wiring & Circuit Breaker

Requirements

Water Connections

Weight lbs. (kg)

Water Heater

Dimensions*

3/4” NPT

8 lbs. (3.6 kg)

See “Electrical Requirements” on page 8.

3/4” NPT

13 lbs. (5.9 kg)

3/4” NPT

20 lbs. (9 kg)

H 16-5/8” x W 6-1/2” x D 7-3/16”

(H 42.2cm x W 16.5cm x D 18.3 cm)

H 17-3/4” x W 11-1/2” x D 6-1/8”

(H 45.1 cm x W 29.2 cm x D 15.6 cm)

H 18-1/8” x W 17” x D 6-1/8”

(H 46 cm x W 43.2 cm x D 15.6 cm)

* Height dimension includes 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:

• Check the rating plate to ensure this product matches your specifications.

• The manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

• The maximum working pressure is 150 psi. The water supply pressure should not exceed 80 psi. If this occurs, a pressure reducing valve with a bypass should be installed in the cold water inlet line.

• Maximum flow may require water pressure equal to or greater than 40 psi.

Electric Tankless Water Heater • 7

Electrical Requirements

• Follow these steps to determine the electrical requirements for your water heater:

1.) Find your model number on your water heater’s rating plate.

2.) Locate that model number in one of the tables listed below.

For example, if your model is RPVA-24-K5 , find *P**-24-K5 in the appropriate table.

Models within each table are sorted by Voltage first, then by Wattage per Element (KW) .

• Follow the requirements listed for your model.

□ Point-of-use models are listed below.

□ Two-chamber models: page 9.

□ Four-chamber models: page 10.

• Use copper conductors only.

Model

Point-of-Use Models

(For potable water heating only. Not for space heating.)

NOTICE: Models sorted by Voltage , then by Wattage per Element .

Recommended

Breaker Size

(Amps)

Voltage Number of

Elements

Wattage per Element

(KW)

Current per

Breaker

(Amps)

Recommended

Wire Size

(AWG)

*

25 120 1 2.4

20.00

10

30 120 1 3 25.00

10

Element Type

*P**-24-K5

*P**-30-K5

*P**-35-K5

*P**-40-X5

*P**-78-X5

*P**-35-E5

30

20

40

20

120

208

208

240 ‡

1

1

1

1

3.5

4

8

3.5

29.17

19.23

37.5

14.58

10

12

8

12

Single

Single

Single

Single

Single

Single

*P**-45-E5

*P**-55-E5

*P**-70-E5

*P**-80-E5

*P**-90-E5

20

25

30

40

40

240 ‡

240

‡

240

‡

240

‡

240

‡

240

‡

1

1

1

1

1

4.5

5.5

7

8

9

18.75

22.92

29.17

33.33

37.50

12

10

10

8

8

Single

Single

Single

Single

Single

*P**-120-E5 60 1 12 50 6

† Dual

*P**-30-Y5 15 277 1 3 10.83

14

* All wiring/conductors must be rated for 90°C or greater.

† Maximum recommended wire size is #6 cu 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.

Single

8 • Electric Tankless Water Heater

Model

Point-of-Use Models

(For potable water heating only. Not for space heating.)

NOTICE: Models sorted by Voltage , then by Wattage per Element .

Recommended

Breaker Size

(Amps)

Voltage Number of

Elements

Wattage per Element

(KW)

Current per

Breaker

(Amps)

Recommended

Wire Size *

(AWG)

20 277 1 4 14.44

12

Element Type

*P**-40-Y5

*P**-60-Y5 25 277 1 6 21.66

10

Single

Single

*P**-73-Y5 30 277 1 7.3

26.35

10 Single

*P**-90-Y5 40 277 1 9 32.49

8

* All wiring/conductors must be rated for 90°C or greater.

† Maximum recommended wire size is #6 cu 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.

Single

Model

Two-Chamber Models

(For potable water heating only. Not for space heating.)

NOTICE: Models sorted by Voltage , then by Wattage per Element .

Recommended

Breaker Size

(Amps)

Voltage Number of

Elements

Wattage per

Element (KW)

Current per

Breaker

(Amps)

Recommended

Wire Size *

(AWG)

Element

Type

208 2 7 33.65

8 Single

*2**-140-X5

40 amps each

(2 circuits)

*2**-120-E5

60 amps

*2**-140-E5

60 amps

*2**-160-E5

40 amps each

(2 circuits)

*2**-180-E5

40 amps each

(2 circuits)

240

240

240

240

2

2

2

2

6.1

7

8

9

50

58.34

33.33

37.5

6 †

6 †

8

8

Single

Single

Single

Single

* All wiring/conductors must be rated for 90°C or greater.

† Maximum recommended wire size is #6 cu AWG.

Electric Tankless Water Heater • 9

Model

*4**-280-X5

*4**-180-E5

*4**-220-E5

*4**-240-E5

*4**-280-E5

*4**-320-E5

Four-Chamber Models (Single Phase)

For potable water heating only. Not for space heating.

NOTICE: Models sorted by Voltage , then by Wattage per Element .

Recommended

Breaker Size

(Amps)

Voltage Number of

Elements

Wattage per

Element (KW)

Current per

Breaker

(Amps)

Recommended

Wire Size *

(AWG)

Element

Type

208 4 7 67.31

6

† Single 70 amps each

(2 cirucits)

40 amps each

(2 circuits)

50 amps each

(2 circuits)

60 amps each

(2 circuits)

60 amps each

(2 circuits)

70 amps each

(2 circuits)

240

240

240

240

240

4

4

4

4

4

4.5

5.5

6

7

8

37.50

45.83

50.00

58.33

66.67

8

6

6 †

6

†

6

†

Single

Single

Single

Single

Single

* All wiring/conductors must be rated for 90°C or greater.

† Maximum recommended wire size is #6 cu AWG.

10 • Electric Tankless Water Heater