Hubbell 280-3 User manual

INSTALLATION, OPERATION, AND
MAINTENANCE MANUAL FOR
THE HUBBELL TANKLESS WATER HEATER
ELECTRIC HEATER COMPANY
Edition 2016A

2
HUBBELL
ELECTRIC HEATER COMPANY
P.O. BOX 288
STRATFORD, CT 06615-0288
PHONE: [phone]
FAX: [phone]
INTERNET: http://www.buytankless.com
Important Safety Information
1. You must read and follow all instructions. Serious bodily injury or death could occur
if you ignore this warning.
2. All circuit breakers and/or disconnect switches servicing the heater must be turned off
when installing, uninstalling, or repairing this water heater.
3. The Hubbell Tankless Water Heater must be grounded.
4. The unit must be installed by a licensed electrician and plumber.
5. The unit must be wired in accordance with the current version of the National
Electrical Code (US) or Canadian Electric Code (Canada).
6. This installation must comply with all national, state, and local plumbing and
electrical codes.
7. When the heater is not within sight of the electrical circuit breakers, an additional
local means of disconnection of all ungrounded conductors must be provided that is
within sight of the appliance or a circuit breaker lockout must be used. (Ref. NEC
422.31)
8. If the Hubbell Tankless Water Heater is installed in a location where water damage
could occur in the event of a leak, it is recommended that a drip pan be installed and
connected to a suitable drain. Alternatively, an active water leak detector and shut off
valve can be installed to turn off your water supply in the event a leak is detected.
9. If water supply has a high mineral content, a water softening system is recommended.
Damage to the water heater resulting from scale or hard minerals will not be covered
under warranty.
10.When the heater is installed in a well water system or if the plumbing system is prone
to introducing air into the heater, it is highly recommended that an air separator be
installed in the cold water feed to the heater to avoid possible failure of the heating
element and/or heating chamber.

3
TABLE OF CONTENTS
SECTION
TITLE
PAGE No.
I
TANKLESS WATER HEATER OPERATING PRINCIPLE
4
II
GENERAL DESCRIPTION AND CONSTRUCTION
5
III
INSTALLATION
10
IV
OPERATION AND MAINTENANCE
15
V
TROUBLESHOOTING
21
VI
SERVICING & REPLACEMENT OF PARTS
27
VII
PARTS LIST
32
VIII
WARRANTY
33
APP. I
SUB-PANEL WIRING DETAILS
36

4
SECTION I–TANKLESS WATER HEATER OPERATING PRINCIPLE
How the Hubbell Tankless Water Heater Works:
For the most part, operating your new tankless water heater is very similar to using any
traditional water heater system. However, it is very important that you carefully read all of
the set-up procedures and operating instructions to ensure maximum performance and
energy savings from your new water heater.
Your Hubbell Tankless Water Heater does not store hot water like a conventional tank-type
water heater. It contains high powered heating elements that are capable of heating water
instantly on-demand as you need it. As soon as you turn on a hot water faucet, a
sophisticated flow sensor within the heater recognizes that you have turned on the water.
This sensor measures the water flow rate while two other sensors measure the incoming and
outgoing water temperature. This information is transmitted continually to the
microprocessor controller which determines the precise amount of power to send to the
heating elements to heat the water to your desired temperature. The Hubbell tankless water
heater only uses as much power as is needed to meet the demand by fully modulating the
heating elements from 0 to 100%. Since your new water heater works on a demand basis, it
will absolutely never run out of hot water no matter how many back to back showers you
run!
It is important to keep in mind that every tankless water heater has a maximum flow rate. If
you exceed this flow rate, the heater will not be capable of fully heating water. How much
hot water your heater can provide will depend on the model you have selected and your
incoming water temperature. If you live in an area of the country where inlet cold water
temperature average 55° F or you have cold winters, you will probably NOT be able to run
multiple large water demand fixtures at the same time. However, you will be able to run all
your hot water fixtures back to back without ever having to wait. You will enjoy
UNLIMITED HOT WATER. See the charts in Section II to determine the maximum flow
rates.
Moreover, since a tankless water heater eliminates the ongoing thermal losses caused by
storing hot water in a tank, you will enjoy significant energy savings over a conventional
tank type water heater.
When you use hot water from a conventional tank type water heater, you need to mix a
considerable volume of cold water to cool the hot water down to a safe, comfortable level.
You need to do this because the heater is set at an extremely high temperature to prevent it
from running out of hot water quickly. With a tankless water heater, you typically set the
temperature at a much lower level since it is capable of heating your water on demand. This
level will be much closer to the actual temperature at which you feel comfortable showering
or bathing. As such, you will no longer need to mix much cold water to run a shower or
bath; in fact, you may mix very little or no cold water. This is perfectly normal and means
that you are no longer wasting energy by overheating your water.

5
SECTION II –GENERAL DESCRIPTION AND CONSTRUCTION
Product Overview:
Inlet Temp. Sensor Control Fuse
Heating Element Temperature
Controller
Heating Chamber LED Digital Display
(with buttons)
Hi-Limit Switch
Element Switching
Device (Triac)
Outlet Temp.
Sensor Power Distribution
Block
Ground Lug
Flow Meter
Hot Water Outlet Cold Water Inlet
Drain
3-Element Design (Models 280-3, 240-3, and 220-3)
Control Fuse
Heating Element Temperature
Controller
Heating Chamber LED Digital Display
(with buttons)
Hi-Limit Switch
Element Switching
Device (Triac)
Outlet Temp.
Sensor Power Distribution
Block
Ground Lug
Flow Meter
Hot Water Outlet
Cold Water Inlet
Drain
2-Element Design (Models 180-2, 165-2, 145-2, and 110-2)
Inlet Temp. Sensor

6
Hubbell Tankless Water Heater Selection Overview:
40°F 45°F 50°F 55°F 60°F 65°F 70°F 75°F
280-3 27 112.5 200 2.8 3.1 3.4 3.7 4.1 4.6 5.3 6.2
240-3 24 100.0 200 2.5 2.7 3 3.3 3.6 4.1 4.7 5.5
220-3 21 87.5 200 2.2 2.4 2.6 2.9 3.2 3.6 4.1 4.8
180-2 18 75.0 150 1.9 2.1 2.2 2.5 2.7 3.1 3.5 4.1
165-2 16 66.7 125 1.7 1.8 2 2.2 2.4 2.7 3.1 3.6
145-2 14 58.3 100 1.5 1.6 1.7 1.9 2.1 2.4 2.7 3.2
110-2 11 45.8 100 1.2 1.3 1.4 1.5 1.7 1.9 2.1 2.5
Model
No.
kW
Amps @
240V
Min. Required
Home Service
(Amps)
Max. flow (GPM) of water heated to 105°F with
incoming cold water temperature of
Note: Recovery rates (GPM) are based upon an actual supply voltage of 240 volts with no
voltage drop. If the actual supply voltage is less than 240 volts, the recovery rating (GPM) will
be reduced. Please see the wattage de-rating and flow rate formulas at the end of Section II to
determine the actual power (kW) and recovery rate (GPM) when voltage is less than 240 volts.
Tankless Pressure Drop Chart:
Technical Specifications Common to All Models:
Materials:
Copper Exchanger /
Stainless Steel Casing
Plumbing
Connection:
¾” Copper, CPVC,
or PEX
Voltage:
208-240 Volts / 1 Ph
Operating Range:
5 –150 psi
Frequency:
50 / 60 Hz
Protection:
Thermal Auto Reset
Energy Efficiency:
98%
0
2
4
6
8
10
12
14
16
012345678
2-Element
3-Element
GPM
Pressure Drop (psi)

7
Model 280-3
Our most powerful residential electric tankless water
heater. This 27 kW water heater is configured for
cold climates where the incoming water temperature
can drop below 45° F. The Model 280-3 is well suited
for homes in the northern U.S. and Canada, and those
in the southern U.S. that have large Roman-style or
Jacuzzi tubs and that have generally more demanding
water usage needs.
Technical Specifications:
Dimensions:
17” x 16.2” x 3.6”
Customer Double-Pole
Circuit Breaker / Fused
Disconnect Required:
1 x 125A or
2 x 60A or
3 x 40A
Weight:
20 lbs.
kW / Elements:
27 kW / 3 elements
Max. Amps:
112.5 A @ 240 V
Model 240-3
The 24 kW water heater is configured for climates
where incoming water temperatures are in the 50° -
70° F range. The Model 240-3 is suitable as a whole
house water heater.
Technical Specifications:
Dimensions:
17” x 16.2” x 3.6”
Customer Double-Pole
Circuit Breaker / Fused
Disconnect Required:
1 x 110A or
2 x 60A or
3 x 40A
Weight:
20 lbs.
kW / Elements:
24 kW / 3 elements
Max. Amps:
100 A @ 240 V
Model 220-3
The 21 kW, water heater is configured for cold
climates where the incoming water temperature can
drop below 55° F. The Model 220-3 is well suited
for homes in the northern U.S. and Canada, and
those in the southern U.S. that have large Roman-
style or Jacuzzi tubs and that have generally more
demanding water usage needs.
Technical Specifications:
Dimensions:
17” x 16.2” x 3.6”
Max. Amps:
87.5 A @ 240 V
Weight:
20 lbs.
Customer Double-Pole
Circuit Breaker Required:
1 x 100A or
2 x 50A
kW / Elements:
21 kW / 3 elements
100 105 110 115 120 125
40 3.1 2.8 2.6 2.5 2.3 2.2
45 3.4 3.1 2.8 2.6 2.5 2.3
50 3.7 3.4 3.1 2.8 2.6 2.5
55 4.1 3.7 3.4 3.1 2.8 2.6
60 4.6 4.1 3.7 3.4 3.1 2.8
65 5.3 4.6 4.1 3.7 3.4 3.1
70 6.2 5.3 4.6 4.1 3.7 3.4
75 7.4 6.2 5.3 4.6 4.1 3.7
Outlet Temp. (°F)
MaximumFlowRate (GPM)
Inlet
Temp.
(°F)
100 105 110 115 120 125
40 2.7 2.5 2.3 2.2 2.1 1.9
45 3 2.7 2.5 2.3 2.2 2.1
50 3.3 3 2.7 2.5 2.3 2.2
55 3.6 3.3 3 2.7 2.5 2.3
60 4.1 3.6 3.3 3 2.7 2.5
65 4.7 4.1 3.6 3.3 3 2.7
70 5.5 4.7 4.1 3.6 3.3 3
75 6.6 5.5 4.7 4.1 3.6 3.3
Outlet Temp. (°F)
MaximumFlowRate (GPM)
Inlet
Temp.
(°F)
100 105 110 115 120 125
40 2.5 2.3 2.1 2 1.9 1.8
45 2.7 2.5 2.3 2.1 2 1.9
50 3 2.7 2.5 2.3 2.1 2
55 3.3 3 2.7 2.5 2.3 2.1
60 3.8 3.3 3 2.7 2.5 2.3
65 4.3 3.8 3.3 3 2.7 2.5
70 5 4.3 3.8 3.3 3 2.7
75 6 5 4.3 3.8 3.3 3
Outlet Temp. (°F)
MaximumFlowRate (GPM)
Inlet
Temp.
(°F)

8
Model 180-2
The 18 kW water heater is configured for climates
where incoming water temperatures are in the
60° -70° F range. The Model 180-2 is suitable as a
whole house water heater.
Technical Specifications:
Dimensions:
13.5” x 16.2” x 3.6”
Max. Amps:
75 A @ 240 V
Weight:
16 lbs.
Customer Double-Pole
Circuit Breaker Required:
1 x 80A or
2 x 40A
kW / Elements:
18 kW / 2 elements
Model 165-2
The 16 kW Model 165-2 is designed for moderate
climates where the coldest incoming water
temperature is 60° F or greater. As a whole house
model, the Model 165-2 is best suited to homes in the
southernmost regions of the U.S. (i.e. Southern
California, Texas, Florida, etc.), as well as Mexico
and the Caribbean.
Technical Specifications:
Dimensions:
13.5” x 16.2” x 3.6”
Max. Amps:
67 A @ 240 V
Weight:
16 lbs.
Customer Double-Pole
Circuit Breaker Required:
1 x 80A or
2 x 40A
kW / Elements:
16 kW / 2 elements
Model 145-2
The 14 kW Model 145-2 tankless water heater is
configured for climates where the lowest incoming
water temperature is above 70° F. The Model 145-2
is used primarily in warm climates as a whole house
unit in tropical climates.
Technical Specifications:
Dimensions:
13.5” x 16.2” x 3.6”
Max. Amps:
59 A @ 240 V
Weight:
16 lbs.
Customer Double-Pole
Circuit Breaker Required:
1 x 70A or
2 x 35A
kW / Elements:
14 kW / 2 elements
100 105 110 115 120 125
40 2.1 1.9 1.8 1.6 1.5 1.4
45 2.2 2.1 1.9 1.8 1.6 1.5
50 2.5 2.2 2.1 1.9 1.8 1.6
55 2.7 2.5 2.2 2.1 1.9 1.8
60 3.1 2.7 2.5 2.2 2.1 1.9
65 3.5 3.1 2.7 2.5 2.2 2.1
70 4.1 3.5 3.1 2.7 2.5 2.2
75 4.9 4.1 3.5 3.1 2.7 2.5
Outlet Temp. (°F)
MaximumFlowRate (GPM)
Inlet
Temp.
(°F)
100 105 110 115 120 125
40 1.8 1.7 1.6 1.5 1.4 1.3
45 2 1.8 1.7 1.6 1.5 1.4
50 2.2 2 1.8 1.7 1.6 1.5
55 2.4 2.2 2 1.8 1.7 1.6
60 2.7 2.4 2.2 2 1.8 1.7
65 3.1 2.7 2.4 2.2 2 1.8
70 3.6 3.1 2.7 2.4 2.2 2
75 4.4 3.6 3.1 2.7 2.4 2.2
Outlet Temp. (°F)
MaximumFlowRate (GPM)
Inlet
Temp.
(°F)
100 105 110 115 120 125
40 1.6 1.5 1.4 1.3 1.2 1.1
45 1.7 1.6 1.5 1.4 1.3 1.2
50 1.9 1.7 1.6 1.5 1.4 1.3
55 2.1 1.9 1.7 1.6 1.5 1.4
60 2.4 2.1 1.9 1.7 1.6 1.5
65 2.7 2.4 2.1 1.9 1.7 1.6
70 3.2 2.7 2.4 2.1 1.9 1.7
75 3.8 3.2 2.7 2.4 2.1 1.9
Outlet Temp. (°F)
MaximumFlowRate (GPM)
Inlet
Temp.
(°F)

9
Model 110-2
The 11 kW Model 110-2 tankless water heater is
designed for moderate climates where the lowest
incoming water temperature is above 70° F. The
Model 110-2 is a point of use or booster model in
warm climates as opposed to a whole house water
heater.
Technical Specifications:
Dimensions:
13.5” x 16.2” x 3.6”
Max. Amps:
46 A @ 240 V
Weight:
16 lbs.
Customer Double-Pole
Circuit Breaker Required:
1 x 50A or
2 x 25A
kW / Elements:
11 kW / 2 elements
Alternate Voltage Table
The tables below lists the power in kW and the amperages for each model when connected
to voltages other than 240 volts.
Wattage De-rating Formula:
Applied Voltage2
× Rated Wattage = Actual Wattage
Rated Voltage2
For example: If installing a 27 kW unit, Model 280-3, when actual voltage is 212 V,
2122
=
44,944
= 0.78 × 27,000 W = 21,060 W @ 212 V
2402
57,600
Amperage Formula:
Watts
=Amps (Single Phase)
Volts
Flow Rate Formulas:
To determine power (kW) requirement
____GPM × ____ °F T × 0.1465 = ____ kW
To determine temperature rise
____ kW × 6.824 ÷ ____ GPM = ____°F T
To determine flow rate
____ kW × 6.824 ÷ ____ °FT = ____ GPM
100 105 110 115 120 125
40 1.3 1.2 1.1 1 0.9 0.9
45 1.4 1.3 1.2 1.1 1 0.9
50 1.5 1.4 1.3 1.2 1.1 1
55 1.7 1.5 1.4 1.3 1.2 1.1
60 1.9 1.7 1.5 1.4 1.3 1.2
65 2.1 1.9 1.7 1.5 1.4 1.3
70 2.5 2.1 1.9 1.7 1.5 1.4
75 3 2.5 2.1 1.9 1.7 1.5
Outlet Temp. (°F)
MaximumFlowRate (GPM)
Inlet
Temp.
(°F)
208 220 230
280-3 20.28 22.69 24.80
240-3 18.03 20.17 22.04
220-3 15.77 17.65 19.29
180-2 13.52 15.13 16.53
165-2 12.02 13.44 14.69
145-2 10.52 11.76 12.86
110-2 8.26 9.24 10.10
Connected Voltage
Power(kW)
Model
No.
208 220 230
280-3 97.50 103.13 107.81
240-3 86.67 91.67 95.83
220-3 75.83 80.21 83.85
180-2 65.00 68.75 71.88
165-2 57.78 61.11 63.89
145-2 50.56 53.47 55.90
110-2 39.72 42.01 43.92
Connected Voltage
Amperage
Model
No.

10
SECTION III–INSTALLATION
WARNING: Serious bodily injury or death may occur if the following warnings are
ignored.
 All circuit breakers and/or disconnect switches servicing this heater must be turned
off before installing, repairing or uninstalling this water heater.
 Installation of this product is restricted to indoor locations.
 Installation MUST be done by a licensed electrician and licensed plumber.
Locating and Mounting Instructions:
Your tankless water heater can be installed just about anywhere! Due to the small size of
your water heater, it can be mounted in many small spaces, including closets, under sinks, in
pantries, or under stair storage areas. However, there are some important guidelines to
follow that will ensure that your installation is both safe and convenient in the event that
future servicing is required.
This product is designed to be installed indoors only. You may be able to install your unit in
an outdoor location as long as it is mounted in a suitable enclosure that protects it from rain,
splashed water, direct sunlight, debris and insects. This product should NOT be installed in a
location where it may be subjected to freezing temperatures. If the water inside your tankless
water heater freezes, it can cause severe and permanent damage that is not covered under
your warranty. If you suspect that your tankless water heater may have frozen, do not turn
on the heater until it has thawed and you have inspected the system for leaks.
When selecting an installation location, give consideration to your existing plumbing
configuration, location of your main electrical panel, and location of your bathroom, kitchen
and laundry area. Try to choose a location that does not require you to make major
plumbing alterations, that is close to your main electrical panel (this will reduce the amount
of wire that you need to install), and that is physically close to the hot water fixtures that you
use most often. By locating the heater close to the points-of-use, you will reduce the amount
of time it takes for the hot water to travel from the water heater to your faucet. You should
also give consideration to future servicing. Do NOT locate the water heater in a location
that is difficult to access. In most cases, installing your tankless water heater in the same
location as your old conventional tank-type water heater will make the most sense.
You should avoid installing your tankless water heater in a location prone to excessive
humidity, moisture, or dust, or in an area where it may be splashed with water or other
liquids. Do NOT install under water pipes or air conditioning lines that might leak or
condense moisture that could then drip onto the heater. Do NOT install above electrical
boxes or junctions.
If you plan to install your water heater on a second floor or in a heated attic space, make sure
that you follow all code requirements for such installations as required for your area. We
recommend that you install a drip pan (connected to a drain) below the water heater to avoid
property damage in the unlikely event of a leak. Alternatively, you can install an active
water leak detector and shut-off valve designed to turn off your water supply in the event
that a leak is ever detected.
Mounting the unit:
Leave a minimum of 4” to both sides and 12” on the top and bottom of the unit.
Mount the water heater securely to the wall by putting four (4) screws through the
mounting holes.

11
Install a ¼” diameter bead of sealing caulk around the entire perimeter of the heater
between the heater back panel and the wall. This prevents any moisture or debris
from accumulating.
Plumbing Installation Instructions:
IMPORTANT INFORMATION:
Ensure all fitting installations comply with local plumbing and building codes.
 This water heater does not require a temperature and pressure (T&P) relief valve.
You may install a T&P relief valve if the county, city or state plumbing code requires
it.
Installations in the Commonwealth of MASSACHUSETTS and KENTUCKY require
a T&P relief valve.
When connecting to a plumbing system that utilizes Flex or PVC, a T&P relief valve
should be used as added safety.
 Do not connect the unit directly to CPVC pipe. You must use at least three feet of
copper pipe prior to connecting to any CPVC connection.
WARNING: Do not solder any pipes with the unit connected to the pipes. Doing so
will damage the flow meter and void your warranty.
 Before energizing the heater, run water for a minimum of three (3) minutes and
verify that all air has been removed.
 Installation of an air separator device is recommended for installations where air can
be easily introduced into the water system (i.e. Well water systems, lake pumps, and
other municipal systems).
 A shut off valve MUST be installed on inlet side of unit. A shut off valve on the
outlet is recommended.
Pipe Preparation:
Cut the tube so that the ends are square. WARNING: Ensure that there are no burrs or
damage to the cut end. This will prevent any damage to the internal o-ring.
Once the tubing end is cut square and clean, mark the pipe to be installed at a distance
of 1 ¾” from the end of the pipe. This is the insertion depth.
Check that fittings and tubing are clean, in good condition and are free from damage
and foreign objects.

12
Flushing the Line:
 Before connecting the copper pipe to the water heater, it is extremely important to
flush the lines to eliminate all plumbing paste, residue, or debris in the lines.
Installation to Quick-Connect Fitting:
Cut the pipe or tubing squarely and inspect the outside diameter of the pipe or tubing
to be sure there is no damage, nicks, burrs, or debris.
Deburr and clean pipe or tubing as necessary.
Use the insertion depth specified in the table below.
Insertion Depth Guide
Size
Insertion Depth
¾” CTS
1 1/8”
1” CTS
1 ¼”
If using PEX tubing, insert the supplied stiffener into the end of the pipe.
 Make certain to push the tubing completely into the fitting until it comes into contact
with the internal tube stop.
 Insert push ring clip.
Connect the cold water line to the water heater inlet marked cold water. Connect the
hot water line to the water heater outlet marked hot water.
 After inserting both fittings, open the hot water faucet and allow water to run
through the water heater for at least three (3) minutes, cycling the flow on and off
every minute. This process clears all the air from the lines and must be performed
prior to turning on the power at the unit. WARNING: Failure to do this may
damage the flow meter or heating elements and will void your warranty.
Disconnecting a Joint:
Ensure the system has been depressurized before removing fitting.
Remove push ring clip.
Push the push ring in squarely against the face of the fitting.
With the push ring held securely in this position, the tubing can be removed.
Tube Stop

13
Checking for Leaks and Purging Air:
If unit has been wired, verify all circuit breakers supplying power to the unit are
turned off.
Open all hot water taps supplied by the unit and inspect water connections for leaks.
With all hot water taps still open, allow the water to run for a minimum of 3
minutes. Inspect each tap to ensure all air in the lines has been purged. This process
purges all the air from the water lines and MUST be performed prior to turning on the
power at the unit. WARNING: FAILURE TO FOLLOW THIS STEP CAN CAUSE
PERMANENT DAMAGE TO THE HEATING ELEMENTS.
Close all hot water taps.
Close all hot water taps.
Typical Accessory Piping (Optional)

14
Electrical Installation Instructions:
IMPORTANT INFORMATION:
The unit must be wired in accordance with the current version of the National
Electrical Code (US) or Canadian Electric Code (Canada).
The unit must have its own independent circuits.
When the heater is not within sight of the electrical circuit breakers, an additional
local means of disconnection of all ungrounded conductors must be provided that is
within sight of the appliance or a circuit breaker lockout must be used. (Ref. NEC
422.31)
 Wire entry must be through the electrical KO provided in the bottom of the unit.
For Canada, per Canadian Electric Code, C22.1-02, the unit must be wired by a single
feed installation with one (1) double-pole circuit breaker.
For US, the unit may be wired by a single feed installation with one (1) double-pole
circuit breaker or by a multiple feed installation with multiple double-pole circuit
breakers as shown below.
Wiring to the water heater:
 Connect the power wire from the main panel to the power distribution block.
 Connect the main ground wire to the ground lug in the heater.
 Make sure the connections are securely tightened.
Electrical Specifications:
Hubbell Tankless Model No.
110-2
145-2
165-2
180-2
220-3
240-3
280-3
kW @ 240V
11
14
16
18
21
24
27
Amps @ 240V
45.8
58.3
66.7
75.0
87.5
100.0
112.5
Min. Recommended
Amperage to Home
100
100
125
150
200
200
200
Multiple Circuit Installation: (See schematic below)
Minimum Double-Pole Circuit
Breaker Size
(quantity x amps) (US only)
2x25
2x35
2x40
2x40
2x50
2x60
2x60
3x40
3x40
Min. Feed Wire Size at 75°C
THHN or Equivalent
8
8
8
8
8
6
6
8
8
Single Circuit Installation:
Minimum Double-Pole Circuit
Breaker Size
(US and Canada)
50
70
80
80
100
110
125
Min. Feed Wire Size at 75°C
THHN or Equivalent
8
6
4
4
3
2
1
□Tankless water heaters are considered a non-continuous load.
□If 3 circuits are used, it is acceptable to install two conductors in one line side port and
the third conductor in the second line side port of the power distribution block.
Alternatively, one conductor may be installed in each line side port and the third
conductor in an open load side port of the power distribution block.
□60°C or 90°C wire may be used. Refer to NEC table 310.16 for sizing.
□Conductors should be sized to maintain a voltage drop of less than 3% under load.

15
Alternate Voltage Configuration Settings:
The unit is factory configured and optimized for 240 volts. If the actual voltage
supplied is less or equal to 230 volts, set the power factor in the configuration menu
(see Temperature Controller User Interface Instructions in Section IV) according to
the Alternate Voltage Table in Section II.
Sub-panel Wiring:
When your new Hubbell Tankless Water Heater is to replace an existing tankless
water heater that utilizes a sub-panel with circuit breakers and you are keeping the
existing sub-panel, see Appendix I for additional wiring details.
SECTION IV –OPERATION AND MAINTENANCE
First Use of your Hubbell Tankless Water Heater:
Once the water supply is on and air has been purged from the system, power the unit on at
the main panel. The unit is now operating automatically. When water flows through the unit,
the heating elements turn on to heat the water to the displayed setpoint temperature. When
the water flow stops, the heating elements turn off.
You can adjust the setpoint upward or downward by pressing the UP or DOWN button.
Displaying Celsius or Fahrenheit degrees and adjusting other settings for your tankless water
heater can be done via the configuration menu, described below.
Upper Button to
Increase Temperature
Digital Display Lower Button to
Decrease Temperature
Most people feel comfortable showering or bathing at a temperature between 98°and
105°F (37° to 41°C). We recommend that you set the output water temperature of
your water heater in the range of 105° - 110°F (approx.41° - 43°C). This will ensure
you have adequate hot water to meet all of your household needs while also
maximizing your available water flow rate, reducing the risk of scalding to children
and the elderly, and increasing the energy savings you achieve.
Circuit Breaker 1
Circuit Breaker 2
Circuit Breaker 1
Circuit Breaker 2
Circuit Breaker 3
Tankless Power
Distribution Block
L1
L2
Tankless Power
Distribution Block
L1
L2
2 Circuit Breaker Installation
3 Circuit Breaker Installation

16
NOTE: All newer model dish washing machines are equipped with an internal
heating element, and most clothes washing detergents are now designed for use in
cold and warm water. There is no longer a need to set your water heater to a
temperature above 125°F. Temperatures above this level (which most traditional water
heaters are set to deliver) can cause serious scalding injuries to small children or
elderly persons in your home.
Maintenance:
The Hubbell Tankless Water Heater requires no maintenance other than to
periodically check around the outside of the unit for leaks. If a water leak is detected
from your water heater, turn off the water supply at the shut-off valve on the inlet side
of the water heater, turn off the power to the heater at the main electrical panel and
call a service technician or plumber for evaluation and repair.
When any maintenance is performed on the water heater or the plumbing system that
may introduce air into the water supply pipes, it is important to turn the power off to
the water heater and purge the air out of the lines before restoring power to the unit.
See Checking for Leaks and Purging Air in Section III.
Temperature Controller User Interface Instructions:
1. The display is always on when power is applied to the unit:
a. To turn the unit OFF, press and hold the DOWN button until display shows
OFF.
b. The controller will preserve all its settings during any power outage or
disconnect.
2. To change setpoint temperature (the temperature is fully adjustable in 1° increments).
a. Press the UP or DOWN button to change the setpoint temperature.
b. Pressing and holding either the UP or DOWN button will fast scroll.
3. Configuration Menu.
a. To enter configuration menu, press and hold the UP and DOWN buttons
simultaneously for 7 seconds. (Note that the display will change during the time
you are holding the buttons. You are in the configuration menu and can release
the buttons when the first character of the display is ‘P’).
b. To scroll through menu items, press the UP or DOWN button.
c. To leave the configuration menu, wait 7 seconds without pushing any buttons.
d. To make a change to a specific configuration menu item, simultaneously press
the UP and DOWN buttons. The menu item setting will now flash indicating it
can be changed.
e. To scroll through menu item settings, press the UP or DOWN key.
f. When the desired setting is displayed, simultaneously press the UP and DOWN
buttons to lock in the selection and return back to the configuration menu.
g. Configuration Menu Items:
i. Power Setting - Sets the total kW rating of water heater.
1. P###, where ### is adjustable from 001 to 054 (Note
that the kW selection should equal the kW based
upon the actual voltage measured to the heater. Please see the
nameplate on the front cover of the heater for a listing of kW
ratings at various voltages).
ii. Temperature Range –Sets the temperature adjustment range
1. r001, 60° to 140°F (15°-60°C) (Factory Default)
2. r002, 32° to 194°F (0°-90°C)
3. r003, 32° to 104°F (0°-40°C)
iii. Display units –Sets the display units to either Fahrenheit/Gallons or
Celsius/Liters.
1. dEFF, for degrees Fahrenheit and Gallons. (Factory
Default)
2. dECC, for degrees Celsius and Liters.

17
iv. Normal Display Mode–Sets the display to show various values.
1. dSP1, to display setpoint temperature only. (Factory
Default)
a. setpoint is displayed as ###
2. dSP2, to display measured inlet temperature intermittently with
setpoint temperature.
a. Inlet temperature is displayed as i###
3. dSP3, to display measured outlet temperature intermittently with
setpoint temperature.
a. Outlet temperature is displayed as o###
4. dSP4, to display measured flow rate intermittently with setpoint
temperature
a. Flow rate is displayed as F##.#, in tenths of a gallon or liter.
5. dSP5, to display inlet temp, outlet temp, flow rate and setpoint all
intermittently.
v. Power Limiting Factor –Sets the % of heater output allowed by the
controller
1. L###, where ### is a percentage from 001 to 100
(Factory Default 100). This feature allows a user to
limit the kW rating of the unit by a specific percentage and effectively
lower the total amp draw of the unit.
vi. Heater Quantity –Sets the controller to perform calculations using the
number of heating elements in the unit.
1. E001, for one heating element and all 3-phase units
2. E002, for two heating elements
3. E003, for three heating elements
4. E004, for four heating elements
vii. Calibration –Used to calibrate the heater. (For factory use only)
1. CA #, where ## equals the degrees of calibration from
-3 to 3. Default is 0.
viii. Low/High Flow –Sets the unit as either a low flow or high flow unit.
1. LF, for low flow (Factory Default).
2. HF, for high flow (NOT TO BE USED WITH THE MODELS
LISTED IN THIS MANUAL).
ix. Remote Control –Sets the operation of the remote control
function (see Priority and Remote Controls in this section).
1. iPOF, disables the remote control (Factory Default).
2. iPHi, 24VDC signal or closed relay connected to P2 and
P3 will allow the heater to operate and loss of 24VDC
signal or open relay connected to P2 and P3 will inhibit the heater
operation.
3. iPLo, 24VDC signal or closed relay connected to P2 and P3 will inhibit
the heater operation and loss of 24VDC signal or open relay connected
to P2 and P3 will allow the heater to operate.
x. Display Lock –Allows the user to lock the heater parameters. When the
display is locked the temperature setpoint cannot be changed and although the
configuration menu will still be accessible, no changes can be made to any
parameters, except to change the display lock. With the display lock on,
attempting to change the temperature setpoint will cause the display to show,
Locd.
1. LcOn, to turn the display lock on.
2. LcOF, to turn the display lock off (Factory Default).
xi. Software Version –Displays the version number of the
software
1. Sd##, where ## is the version of the display software.

18
POINT IS FLASHING
2. Sb##, where ## is the version of the main board software.
h. After this menu item, the configuration menu cycles back to the first item.
4. Diagnostic Menu Display
a. To display common diagnostic data useful for troubleshooting, when in normal
display mode press and release the UP and DOWN buttons
simultaneously.
b. The display will intermittently display the following values: flow
rate (F##.#), measured inlet temp (i###), measured outlet temp
(o###), setpoint (###).
c. These values and settings will continue to display and scroll until
either the UP or DOWN button is pressed. The display then returns
to normal display mode.
5. Configuration Settings Display
a. To display all configuration settings, when in normal display mode press and
release the UP and DOWN buttons simultaneously twice.
b. The display will scroll through all configuration settings.
c. The display will continue to scroll until either the UP or DOWN button is
pressed and will then return to normal display mode.
6. Power Rate Display
a. The decimal point in the display’s rightmost digit is a visual
indicator of how much power is required to meet the demand. A
blinking decimal point indicates that the triac is being sent
a signal to energize and thus turn the element on. The
decimal point light will blink at a faster rate as the controller is calling for more
heat. When the unit is calling for full power the light is solid.
b. If the amount of power required exceeds the capacity of the heater, then the
entire display will intermittently flash. (Note that the display will only flash
when the display configuration is set to ‘dSP1’.)
7. Cost Calculator –Allows the user to view the amount of power and hot water
consumed and the cost of operation.
a. To display the Cost Calculator values, when in normal display mode press and
release the UP and DOWN buttons simultaneously three times.
b. The display will scroll through the Cost Calculator Values since last reset
i. C###, where ### equals the total cost of operation
ii. ####, where #### equals the total number of kW∙Hrs consumed
iii. H0##, where ## equals water usage up to the ten thousands place,
followed by h###, where ### equals water usage up to the hundreds
place. Example: H012, h345 equals 12,345 gallons of water used.
iv. To reset these values to 0, press and hold the UP and DOWN buttons
simultaneously for 5 seconds. When the display shows ‘0000’, the cost
calculator has been reset.
c. To enter a specific cost per kW∙Hr value, while displaying the Cost Calculator
values above press and release the UP and DOWN buttons simultaneously.
i. The display shows the cost per kW∙Hr as #.### (Factory Default 0.114)
ii. Press the UP or DOWN button to adjust the cost per kW∙Hr. Holding the
UP or DOWN buttons will fast scroll.
iii. Press the UP and DOWN buttons simultaneously to lock in the cost per
kW∙Hr.
iv. Press the UP or DOWN button to return to Cost Calculator values.
v. Press the UP or DOWN button to return to normal display mode.

19
8. Error Code
a. Err1, indicates a failure of element #1
b. Err2, indicates a failure of element #2
c. Err3, indicates a failure of element #3
d. Err4, indicates a failure of element #4
e. Err5, indicates a failure of the inlet thermistor
f. Err6, indicates a failure of the outlet thermistor
g. Err7, indicates a failure of the display unit to communicate with the main board
h. Err8, indicates that water has been detected in the case
Remote Display
An optional remote display may be supplied and connected to the TK2000 control board as
shown below.
Priority and Remote Controls:
Optionally, the tankless water heater may be connected to another electrical device (10A @
240VAC max.) that will give priority to the water heater over that device to ensure that both do
not operate at the same time and/or the tankless water heater may be wired to a remote switch,
relay, or provided with a 24VDC signal (such as from a building maintenance system) to allow
the tankless water heater to be remotely controlled. The diagram and description below provide
details on how connections to the tankless water heater control board are to be made.
1. Priority Relay (10A@240VAC max.)
a. When the unit is demanding power (calling for heat):
i. The connection between the terminals marked C and NO are closed and
will allow power to pass through.
ii. The connection between the terminals marked C and NC are open and will
not allow power to pass through.
b. When the unit is not demanding power (not calling for heat):
i. The connection between the terminals marked C and NO are open and will
not allow power to pass through.
ii. The connection between the terminals marked C and NC are closed and
will allow power to pass through.
2. Remote Control
a. When a 24VDC signal (5mA draw max.) is supplied between terminals P1 and
P2, the heater will either operate or be inhibited (displayed as Hld) as determined
by the Remote Control settings as shown above. Loss of 24VDC signal has the
opposite effect.
b. When wired to a volt-free contact (10A max.) between terminal P2 and P3 (output
signal 24VDC@5mA), opening or closing the contact will allow the heater to
either operate or inhibit (displayed as Hld) operation as
determined by the Remote Control settings as shown above.

20
TK2000 Control Board Wiring Detail
Remote
Display
Outlet
Thermistor
Inlet
Thermistor
Leak
Detection
F1 F2 F3
Flow
Meter
Display
Auxiliary
P1(0VDC) P2(+24VDC) P3
Remote
Control
Priority
Relay
NC
NO
C
Power and Triac Wiring