Hubbell TXA, ETXA, MTXA Description, Installation And Operation Manual

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INSTALLATION, OPERATION, AND

MAINTENANCE MANUAL FOR THE

HUBBELL MODEL TXA / ETXA/

MTXA TANKLESS WATER HEATER

ELECTRIC HEATER COMPANY

Edition 2019

HUBBELL

ELECTRIC HEATER COMPANY

P.O. BOX 288

STRATFORD, CT 06615-0288

PHONE: (203) 378-2659 FAX:

(203) 378-3593

INTERNET: http://www.hubbellheaters.com

Important Safety Information

You must read and follow all instructions. Serious bodily injury or death could occur if you ignore this warning.

All circuit breakers and/or disconnect switches servicing the heater must be turned off when installing, uninstalling, or repairing this water heater.

The Hubbell Tankless Water Heater must be grounded.

The unit must be installed by a licensed electrician and plumber.

The unit must be wired in accordance with the current version of the National Electrical Code (US) or Canadian Electric Code (Canada).

This installation must comply with all national, state, and local plumbing and electrical codes.

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)

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.

It is recommended that water hardness levels in excess of 12 grains per gallon [approx. 200ppm (mg/l)] be treated prior to entering the water heater. Unless treated, water at or above this hardness level will cause scaling which will significantly impact the water heater performance.

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.

TABLE OF CONTENTS

Table of Contents

HUBBELL ELECTRIC HEATER COMPANY ...................................................................................2

SECTION I – TANKLESS WATER HEATER OPERATING PRINCIPLE ................................4

• How the Hubbell Tankless Water Heater Works: .................................................................................. 4

SECTION II – GENERAL DESCRIPTION AND CONSTRUCTION......................................5

• Technical Specifications Common to All Models: .................................................................................. 5

• Tankless Water Heater Maximum Flow Rates:...................................................................................... 7

• Formulas:............................................................................................................................................... 8

SECTION III – INSTALLATION............................................................................................9

• Locating and Mounting Instructions:..................................................................................................... 9

• Plumbing Installation Instructions: ...................................................................................................... 10

• Flushing the Line: .............................................................................................................................. 10

• Checking for Leaks and Purging Air................................................................................................. 10

Typical Accessory Piping ......................................................................................................11

Electrical Installation Instructions: ........................................................................................12

WIRING DIAGRAMS:............................................................................................................13

SECTION IV – OPERATION AND MAINTENANCE ..........................................................27

• Maintenance: ...................................................................................................................................... 27

• First Use of your Hubbell Tankless Water Heater:............................................................................... 27

• Temperature Controller User Interface Instructions: .......................................................................... 28

• Configuration Menu............................................................................................................................. 28

Power and Triac Wiring .......................................................................................................32

SECTION V – TROUBLESHOOTING................................................................................34

Initial Evaluation: ................................................................................................................34

• Advanced Troubleshooting:................................................................................................................. 35

SECTION VII – PARTS LIST .............................................................................................46

SECTION VIII – WARRANTY.............................................................................................47

• WARRANTY PROCEDURE ..................................................................................................................... 48

NOTES:...............................................................................................................................49

SECTION I – TANKLESS WATER HEATER OPERATING PRINCIPLE

How the Hubbell Tankless Water Heater Works:

For the most part, operating the new tankless water heater is very similar to using any traditional water heater system. However, it is very important that, all the set-up procedures

and operating instructions are carefully read to ensure maximum performance and energy savings from the new water heater.

The Hubbell TXA Series 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 needed. Due to these high powered elements, dry firing the TXA series heater is a possibility. To prevent this, a low water detection system has been installed to keep the elements from turning on if the unit has not been properly purged of air.

Once the air has been purged and as soon as there is a hot water demand, a sophisticated flow sensor within the heater recognizes the demand and initiates the heating process. 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 the 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%.

It is important to keep in mind that all tankless water heaters are subject to a maximum flow rate. If this flow rate is exceeded, the heater will not be capable of fully heating water. The amount of water that can be heated by the tankless water heater at any given time will depend on the model selected and the incoming water temperature. 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, there will be a significant energy savings compared to a conventional tank type water heater.

SECTION II – GENERAL DESCRIPTION AND CONSTRUCTION

Technical Specifications Common to All Models:

Materials:

Stainless Steel Exchanger and Casing

Plumbing Connection:

Low Flow

1” FNPT

Energy Efficiency:

98%

High Flow

1” FNPT Voltage:

208-600 Volts

Operating Range:

5 – 150 psi

Frequency:

50 / 60 Hz

Protection:

Thermal Auto Reset

Product Overview TXA/MTXA:

Notes:

Transformers are only installed on 3-phase models over 240 volts.

System components and layout are subject to change without notice.

Hi-Limit Switches

Heating Elements

Element Switching

Devices (Triacs)

Transformer

Flow Meter

Control Board

Control Fuse

Ground Lug

Power Distribution

Block

Magnetic

Contactor

Heating Chamber

Vent Drain

Cold Water Inlet

Hot Water Outlet

Inlet Thermistor

Outlet Thermistor

Product Overview ETXA:

Notes:

1. Construction of ETXA is similar to TXA, with the addition of a mechanical tempering

valve, factory set at 85°F.

2. System components and layout are subject to change without notice.

Mechanical

Tempering Valve

Tankless Water Heater Maximum Flow Rates:

For alternate power (kW) values, the maximum flow rate can be calculated using the formulas on the following page.

Formulas:

Wattage De-rating Formula:

Applied Voltage

Rated Voltage

× Rated Wattage = Actual Wattage

For example: If installing a 27 kW unit when actual voltage is 212 V,

212

44,944

= 0.78 × 27,000 W = 21,060 W @ 212 V

240

57,600

Amperage Formula:

Watts

= Amps (Single Phase)

Watts

÷1.73 = Amps (3-Phase)

Volts 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

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 MUST be done by a licensed electrician and licensed plumber.

Locating and Mounting Instructions:

The Hubbell TXA series tankless water heater can be installed just about anywhere. However, there are some important guidelines to follow that will ensure that the installation is both safe and convenient if future servicing is required.

The unit may be installed in either indoor or outdoor locations due to the NEMA 4 -12 enclosure rating, 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 the

tankless water heater freezes, it can cause severe and permanent damage that is not covered under the warranty. If you suspect that the tankless water heater may have frozen, do not turn on the heater until it has thawed, and it has been inspected for damage. (Hubbell has options for internal heaters for low ambient conditions.)

When selecting an installation location, consider the existing plumbing configuration, the location of your main electrical panel, and location of the point of use. Try to choose a location that does not require major plumbing alterations, that is close to the main electrical panel (this will reduce the amount of wire needed to install), and that is physically close to the hot water fixtures. By locating the heater close to the points of use, this will reduce the amount of time it takes for the hot water to travel from the water heater to the point of use.

Consideration should also be given to future servicing. Do NOT locate the

water heater in a location that is difficult to access or on a horizontal surface, like the ceiling or floor. This will affect the operation of the high limits.

Avoid installing the tankless water heater in a location prone to excessive humidity, moisture, or dust, or in an area where it may be splashed with corrosive 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 installation of the water heater is such, that leaks may cause water damage, make sure that all code requirements for such installations as required for your area are followed. Hubbell recommends that a drip pan (connected to a drain) is installed below the water heater to avoid property damage in the unlikely event of a leak. Alternatively, an active water leak detector and shut-off valve designed to turn off the water supply if a leak is ever detected may be installed.

Mounting the unit:

• Leave a minimum of 12” to bot h sides 11” on the bottom and 36” in front of the unit.

• Mount the water heater securely to the wall by putting four (4) screws through the

mounting holes.

• 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.

• It is recommended that this unit be installed in plumbing systems use copper or

stainless steel piping only. If using plastic piping such as PEX or PVC is required, then contact the Hubbell Heater for more information.

• WARNING: DO NOT SOLDER ANY PIPING WHILE THE UNIT IS

CONNECTED TO THE PIPING. 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).

• Shut off valves MUST be installed on both the inlet side and outlet piping of

unit.

• WARNING: DO NOT SUPPLY WATER TO THE UNIT THAT IS

HOTTER THAN 130°F.

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 and damaging the flow meter.

• After completing plumbing installation, 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 AND/OR HEATING ELEMENTS AND WILL VOID YOUR WARRANTY.

Checking for Leaks and Purging Air:

• Verify circuit breakers and service disconnect 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.

Typical Accessory Piping

Water Hammer Arrestor (Optional)

Temperature and Pressure Gauge (Optional)

Ball Valve

(Recommended)

Pressure Relief Valve (If required by code)

Tankless Hot Water Valve with Purge valve Connection (Optional)

Union Fittings

Strainer

(Recommended)

Water Treatment

(Optional)

Air Separator (Recommended)

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 (service disconnect) 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)

•

For Canada, per Canadian Electric Code, C22.1-02, the unit must be wired by a single feed installation with one (1) three-pole circuit breaker.

•

For US, the unit may be wired by a single feed installation with one (1) three-pole circuit breaker or by a multiple feed installation with multiple double-pole circuit breakers.

Wiring to the water heater:

•

Connect the power wire from the main panel to the power distribution block or magnetic contactor as applicable.

•

Connect the main ground wire to the ground lug in the heater.

•

Make sure the connections are securely tightened.

Electrical Specifications:

•

Tankless water heaters are considered a non-continuous load.

•

If a multiple feed installation is used, it is acceptable to install up to two conductors in one-line side port. Additionally, when a power distribution block is supplied, additional conductors may be installed in an open load side port of the power distribution block.

•

Wiring sizing listed is for 75°C THHN. 60°C or 90°C wire may be used. Refer to NFPA70 table 310.15 (B) for proper sizing.

•

Wiring penetrations are recommended in bottom of heater.

•

Conductors should be sized to maintain a voltage drop of less than 3% under load.