Bradford-White M-2-50T6DS User Manual

RESIDENTIAL ELECTRIC AND LIGHT DUTY

COMMERCIAL ELECTRIC WATER HEATERS

SERVICE

MANUAL

Troubleshooting Guide

and Instructions for Service

(To be performed ONLY by

qualified service providers)

Photo is of

M-2-50T6DS

Models Covered

by This Manual:

Residential Energy Saver: M1& M2(HE) UprightModels. M1& M2 Lowboy Models. M1& M2 UtilityModels. M1& M2 Wall HungModels.

Light DutyEnergy Saver: LD Upright Models. LD Utility Models. LD Lowboy. LD WallHung.

Dairy Barn Deluxe Energy Saver: DB Models.

Manual 238-47104-00A

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Table of Contents

Page Service Procedure

Introduction ………………………………………………………………………. 2

Tools……………………………………………………………………………… 2

General Information ……………………………………………………………… 3 - - -

Sequence of Operation …………………………………………………………… 6 - - -

Single Element Operation ……………………………………................... 6 - - -

Double Element, Non-Simultaneous, Single Phase………………………. 7 - - -

Double Element, Simultaneous, Single Phase, 4 wire Service …............... 8 - - -

Double Element, Non-Simultaneous, 3 Phase ………................................ 9 - - -

Double Element, Simultaneous, 3 Phase ………………………………… 10 - - Double Element, Non-Simultaneous, Single Phase, Off Peak …………... 11 - - -

Troubleshooting …………………………………………………………………. 12 - - -

Line Voltage and High Limit ECO Testing……………………………………… 14 RE-I

Heating Element Testing ……………................................................................... 15 RE-II

Residential Thermostat Testing ……..................................................................... 16 RE-III

Single Element ……………………………............................................... 16

Double Element, 4 wire, Simultaneous, Single Phase …………………... 16

Double Element, Non-Simultaneous, Single Phase ………....................... 17

Double Element, Non-Simultaneous, 3 Phase …………………………... 19 Double Element, Simultaneous, 3 Phase ………………………………... 21 Double Element, Non-Simultaneous, Single Phase, Off Peak ………….. 23

Light Duty Commercial Thermostat Testing …..................................................... 25 RE IV

Double Element, Non-Simultaneous, Single Phase ……………………... 25 Double Element, Simultaneous, Single Phase …………………………... 27 Double Element, Non-Simultaneous, 3 Phase …………………………... 29 Double Element, Simultaneous, 3 Phase ………………………………... 31

Thermostat Removal and Replacement …………………………………………. 33 RE-V

Heating Element Removal and Replacement ……………………………………. 34 RE-VI

Dip Tube and Anode Inspection and Replacement ……………………………… 35 RE-VII

Generic Parts List ………………………………………………………………... 36 - - -

Page 2

This service manual is designed to aid service and maintenance professionals on the function, proper diagnosis and repair of Bradford White residential electric and light duty commercial electric water heaters.

The text and illustrations in this manual provide step by step instructions to facilitate proper operation and troubleshooting procedures. Contact the Bradford White Technical Support Group immediately if diagnosis can not be made using the methods described in this service manual.

Introduction

Residential and Light Duty

Commercial Electric Water Heaters

Tools

- Multi Meter. - Phillips Head Screw Driver.

- 1-½ Deep Well Socket (element removal). - Thermometer.

- ¼" Nut Driver. - Drain Hose.

- Various Hand Tools: Pipe Wrench, Channel Locks, Pliers (common & needle nose), Wire cutters, Wire Strippers, Flash Light.

GENERAL INFORMATION

120 VOLT

Ungrounded

Grounded

(Neutral)

Grounding

BLACK

WHITE

GREEN

120

240 VOLT

Ungrounded

Grounding

BLACK

RED

GREEN

240 120

120

ABCNeutral

RED BLACK RED

120

120 208

208 208

208 3Ph

277

ABCNeutral

RED BLACK RED

277

277 480

480 480

480 3Ph/277 1 Ph

120

ABCNeutral

RED BLACK RED

120

120 240

240 240

240 3Ph

Common Service Wire Configurations

Amps = Watts (for single phase units) Example 4500W/240V = 18.75A

Volts

Amps = Watts (for balanced 3 phase units) Example 4500W/240V x 1.732 = 10.82A

Volts x 1.732

Watts = Amps x Volts Example 18.75A x 240V = 4500W

Ohms = Volts Example (240V) / 4500W = 12.8 Ohms

Watts

Commonly Used Formulas

Page 3

GENERAL INFORMATION

Wattage Limitations at Various Voltages

Residential Electric Upright M1 & M2 Series (Non-Simultaneous operation)

aximum

Wattage

lement

Upper/Lower

Voltage

,000

21000,3/000,3

6,000

,000/6,00 0 208, 240

,000

77, 480

Residential Electric Upright M1 & M2 Series (Simultaneous Operation)

Maximum

Wattage

Element

Upper/Lower

Voltage

3,000

021005,1/005,1

10,000

802000,5/000,5

11,000

042005,5/005,5

12,000

6,000/6,000

277, 480

6,000/6,00 0

Residential High Efficiency Upright M2HE Series (Simultaneous Operation)

Light Duty Commercial Electric LD Series (Simultaneous Operation)

Residential Electric Lowboy M1 & M2 Series (Non-Simultaneous Operation)

Maximum

Wattage

Single

Element

Voltage

3,000

021000,3

6,000

042,802000,6

6,000

772000,6

6,000

084000,6

Residential Electric Utility Series (Single Element Operation) Light Duty Utility Series (Single Element Operation)

Dairy Barn Deluxe DB Series (Non-Simultaneous Operation)

Dairy Barn Deluxe DB Series (Simultaneous Operation)

esidential High Efficiency Upright M2HE Series (Non-Simultaneous operation)

Residential Electric Lowboy M1 & M2 Series (Simultaneous Operation)

Page 4

Light Duty Commercial Electric LD Series (Non-Simultaneous Operation)

GENERAL INFORMATION

Surface M ount

Combination Thermostat/

ECO (high limit)

89T Series

Manual

CO (high limit) R

eset button

Temperature

control Dial

Temperature

control Dial

Surface Mount

Thermostat

59T Series

Surface Mount

Combination Thermostat/

ECO (high limit)

89T Series

Surface Mounted Thermostats

Surface mounted thermostats are mounted into a bracket which holds the thermostat against the side of the tank. S

urface mounted thermostats respond to tank surface temperatures to sense a call for heat, set point temperature settings and high limit (ECO) activation. It is import that the entire back surface of the thermostat is in full contact or flush with the tank. Improperly mounted thermostat will lead to improper heater operation.

1-½ Hex Screw-in Flange

Terminal Block Screw

Terminal Block

Zinc Plated Copper or Incoloy Sheath

Element Rating Ink Stamped on side of Terminal Block.

Direct Immersion “Screw-in” Type Heating Element

Page 5

SEQUENCE OF OPERATION

esidential and light duty commercial electric water heaters are designed to operate using several different operating m

odes. The common modes and sequence of operation are as follows:

. Single Element Operation.

. Double Element Non-Simultaneous Operation (single phase).

. Double Element Non-Simultaneous Operation (3 phase).

4. Double Element Simultaneous Operation (single phase).

5. Double Element Simultaneous Operation (3 phase).

Sequence of Operation- Single Element Operation.

Line voltage is applied across terminals L1 &L3 of the thermostat. ECO is closed, so there is voltage at terminal L4 and to one side of the element.

When the thermostat is satisfied, it opens at terminal T2 interrupting current flow through the element. System is now in stand-by mode, waiting for the next call for heat.

ECO

Closed

Thermostat closed

at terminal T2

Thermostat opens

at terminal T2

Tank is cold therefore thermostat is closed at terminal T2 (calling for heat). This completes the circuit and allows current to flow through the element.

Page 6

Non-Simultaneous and Simultaneous Operation

Double element electric water heaters are designed to operate in a Non-Simultaneous or Simultaneous mode.

Non-Simultaneous Mode: Allows only one heating element to operate at a time. For example, when the tank is cold, the upper element is energized first, heating the top of the tank. Only when the upper thermostat is satisfied, the upper e

lement is de-energized and power is directed to the lower thermostat, energizing the lower element and heating the bottom portion of the tank until the lower thermostat is satisfied. As hot water is drawn off the tank, it is replaced with cold water delivered through the dip tube to the bottom of the tank. The bottom of the tank cools, the lower thermostat will call for heat energizing the lower element. If enough hot water is drawn from the tank, the top portion of the tank cools and the upper thermostat will call for heat, de-energizing the lower element and allowing only the top element to e

nergize until the upper thermostat is satisfied.

imultaneous mode: allows both heating elements to operate at the same time. That is, if either thermostat (upper or

lower) is calling for heat, the corresponding heating element is energized independent of the other.

SEQUENCE OF OPERATION

Sequence of Operation- Double Element, Non-Simultaneous Operation, Single Phase.

Line voltage is applied across terminals L1 & L3 of the upper thermostat. ECO is closed, so there is voltage at terminal L4 and to one side of the upper and lower elements.

Tank is cold therefore both thermostats are closed at terminal T2 & 2 (calling for heat). The circuit is complete through the upper thermostat only, allowing current to flow through upper element.

1 2

ECO

Closed

Thermostat closed

at terminal T2

When upper thermostat is satisfied, it opens at terminal T2 interrupting current flow through upper element, and closes at terminal T4 allowing voltage to pass to terminal 1 of lower thermostat. This completes the circuit through the lower thermostat and allows current flow through lower element.

Thermostat closed

at terminal T4

Thermostat open

between terminals

1 and 2

Upper

T’stat

Upper

Element

Upper

T’stat

Upper

Element

Lower T’sta t

Lower

Element

Lower T’sta t

Lower

Element

When the lower thermostat is satisfied, it opens at terminal 2 interrupting current flow through lower element. The system is now in stand-by mode waiting for the next call for heat

The lower thermostat/element combination will generally cycle on and off more often then the upper. In some cases, such as a cold tank or in high demand periods, the upper thermostat will call for heat (opening at terminal T4 and closing at terminal T2) prior to the lower thermostat being satisfied. This will interrupt current flow through the lower thermostat and element and allow current to flow through the upper element only. When the upper thermostat is satisfied, it resumes operation as described in sequence #3 above.

Thermostat closed between terminals

1 and 2

Upper T’stat

Upper

Element

Lower T’stat

Lower

Element

Upper

T’sta t

Upper

Element

Lower T’stat

Lower

Element

Upper T’stat

Upper

Element

Lower T’stat

Lower

Element

Thermostat closed

t terminal 2

Thermostat closed

at terminal T2

Page 7

SEQUENCE OF OPERATION

Sequence of Operation- Double Element, Simultaneous Operation, Single Phase, 4 wire service installation.

4 wire, double element heater wired for simultaneous operation is essentially two single element systems operating

ndependently. The heaters are wired internally with two independent circuits, one circuit for each thermostat/element combination. When installed using a two wire service, the blue and red (or white) wires will be connected together, likewise black and yellow wires will be connected together.

Line voltage from circuit one is applied across terminals L1 & L3 of the lower thermostat. Likewise, line voltage from circuit two is applied across terminals L1 & L3 of the upper thermostat. ECO in both upper and lower thermostat is closed, so there is voltage at terminal L4 of each thermostat and to one side of the upper and lower elements.

Tank is cold therefore both thermostats are closed at terminal T2 (calling for heat). This completes the circuit through the thermostats and allows current to flow through the elements.

Circuit one

Circuit two

ECO

Closed

ECO

Closed

Circuit one

Circuit two

Thermostat closed

t terminal T2

Thermostat closed

at terminal T2

When either thermostat is satisfied, it will open at terminal T2, interrupting current flow through the corresponding element. As both thermostats satisfy, the system will be in stand-by mode waiting for the next call for heat. Thermostats will operate independent of the other.

Circuit one

Circuit two

Thermostat open

at terminal T2

Thermostat open

at terminal T2

Page 8

SEQUENCE OF OPERATION

Sequence of Operation- Double Element, Non-Simultaneous Operation, 3 Phase.

Line voltage is applied across terminals L1 & L3 of upper thermostat. Likewise, Line voltage is applied to terminal L3 of lower thermostat. ECO in both upper & lower t

hermostat is closed, so there is voltage at terminal L4 of both thermostats and to one side of both upper & lower elements.

Tank is cold therefore both thermostats are closed at terminal T2 (calling for heat). The circuit is complete through the upper thermostat only allowing current to flow through the upper element.

When the upper thermostat is satisfied, it opens at terminal T2 interrupting current flow through upper element, and closes at terminal T4 allowing voltage to pass to terminal L1 of lower thermostat. This completes the circuit through the lower thermostat allowing current flow through lower element.

When the lower thermostat is satisfied, it opens at terminal T2 interrupting the current flow through the lower element. The system is now in stand-by mode waiting for the next call for heat.

ECO

Closed

1 2

Thermostat closed

at terminal T2

Thermostat closed

at terminal T2

Thermostat closed

at terminal T4

Thermostat closed

at terminal T2

Thermostat closed

at terminal T4

Thermostat open

at terminal T2

Thermostat closed

at terminal T2

Thermostat closed

at terminal T2

ECO

Closed

Page 9

SEQUENCE OF OPERATION

Line voltage is applied across terminals L1 & L3 of upper thermostat. Line voltage also extends to terminal L1 of lower thermostat. Also, line voltage is applied to terminal L3 of lower thermostat. ECO in both upper & lower thermostat is closed, so there is voltage at terminal L4 of both thermostats a

nd to one side of both upper & lower

elements.

Tank is cold therefore both thermostats are closed at terminal T2 (calling for heat). This completes the circuit through the thermostats and allows current to flow through the elements.

Sequence of Operation- Double Element, Simultaneous Operation, 3 Phase.

Thermostat closed

at terminal T2

ECO

Closed

ECO

Closed

Thermostat closed

at terminal T2

Thermostat open

at terminal T2

Thermostat open

at terminal T2

Page 10

SEQUENCE OF OPERATION

Sequence of Operation- Double Element, Non-Simultaneous Operation, Single Phase, Off Peak.

Some electric utility companies will offer discounts for using electricity during “Off Peak” Times of the day. The system allows the use of an “Off Peak” meter, which interrupts power to the lower element during high power demand periods.

Line voltage is applied across terminals L1 & L3 of the upper thermostat. Line voltage from o

ff peak meter is supplied to terminal L1 of lower thermostat. ECO in the upper thermostat is closed, so there is voltage at terminal L4 of upper thermostat and to one side of the upper element.

Tank is cold therefore both thermostats are closed at terminal T2 (calling for heat). The circuit is complete through the upper thermostat only, allowing current to flow through upper element.

When upper thermostat is satisfied, it opens at terminal T2 interrupting current flow through upper element, and closes at terminal T4 allowing voltage to pass to one side of the lower element. This completes the circuit through the lower thermostat and off peak meter allowing current flow through lower element.

When the lower thermostat is satisfied, it opens at terminal T2 interrupting current flow through lower element. The system is now in stand-by mode waiting for the next call for heat

During peak power demand periods as determined by the local utility, the off peak meter will interrupt power to terminal L1 of lower thermostat. Only the top thermostat/element combination is allowed to operate during this period.

ECO

Closed

From

Off Peak

Meter

Thermostat closed

at terminal T2

Thermostat closed

at terminal T4

From

Off Peak

Meter

Thermostat closed

at terminal T2

Thermostat closed

at terminal T2

Thermostat open

at terminal T2

ff Peak

Power interrupted

hermostat closed

at terminal T2

Page 11

TROUBLESHOOTING

Most common cause for improper electric water heater operation can be linked to heating element failure.

When troubleshooting an electric water heater with the incidence of “No Hot Water” or “Insufficient Amount of Hot Water” Its always a good idea to check the heating elements first following the procedure on page 15.

Common Heating Element Failures Are:

1. Dry Firing. Element may be partially submerged in water or most likely, completely exposed with no water in tank. In some cases sediment or lime build up around an element can eventually cause an air pocket, and within seconds, result in a dry fired element. At this point the element becomes inoperative. When element replacement is required, be sure tank is full of water prior to energizing the water heater.

2. Grounded Element. An element with a short circuit to ground will in most cases cause the circuit breaker in the service panel to open or shut off. In some cases there may not be enough current draw for the circuit breaker to open. This will allow the heating element to be in continuous operation resulting in over heated water, limited only by the ECO or Energy Cut Off located in the thermostat. Repeated actuation of the ECO reset button on the thermostat usually is the result of a grounded element.

3. Sediment build up. Slow hot water recovery can usually be traced back to sediment or lime build up around heating element. Sediment build up can also over time cause a dry fired element.

Illustration 1, below shows a common “Screw-In” type heating element identifying certain features commonly referred to throughout this manual.

1-½ Hex Screw-in Flange

Terminal Block Screw

Terminal Block

Zinc Plated Copper or Incoloy Sheath

Element Rating Ink Stamped on side of Terminal Block.

Illustration 1

Typical Direct Immersion “Screw-In”

Type Heating Element

Page 12

0642

4500W 240V

RC02404524

+ 28 hidden pages

Bradford-White M-2-50T6DS User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual