Bradford-White M-2-50T6DS User Manual

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R DENTIAL ELECTRIC AND LI

C ERCIAL ELECTRIC WATER HEATERS

Photo is of

M-2-50T6DS

S ICE MANUAL

T eshooting Guide a structions for Service

(To be performed ONLY by qua ce providers)

M

Covered

b

 

Reside

nergy 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.

M

l 238-47104-00A

Save this manual for future reference

Residential and Light Duty

Commercial Electric Water Heaters

Table of Contents

Page

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

Heating Element Testing ……………................................................................... 15

Residential Thermostat Testing ……..................................................................... 16 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 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 Heating Element Removal and Replacement ……………………………………. 34 Dip Tube and Anode Inspection and Replacement ……………………………… 35 Generic Parts List ………………………………………………………………... 36

Service Procedure

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RE-IRE-IIRE-III

RE IV

RE-VRE-VIRE-VII

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Introduction

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.

 

 

Tools

 

- Multi Meter.

- Phillips Head Screw Driver.

- 1-½Deep 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.

Page 2

2

 

 

 

 

 

 

GENERAL INFORMATION

 

 

 

 

 

 

Commonly Used Formulas

 

 

 

 

 

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 2

Example (240V)2 / 4500W = 12.8 Ohms

 

 

Watts

 

 

 

Common Service Wire Configurations

 

120 VOLT

 

 

240 VOLT

 

BLACK

WHITE

GREEN

BLACK

RED

GREEN

Grounded

Ungrounded

(Neutral)

Grounding

Ungrounded

Ungrounded

Grounding

 

 

120

 

0

 

 

 

 

 

240

 

120

 

 

 

 

 

120

 

 

 

 

 

120

 

 

 

 

 

208 3Ph

 

 

240 3Ph

 

480 3Ph/277 1 Ph

Neutral

A

B

 

C

Neutral

A

 

B

C

Neutral

A

 

B

C

 

 

120

 

 

 

 

120

 

 

 

 

277

 

 

120

 

 

 

120

 

 

 

277

 

 

 

 

120

 

208

 

120

 

240

 

277

 

 

480

 

 

 

208

208

 

 

 

240

240

 

 

 

480

480

 

 

RED

BLACK

RED

 

RED

BLACK

RED

RED

BLACK

RED

 

 

 

 

 

 

Page 3

 

 

 

 

 

 

 

3

GENERAL INFORMATION

Wattage Limitations at Various Voltages

Residential Electric Upright M1 & M2 Series (Non-Simultaneousoperation)

Residential High Eff ncy Upright M2HE Series (Non-Simultaneousoperation)

Residential Electric Lowboy M1 & M2 Series (Non-SimultaneousOperation)

Dairy Barn Deluxe DB Series (Non-SimultaneousOperation)

Maximum

Element

Voltage

Wattage

Upper/Lower

 

3,000

3,000/3,000

120

 

 

 

6,000

6,000/6,000

208, 240

 

 

 

6,000

6,000/6,000

277, 480

 

 

 

Residential Electric Upright M1 & M2 Series (Simultaneous Operation)

Residential High Efficiency Upright M2HE Series (Simultaneous Operation)

Residential Electric Lowboy M1 & M2 Series (Simultaneous Operation)

Light Duty Commercial Electric LD Series (Non-SimultaneousOperation)

Light Duty Commercial Electric LD Series (Simultaneous Operation)

Dairy Barn Deluxe DB Series (Simultaneous Operation)

Maximum

Element

Voltage

Wattage

Upper/Lower

 

3,000

1,500/1,500

120

 

 

 

10,000

5,000/5,000

208

 

 

 

11,000

5,500/5,500

240

 

 

 

12,000

6,000/6,000

277, 480

 

 

 

Residential Electric Utility Series (Single Element Operation)

L

ngle Element Operation)

 

 

 

 

Maximum

Single

Voltage

Wattage

Element

 

3,000

3,000

120

 

 

 

6,000

6,000

208, 240

 

 

 

6,000

6,000

277

 

 

 

6,000

6,000

480

 

 

 

Page 4

4

GENERAL INFORMATION

Surface Mounted Thermostats

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

Manual

ECO (high limit)

Reset button

Temperature

 

Temperature

control Dial

 

control Dial

Surface Mount

Surface Mount

Surface Mount

Combination Thermostat/

Combination Thermostat/

Thermostat

ECO (high limit)

ECO (high limit)

59T Series

89T Series

89T Series

 

Direct Immersion “Screw-in”Type Heating Element

1-½Hex

Screw-inFlange

Terminal Block

Screw

Terminal Block

Zinc Plated Copper or

Incoloy Sheath

Element Rating Ink Stamped

on side of Terminal Block.

Page 5

5

SEQUENCE OF OPERATION

Residential and light duty commercial electric water heaters are designed to operate using several different operating modes. The common modes and sequence of operation are as follows:

1.Single Element Operation.

2.Double Element Non-SimultaneousOperation (single phase).

3.Double Element Non-SimultaneousOperation (3 phase).

4.Double Element Simultaneous Operation (single phase).

5.Double Element Simultaneous Operation (3 phase).

Sequence of Operation- Single Element Operation.

1Line 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.

2Tank is cold therefore thermostat

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

1

ECO

Closed

2

Thermostat closed at terminal T2

3 When the thermostat is satisfied, it opens at

3

terminal T2 interrupting current flow through the

 

element. System is now in stand-bymode, waiting

 

for the next call for heat.

 

 

Thermostat opens

 

at terminal T2

Page 6

6

SEQUENCE OF OPERATION

Non-Simultaneousand Simultaneous Operation

Double element electric water heaters are designed to operate in a Non-Simultaneousor 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 element isde-energizedand 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-energizingthe lower element and allowing only the top element to energize until the upper thermostat is satisfied.

Simultaneous 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- Double Element,Non-SimultaneousOperation, Single Phase.

1Line 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.

2Tank 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.

3When 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.

4When the lower thermostat is satisfied, it opens at terminal 2 interrupting current flow through lower element. The system is now in stand-bymode waiting for the next call for heat

1

2

ECO

 

Closed

Thermostat closed

 

at terminal T2

Upper

Upper

T’stat

T’stat

Upper

Upper

Element

Element

 

Thermostat closed

 

at terminal 2

Lower

Lower

T’stat

T’stat

Lower

Lower

Element

Element

5

The lower thermostat/element

 

 

combination will generally

 

 

cycle on and off more often

3

 

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

Thermostat closed

 

T4 and closing at

at terminal T4

 

 

 

terminal T2) prior to the lower

T’stat

 

 

Upper

thermostat being satisfied. This

 

will interrupt current flow

 

 

through the lower thermostat

 

and element and allow current

Element

 

 

Upper

to flow through the upper

 

 

element only. When the upper

 

thermostat is satisfied, it

 

T’stat

resumes operation as

 

 

 

Lower

described in sequence #3

 

above.

 

Lower

 

 

Element

4

5

Thermostat open between terminals 1 and 2

 

Thermostat closed

 

at terminal T2

Upper

Upper

T’stat

T’stat

Upper

Upper

Element

Element

 

Thermostat closed

 

between terminals

 

1 and 2

Lower

Lower

T’stat

T’stat

Lower

Lower

Element

Element

Page 7

7

SEQUENCE OF OPERATION

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

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

1Line 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.

2Tank 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.

3When 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-bymode waiting for the next call for heat. Thermostats will operate independent of the other.

1

Circuit two

 

2

Circuit two

 

 

 

Circuit one

 

 

Circuit one

 

 

 

ECO

Thermostat closed

 

 

 

Closed

 

 

 

at terminal T2

 

 

 

 

 

ECO

Closed

Thermostat closed at terminal T2

3

Circuit two

 

Circuit one

Thermostat open at terminal T2

Thermostat open at terminal T2

Page 8

8

SEQUENCE OF OPERATION

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

1Line 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 thermostat is closed, so there is voltage at terminal L4 of both thermostats and to one side of both upper & lower elements.

1

2

ECO

Closed Thermostat closed at terminal T2

2Tank 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.

3When 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.

4When the lower thermostat is satisfied, it opens at terminal T2 interrupting the current flow through the lower element. The system is now in stand-bymode waiting for the next call for heat.

5The 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.

ECO

 

Closed

Thermostat closed

 

at terminal T2

3

4

Thermostat closed

Thermostat closed

at terminal T4

at terminal T4

Thermostat closed

at terminal T2 Thermostat open at terminal T2

5

Thermostat closed at terminal T2

Thermostat closed at terminal T2

Page 9

9

SEQUENCE OF OPERATION

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

1Line 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 and to one side of both upper & lower elements.

2Tank 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.

3When 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-bymode waiting for the next call for heat. Thermostats will operate independent of the other.

1

2

ECO

 

Closed

Thermostat closed

 

at terminal T2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ECO

Thermostat closed

 

 

 

Closed

 

 

 

 

at terminal T2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

Thermostat open at terminal T2

Thermostat open at terminal T2

Page 10

10