Bradford-White Corp S-SW2-75R 6DS, S-SW2-115R6DS, S-SW2-60R 6DS User Manual
Solar Water Heater With Electric Backup
Solar Saver® Heaters
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
S-SW2-60R6DS
S-SW2-75R6DS
S-SW2-115R6DS
Manual 238-47297-00A
Save this manual for future reference
Table of Contents
Page Service Procedure
Introduction ………………………………………………………………………. 2
Tools……………………………………………………………………………… 2
General Information ……………………………………………………………… 3 - - -
Sequence of Operation …………………………………………………………… 5 - - -
Troubleshooting ……………………………………………………………….…. 6 - - -
Line Voltage and High Limit (ECO) Testing…………………………………..… 8 RE-I
Heating Element Testing ……………................................................................... 9 RE-II
Thermostat Testing ……........................................................................................ 10 RE-III
Thermostat Removal and Replacement …………………………………………. 12 RE-IV
Heating Element Removal and Replacement ……………………………………. 13 RE-V
Dip Tube and Anode Inspection and Replacement ……………………………… 14 RE-VI
Generic Parts List ………………………………………………………………... 15 - - -
Page 2
This service manual is designed to aid service and maintenance professionals on the function, proper diagnosis and repair of
Bradford White solar water heaters with electric backup. Required service for system components beyond the solar water
heater should be directed to the system installer or directly to the system component manufacturer. System components
include such items as the solar controller, solar collector and circulator.
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 for Bradford White supplied equipment if
diagnosis can not be made using the methods described in this service manual. Contact the solar component manufacturer for
assistance regarding other equipment.
Introduction
Solar Water Heater With
Electric Backup
Tools
- Multi Meter. - Phillips Head Screwdriver.
- 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,
Flashlight.
2
G
ENERAL INFORMATION
240 VOLT
Ungrounded
Ungrounded
Grounding
BLACK
RED
GREEN
240 120
120
Service Wire Configuration
Single Phase Amps = Watts Example 4500W/240V = 18.75A
Volts
Watts = Amps x Volts Example 18.75A x 240V = 4500W
Ohms = Volts Example (240V) / 4500W = 12.8 Ohms
Watts
2
2
Commonly Used Formulas
Page 3
Wattage Limitation at 240 Volts
Solar Water Heater with Double Electric Element Backup Series (Non-Simultaneous operation)
Maximum
Wattage
Element
Upper/Lower
5,500
5,500/5,500
3
G
ENERAL INFORMATION
Upper thermostat
Surface Mount
With
ECO (high limit)
89T Series
Manual
ECO (high limit)
Reset button
Temperature
control Dial
Lower thermostat
Surface Mount
59T Series
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 important 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 Incoloy Sheath
Element Rating Ink Stamped
on side of Terminal Block.
Direct Immersion “Screw-in” Type Heating Element
Page 4
4
Non-Simultaneous Operation
Non-Simul taneous 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 is de-energized and power is directed to the lower thermostat, energizing the lower element and heating the
b
ottom 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. When the tank cools at the lower thermostat level,
the 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 energize until the upper thermostat is satisfied.
The lower thermostat in the solar water heater is located above the internal heat exchanger. This design allows the heat
exchanger to be in cooler water during short draws, providing more heat transfer from the solar heating system.
S
EQUENCE 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, the thermostats are closed
at terminals T2 & 2 (calling for heat). The circuit is
complete through the upper thermostat only,
allowing current to flow through the upper element.
1
2
1 2
ECO
C
losed
Therm ostat closed
at terminal T2
When the upper thermostat is satisfied, it opens at
terminal T2, interrupting current flow through the
upper element. Terminal T4 closes, allowing voltage
to pass to terminal 1 of the lower thermostat. This
completes the circuit through the lower thermostat
and allows current flow through the lower element.
3
3
Thermostat closed
at terminal T4
4
Thermostat open
between terminals
1 and 2
Upper
T’stat
Upper
Element
Upper
T’stat
Upper
Element
Lower
T’stat
Lower
Element
Lower
T’stat
Lower
Element
When the lower thermostat is satisfied, it opens at
terminal 2, interrupting current flow through the
lower element. The system is now in stand-by mode
waiting for the next call for heat
4
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.
5
5
Thermostat closed
between terminals
1 and 2
Upper
T’stat
Upper
Element
Lower
T’stat
Lower
Element
Upper
T’stat
Upper
Element
Lower
T’stat
Lower
Element
Upper
T’stat
Upper
Element
Lower
T’stat
Lower
Element
Thermostat closed
at terminal 2
Therm ostat closed
at terminal T2
Page 5
Solar water heaters with double electric element backup are designed to operate using a single operating mode detailed
as follows:
5
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