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158--01753

 

» Easy to Install

 

» External Manual Override 

Switch

 

» Match Water Heater Off 

Times to Peak Energy 
Periods of Utility to 
Reduce Demand

 

» External Load Indicator

 

» 25 A (6250 W) Resistive, 

208-250 VAC, 60 HZ

 

» 1500 W Tungsten, 

208-250 VAC, 60 HZ

 

» 2 HP, 20 FLA, 80 LRA @ 

208-250 VAC, 60 HZ

•  Disconnect power at the circuit breaker(s) or disconnect switch(es) 

before installing or servicing.

•  Installation and/or wiring must be in accordance with national and 

local electrical code requirements.

•  Use #14 - #10 AWG wires, rated at least 90° C - COPPER conductors 

ONLY.

•  Do not remove insulator.
•  KEEP DOOR CLOSED AT ALL TIMES when not servicing.
•  Turning this switch off will still leave the possibility for hazardous 

voltage at the water heater.

•  More than one circuit breaker or disconnect switch may be required 

to de-energize the equipment before servicing.

WARNING

Risk of Fire or Electric Shock

NOTICE

•  Rotate timer dial clockwise only.
•  Do not move the clock hands on the timer. Moving the clock hands 

can damage the timer.

WH21 Electric Water Heater

Time Switch

Step 6

Using pliers, grip folded down hasp on side of case and rotate it 
upward as shown. Also, install exter nal push button in the inside of 
cover by inserting plastic button into the rectangular and round holes 
as shown then pressing round tabs into round hole in cover. Close 
cover to make sure the holes in cover line up. Adjust, if required.

Step 8

Check wiring, time setting (a.m./p.m.) and program. If hard wired, also 
close Water Heater Terminal Box. Restore electric service (the reverse 
of Step 2).

Operating Instructions

This Time Switch will repeat a preset schedule daily except when the 

EXTERNAL MANUAL PUSH  BUTTON

 is used. This manual button 

permits the user to turn the water heater 

ON

 and 

OFF

 

ahead

 of the 

schedule. The Time Switch will resume the 

preset

 program by the next 

scheduled 

ON

 or 

OFF

 operation. The diagram on the right shows the 

mechanism and wiring of this Time Switch. The 

TIME MARK

 is used to 

line up the correct time of day on the 

TIME DIAL

. The 

ON

 and 

OFF

 

TRIPPERS

 turn the water heater 

ON

 and 

OFF

 at the times indicated 

by their respective position on the 

TIME DIAL

To Set Program

1.  Grasp time dial firmly. 

PULL

 and remove time  dial completely from 

timer.

2.  Remove all 

ON

 trippers (silver) and 

OFF

 trippers (brass). Use 

pencil or paper clip if necessary.

3.  Insert 

OFF

 trippers (brass) in slots for desired 

OFF

 times, but 

NOT 

CLOSER

 than 2 hours apart.

4.  Insert 

ON

 trippers (silver) in slots for desired 

ON

 times, but 

NOT 

CLOSER

 than 2 hours apart. 

ON

 and 

OFF

 trippers may be spaced 

1/2 hour apart from each other.

5.  Replace time dial. 

PUSH IN FIRMLY

. If any trip pers are near the 

time mark, rotate time dial to avoid interference with mechanism 
inside.

6.  Turn time dial 

CLOCKWISE

 one or more revolu tions until correct 

time-of-day is opposite time  mark.

TO STOP AUTOMATIC OPERATION:

 (But with out stopping timer) 

PULL

 outward on time dial until it clicks. 

TO RESUME AUTOMATIC OPERATION: PUSH

 inward on time dial. 

AFTER POWER FAILURE:

 (or if water heater was disconnected at 

main panel) time dial must be reset to correct time-of-day. 

DISCONNECT POWER AT THE CIRCUIT BREAKER(S) OR 
DISCONNECT SWITCH(ES) BEFORE INSTALLING OR SERVICING. 
TURNING THIS SWITCH OFF WILL STILL LEAVE THE POSSIBILITY 
FOR HAZARDOUS VOLTAGE AT THE WATER HEATER.

Step 7

Set the daily program - see operating instruc tions on page 7. Each 
individual household should determine a schedule to suit their own 
needs. Adjustments should be made for family size, hot water needs, 
appliances, etc. In areas where time -of-day rates are in effect, consult 
the electric utility company to find when the lowest rates apply. Then 
set the time switch to operate the water heater when the electric rates 
are lowest and adjust the schedule accordingly. 
In setting the schedule, consider the facts that the temperature and 
quantity of hot water will decline during the OFF periods depending on 
amount used and Iength of OFF time. A typical schedule could be ON 
at 6 a.m., OFF at 8 a.m. for morning use, and ON again at 5 p.m. and 
OFF again at 10 p.m.

External 
Push Button

Hasp

Adjust if required.
To open the door, 
push the hasp 
gently to the left 
while pulling on the 
door of the unit.

ON Tripper

OFF Tripper

Time Mark

ON Tripper

OFF Tripper

OFF Tripper 

(Brass)

ON Tripper 

(Silver)

View of Dial at Midnight

Typical Program

ON TRIPPER 

(SILVER)

OFF TRIPPER 

(BRASS)

TIME DIAL

TERMINAL 

BLOCK

INDICATOR 

LAMP

TIME MARK

MANUAL 

CONTROL

GROUNDING 

SCREW

GRD

LINE 1
LINE 2

GRD

250V 
FROM 
FUSE 
BOX

{

TO 
WATER 
HEATER

}

Page 6

Page 7

Page 8

To purchase extra trippers

: order part no. 156EB1945A for a set of 

two (2) ON and two (2) OFF trippers. 

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