
Connect the GREEN wire to the grounding screw in the box. If 
a plastic box, connect to ground as supplied.
Make sure all twist connectors are tight.
If a 3-Way Switch Setup:
NOTE: The distance between 
switch timer and remote switch 
must not exceed 100 feet.
 Locate the COMMON 
wire connected to first old 
switch. It might be attached 
to a different colored screw, 
or find markings on old switch.
Connect BLACK wire from switch timer to COMMON wire, 
using a twist connector.
Connect the other two wires from the old switch to the Blue 
and RED wires from the switch timer.
Connect the GREEN wire to the grounding screw in the box. If 
a plastic box, connect to ground as supplied.
Using diagram #1 below. Identify and remove wire “C” from 
the “Common” terminal of your existing remote switch. 
Using diagram # 2 below, remove and reconnect wires “B”  
and “C” to the “Common” terminal of your remote switch, 
using the supplied piece of jumper wire, if necessary. Follow 
diagram # 3 below, if using a new single-pole remote switch. 
NOTE: For new construction or to replace a dimmer switch, 
a lighted switch, or a 3-way switch without screw terminals, 
a single-pole switch can be used at the remote location, as 
shown.
NOTE: If the building’s wiring colors don’t allow you to tell 
wire “A” from “B,” just pick one of the two wires and connect 
as if it is wire “B.” After the installation is complete, if the con-
trolled light or device will not turn on properly, simply reverse 
wires “A” and “B.” See Steps J and K for how to check.
Tuck wires into the timer wall box leaving room for the timer.
Using screws provided, mount the switch timer into the wall 
box, then install the wall plate.
Install the remote 3-way switch in its box and install wall 
plate. Turn the power back on at the service panel.
Make sure the switch timer displays “MAN” mode. Do the fol-
lowing test with the remote switch in each of its 2 positions:  
Press the ON/OFF button on the switch timer several times. 
Each time that you push the ON/OFF button, the switch timer 
should “click” and the controlled light or device (the “load”) 
should turn on or off. If so, proceed to Step K.
If the timer clicks but the load does not operate, re-check 
your wiring and make sure the load is functional.
c.
d.
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
-
Self-Adjusting Wall Switch Timer
Turn off power at the service panel by REMOVING FUSE or 
TURNING THE CIRCUIT BREAKER OFF.
Remove the existing wall switch.
Trim building wires to 7/16” as shown.
If a Single Switch Setup:
Connect one of the two wires 
from the wall to the black wire 
from the switch timer, using 
the twist connectors provided. 
Connect the other wire from 
the wall to the blue wire from 
the switch timer, using the 
twist connectors provided.
NOTE: The RED wire is not used in single-switch installations. 
Cap with a twist connector.
1.
2.
3.
a.
b.
Resistive (heater) 15 Amp, 120-277 VAC
Tungsten (incandescent) 15 Amp @ 120 VAC, 6 Amp @ 208-277 VAC
Ballast (fluorescent) 8 Amp @ 120 VAC, 4 Amp @ 208-277 VAC
Motors 1 H.P. @ 120 VAC, 2 H.P. @ 240 VAC
DC Loads 4 Amp @ 12 VDC, 2 Amp @ 28 VDC
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Installation and User Instructions
MODEL ST01 Series
2 – Install the Switch Timer
Ratings
Before installing the switch timer into the wall, make sure the 
supplied battery is installed and working. 
Open the access door to reveal the battery tray, located below 
the ON/OFF keypad.
If there is a pull tab at the battery tray, remove the tab to con-
nect the installed battery. Make sure battery tray is pushed 
fully into place. Proceed to Step 6.
If the battery was supplied loose, use a flat screwdriver to pry 
loose the battery tray.
Place the supplied “CR2” battery into the tray, observing + 
and – markings on tray.
Replace the battery tray into the switch timer.
The display will initialize itself then flash “12:00 AM” in 
MANual mode.
Press the ON/OFF button. The switch timer should “click.”
NOTE: If display doesn’t flash “12:00 am”, the battery may be 
dead. Replace the battery before installing the switch timer.
1.
2.
3.
4.
5.
6.
7.
1 – Before Installing Switch Timer, Install and Check Battery
BLACK WIRE
BLUE WIRE
RED WIRE
(capped, not connected)
RED WIRE
BLUE WIRE
BLACK WIRE
WIRE FROM
“COMMON” OF
OLD SWITCH
DIAGRAM 1:
TYPICAL
EXISTING
2-SWITCH
SETUP
LOAD
NEUTRAL
3-WAY 
MAIN SWITCH
WIRE “A”
“COMMON” TERMINAL
LINE
3-WAY 
REMOTE SWITCH
WIRE “B”
WIRE “C”
DIAGRAM 2:
2-SWITCH SETUP,
TIMER INSTALL
RE-USING EXISTING
REMOTE 3-WAY SWITCH
LOAD
NEUTRAL
WIRE “A”
“COMMON” TERMINAL
LINE
3-WAY 
REMOTE SWITCH
WIRE “B”
NOT USED
BLACK
TIMER
BLUE
RED
WIRE “C”
JUMPER
DIAGRAM 3:
2-SWITCH SETUP,
TIMER INSTALL USING 
NEW SINGLE-POLE 
REMOTE SWITCH
LOAD
NEUTRAL
WIRE “A”
LINE
SINGLE-POLE
REMOTE SWITCH
WIRE “B”
BLACK
TIMER
BLUE
RED
WIRE “C”
JUMPER
158ST13133
Observed Problem Possible Cause What to Do
Switch timer does not switch ON/OFF but 
display looks normal.
Switch timer is not set in AUTO, RANDom, or 
MANual mode.
Press MODE to select the operational mode you 
want to use.
Switch timer won’t enter AUTO or  
RANDom mode when you press MODE.
The time of day or timer settings have not 
been set.
Make sure the time of day and at least one sched-
uled activity have been set.
Switch timer switches at incorrect times 
or skips some of the programmed times.
Programmed schedule(s) are incorrect. Press ON/OFF to review the settings and revise 
them as necessary. See instructions at the left.
Switch timer is in RANDom mode, which var-
ies switching times up to ±20 minutes (to give 
your home a “lived-in” look).
If you don’t want to keep the switch timer in 
RANDom mode, press MODE to change to AUTO 
mode.
The Astronomic and Specific switching times 
are in conflict. For example, you’ve set ON to 
DUSK and OFF at 8 pm, and due to seasonal 
changes, DUSK has advanced to 8:30 pm. 
NOTE: Your switch timer automatically skips 
any conflicting ON event as summer ap-
proaches to prevent unwanted operation of 
lights or other controlled devices. See “What 
to Do” if you want to identify and remove 
conflicting settings.
Complete the steps for setting the Time and 
Date, then temporarily change the date to 
June 21st.
Review the DAWN and DUSK settings by 
pushing the ON/OFF button. 
Make sure the specific ON or OFF time set-
tings won’t interfere with these DAWN and 
DUSK times. Make changes as necessary.
When finished, change the Date setting back 
to today’s date. 
1.
2.
3.
4.
The lights or controlled devices don’t 
match the programmed ON/OFF status 
immediately after setting the time or 
programming a schedule.
Switch timer does not “catch up” automati-
cally to the programmed load state. The status 
of the switch timer will remain as is until it 
comes to the next programmed ON/OFF time.
After entering your schedules or the time, then 
returning to the AUTO mode, push the ON/OFF but-
ton to change the load state if necessary.
Load only operates when the remote 
(3-way) switch is in one position, or the 
switch timer ignores the remote switch.
The remote switch is wired incorrectly.
Recheck the wiring, especially for the jumper, 
according to “If a 3-way Switch Timer” and “If a 
Multiple Switch Timer Setup.”
The switch timer ignores a 3-way remote 
switch even though it is wired correctly.
There is an excessive length of wire (more 
than 100 feet), or there is buried wire to the 
switch.
Eliminate the condition: either replace the buried 
cable, do without the remote switch, or contact 
Intermatic Customer Service for more options.
The remote switch is not functioning properly 
or worn out. Replace the remote switch.
The load turns off immediately after being 
turned on.
The remote switch or switch timer is wired 
wrong.
There is an excessive length of wire 
(greater than 100 feet)
There is buried wire to the remote switch.
The switch timer is not functioning properly.
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If the problem persists with the switch timer’s red 
wire disconnected or with a remote switch tempo-
rarily connected right at the switch timer, replace 
the non-functioning switch timer. Otherwise, try 
the above suggestions.
The battery tray is difficult to replace.
Battery is not seated in the tray.
The tray is misaligned.
The contact tabs of the tray are bent.
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•
•
Seat the battery in the tray, then reinstall.
The switch timer operation is sluggish or 
not switching ON/OFF at all.
Though the “BATT” message is not being 
displayed, the battery is getting weak. 
Replace the battery. To test the battery, press the 
ON/OFF button. The timer should “click.”
Timer shows ON but the light or other 
controlled device is OFF.
The light or controlled device itself may be 
switched OFF.
Make sure the light or controlled device is 
switched ON and plugged in.
Troubleshooting Guide
LIMITED ONE-YEAR WARRANTY
If within one (1) year from the date of purchase, this product fails due to a defect in material or workmanship, Intermatic Incorporated will repair or replace it, at its sole option, free of charge. This warranty is 
extended to the original household purchaser only and is not transferable. This warranty does not apply to: (a) damage to units caused by accident, dropping or abuse in handling, acts of God or any negligent use; 
(b) units which have been subject to unauthorized repair, opened, taken apart or otherwise modified; (c) units not used in accordance with instructions; (d) damages exceeding the cost of the product; (e) sealed 
lamps and/or lamp bulbs, LED’s and batteries; (f) the finish on any portion of the product, such as surface and/or weathering, as this is considered normal wear and tear; (g) transit damage, initial installation costs, 
removal costs, or reinstallation costs.
INTERMATIC INCORPORATED WILL NOT BE LIABLE FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL 
DAMAGES, SO THE ABOVE LIMITATION OR EXCLUSION MAY NOT APPLY TO YOU. THIS WARRANTY IS IN LIEU OF ALL OTHER EXPRESS OR IMPLIED WARRANTIES. ALL IMPLIED WARRANTIES, INCLUDING THE 
WARRANTY OF MERCHANTABILITY AND THE WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE, ARE HEREBY MODIFIED TO EXIST ONLY AS CONTAINED IN THIS LIMITED WARRANTY, AND SHALL BE OF 
THE SAME DURATION AS THE WARRANTY PERIOD STATED ABOVE. SOME STATES DO NOT ALLOW LIMITATIONS ON THE DURATION OF AN IMPLIED WARRANTY, SO THE ABOVE LIMITATION MAY NOT APPLY TO 
YOU.
This warranty service is available by either (a) returning the product to the dealer from whom the unit was purchased, or (b) mailing the product, along with proof of purchase, postage prepaid to the authorized 
service center listed below. This warranty is made by: Intermatic Incorporated/After Sales Service/7777 Winn Rd., Spring Grove, Illinois 60081-9698/815-675-7000 http://www.intermatic.com Please be sure to wrap 
the product securely to avoid shipping damage.
INTERMATIC INCORPORATED 
SPRING GROVE, ILLINOIS 60081-9698
Electrical shock hazard. Risk of injury or death. Remove electrical power 
at service panel before installing.
Risk of fire or burns from used battery. Do not recharge, disassemble, heat 
above 100˚ C, crush, or incinerate the lithium battery. Keep battery out of 
reach of children. Replace only with Panasonic type CR2 or equivalent 
CR2 battery approved by Underwriters Laboratories (UL). Use of a differ-
ent battery type may present a risk of fire or explosion upon disposal of 
battery.
Risk of fire. Do not use timer to control devices that could have danger-
ous consequences due to inaccurate timing, such as sun lamps, sauna, 
heaters, crock pots, etc.
•
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          WARNING
Follow local electrical codes during installation.
Risk of timer damage due to leakage if weak battery is not replaced promptly.
Dispose of used battery promptly per local regulations.
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NOTICE
See ez set instructions and wiring illustrations: 
http://waterheatertimer.org/ST01C-program.html  
 
http://waterheatertimer.org/Intermatic-timers-and-manuals.html#ST01C