EWC Controls ULTRA-ZONE ST2E Series Technical Bulletin

Excellence Without Compromise
CONTROLS INC.
Congratulations on purchasing the ST2E/ST3E series
ULTRA-ZONE Control Panel. The ST series of zone control
panels are still the same popular, field proven zone control
panels that have been in use for the last seventeen years! The
new "E" series revision has a few upgrades to enhance the
reliability, protection and operation of the board.
First and most important is the replacement of the old 3 amp
slo-blo fuse, with an integrated Thermal Circuit breaker or
Polyfuse. This means no more running to the electronics store
to buy a fuse, after the spare fuse that was provided has blown.
The Polyfuse protects the panel against shorts in the thermostat
or damper field wiring. It does not protect against shorts in the
H V A C e q u i p m e n t f i e l d w i r i n g . S e e p a g e 2 .
The location of the J1 jumper on the panel has also changed, and
there is now an arrow pointing to it. The J1 jumper enables
fan operation in Heat mode as well as Cooling mode.
With the exception of the Polyfuse and the J1 jumper, all
other changes have no direct bearing on the wiring,
i n s ta l l a t i o n , o r o p e r a t i o n o f t h e c o n t r o l pa n e l .
The ST series zone control panels are the most versatile
and rugged relay based logic control systems in use today.
The Master/Slave circuitry of these panels can be utilized
to satisfy numerous control applications and job specifications.
The heating/cooling changeover operation is still controlled by a
changeover subbase on the zone 1 thermostat, or a separate
remote selector switch can be used instead. This allows
for inexpensive standard 2 or 3 wire thermostats to be used in all
z o n e s d e p e n d i n g o n t h e f i e l d a p p l i c a t i o n .
The table on Page 6 shows the types of digital programmable
thermostats that are compatible with the ST2E or ST3E panels.
The diagrams included with this bulletin are based upon the
most frequently asked questions regarding the wiring of these
panels. There are additional diagrams available through the
Te c h n i c a l S u p p o r t H o t l i n e @ 1 - 8 0 0 - 5 2 6 - 4 0 4 8 .
Contact the Hotline if you find yourself on the job site and
unsure of the exact wiring for your ST Series Control Panel.
TB-115
EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX 732-446-5362
P/N 090375A0115 REV. N
©
11.5.20
Copyright 2009 EWC Controls All Rights Reserved
T E C H N I C A L
Models EWC-ST-2E & EWC-ST-3E
(DISPONIBLE EN ESPAÑOL EN EWCCONTROLS.COM)
ewccontrols.com/acrobat/090375a0248.pdf
SW2
ZONE2
MOTOR
M6
OPEN
M4
M2
M1
CLOSE
ZONE1 SW1
MOTOR
M6
OPEN
M4
M2
M1
CLOSE
24VAC
T'FORMER
2
CB1
1
SYSTEM
B
O
J1
X
Y
W
G
R
EWC CONTROLS INC.
Englishtown, NJ

TABLE OF CONTENTS

PAGE
1 Introduction
2
Application
5
Typical 5 zone control panel diagram
6
Thermostat Requirements (See Notes)
7 Checkout
8
EWC-ST -3E Wiring
Power Requirements: 24V 60Hz 40VA
Wiring Connections: Screw Terminal blocks
for Thermostat gauge
Mounting: Mounts with 4 screws and
mollies (included).
Panel Dimensions: Length:
Width: 9 7/8" (251mm); Depth: 1 9/16" (40mm).
WARNING: THESE PANELS ARE DESIGNED
FOR USE WITH 24 VOL TS.
ANY OTHER VOL TAGE!
AVOID ELECTRIC SHOCK OR EQUIPMENT
DAMAGE
B U L L E T I N
Model EWC-ST-2E
CAUTION
PLEASE read all
instructions carefully
before starting the
installation
procedures.
ADDITIONAL
ZONE PANEL
ULTRA-ZONE
CONTROL SYSTEM
EWC-ST-2E
& Specifications
Notes
Procedures
Diagram

SPECIFICATIONS

wire connections.
10" (254mm);
DO NOT USE
USE CAUTION TO
E-Mail- info@ewccontrols.com
ZONE2
T'STAT
C
W
Y
R
ZONE1
T'STAT
C
W
Y
R
R1
O
B
G
O
R
C
+ _
1