EWC Controls Ultra-Zone UZC4 Technical Bulletin

®

Forced Air Zone Controls

Model UZC4 Zone Control

The UZC4 Universal Zone Control System allows you to easily
upgrade an inefficient single zone HVAC system, into an
Automated, Multi-zone, Energy saving, Comfort producing,
Safety Minded, HVAC system. With Superior design, Intuitive
firmware, Building Code Compliant support, Simple setup
options, and Easy to understand wiring, the UZC4 Zoning
system is the Designer/Contractors dream. Combined with
Patented EWC motorized dampers and practically any Off-the­shelf Conventional or Heat Pump style Thermostats,

EWC has set a New Industry Standard in Large
Residential and Commercial HVAC Air Zoning Systems.

Zone
Capacity

The main module controls four air zones
using 24 vac motorized air dampers and
may be expanded up to 22 zones, using

ZXM2 Expansion Modules. See page 23.

Compatible
HVAC
Systems

The UZC4 will Control 2, 3 & 4 stage
Conventional, GeoThermal or Dual Fuel
Heat pumps, without the need for dual
fuel kits. Also single or multi-stage Gas,
Oil, & Hydronic HVAC systems, with
single or two stage cooling and Constant
or Variable speed fan systems.

Compatible
Thermostats

Automatic
Heat/Cool
Changeover

Status LED

Compatible with most Off the shelf 1 or 2
stage Conventional Heat/Cool or Heat
Pump Thermostats. All Mechanical,
Digital/Electronic, Dual Mode, and Internet
Compatible Thermostats that operate on
24vac. Battery powered or Power robbing
thermostats that draw less than 20 ma of
current are also compatible. Zone 1 will
accept One Zone Mode, Carbon Dioxide
Safety and Auxiliary/Dehumidify mode
inputs. See pages 9-11 & 14-17 for details.

The UZC4 Zone system features
automatic changeover from any
thermostat allowing for individual zone
comfort from the HVAC system.

The STATUS LED pulses as a steady
heart beat to indicate active Micro­processor status.

System LEDs

On board Multi-colored LED’s will
illuminate to indicate system status,
HVAC system mode, and active / inactive
zone identification. See page 22 for details.

Damper LEDs

Damper 1 thru Damper 22 green LEDs
will indicate which zone dampers are
demanded to energize Open or Closed.

Operating
Power

TB-221

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [e-mail]

P/N 090375A0221 Revision S 09.04.12

INPUT VOLTAGE: 19-30VAC 60 Hz

Transformer 40-100VA MAX. NEC Class

2.

CURRENT DRAW: Max 22VA @ 24VAC.
OVER-CURRENT PROTECTION: 4.0

amp or 100VA.

Copyright © 2004 EWC Controls Inc., All Rights Reserved

HVAC ZONE
CONTROl SYSTEM

FA

FA
24V
24V

RESET

MXR
MXC
M6
M4
M2
M1

M6
M4
M2
M1

M6
M4
M2
M1

M6
M4
M2
M1

M6
M4
M2
M1

M6
M4
M2
M1

NC
NO

C

G

Y2

Y1

O

B

W1

W2

E

RC

RH

RH

RC
LINK

W

E

Box Contents

Manual
and
Automatic
Thermal
Circuit
Breakers

Operating
Conditions

Indoor Fan
Control

Leave this bulletin on the job site for future reference!

J1

TB1

TB2

TB3

TB4

TB5

TB6

TB7

TB8

TB9

JMP3

C

JMP1

C1

R
C

D1

CB1

F1

K1

Z
O

4

N
E

K2

Z
O

3

N
E

K3 K4

Z
O

2

N
E

K5

Z
O

1

N
E

O
A

D
M
P
R

K7

E
B
D

K8

A
U
X

K9

R
L
Y

K10 K11

H
V
A
C

S

K12 K13

Y
S
T
E

M

K14

CONTROLS INC.
Englishtown, NJ

D2

JMP2

14

7

OFF

STAGING

TIMER

C2

LED19

GROUND FAULT

R1

21

28

40

35

37

42

34

OAS

C54

R20

R19

HP

SYSTEM

>

HP

DF

< >

D3

OFF

FAN PRG

<

PURGE

90

s

<

STAGES

OAS

<

OFF

50

<

OFF

SAS

<

FAN

GAS

<

R5

D4

TSTAT

HC

>

1

CS#

<

RV

O

<

OFF

<

RA

AUX RLY

<

R6

RAS

OFF

<

D5

0

RA LMT

<

FAN CTRL

ANY

<

R7

D6

R8

D7

R9

D8

R10

D9

R11

D10

STATUS

R12

OAS

D11

SAS

RAS

ZONE

R13

ZONE

D12

ZONE

ZONE

DMPR

R14

BYPASS

D13

AUX RELAY

FAN

COMPRESSOR2

R15

COMPRESSOR1

D14

REV

W1 HEAT

W2 HEAT

EMERGENCY

R16

D15

R17

D16

R18

C53

CONV

%

>

>

ZDL

R48

C17

Y1

R50

SW1

LIMIT

LIMIT
LIMIT

4
3
2
1

VALVE

COOLING

LIMIT

R2

>

>

R

>
>
>

>

2

B

>

>

>

TIMER
RESET

OPEN

OPEN

OPEN

OPEN

43

GAS

>

180

TMR

>

ON
ON
HYDRO

HP

ON

>

ON

+10

U14

U19

OPENOA

DMPR

R52

R53

R54

R55

R63

140

130

46

120

49

110

52

1ST

STAGE

HEATING

LIMIT

R3

R21

R22

BANK1

R29
R30

ON

s

DA

Z

1

>

U1

R31
R32
R33
R34
R35
R36

BANK2

R37
R38
R39
R40
R41
R42
R43
R44

C8

C7

U15

R47

C10C9C11

C12

C13

C14

C15

C18

R49

C19

C22

R58

C21

R51

CPU

RESET

U17

U18

LED1

LED2

LED3

LED4

LED5

LED6

LED7

LED8

LED9

LED10

LED11

LED12

LED13

LED14

LED15

LED16

LED17

LED18

Z1

R56

R57

R60

R61

26

150

19

160

12

170

5

STAGE

MULTI

DIFFERENTIAL

R4

R23

D17

R24

D18

R25

D19
D20

R26

D21

R27
R28

D22

R50

R45

C3

R46

D23

U2

C4

U3

C5

U4

C6

U5

C16

J2

U6

C20

U7

SW2

C23

U8

C24

U9

C52

R135

R134

UZC4

33

40

47

R64

HEAT

R65

S

R66

E

C25

R67

R69

R71

R75

R77

R79

R83

R85

R87

R91

R93

R95

R99

R101

R103

R107

R109

R111

R112

R115

R117

R119

R120

R123

R125

R126

R127

R128

R129

R130

R133

SW3

R68

R70

R72

R73

R74

R76

R78

R80

R81

R82

R84

R86

R88

R89

R90

R92

R94

R96

R97

R98

R100

R102

R104

R105

R106

R108

R110

R113

R114

R116

R118

R121

R122

R124

R130

R132

N
S

C26

O

C27

R
S

TB11

C28

T

C29

S
T

C30

A
T
4

C31

C32

TB12

C33

T
S
T

C34

A

C35

T
3

C36

C37

TB13

C38

T

C39

S
T
A
T

C40

2

C41

C42

TB14

C43

T
S

C44

T
A

C45

T
1

C46

C47

C48

C49

C50

C51

EMERGENCY

NORMAL

* UZC4 Zone Control Panel
* Supply Air Sensor
* Technical Bulletin TB221
* Mounting Hardware

The main UZC4 module has a Manual
Reset circuit breaker with a Ground
Fault Indicator that protects all
connected modules and thermostat
circuitry. All modules have separate
damper motor Thermal Breakers too.
They protect the damper motor circuitry
from shorts in the field wiring. The
breakers will not protect against shorts
in the HVAC system wiring.

CAUTION: When the thermal

breaker is tripped it will get quite
hot. To reset the breaker: Shut off

power to the panel. Find and repair
the short. Restore the 24VAC power.

TEMPERATURE: -20° to 160°F (-29° to 71°C)

HUMIDITY: 0% - 95% RH Non-Condensing.

The UZC4 allows constant operation of
the Indoor Fan by Thermostat #1 only, or
by each individual thermostat. When
controlled by thermostat #1, All Zone
dampers will respond. When controlled
individually, Zones not calling for
continuous fan will close.

TB10

TB15

Figure 1.

SAS
SAS
OAS
OAS
RAS
RAS

C
W1
W2
O
Y1
Y2
R
G

C
W1
W2
O
Y1
Y2
R
G

C
W1
W2
O
Y1
Y2
R
G

C
W1
W2
O
Y1
Y2
R
G

ONE
ZONE
AUX R

CO
CO

1

E

B

E

B

E

B

E

B

2

2

UZC4 STANDARD FIRMWARE AND HARDWARE FEATURESUZC4 STANDARD FIRMWARE AND HARDWARE FEATURES

Indoor Fan
Control
During
Heating

Built-In
Timer
Settings

Definitions
are explained
below

*Short Cycle
Timer

*Changeover
Timer

*Inter-stage
Timer

*Opposite
Mode
Delay Timer

*Staging
Timer / OAS

21

14

7

OFF

MULTISTAGE

Timer / OAS

28

35

42

OFF or
7 to 42
minutes or
7 to 42
degrees F.

Use when Timer
or Outside Air
Changeover is
required.
See Page 7

*Supply/Return
Air Limit
Delay Timer

2

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [e-mail]

A dip switch is provided to enable automatic fan
operation in heat mode. Useful for straight
electric heat or hydronic heat applications.
NOTE: Fan mode is automatically set when
Heat Pump is selected.

The panel has built-in delay timers that
insure safe & reliable operation.

*Short Cycle Timer

*Changeover Timer
*Inter-stage Timer

*Opposite Mode

3 minutes - Fixed.
4 minutes - Fixed.

2 minutes - Fixed.

20 minutes - Fixed.

Delay Timer

*Staging Timer
OAS Setting

*Supply / Return

7 to 42 minutes
or 7 to 42 F°

3 minutes - Fixed.

Air Limit Delay Timer

When all zone demands are satisfied, the
panel will not resume the same mode
operation for a minimum of 3 minutes.

When a demand to Change Over has
been honored. A 4 minute delay timer
prevents the system from rapidly
changing between Heat to Cool, or Cool
to Heat mode.

2 minute time delay that occurs between
thermostatic demands to stage up or down.

A 20 minute delay must expire, or all
active zone(s) must satisfy, before
the UZC4 will honor a thermostat
demand to changeover to the
opposite mode of system operation. The
delay is fixed & cannot be changed or defeated.

The STAGING TIMER sets the
amount of continuous & cumulative
call time in 1st stage, before second
stage heat or cool is energized. Also
applies to 3rd & 4th stage heat.
NOTE: The potentiometer also
serves as the 2nd or 3rd stage Heat,

Outside Air Changeover Setting.

The UZC4 can inhibit 2nd or 3rd stage
heat based on Time or Outside Air
Temperature. All staging scenarios
depend upon the type of thermostat
used. See page 5 & 7 for details.

NOTE: An Optional OAS Sensor is required to
use the OAS feature. NOTE: Y2 Output
defaults to 30 minutes, if OAS is chosen and
single stage thermostats are used.

The time delay of 3 minutes must
expire before the UZC4 will re­energize heat or cool mode. This
occurs when the processor detects
the supply or return air temperature is
higher or lower than the Heat/Cool
limit settings.

Cooling and Heating Limit Controls

The operational sequence of the limit controls depends upon the
dip switch settings chosen on the UZC4 main module. Multistage
Heat Pump sequence will differ from Conventional Gas/Electric.

43

40

37

34

COOLING LIMIT

130

120

110

1st STAGE

HEAT LIMIT

19

12

5

MULTI STAGE HEAT

DIFFERENTIAL

Example:

Example:

Hi Temp. limit=130

Hi Temp. limit=130

Plus M. stg T= 40

Plus M. stg T= 40

New limit F = 170

New limit F = 170°

Timer Reset
BUTTON

CPU Reset
BUTTON

Emergency
Heat
Switch

140

26

TIMER
RESET

SYSTEM
RESET

NORM

46

52

150

170

33

40

47

EM

49

160

Press & Hold the SYSTEM RESET
button for 5 seconds. That will reset
the Main & Expansion modules on a
UZC4 Zoning System.

NOTE: A three minute startup delay

occ urs wh enever the CPU Reset button
is pushed, upon any initial pow er up, or
when a power failure has occurred.

An On-Board Switch is provided that
allows the user to set the system to the
Emergency heat mode. This switch is
shown in the NORMAL position.

NOTE: An Emergency terminal is also
provided at every Thermostat terminal
block, allowing Heat Pump
Thermostats to be connected to every
zone.

The Adjustable Cooling Limit
potentiometer sets the supply air
temperature at which the 1st & 2nd
stage cooling is cycled off and the fan
continues to run, allowing the coil to
warm up.

The Adjustable Heating Limit
potentiometer sets the 1st or 2nd stage
heat supply air temperature, at which
the heating is cycled off and the fan
continues to run, allowing the heat
exchanger or coil to cool down.

The Adjustable Multistage Heat
differential potentiometer sets the 2nd
and/or, 3rd, & 4th stage heat supply air
temperature, at which the heating is
cycled off and the fan continues to run,
allowing the heat exchanger or coil to
cool down.
NOTE: Allows the supply air sensor to
be installed in the supply air plenum,
regardless of the coil/heat exchanger
configuration. Allows the installer to
fine tune virtually any multistage
heating system!

Momentarily pressing the TIMER
RESET button will clear any Active

Time Delay. This enables you to test
and certify the installation faster.
NOTE: Do not use sharp objects to
press the button. Use your finger tip or
the eraser head of a pencil.

UZC4 ADVANCED FIRMWARE AND HARDWARE FEATURES CONTINUEDUZC4 ADVANCED FIRMWARE AND HARDWARE FEATURES CONTINUED

*FIRE ALARM
INTERLOCK
FEATURE

Building
Code
Compliant
Support

Fire Alarm
Activation
Over-rides
ALL functions
and features

All Connected
Dampers will
close and the
HVAC system
will shut down

*Demand
Based
Ventilation

CO2 MONITOR &
FRESH AIR
INTERFACE
FEATURE

Building
Code
Compliant
Support

This feature is
not affected by
Heat/Cool
Operations

Fire Alarm
Activation
Over-rides
this feature

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [e-mail]

The UZC4 includes a Fire Alarm
system interlock feature.

Wire the UZC4 into your building
Fire Alarm system, and achieve full
HVAC system shutdown, and
Closure of all Duct dampers, in the
event of Fire Mode Activation.

The circuit is normally closed and
must open to activate this mode. A
Fail Safe dry contact is required on
the Fire Alarm System.

When the Fire alarm system resets
to normal, the UZC4 will also
resume normal operation. Clip the
on-board jumper and wire as shown
on page 17.

The UZC4 includes a Carbon
Dioxide and Fresh Air interface
feature.

Wire the UZC4 up to a separate
CO2 Monitor with auxilary dry
contacts. When the CO2 Monitor
activates, the UZC4 will open a
fresh air damper connected to it’s
OA damper terminal block, and
start the HVAC system fan.

The circuit is normally open and
must close to activate this mode. A
normally open dry contact is
required on the C02 Monitor or
Fresh air Timer or Other Device.

When the CO2 monitor resets to a
normal CO2 level, the UZC4 will
close the fresh air /auxilary damper.

Other external dry contact devices
can be connected to the CO2
terminals such as a Manual Switch,
Enthalpy Control, or ClockTimer.
See page 16.

NOTE: Cooling & Heating
operations are not affected by
activation of this feature.
NOTE: Activation of the Fire Alarm
Interlock feature will over-ride the
CO2 Monitor feature.

AUXILARY or
DeHUMIDIFY
INTERFACE
RELAY

Enhanced
Comfort
Solution

Auxiliary “dry”
SPDT output

This feature is
affected by
Heat/Cool
Operations

Fire Alarm
Activation
Over-rides
this feature

ELECTRONIC
BYPASS
DAMPER
SUPPORT
FEATURE

Enhanced
Airflow
Solution

Fire Alarm
Activation
Over-rides
this feature

The UZC4 includes an Auxiliary
Interface Input and SPDT action
Dry Contact Output. This allows

the Installer to connect various
Auxiliary controls such as
Humidify or DeHumidify controls.
Simply connect the Controlled
Device or Circuit to the “Output”
dry contacts and achieve
integrated control without 3rd
party isolating relays.

See Page 14 and 15 for example
control and wiring solutions.

The Auxiliary input logic can be
field selected as (DA) Direct Acting
to humidify or (RA) Reverse Acting
to Dehumidify.

The UZC4 activates a unique algorithm to
rapidly de-humidify the home without
over-cooling it. See page 14.

The UZC4 includes support for
an Electronic Bypass Damper.

Wire up a EWC Model “EBD”
Bypass Damper to achieve
precise control of the HVAC
system static pressure and
bypass damper operations.

Wire up the Model “EBD” damper
as shown on page 17.

The UZC4 defaults the Bypass
Damper to the “Open” position
during “IDLE” periods. It will also
maintain that position for 45
seconds; at the start of any
thermostat demand for Heating,
Cooling, or Fan only Operation.

The 45 second time delay
allows a constant or variable
speed fan to start in a “Quiet
Mode” and does away with
noisy air duct velocities upon
system startup.

A Latent cooling effect is also
achieved by using this feature.

After 45 seconds the UZC4 will
release control of the system static
pressure to the EBD diaphragm
control and a gradual increase in
system static pressure is
achieved. NOTE: The UZC4 will not

resume control of the “EBD”, until the
next “IDLE” period begins.

3

UZC4 ADVANCED FIRMWARE AND HARDWARE FEATURES CONTINUEDUZC4 ADVANCED FIRMWARE AND HARDWARE FEATURES CONTINUED

RETURN AIR
MONITORING
FEATURE

Enhanced
HVAC System
Safety and
Energy
Savings
Solution

Note: If this
feature is
“Enabled”
but the “RAS” is
not connected or
is not detected;
The “RAS” LED
will blink rapidly
as a warning and
The UZC4 will
not allow RAS
operations to
occur.

Note: When the
Return Air sensor
detects a return
air temperature
between the
Stage Up Value
and
the Stage Down
Value, the “RAS”
LED will blink
slowly as a
warning. The UZC4
will also hold at the
current staging
until the system
status changes
sufficiently to
allow a stage up
or down.

The UZC4 includes a RETURN AIR TEMPERATURE SENSING feature.

Connect an OPTIONAL Return Air Sensor (#RAS) to the UZC4 and achieve the ability to
STAGE DOWN the HVAC system if the return air temperature exceeds the return air
temperature limit set points. Set the “RAS” Dipswitch #6 to the “ON” position, and
choose either (0) or (+10) at the “RA LIMIT” Dipswitch # 7. Both switches are located
on the Dipswitch Bank#2.

The UZC4 will now monitor the return air temperature and allow Stage up, or if necessary
Stage Down the cooling or heating operation to maintain a return air temperature within
the following values. As stated above, choose either (0) to accept the default return air
limit values for your particular HVAC system or choose (+10) to offset the default values
10 degrees higher. Note: The (+10) offset applies to heating operations only. The default

return air temperature limit set points for cooling operations cannot be offset.

RETURN AIR LIMITS DURING HEATING CYCLE FOR HEAT PUMPS ONLY:

Default (0) set points:

If the Return Air temperature is:

80 degree F. or below, Stage Up is allowed.
105 degree F. or above, Stage Down is forced.

Default (+10) set points:

If the Return Air temperature is:

90 degree F. or below, Stage Up is allowed.
115 degree F. or above, Stage Down is forced.

RETURN AIR LIMITS DURING HEATING CYCLES FOR GAS, OIL, STRAIGHT ELECTRIC:

Default (0) set points:

If the Return Air temperature is:
80 degree F. or below, Stage Up is allowed.

115 degree F. or above, Stage Down is forced.
Default (+10) set points:

If the Return Air temperature is:

90 degree F. or below, Stage Up is allowed.
125 degree F. or above, Stage Down is forced.

RETURN AIR LIMITS DURING COOLING CYCLES FOR ALL HVAC SYSTEM TYPES:

Default (0) set points:

If the Return Air temperature is:

65 degree F. or above, Stage Up is allowed.
55 degree F. or below, Stage Down is forced.
Default +10 applies to heating operations only.

The Return Air Sensing Feature cannot cycle the 1st stage equipment off-line. It can only force a
Stage Down when the equipment is in 2nd stage cool or 2nd, 3rd, or 4th stage heat, and the selected
return air set points above have been exceeded. The Supply Air Sensing feature is the only monitor

4

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [e-mail]

that can cycle the 1st stage equipment off-line.

A three minute delay will occur after a forced stage down. If a stage up demand is present, the UZC4
will allow the stage up to re-occur when the three minute delay has expired and the return air
temperature is back to normal.

The UZC4 will automatically adapt to the “GAS,OIL,ELECTRIC” set points when a Heat Pump
system stages up to Fuel or Auxiliary mode.

This powerful feature will enhance the efficiency of your Zoned HVAC system and protect the
equipment from excessive bypass temperatures during low load conditions.

UZC4 ADVANCED FIRMWARE AND HARDWARE FEATURES CONTINUED UZC4 ADVANCED FIRMWARE AND HARDWARE FEATURES CONTINUED

MODULE TO MODULE FACTORY POWER WIRING

The UZC4 includes Factory Power Wiring on
all expanded systems. The 24 vac power to the
expansion modules is fed through the bus
cable. The bus cable feeds power to all module
processors & thermostats. Damper Motor

terminal blocks are isolated and powered
separately. This simplifies your wiring,

reduces the chances of polarity reversal and
allows more connected dampers per zone.

DIRECT DUAL FUEL COMPATIBLE FIRMWARE

The UZC4 is fully compatible with Dual Fuel
Heat Pumps, and other Hybrid HVAC systems.
Dual Fuel kits are not required. Select staging
based on Adjustable Time Delay, an Optional
Outside Air temperature Sensor, or allow the
thermostats to control staging. The intelligent
firmware does the rest.

* 7 TO 42 MINUTE STAGE UP TIME DELAY SETTINGS

RAPID DE-HUMIDIFY FIRMWARE

The UZC4 will perform a unique de-humidify
function when a demand to de-humidify is
detected at the Auxilary Input terminal. The
UZC4 will energize the Emergency heat relay to
activate one electric strip bank at the same
time the Y1 cool is active, so long as the
demand to de-humidify is detected. This

powerful feature will rapidly de-humidify your
home, and tempers (reheats) the supply air to
prevent over-cooling. See Page 14 for details.

CO2 DEMAND BASED VENTILATION SUPPORT

The UZC4 includes support for Demand Based
Ventilation Control scenarios. Designed to
help meet or exceed local building codes and
ASHRAE ventilation standards. Simply
connect your CO2 Monitor and a Fresh Air
damper to the UZC4.

*ZONE DEMAND LIMITING FEATURE

* 7 TO 42 DEGREE F. OUTSIDE AIR CHANGEOVER

* MULTI- STAGE HEAT ADJUSTABLE LIMIT CONTROL

* ELECTRONIC BYPASS DAMPER SUPPORT

* AUXILARY MULTI-FUNCTION SUPPORT RELAY

THERMOSTATIC DEMAND STAGE UP ON ALL ZONES

The UZC4 is the first Zone Control System to allow 4 stage thermostats to be connected to all zones

* STATUS LED’s ARE INCLUDED ON ALL MODULES

*ONE ZONE MODE SETBACK CAPABILITY

* SIMPLIFIED WIRING AND SYSTEM SETUP

* FIRE ALARM INTERFACE

The UZC4 is capable of numerous staging sequences depending on the type of HVAC system being
controlled, the type of thermostats connected, and the programmed staging sequence you desire.

As always you can still control a multi-stage HVAC system using inexpensive single stage thermostats
and sequence the staging by on-board adjustable time delay, or by using an optional outdoor air sensor
(OAS) and sequence the staging via an outdoor air set point.

You can still control a state of the art multi-stage Heat Pump using single or two stage conventional
thermostats and sequence the staging by time delay or outside air set point.

You can choose to control most any multi-stage Heat Pump or Conventional HVAC system with OEM
multi-stage thermostats on all zones. The UZC4 can be programmed to stage up or down based on the
thermostat inputs from each zone. The UZC4 allows a level of versatility that has never before been
offered by any zoning company. You can choose to install 3 or 4 stage thermostats on the largest zones, 2
stage thermostats on medium sized zones and single stage thermostats on the small zones.

To achieve staging via thermostatic demand only; Choose (TMR) Timer setting on Dipswitch #5 Bank 1
And then set the Multi-Stage Timer setting to (0) Zero. Setting the Timer to zero disables Timed Staging
and the UZC4 will stage up or down only when the thermostat(s) demand it.

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [e-mail]

5

Selecting the Options Using the DIP Switches

***FS = Factory Settings

SWITCH LEGEND

FS HP < SYSTEM > GAS

DF < HP > CONV FS

FS OFF < FAN PRG > ON

90s < PURGE > 180s FS
OAS < STAGES > TMR FS
FS OFF < 50% R > ON

FS OFF < SAS > ON
FS GAS < FAN > HYDRO

HC < TSTATS > HPFS

FS1 < CS# > 2

FS O < RV > B
FS OFF < ZDL > ON

RA < AUX RLY > DA FS

FS OFF < RAS > ON
FS 0 < RA LIMIT > +10

FS ANY < FAN CTRL > Z1

Bank1

Bank2

RECORD YOUR DIP SWITCH

1

1

2

2

3

3

Programming and setting up the
UZC4 is very easy! Check the

4

4

5

5

6

6

7

7

8

8

Switch Legend and refer to the
following pages for an explanation of
each dip switch function and choose
your settings. Some functions may

not apply to your application. Use a
pencil to fill in the square & record
your settings. If the settings get

changed later on, you will have a
record of the original settings.

1

1

NOTE: When you choose “HP” at
switch #1, Bank 1, the fan mode is

2

2

3

3

4

4

5

5

6

6

7

7

8

8

automatically set for you. There is no
need to move switch #8, Bank1.
Leave it in the “GAS” factory setting.

RECORD YOUR DIP SWITCH

SETTINGS HERE

SETTINGS HERE

Detailed explanations of each Dip Switch Function are included on the following
pages. Please study and familiarize yourself with all of the functions and features, prior

to activating the Zoned HVAC system. Not all features will apply to your application.

The UZC4 comes from the factory pre-set to operate a 2 stage Heat Pump using
heat pump thermostats to control the staging.

Failure to properly set all dip switches to the correct and/or desired positions will result
in improper operation of the controlled HVAC System.

Please read and study the entire Technical Bulletin and if necessary, Call the EWC
Technical Support Hotline when assistance is required.

Leave this Technical Bulletin with the Home or Building Owner for future reference.

CONTINUED ON NEXT PAGE...

6

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [e-mail]

Selecting the Options Using the DIP Switches - BANK1

HP < SYSTEM > GAS

1

Choose the type of HVAC system you want to control. Select HP, if your system is any type of heat pump. Select GAS,
if your system is a any type of Gas / Oil furnace, or any straight Electric furnace or Hydronic (hot water / steam)
heating system.

DF < HP > CONV

2

If you chose “HP” at switch #1, then choose the type of Heat Pump you want to control. Select DF, if your system is a Dual Fuel
heat pump with Gas or Oil furnace backup heat. Select CONV, if your system is a Conventional heat pump with Electric resistance
backup / supplemental heat. Also applies to Ground source / Geothermal heat pumps with Electric backup heat.

OFF < FAN PRG > ON

3

Select ON, if you want the UZC4 to force the indoor blower ON at the end of a heat/cool call to assist the zone purge cycle.
Selecting OFF will allow the HVAC system to operate the indoor blower, without interference from the UZC4.

90S < PURGE > 180S

4

Select 90S or 180S, if you want the zone dampers to hold position for 90 seconds or 180 seconds at the end of any heat or cool call.
This allows the HVAC system to purge the remaining hot or cold air, into the zone(s) that were calling for it.

OAS < STAGES > TMR

5

Select OAS, if you want to delay multi-stage operations based on the outside air temperature sensor. Select TIMER, if you want to

delay stage up based on the adjustable on-board timer. Both features are very useful when using single stage thermostats on all zones.

NOTE1: Y2/W2 stage up defaults to a 30 minute delay, when OAS is chosen. NOTE2: An optional Outside Air Sensor (Part#OAS) is required

to use the OAS feature. NOTE3: Thermostat demands to stage up, will always over-ride the Timer or OAS staging operations, Unless the
50% rule has been enabled, or the Return Air temperature limit has been exceeded. NOTE4: Thermostatic demands to Stage Down will be
honored unless the Timer is also in use. NOTE5: Disable the Timer by setting to OFF, and the UZC4 will obey Stage up & Stage down

demands via the thermostats only!

OFF < 50% RULE > ON

6

Select OFF, if you do not want to inhibit 2nd stage compressor cooling/heating operations based on the total number of zones calling.

Select ON, if you want to inhibit 2nd stage compressor cooling/heating operations based on the total number of zones calling. Half or more of
the total number of thermostats must be calling or stage up will not occur. NOTE 1: In All Modes, the 50% rule occurs between Y1 and Y2.

NOTE2: In Gas mode the 50% rule occurs between W1 &W2. NOTE3: Emergency mode is never affected by the 50% rule.

OFF < SAS > ON

7

Select OFF, if you do not want to use the Supply air sensor included with the UZC4 Zone Control system. Select ON, if
you want to use the included Supply air sensor. Refer to the data sheet included with the Supply air sensor for

installation details. Refer to page 2 for details on Supply air Sensing Limit Controls and settings. Mount the Supply
Air Sensor in the discharge duct and/or plenum.

GAS < FAN > HYDRONIC

8

Select GAS, if your HVAC system is a gas or oil forced air furnace. Select HYDRONIC, if your HVAC system has a hot
water / steam coil, or straight electric heat with no indoor blower support. Useful when you need the indoor blower to run
automatically in heat mode, just like it does in cool mode. NOTE: When you select HP on dip switch #1, the indoor fan
mode is automatically set for you. If so, then leave this switch in the factory GAS setting.

CONTINUED ON NEXT PAGE...

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [e-mail]

7

Selecting the Options Using the DIP Switches - BANK2

1

HC < TSTAT > HP

Select the type of thermostats you want to use. Select HC, if your thermostats are the standard Heat/Cool type. Select HP, if your
thermostats are Heat Pump types. NOTE1: You cannot mix thermostat types. NOTE2: You do not need HP thermostats to control
a Heat Pump. NOTE3: Thermostat demands to stage up, will always over-ride the Timer or OAS staging operations, unless the 50%
rule has been enabled. NOTE4: Thermostatic demands to stage down will be honored unless the Timer is in use.

IMPORTANT NOTE: The UZC4 Zone Control System allows Heat Pump or Conventional Multi-Stage

thermostats to be wired to all Zones!

Thermostat demands to stage up, will always over-ride any programmed staging operation. The UZC4 will
remain in Multi-stage mode until that terminal is de-energized. If this occurs in dual fuel mode or emergency mode,
the UZC4 will stay in that mode until all Heating demands are satisfied. On the next heating cycle, the UZC4 will
attempt to activate 1st stage heat unless, Emergency Mode is still active, or the outdoor temperature is low and
OAS / DF has been selected. This comfort over-ride feature provides true versatility to your zoning system, and
gives the homeowner comfort control capability over the system.

1 < CS# > 2

2

Choose the number of Condensing Unit Stages you want to control. Select 1, if your CU has a Y1 connection only. Select 2, if
your CU has a Y1 & Y2 connection. NOTE1: This feature must be set correctly for proper Timed & Outdoor Air Sensor staging
operations. NOTE2: Thermostat demands to stage up, will always Over-ride the Timer & OAS staging operations, unless the
50% rule has been enabled, or the Return air temperature limit has been exceeded. NOTE3: All stage up Operations depend upon
the correct setting of this switch.

3

O < RV > B

Choose the type of Reversing Valve you want to control. Select O , if your heat pump reversing valve energizes in cooling and
defaults to heat mode. Select B, if your reversing valve energizes in heating and defaults to cool mode. NOTE: The UZC4 will hold
the “O” output or the “B” output continuously, even during idle periods, until a thermostatic demand to change modes is detected.

NOTE: Proper setting of this switch is critical. The reversing valve will not function properly if this switch is not set correctly.

OFF < ZDL > ON

4

Select ON and the UZC4 will limit HVAC operations based on the total number of zones calling for conditioned air.

16% or 1/6 of the total number of zones (rounded up) must be calling for the same mode of operation, or the UZC4 will not
activate the HVAC system. This feature only activates at 8 or more zones. Select OFF if you do not want to utilize the Zone
Demand Limiter feature. NOTE: Zone 1 is not affected by this feature. Zone 1 demands are always honored. ZDL example:
A zone system has 20 total zones and the ZDL feature is active; At least 4 zones must be calling for the same mode of
operation (Heat or Cool) or the UZC4 will not activate the HVAC system. 18zone=3, 16zone=3, 14zone=3, 12zone=2, 10zone=2, 8zone=2.

5

RA < AUX RLY > DA

Select the control signal type you need, in order to activate your preferred Auxilary Relay function. Choose RA (Reverse
Acting) for De-Humidification Control, or Choose DA (Direct Acting) for Humidification Control, depending on the control input signal
you require. Then connect your controlled device or circuit to the SPDT dry output contacts and achieve integrated control without
the need for 3rd party relays or specialty relays. If this feature is not used, the switch must be in the DA position.

See Pages 14-16 for further information.

6

OFF < RAS > ON

If you connect an OPTIONAL Return Air Sensor to the UZC4, then Select ON, and Choose to use the default set points

for Return Air Temperature Limit Operations, or choose to Offset those set points by 10 degrees higher at the next Dip Switch.

Refer to the data sheet included with the Return air sensor for installation details. Mount the Return Air Sensor in the
return air duct as close to the Blower intake as possible, or in the blower cabinet. Read page 4 for Operational details.

7

0 < RA LIMIT > +10

If you connect an OPTIONAL Return Air Sensor and switch on the “RAS” switch above; then choose “0” to accept the

default set points for Return Air Temperature Limits, or choose “+10” to Offset the default set points 10 degrees higher.

Refer to the data sheet included with the Return air sensor for installation details. Read page 4 for Operational details.

8

ANY < FAN CTRL > Z1

Select which thermostat(s) can activate a demand for Continuous Fan Operation. Choose “ANY”, and the UZC4 will

honor any thermostat demand to activate continuous fan, and only the dampers connected to that zone will open. All others
will close. Choose “Z1”, and the UZC4 will honor a demand to activate continuous fan from zone 1 only. All connected
dampers on all zones will open. Demands to activate continuous fan from any other thermostat will be ignored.
NOTE: Continuous Fan Operations will only occur when there are no active or pending heat or cool operations.

8

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [e-mail]