Johnson Controls 20 J ZJ Series, R-410A Installation Manual

R-410A
ZU SERIES

3 - 5 Ton
60 Hertz

TABLE OF CONTENTS

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Preceding Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Rigging And Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Ductwork. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Condensate Drain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Compressors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Power And Control Wiring. . . . . . . . . . . . . . . . . . . . . . . . . 17

Optional Electric Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Optional Gas Heat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Options/Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Standard Economizer and Power Exhaust Set Point

Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Airflow Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

LIST OF TABLES

1 ZU-A3 thru -A5 Unit Limitations . . . . . . . . . . . . . . . . . . . . 7

2 Weights and Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . 8

3 ZU-A3 thru -A5 Unit Accessory Weights . . . . . . . . . . . . . . 8

4 ZU-A3 thru -A5 Unit Physical Dimensions . . . . . . . . . . . 11

5 ZU-A3 thru -A5 Unit Clearances . . . . . . . . . . . . . . . . . . . 11

6 Side Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7 Control Wire Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

8 Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

9 Physical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

10 Electric Heat Minimum Supply Air . . . . . . . . . . . . . . . . . . 27

11 Gas Pipe Sizing - CapacIty of Pipe . . . . . . . . . . . . . . . . . 28

12 Gas Heat Minimum Supply Air . . . . . . . . . . . . . . . . . . . . 29

13 Supply Air Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

14 Altitude/Temperature Correction Factors . . . . . . . . . . . . 34

LIST OF FIGURES

1 Unit Shipping Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Condenser Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3 Compressor Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4 Component Location (ZU-A4 Shown) . . . . . . . . . . . . . . . 6

5 Unit 4 Point Load Weight . . . . . . . . . . . . . . . . . . . . . . . . . 8

6 Unit 6 Point Load Weight . . . . . . . . . . . . . . . . . . . . . . . . . 8

7 Center of Gravity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

8 ZU-A3 thru -A4 Physical Dimensions . . . . . . . . . . . . . . . . 9

9 ZU-A5 Physical Dimensions . . . . . . . . . . . . . . . . . . . . . 10

10 ZU-A3 thru -A5 Unit Bottom Duct Openings . . . . . . . . . 12

11 ZU-A3 thru -A5 Unit Electrical Entry . . . . . . . . . . . . . . . 13

12 ZU-A3 thru -A5 Unit Side Duct Openings . . . . . . . . . . . 13

13 ZU-A3 thru -A5 Unit Left Duct Opening . . . . . . . . . . . . . 14

14 ZU-A3 thru -A5 Roof Curb . . . . . . . . . . . . . . . . . . . . . . . 14

15 ZU-A3 thru -A5 Transition Roof Curb . . . . . . . . . . . . . . . 15

16 Side Panels With Hole Plugs . . . . . . . . . . . . . . . . . . . . . 15

Air Balance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Checking Air Quantity. . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Cooling Sequence Of Operation. . . . . . . . . . . . . . . . . . . . 42

No Outdoor Air Options . . . . . . . . . . . . . . . . . . . . . . . . . 42

Cooling Operation Errors . . . . . . . . . . . . . . . . . . . . . . . . 42

Electric Heating Sequence Of Operations . . . . . . . . . . . . 44

Electric Heat Operation Errors. . . . . . . . . . . . . . . . . . . . 44

Gas Heating Sequence Of Operations . . . . . . . . . . . . . . . 45

Ignition Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Gas Heating Operation Errors . . . . . . . . . . . . . . . . . . . . 45

Start-Up (Cooling) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Start-Up (Gas Heat) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Checking Gas Heat Input . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Charging The Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Fan On And Off Delays. . . . . . . . . . . . . . . . . . . . . . . . . . . 54

15 Airflow Performance - Side Duct Application . . . . . . . . . 36

16 Airflow Performance - Bottom Duct Application . . . . . . . 37

17 RPM Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

18 Indoor Blower Specifications . . . . . . . . . . . . . . . . . . . . . . 38

19 Power Exhaust Specifications . . . . . . . . . . . . . . . . . . . . 38

20 Motor Sheave Datum Diameters . . . . . . . . . . . . . . . . . . 40

21 Additional Static Resistance . . . . . . . . . . . . . . . . . . . . . . 41

22 Electric Heat Limit Setting . . . . . . . . . . . . . . . . . . . . . . . . 44

23 Electric Heat Anticipator Setpoints . . . . . . . . . . . . . . . . . 45

24 Gas Heat Anticipator Setpoints . . . . . . . . . . . . . . . . . . . . 47

25 Gas Rate Cubic Feet Per Hour . . . . . . . . . . . . . . . . . . . . 49

26 Gas Heat Stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

27 Unit Control Board Flash Codes . . . . . . . . . . . . . . . . . . . 55

28 Ignition Control Flash Codes . . . . . . . . . . . . . . . . . . . . . . 55

17 Return Downflow Plenum With Panel . . . . . . . . . . . . . . 16

18 Discharge Panel In Place . . . . . . . . . . . . . . . . . . . . . . . . 16

19 Condensate Drain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

20 Field Wiring Disconnect . . . . . . . . . . . . . . . . . . . . . . . . . 18

21 Typical Control Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . 19

22 Side Entry Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . 28

23 Bottom Entry Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . 28

24 Enthalpy Set Point Chart . . . . . . . . . . . . . . . . . . . . . . . . 32

25 Honeywell Economizer Control W7212 . . . . . . . . . . . . . 32

26 Belt Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

27 Altitude/Temperature Correction Factors . . . . . . . . . . . . 34

28 Dry Coil Delta P . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

29 Typical Flame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

30 Typical Two Stage Gas Valve . . . . . . . . . . . . . . . . . . . . 50

31 Typical Single Stage Gas Valve . . . . . . . . . . . . . . . . . . . 50

32 Unit Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

689670-BIM-A-0311

689670-BIM-A-0311

General

UP ZU units are single package air conditioners with optional
gas heating designed for outdoor installation on a rooftop or
slab and for non-residential use. These units can be equipped
with factory or field installed electric heaters for heating
applications.

These units are completely assembled on rigid, permanently
attached base rails. All piping, refrigerant charge, and electrical
wiring is factory installed and tested. The units require electric
power, gas supply (where applicable), and duct connections.
The electric heaters have nickel-chrome elements and utilize
single-point power connection.

Before performing service or maintenance operations on
unit, turn off main power switch to unit. Electrical shock
could cause personal injury. Improper installation,
adjustment, alteration, service or maintenance can
cause injury or property damage. Refer to this manual.
For assistance or additional information consult a
qualified installer, service agency or the gas supplier.

Safety Considerations

This is a safety alert symbol. When you see this symbol
on labels or in manuals, be alert to the potential for
personal injury.

Understand and pay particular attention the signal words

DANGER, WARNING or CAUTION.
DANGER indicates an imminently hazardous situation, which,

if not avoided, will result in death or serious injury
WARNING indicates a potentially hazardous situation, which,

if not avoided, could result in death or serious injury
CAUTION indicates a potentially hazardous situation, which, if

not avoided may result in minor or moderate injury
used to alert against unsafe practices and hazards involving
only property damage.

Improper installation may create a condition where the
operation of the product could cause personal injury or
property damage. Improper installation, adjustment,
alteration, service or maintenance can cause injury or
property damage. Refer to this manual for assistance or
for additional information, consult a qualified contractor,
installer or service agency.

.

.

. It is also

This system uses R-410A Refrigerant which operates at
higher pressures than R-22. No other refrigerant may be
used in this system. Gage sets, hoses, refrigerant
containers and recovery systems must be designed to
handle R-410A. If you are unsure, consult the equipment
manufacturer. Failure to use R-410A compatible servicing
equipment may result in property damage or injury.

If the information in this manual is not followed exactly, a
fire or explosion may result causing property damage,
personal injury or loss of life.

Do not store or use gasoline or other flammable vapors
and liquids in the vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS:
a. Do not try to light any appliance.
b. Do not touch any electrical switch; do not use any

phone in your building.

c. Immediately call your gas su pplier from a neighbor’s

phone. Follow the gas supplier’s instructions.

d. If you cannot reach your gas supplier, call the fire

department.

Installation and service must be performed by a qualified
installer, service agency or the gas supplier.

Due to system pressure, moving parts, and electrical
components, installation and servicing of air conditioning

This product must be installed in strict compliance with
the installation instructions and any applicable local,
state and national codes including, but not limited to
building, electrical, and mechanical codes.

2 Johnson Controls Unitary Products

equipment can be hazardous. Only qualified, trained service
personnel should install, repair, or service this equipment.
Untrained personnel can perform basic maintenance functions
of cleaning coils and filters and replacing filters.

Observe all precautions in the literature, labels, and tags
accompanying the equipment whenever working on air
conditioning equipment. Be sure to follow all other applicable
safety precautions and codes including ANSI Z223.1 or CSA­B149.1- latest edition.

689670-BIM-A-0311

Wear safety glasses and work gloves. Use quenching cloth and
have a fire extinguisher available during brazing operations.

Inspection

As soon as a unit is received, it should be inspected for possible
damage during transit. If damage is evident, the extent of th e
damage should be noted on the carrier’s freight bill. A separate
request for inspection by the carrier’s agent should be made in
writing.

This product must be installed in strict compliance with
the enclosed installation instructions and any applicable
local, state and national codes including, but not limited
to, building, electrical, and mechanical codes.

The furnace and its individual shut-off valve must be
disconnected from the gas supply piping system during
any pressure testing at pressures in excess of 1/2 PSIG.

Pressures greater than 1/2 PSIG will cause gas valve
damage resulting in a hazardous condition. If it is
subjected to a pressure greater than 1/2 PSIG, the gas
valve must be replaced.

The furnace must be isolated from the gas supply piping
system by closing its individual manual shut-off valve
during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2 PSIG

• Electric Heater Accessory 42” cabinet

Renewal Parts

Contact your local UP

parts distribution center for authorized

replacement parts.

Approvals

Design certified by CSA as follows:

1. For use as a cooling only unit, cooling un it wi th

supplemental electric heat or a forced air furnace.

2. For outdoor installation only.

3. For installation on combustible material and may be

installed directly on combustible flooring or, in the U.S., on

wood flooring or Class A, Class B or Class C roof covering

materials.

4. For use with natural gas (convertible to LP w it h ki t).

This product must be installed in strict compliance with
the enclosed installation instructions and any applicable
local, state, and national codes including, but not limited
to, building, electrical, and mechanical codes.

Reference

Additional information is available in the following reference
forms:

• Technical Guide - 528196

• General Installation - 689670

• Pre-start & Post-start Check List

• Economizer Accessory ­Downflow Factory Installed
Downflow Field Installed
Horizontal Field Installed

• Motorized Outdoor Air Damper

• Manual Outdoor Air Damper (0-100%)

• Manual Outdoor Air Damper (0-35%)

• Gas Heat Propane Conversion Kit

• Gas Heat High Altitude Kit (Natural Gas)

• Gas Heat High Altitude Kit (Propane)

•–60F Gas Heat Kit

Improper installation may create a condition where the
operation of the product could cause personal injury or
property damage.

This system uses R-410A Refrigerant which operates at
higher pressures than R-22. No other refrigerant may be
used in this system.

Johnson Controls Unitary Products 3

689670-BIM-A-0311

Z U -A5 N08 A T A AA 6 0 1 2 4 A

Product Category

Z = A/C, Single Pkg., R-410A

A = Std. Motor

Airflow

B = Std. Motor/Econo./Barometric Relief (Downflow

Only)
C = Std. Motor/Econo./Power Exhaust (Downflow Only)
D = Std. Motor/Motorized Damper (Downflow Only)
E = Std. Motor/Horizontal Economizer (No Baro.)
F = Std. Motor/Slab Econo./Power Exhaust

(Downflow Only)
G = Std. Motor/Slab Econo./Barometric Relief

(Downflow Only)
N = Hi Static
P = Hi Static/Econo./Barometric Relief

(Downflow Only)
Q = Hi Static/Econo./Power Exhaust

(Downflow Only)
R = Hi Static/Motorized Damper (Downflow Only)
S = Hi Static/Horizontal Economizer (No Baro.)
T = Hi Static/Slab Econo./Power Exhaust

(Downflow Only)
U = Hi Static/Slab Econo./Barometric Relief

(Downflow only)

Product Generation

6 = Sixth Generation

-A3 = 3 Ton

Nominal Cooling Capacity

-A4 = 4 Ton

-A5 = 5 Ton

Product Identifier

U = 11.8+ EER/14.0 SEER A/C

Voltage

T = 208/230-3-60
W = 460-3-60
X = 575-3-60

Product Style

A = Style A
B = Style B
C = Style C

A = No Options Installed

Installation Options

B = Option 1
C = Option 2
D = Options 1 & 2
E = Option 3
F = Option 4
G = Options 1 & 3
H = Options 1 & 4
J = Options 1, 2 & 3
K = Options 1, 2, & 4
L = Options 1,3 & 4
M = Options 1, 2, 3, & 4
N = Options 2 & 3
P = Options 2 & 4
Q = Options 2, 3, & 4
R = Options 3 & 4
S = Option 5
T = Options 1 & 5
U = Options 1, 3, & 5
V = Options 1, 4, & 5
W = Options 1, 3, 4, & 5
X = Option

s 3 & 5
Y = Options 4 & 5
Z = Options 3, 4 & 5

1 = Disconnect
2 = Non-Pwr'd Conv. Outlet
3 = Smoke Detector S.A.
4 = Smoke Detector R.A.
5 = Pwr'd Conv. Outlet

Options

SS Drain Pan

Configuration Options (not required for all units)

These four digits will not be assigned until a quote is requested, or an order placed.

CPC Controller, DFS, APS

Johnson Controller UNT 1126 (N2 protocol), DFS, APS

Honeywell Controller, DFS, APS

Novar Controller, DFS, APS

Simplicity IntelliComfort Controller

Simplicity IntelliComfort Controller w/Simplicity®Linc

2" Pleated filters

BAS Ready Unit with Economizer

Shipping Bag

Any Combination of Additional Options that Don’t Have an Option Code Pre-assigned

AA = None
AB = Phase Monitor
AC = Coil Guard
AD = Dirty Filter Switch
AE = Phase Monitor & Coil Guard
AF = Phase Monitor & Dirty Filter Switch
AG = Coil Guard & Dirty Filter Switch
AH = Phase Monitor, Coil Guard & Dirty Filter Switch

Additional Options

RC = Coil Guard, Shipping Bag & American Flag
TA = Technicoat Condenser Coil
TJ = Technicoat Evaporator Coil
TS = Technicoat Evaporator & Condenser Coils

3-5 Ton Model Number Nomenclature

ZZ = If desired option combination is not listed above, ZZ will be assigned and configuration options will be

located in digits 15-18.

C00 = Cooling Only. No heat installed

Heat Type and Nominal Heat Capacity

(Unit Size Allowed)

A06 = 60 MBH Input Aluminized Steel,
Single Stage (-A3, -A4)
A08 = 80 MBH Input Aluminized Steel,
Single Stage (-A3, -A4, -A5)
A11 = 120 MBH Input Aluminized Steel,
Single Stage (-A3, -A4, -A5)
A16 = 160 MBH Input Aluminized Steel,
Single Stage (-A5)
B06 = 60 MBH Input Stainless Sleel,
Single Stage (-A3, -A4)
B08 = 80 MBH Input Stainless Steel,
Single Stage (-A3, -A4, -A5)
B11 - 120 MBH Input Stainless Steel,
Single Stage (-A3, -A4, -A5)
B16 = 160 MBH Input Stainless Steel,
Single Stage (-A5)

E03 = 3 KW (-A3)
E06 = 6 KW (-A3, -A4, -A5)
E08 = 9 KW (-A3, -A4, -A5)
E15 = 15 KW (-A3, -A4, -A5)
E20 = 20 KW (-A4, -A5)
E23 = 24 KW (-A5)

Single Stage Natural Gas Heat Options

Electric Heat Options

Two Stage Natural Gas Heat Options

N06 = 60 MBH Output Aluminized Steel,
Two Stage (-A3, -A4)
N08 = 80 MBH Input Aluminized Steel,
Two Stage (-A3, -A4, -A5)
N11 = 120 MBH Input Aluminized Steel,
Two Stage (-A3, -A4, -A5)
N16 = 160 MBH Input Aluminized Steel,
Two Stage (-A5)
S06 = 60 MBH Input Stainless Sleel,
Two Stage (-A3, -A4)
S08 = 80 MBH Input Stainless Steel,
Two Stage (-A3, -A4, -A5)
S11 - 120 MBH Input Stainless Steel,
Two Stage (-A3, -A4, -A5)
S16 = 160 MBH Input Stainless Steel,
Two Stage (-A5)

4" Pleated filters

EA = ElectroFin Condenser Coil
EJ = ElectroFin Evaporator Coil
ES = ElectroFin Cond & Evap Coils

Nomenclature

4 Johnson Controls Unitary Products

689670-BIM-A-0311

Bracket
Screws

Turn down

Condenser
Coil External
Protective
Covering

Barometric
Relief Hood
in Shipping
Location
(if Included)

Toolless
Doorknobs

Installation
Instruction
Packet

Installation

Installation Safety Information

Read these instructions before continuing this appliance
installation. This is an outdoor combination heating and cooling
unit. The installer must assure that these instructions are made
available to the consumer and with instructions to retain them
for future reference.

1. Refer to the unit rating plate for the approved type of gas
for this product.

2. Install this unit only in a location and position as specified
on Page 7 of these instructions.

3. Never test for gas leaks with an open flame. Use
commercially available soap solution made specifically for
the detection of leaks when checking all connections, as
specified on Pages 5, 29, 30 and 48 of these instructions.

4. Always install furnace to operate within the furnace's
intended temperature-rise range with the duct system and
within the allowable external static pressure range, as
specified on the unit name/rating plate, specified on
Page 50 of these instructions.

5. This equipment is not to be used for temporary heating of
buildings or structures under construction.

3. Remove the condenser coil external protective covering
prior to operation.

4. Remove the toolless doorknobs and instruction packet
prior to installation.

Figure 2: Condenser Covering

Preceding Installation

1. Remove the two screws holding the brackets in the front,

Figure 1: Unit Shipping Bracket

2. Turn each bracket toward the ground and the protective

Johnson Controls Unitary Products 5

FIRE OR EXPLOSION HAZARD
Failure to follow the safety warning exactly could result

in serious injury, death or property damage.
Never test for gas leaks with an open flame. use a

commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage,
personal injury or loss of life.

rear and compressor side fork-lift slots.

plywood covering will drop to the ground.

Figure 3: Compressor Section

5. If a factory option convenience outlet is installed, the
weatherproof outlet cover must be field installed. The cover
shall be located behind the filter access panel. To install
the cover, remove the shipping label covering the
convenience outlet, follow the instructions on the back of
the weatherproof cover box, and attach the cover to the
unit using the (4) screws provided.

208/230-3-60 and 380/415-3-50 units with factory
installed Powered Convenience Outlet Option are wired
for 230v and 415v power supply respectively. Change
Tap on transformer for 208-3-60 or 380-3-50 operation.
See unit wiring diagram.

689670-BIM-A-0311

Intelligent control board

for safe and efficient

operation

“Simplicity®” Control board w/

screw connectors for T-stat

wiring and Network

Connections

Disconnect location

(optional disconnect switch)

Filter access

(2" or 4”

filter options)

Filter drier (solid core)

Slide out motor and

blower assembly for

easy adjustment

and service

Base rails w/

forklift slots

(three sides)

and lifting

holes

Toolless door

latch

Side entry power

and control wiring

knockouts

Belt-drive blower

motor

Power ventor

motor

20-gauge aluminized

steel tubular heat
exchanger for long life
(stainless steel option)

Two-stage gas heating to

maintain warm, comfortable

temperature

Slide-out drain pan

with ¾" NPT

connection

Compressor access (high-

efficiency compressor w/

crankcase heater)

Second model nameplate

inside hinged access

panel

Roof curbs in eight-and

fourteen-inch heights.

Roof curbs for transitioning

from DHB/DUC/DHC/DUS footprint

to the ZU Series footprint

are available

(field-installed accessory)

Micro-Channel Aluminum

Tube/Aluminum Fin

Condenser

Limitations

These units must be installed in accordance with the following:
In U.S.A.:

1. National Electrical Code, ANSI/NFPA No. 70 - Latest
Edition

2. National Fuel Gas Code, ANSI Z223.1 - Latest Edition

3. Gas-Fired Central Furnace Standard, ANSI Z21.47 - Latest
Edition

4. Local building codes, and

5. Local gas utility requirements

In Canada:

1. Canadian Electrical Code, CSA C22.1

2. Installation Codes, CSA - B149.1.

3. Local plumbing and waste water codes, and

4. Other applicable local codes.

Refer to unit application data found in this document.
After installation, gas fired units must be adjusted to obtain a

temperature rise within the range specified on the unit rating
plate.

If components are to be added to a unit to meet local codes,
they are to be installed at the dealer’s and/or customer’s
expense.

Size of unit for proposed installation should be based on heat
loss/heat gain calculation made according to the methods of Air
Conditioning Contractors of America (ACCA).

This furnace is not to be used for temporary heating of buildings
or structures under construction.

The Simplicity® control board used in this product will
effectively operate the cooling system down to 0°F when
this product is applied in a comfort cooling application
for people. An economizer is typically included in this
type of application. When applying this product for
process cooling applications (computer rooms,
switchgear, etc.), please reference applications bulletin
AE-011-07 or call the applications department for
Unitary Products @ 1-877-UPG-SERV for guidance.
Additional accessories may be needed for stable
operation at temperatures below 30° F.

Figure 4: Component Location (ZU-A4 Show n)

6 Johnson Controls Unitary Products

Table 1: ZU-A3 thru -A5 Unit Limitations

689670-BIM-A-0311

Size

(Tons)

-A3

(3.0)

-A4

(4.0)

-A5

(5.0)

Model Unit Voltage

208/230-3-60 187 252 125

ZU

ZU

ZU

460-3-60 432 504 125
575-3-60 540 630 125

208/230-3-60 187 252 125

460-3-60 432 504 125
575-3-60 540 630 125

208/230-3-60 187 252 125

460-3-60 432 504 125
575-3-60 540 630 125

Location

Use the following guidelines to select a suitable location for
these units:

1. Unit is designed for outdoor installation only.

2. Condenser coils must have an unlimited supply of air.
Where a choice of location is possible, position the unit on
either north or east side of building.

3. Suitable for mounting on roof curb.

4. For ground level installation, use a level concrete slab with
a minimum thickness of 4 inches. The length and width
should be at least 6 inches greater than the unit base rails.
Do not tie slab to the building foundation.

5. Roof structures must be able to support the weight of the
unit and its options/accessories. Unit must be installed on a
solid, level roof curb or appropriate angle iron frame.

6. Maintain level tolerance to 1/2” across the entire width and
length of unit.

Unit Limitations

Applied Voltage Outdoor DB Temp

Min Max Max (°F)

Code, ANSI Z223.1 – Latest Edition (in U.S.A.), or Sections 7.2,

7.3, or 7.4 of Gas Installation Codes, CSA-B149.1 (in Canada) ­Latest Edition, and/or applicable provisions of the local building
codes. Refer to Table 5 for clearances required for combustible
construction, servicing, and proper unit operation.

Do not permit overhanging structures or shrubs to
obstruct condenser air discharge outlet, combustion air
inlet or vent outlets.

Rigging And Handling

Exercise care when moving the unit. Do not remove any
packaging until the unit is near the place of installation. Rig the
unit by attaching chain or cable slings to the lifting holes
provided in the base rails. Spreader bars, whose length
exceeds the largest dimension across the unit, MUST be used
across the top of the unit.

Excessive exposure of this furnace to contaminated
combustion air may result in equipment damage or
personal injury. Typical contaminates include:
permanent wave solution, chlorinated waxes and
cleaners, chlorine based swimming pool chemicals,

If a unit is to be installed on a roof curb other than a UP
roof curb, gasketing must be applied to all surfaces that
come in contact with the unit underside.

water softening chemicals, carbon tetrachloride,
Halogen type refrigerants, cleaning solvents (e.g.
perchloroethylene), printing inks, paint removers,
varnishes, hydrochloric acid, cements and glues,
antistatic fabric softeners for clothes dryers, masonry
acid washing materials.

Clearances

All units require particular clearances for proper operation and
service. Installer must make provisions for adequate
combustion and ventilation air in accordance with section 5.3 of

Before lifting, make sure the unit weight is distributed
equally on the rigging cables so it will lift evenly.

Units may be moved or lifted with a forklift. Slotted openings in
the base rails are provided for this purpose.

LENGTH OF FORKS MUST BE A MINIMUM OF 60 INCHES.

Air for Combustion and Ventilation of the National Fuel Gas

Johnson Controls Unitary Products 7

689670-BIM-A-0311

D

A

CB

LEFT

FRONT

D

A

C

B

E

F

LEFT

FRONT

X

Y

LEFT

FRONT

All panels must be secured in place when the unit is
lifted.

The condenser coils should be protected from rigging
cable damage with plywood or other suitable material.

Figure 6: Unit 6 Point Load Weight

Figure 5: Unit 4 Point Load Weight

Table 2: Weights and Dimensions

Size

(Tons)

-A3
(3)

-A4
(4)

-A5
(5)

Model

ZU 728 723 40 26 175 143 182 223 121 105 92 117 134 154

ZU 768 763 40 26 185 151 192 235 128 111 97 124 141 162

ZU 869 864 40 26 210 171 217 266 145 126 110 140 160 184

Weight (lbs.) Center of Gravity 4 Point Load Location (lbs.) 6 Point Load Location (lbs.)

ShippingOperatingX YABCDABCDEF

Table 3: ZU-A3 thru -A5 Unit Accessory Weights

Unit Accessory

Shipping Operating

Economizer 90 85

Power Exhaust 40 35

Electric Heat

Gas Heat

1

2

1. Weight given is for the maximum heater size available (24KW).

2. Weight given is for the maximum number of tube heat exchangers
available (8 tube).

Weight (lbs.)

49 49

110 110

Figure 7: Center of Gravity

8 Johnson Controls Unitary Products

689670-BIM-A-0311

Ø 25.31

59.00

15.51

29.75

59

LEFT

11 3/8

21 3/16

89

27 5/16

4 3/16

FRONT

See detail A for gas inlet

A

See detail B for drain location

B

C

D

E

F

29.52

Figure 8: ZU-A3 thru -A4 Physical Dimensions

Johnson Controls Unitary Products 9

689670-BIM-A-0311

Ø 24.47 TYP. 2 PL.

15.38

15.38

59.00

15.25

29.69

59

LEFT

11 3/8

21 3/16

89

27 5/16

4 3/16

FRONT

See detail A for gas inlet

A

See detail B for drain location

B

C

D

E

F

Figure 9: ZU-A5 Physical Dimensions

10 Johnson Controls Unitary Products

Table 4: ZU-A3 thru -A5 Unit Physical Dimensions

42” CABINET

Ø 3.126

Ø 2.000

3.184

4.727

7.705

14.594

Gas Pipe Inlet

Gas Exhaust Vent

3/4” FPT

Unit Model Number

ZU-A3 42 89 22 1/8 18 3/16 15 3/16 6 3/16
ZU-A4 42 89 22 1/8 18 3/16 15 3/16 6 3/16
ZU-A5 42 89 22 1/8 18 3/16 15 3/16 6 3/16

ABCDEF

Detail A Detail B

689670-BIM-A-0311

Dimension (in.)

5-3/8

Table 5: ZU-A3 thru -A5 Unit Clearances

Direction Distance (in.) Direction Distance (in.)

1

Top
Front 36 Left 36
Rear 36 Bottom

72 Right 12

2

0

1. Units must be installed outdoors. Over hanging structure or shrubs should not obscure condenser air discharge outlet.

2. Units may be installed on combustable floors made from wood or class A, B or C roof covering materials.

Johnson Controls Unitary Products 11

689670-BIM-A-0311

Bottom condensate drain

Bottom gas
supply entry

FRONT

RETURN

AIR

SUPPLY

AIR

RIGHT

LEFT

20 1/8

19 1/8

17 1/8

6 13/16

6 13/16

32 11/16

14 1/2

16 3/8

18 1/16

25 9/16

12 5/16

27 1/2

24

21

18

89

Ø 2.469

3X Ø 0.875

Bottom power, control

and convenience outlet

wiring entry

Figure 10: ZU-A3 thru -A5 Unit Bottom Duct Openings

TOP VIEW

12 Johnson Controls Unitary Products

Figure 11: ZU-A3 thru -A5 Unit Electrical Entry

Disconnect Swith Cover

Power Entry Ø 2-1/2

Control Entry Ø 7/8

Power Entry Ø 2-1/2

Convenience Outlet Cover

Convenience Outlet
Power Entry Ø 7/8

FRONT

D o t P l u g s

5 - 5 /3 2

3 1 - 1 1 /1 6

2 - 3 1 /3 2

1 8 - 1 /4

Return

Air

Supply Air

A

B

C

D

689670-BIM-A-0311

Figure 12: ZU-A3 thru -A5 Unit Side Duct Openings

Table 6: Side Duct Dimensions

Johnson Controls Unitary Products 13

Unit Model Number

ABCD

Dimension (in.)

ZU-A3 27 3/4 12 1/16 27 1/2 16
ZU-A4 27 3/4 12 1/16 27 1/2 16
ZU-A5 27 3/4 12 1/16 27 1/2 16

689670-BIM-A-0311

4-5/16

30-3/8

Figure 13: ZU-A3 thru -A5 Unit Left Duct Opening

20

2 TYP.

30

50-1/2

Figure 14: ZU-A3 thru -A5 Roof Curb

80-5/8

6

20

RETURN

SUPPLY

8 or 14

RIGHT

INSULATED DECK UNDER

CONDENSER SECTION

INSULATED DECK UNDER

COMPRESSOR SECTION

FRONT

14 Johnson Controls Unitary Products

50-1/2

30-1/2

2TYP

23

689670-BIM-A-0311

4

RETURN

76-5/8

94

FRONT

Figure 15: ZU-A3 thru -A5 Transition Roof Curb

Ductwork

Ductwork should be designed and sized according to the
methods in Manual D of the Air Conditioning Contractors of
America (ACCA) or as recommended by any other recognized
authority such as ASHRAE or SMACNA.

A closed return duct system should be used. This will not
preclude use of economizers or outdoor fresh air intake. The
supply and return air duct connections at the unit should be
made with flexible joints to minimize noise.

The supply and return air duct systems should be designed for
the CFM and static pressure requirements of the job. They
should NOT be sized to match the dimensions of the duct
connections on the unit.

59-1/4

64-1/4

80-5/8

10

RIGHT

26

SUPPLY

painted surface DOWN, facing the downflow duct opening. The
supply panel is secured with the bracket (already in place from
the factory) and two screws. It’s a snug fit for the panel when
sliding it between the heat exchanger and unit bottom, but there
is room. The return panel is secured with four screws.

When fastening ductwork to side duct flanges on unit,
insert screws through duct flanges only. DO NOT insert
screws through casing. Outdoor ductwork must be
insulated and water-proofed.

Refer to Figure 10 for bottom air duct openings. Refer to
Figures 12, 13 and Table 6 for side air duct openings.

Duct Covers

Units are shipped with the side duct openings covered and a
covering over the bottom of the unit. For bottom duct
application, no duct cover changes are necessary. For side
duct application, remove the side duct covers and install over
the bottom duct openings. The panels removed from the side
duct connections are designed to be reused by securing each
panel to its respective downflow opening. But keep in mind that
the supply panel is installed with the painted surface UP, facing
the heat exchanger, while the return panel is installed with the

Figure 16: Side Panels With Hole Plugs
NOTE: Orientation. Panel is “insulation” side up.

Johnson Controls Unitary Products 15

689670-BIM-A-0311

3" Minimum

Figure 17: Return Downflow Plenum With Panel

Figure 18: Discharge Panel In Place

Condensate Drain

Compressors

The scroll compressor used in this product is specifically
designed to operate with R-410A Refrigerant and cannot be
interchanged.

This system uses R-410A Refrigerant which operates at
higher pressures than R-22. No other refrigerant may be
used in this system.

The compressor also uses a polyolester (POE oil), Mobil 3MA
POE. This oil is extremely hygroscopic, meaning it absorbs water
readily. POE oil can absorb 15 times as much water as other oils
designed for HCFC and CFC refrigerants. Take all necessary
precautions to avoid exposure of the oil to the atmosphere.

Do not leave the system open to the atmosphere. Unit
damage could occur due to moisture being absorbed by
the POE oil in the system. This type of oil is highly
susceptible to moisture absorption

POE (polyolester) compressor lubricants are known to cause
long term damage to some synthetic roofing materials.

The side condensate drain is reversible and maybe re-oriented to
the rear of the cabinet to facilitate condensate piping. A
condensate drain connection is available through the base pan
for piping inside the roof curb. Trap the connection per Figure 19.
The trap and drain lines should be protected from freezing.

Plumbing must conform to local codes. Use a sealing compound
on male pipe threads. Install condensate drain line from the 3/4
inch NPT female connection on the unit to an open drain.

Figure 19: Condensate Drain

Exposure, even if immediately cleaned up, may cause
embrittlement (leading to cracking) to occur in one year
or more. When performing any service that may risk
exposure of compressor oil to the roof, take precautions
to protect roofing.

Procedures which risk oil leakage include, but are not limited to,
compressor replacement, repairing refrigerant leaks, replacing
refrigerant components such as filter drier, pressure switch,
metering device or coil.

Units are shipped with compressor mountings which are
factory-adjusted and ready for operation.

Do not loosen compressor mounting bolts.

Filters

Two-inch filters are supplied with each unit. One-inch filters may
be used with no modification to the filter racks. Filters must
always be installed ahead of evaporator coil and must be kept

16 Johnson Controls Unitary Products

689670-BIM-A-0311

clean or replaced with same size and type. Dirty filters reduce
the capacity of the unit and result in frosted coils or safety
shutdown. Refer to physical data tables, for the number and
size of filters needed for the unit. The unit should not be
operated without filters properly installed.

Make sure that panel latches are properly positioned on
the unit to maintain an airtight seal.

Power And Control Wiring

Field wiring to the unit, fuses, and disconnects must conform to
provisions of National Electrical Code (NEC), ANSI/NFPA No.
70 – Latest Edition (in U.S.A.), current Canadian Electrical
Code C221, and/or local ordinances. The unit must be
electrically grounded in accordance with NEC and CEC as
specified above and/or local codes.

Voltage tolerances which must be maintained at the
compressor terminals during starting and running conditions are
indicated on the unit Rating Plate and Table 1.

the wire supplied with the unit must be replaced, replacement
wire must be of the type shown on the wiring diagram and the
same minimum gauge as the replaced wire.

A disconnect must be utilized for these units. Factory installed
disconnects are available. If installing a disconnect (field
supplied or UP supplied accessory), refer to Figure 4 for the
recommended mounting location.

Avoid damage to internal components if drilling holes for
disconnect mounting.

NOTE: Since not all local codes allow the mounting of a

disconnect on the unit, please confirm compliance with
local code before mounting a disconnect on the unit.

Electrical line must be sized properly to carry the load. USE
COPPER CONDUCTORS ONLY. Each unit must be wired with
a separate branch circuit fed directly from the meter panel and
properly fused.

Refer to Figures 20 & 21 and for typical field wiring and to the
appropriate unit wiring diagram mounted inside control doors
for control circuit and power wiring information.

208/230-3-60 units control transformers are factory
wired for 230v power supply respectively. Change tap
on transformer for 208-3-60 operation. See unit wiring
diagram.

The internal wiring harnesses furnished with this unit are an
integral part of the design certified unit. Field alteration to
comply with electrical codes should not be required. If any of

When connecting electrical power and control wiring to
the unit, water-proof connectors must be used so that
water or moisture cannot be drawn into the unit during
normal operation. The above water-proofing conditions
will also apply when installing a field supplied disconnect
switch.

Johnson Controls Unitary Products 17

689670-BIM-A-0311

THREE
PHASE

POWER

SUPPLY

FACTORY OR FIELD

SUPPLIED DISCONNECT

GROUND

LUG

TERMINAL BLOCK TB1

Power Wiring Detail

Units are factory wired for the voltage shown on the unit
nameplate. Refer to Electrical Data Table 8 to size power
wiring, fuses, and disconnect switch.

Power wiring is brought into the unit through the side of the unit
or the basepan inside the curb.

Figure 20: Field Wiring Disconnect

18 Johnson Controls Unitary Products

689670-BIM-A-0311

RC

RH

Y1

Y2

W1

W2

G

LED 1

LED 2

COM

A1

A2

T

T

B

R

Y1

Y2

G

C

X

OCC

W2

W1

THERMOSTAT

1

TERMINALS

UNIT TERMINAL

STRIP TB1

24 VOLT

TRANSFORMER

TO REMOTE SENSOR
2TH040702224 IF USED

NOT
USED

ADD

JUMPER

ADD

JUMPER

4

4

3

2

1

ELECTRONIC PROGRAMMABLE THERMOSTAT 2ET04700224 (INCLUDES SUBBASE).

2

SECOND STAGE COOLING IS NOT REQUIRED ON UNITS LESS ECONOMIZER.

3

SECOND STAGE HEATING IS ONLY REQUIRED ON UNITS WITH A TWO STAGE

ELECTRIC HEATER OR 2 STAGE GAS HEAT.

4

REMOVE JUMPER J2 FROM TERMINALS 4 AND 9 ON JUMPER PLUG CONNECTOR
P6 ON UNITS WITH ECONOMIZER. TERMINALS A1 AND A2 PROVIDE A RELAY
OUT-PUT TO CLOSE THE OUTDOOR ECONOMIZER DAMPERS WHEN THE
THERMOSTAT SWITCHES TO THE SET-BACK POSITION.

COOLING / HEATING (ELECTRONIC THERMOSTAT)

MULTI STAGE

RH

RC

Y

W

G

R

Y1

W1

C

G

ADD

JUMPER

THERMOSTAT

1

TERMINALS

UNIT TERMINAL

STRIP TB1

24 VOLT

TRANSFORMER

1

ELECTRONIC PROGRAMMABLE THERMOSTAT 2ET07701024 (INCLUDES SUBBASE).
TO CONTROL THE ECONOMIZER ON SECOND STAGE COOLING, USE THERMOSTAT
2TH04700224.

COOLING / HEATING (ELECTRONIC THERMOSTAT)

SINGLE STAGE

RV

YC

GF

R

Y1

C

Y2

THERMOSTAT

1

TERMINALS

UNIT TERMINAL

STRIP TB1

24 VOLT

TRANSFORMER

1

24 VOLT THERMOSTAT 2TH07701024. TO CONTROL THE ECONOMIZER
ON SECOND STAGE COOLING, USE THE THERMOSTAT 2TH0401224.

G

COOLING ONLY (24 VOLT THERMOSTAT)

RC

Y

R

Y1

Y2

W1

W

W2

G

C

G

RH

THERMOSTAT

TERMINALS

UNIT TERMINAL

STRIP TB1

24 VOLT

TRANSFORMER

ADD

JUMPER

1

24 VOLT THERMOSTAT 2ET07701024. TO CONTROL THE ECONOMIZER ON THE SECOND
STAGE COOLING OR TO HAVE AN ELECTRIC HEAT ACCESSORY WITH TWO STAGES OF
HEAT, USE THERMOSTAT 2TH0471024.

1

COOLING / HEATING (24 VOLT THERMOSTAT)

Thermostat Wiring

The thermostat should be located on an inside wall
approximately 56 inch above the floor where it will not be
subject to drafts, sun exposure or heat from electrical fixtures or
appliances. Follow the manufacturer's instructions enclosed
with thermostat for general installation procedure. Seven (7)
color-coded, insulated wires should be used to connect the
thermostat to the unit. Refer to Table 7 for control wire sizing
and maximum length.

Typical Control Wiring Detail

Table 7: Control Wire Sizes

Wire Size Maximum Length

18 AWG 150 Feet

1. From the unit to the thermostat and back to the unit.

1

Figure 21: Typical Control Wiring

Johnson Controls Unitary Products 19

689670-BIM-A-0311

Table 8: Electrical Data
ZU-A3 thru -A5 Standard Indoor Blower - Without Powered Convenience Outlet

Size

(Tons)

Volt

Compressors

(each)

OD Fan
Motors

(each)

Supply
Blower

Motor

Pwr
Exh

Motor

Pwr

Conv

Outlet

Electric Heat Option

RLA LRA MCC FLA FLA FLA FLA Model kW Stages Amps

None---18.924.425 30

E03 2.3 1 6.4 18.9 24.4 25 30

208 9.1 68 14.2 1.5 6.0 5.5 0.0

E06 4.5 1 12.5 23.1 30 25 30
E08 6.8 1 18.9 31.1 38 35 40
E15 11.3 2 31.4 46.7 53.6 50 60

None---18.924.425 30

E03 3 1 7.2 18.9 24.4 25 30

230 9.1 68 14.2 1.5 6.0 5.5 0.0

-A3
(3)

E06 6 1 14.4 25.5 32.4 30 35
E08 9 1 21.7 34.6 41.4 35 45
E15 15 2 36.1 52.6 59.5 60 60

None - - - 9.4 11.6 15 15

E03 3 1 3.6 9.4 11.6 15 15

460 4.5 34 7 0.8 3.0 2.2 0.0

E06 6 1 7.2 12.8 15.5 15 20
E08 9 1 10.8 17.3 20 20 20
E15 15 2 18.0 26.3 29.1 30 30

None - - - 7.8 9.6 15 15

575 3.8 28 6 0.6 2.4 1.8 0.0

E08 9 1 8.7 13.8 16.1 15 20
E15 15 2 14.4 21 23.3 25 25

None---21.527 30 35

E06 4.5 1 12.5 23.1 30 30 35

208 11.2 88 17.5 1.5 6.0 5.5 0.0

E08 6.8 1 18.9 31.1 38 35 40
E15 11.3 2 31.4 46.7 53.6 50 60
E20 15 2 41.6 59.5 66.4 60 70

None---21.727 30 35

E06 6 1 14.4 25.5 32.4 30 35

230 11.2 88 17.5 1.5 6.0 5.5 0.0

-A4
(4)

E08 9 1 21.7 34.6 41.4 35 45
E15 15 2 36.1 52.6 59.5 60 60
E20 20 2 48.1 67.6 74.5 70 80

None---10.813 15 15

E06 6 1 7.2 12.8 15.5 15 20

460 5.6 44 8.0 0.8 3.0 2.2 0.0

E08 9 1 10.8 17.3 20 20 20
E15 15 2 18.0 26.3 29.1 30 30
E20 20 2 24.1 33.8 36.6 35 40

None - - - 8.6 10.4 15 15

575 4.5 36 7.0 0.6 2.4 1.8 0.0

E08 9 1 8.7 13.8 16.1 15 20
E15 15 2 14.4 21 23.3 25 25
E20 20 2 19.2 27.1 29.3 30 30

None---26.632.135 45

E06 4.5 1 12.5 26.6 32.1 35 45

208 14.1 88 22 1.5 6.0 5.5 0.0

E08 6.8 1 18.9 31.1 38 40 45
E15 11.3 2 31.4 46.7 53.6 50 60
E20 15 2 41.6 59.5 66.4 60 70
E23 18 2 50.0 70 76.8 70 80

None---26.632.135 45

E06 6 1 14.4 26.6 32.4 35 45

230 14.1 88 22 1.5 6.0 5.5 0.0

-A5
(5)

E08 9 1 21.7 34.6 41.4 40 45
E15 15 2 36.1 52.6 59.5 60 60
E20 20 2 48.1 67.6 74.5 70 80
E23 24 2 57.7 79.7 86.5 80 90

None---14.216.420 20

E06 6 1 7.2 14.2 16.4 20 20

460 7.7 55 12 0.8 3.0 2.2 0.0

E08 9 1 10.8 17.3 20 20 20
E15 15 2 18.0 26.3 29.1 30 30
E20 20 2 24.1 33.8 36.6 35 40
E23 24 2 28.9 39.8 42.6 40 45

None-- - 1011.815 15

E08 9 1 8.7 13.8 16.1 15 20

575 5.1 36 7.5 0.6 2.4 1.8 0.0

E15 15 2 14.4 21 23.3 25 25
E20 20 2 19.2 27.1 29.3 30 30
E23 24 2 23.1 31.9 34.1 35 35

1. Minimum Circuit Ampacity.

2. Dual Element, Time Delay Type.

3. HACR type per NEC.

MCA

(Amps)

Size

Max Fuse2/

2

/

Breaker

3

Size w/

Pwr Exh

(Amps)

3

1

Max Fuse

MCA

1

w/Pwr

Exh

(Amps)

Breaker

(Amps)

20 Johnson Controls Unitary Products

ZU-A3 thru -A5 Hi Static Indoor Blower - Without Powered Convenience Outlet

Compressors

Size

(Tons)

-A3
(3)

-A4
(4)

-A5
(5)

Volt

208 9.1 68 14.2 1.5 6.0 5.5 0.0

230 9.1 68 14.2 1.5 6.0 5.5 0.0

460 4.5 34 7 0.8 3.0 2.2 0.0

575 3.8 28 6 0.6 2.4 1.8 0.0

208 11.2 88 17.5 1.5 6.0 5.5 0.0

230 11.2 88 17.5 1.5 6.0 5.5 0.0

460 5.6 44 8.0 0.8 3.0 2.2 0.0

575 4.5 36 7.0 0.6 2.4 1.8 0.0

208 14.1 88 22 1.5 6.8 5.5 0.0

230 14.1 88 22 1.5 6.8 5.5 0.0

460 7.7 55 12 0.8 3.4 2.2 0.0

575 5.1 36 7.5 0.6 2.7 1.8 0.0

(each)

RLA LRA MCC FLA FLA FLA FLA Model kW Stages Amps

1. Minimum Circuit Ampacity.

2. Dual Element, Time Delay Type.

3. HACR type per NEC.

OD Fan
Motors

(each)

Supply
Blower

Motor

Pwr
Exh

Motor

Pwr

Conv

Outlet

Electric Heat Option

None---18.924.425 30

E03 2.3 1 6.4 18.9 24.4 25 30
E06 4.5 1 12.5 23.1 30 25 30
E08 6.8 1 18.9 31.1 38 35 40
E15 11.3 2 31.4 46.7 53.6 50 60

None---18.924.425 30

E03 3 1 7.2 18.9 24.4 25 30
E06 6 1 14.4 25.5 32.4 30 35
E08 9 1 21.7 34.6 41.4 35 45
E15 15 2 36.1 52.6 59.5 60 60

None - - - 9.4 11.6 15 15

E03 3 1 3.6 9.4 11.6 15 15
E06 6 1 7.2 12.8 15.5 15 20
E08 9 1 10.8 17.3 20 20 20
E15 15 2 18.0 26.3 29.1 30 30

None - - - 7.8 9.6 15 15

E08 9 1 8.7 13.8 16.1 15 20
E15 15 2 14.4 21 23.3 25 25

None---21.527 30 35

E06 4.5 1 12.5 23.1 30 30 35
E08 6.8 1 18.9 31.1 38 35 40
E15 11.3 2 31.4 46.7 53.6 50 60
E20 15 2 41.6 59.5 66.4 60 70

None---21.527 30 35

E06 6 1 14.4 25.5 32.4 30 35
E08 9 1 21.7 34.6 41.4 35 45
E15 15 2 36.1 52.6 59.5 60 60
E20 20 2 48.1 67.6 74.5 70 80

None---10.813 15 15

E06 6 1 7.2 12.8 15.5 15 20
E08 9 1 10.8 17.3 20 20 20
E15 15 2 18.0 26.3 29.1 30 30
E20 20 2 24.1 33.8 36.6 35 40

None - - - 8.6 10.4 15 15

E08 9 1 8.7 13.8 16.1 15 20
E15 15 2 14.4 21 23.3 25 25
E20 20 2 19.2 27.1 29.3 30 30

None---27.432.935 45

E06 4.5 1 12.5 27.4 32.9 35 45
E08 6.8 1 18.9 32.1 39 40 45
E15 11.3 2 31.4 47.7 54.6 50 60
E20 15 2 41.6 60.5 67.4 70 70
E23 18 2 50.0 71 77.8 80 80

None---27.432.935 45

E06 6 1 14.4 27.4 33.4 35 45
E08 9 1 21.7 35.6 42.4 40 45
E15 15 2 36.1 53.6 60.5 60 70
E20 20 2 48.1 68.6 75.5 70 80
E23 24 2 57.7 80.7 87.5 90 90

None---14.616.820 20

E06 6 1 7.2 14.6 16.8 20 20
E08 9 1 10.8 17.8 20.5 20 25
E15 15 2 18.0 26.8 29.6 30 30
E20 20 2 24.1 34.3 37.1 35 40
E23 24 2 28.9 40.3 43.1 45 45

None---10.312.115 15

E08 9 1 8.7 14.2 16.5 15 20
E15 15 2 14.4 21.4 23.7 25 25
E20 20 2 19.2 27.4 29.7 30 30
E23 24 2 23.1 32.2 34.5 35 35

MCA

(Amps)

689670-BIM-A-0311

Size

Max Fuse2/

2

/

Breaker

3

Size w/

Pwr Exh

(Amps)

3

1

Max Fuse

MCA

1

w/Pwr

Exh

(Amps)

Breaker

(Amps)

Johnson Controls Unitary Products 21

689670-BIM-A-0311

ZU-A3 thru -A5 Standard Indoor Blower - With Powered Convenience Outlet

Compressors

Size

(Tons)

-A3
(3)

-A4
(4)

-A5
(5)

Volt

208 9.1 68 14.2 1.5 6.0 5.5 10.0

230 9.1 68 14.2 1.5 6.0 5.5 10.0

460 4.5 34 7 0.8 3.0 2.2 5.0

575 3.8 28 6 0.6 2.4 1.8 4.0

208 11.2 88 17.5 1.5 6.0 5.5 10.0

230 11.2 88 17.5 1.5 6.0 5.5 10.0

460 5.6 44 8.0 0.8 3.0 2.2 5.0

575 4.5 36 7.0 0.6 2.4 1.8 4.0

208 14.1 88 22 1.5 6.0 5.5 10.0

230 14.1 88 22 1.5 6.0 5.5 10.0

460 7.7 55 12 0.8 3.0 2.2 5.0

575 5.1 36 7.5 0.6 2.4 1.8 4.0

(each)

RLA LRA MCC FLA FLA FLA FLA Model kW Stages Amps

1. Minimum Circuit Ampacity.

2. Dual Element, Time Delay Type.

3. HACR type per NEC.

OD Fan
Motors

(each)

Supply
Blower

Motor

Pwr
Exh

Motor

Pwr

Conv

Outlet

Electric Heat Option

None---29.134.635 40

E03 2.3 1 6.4 29.1 34.9 35 40
E06 4.5 1 12.5 35.6 42.5 40 45
E08 6.8 1 18.9 43.6 50.5 45 60
E15 11.3 2 31.4 59.2 66.1 60 70

None---29.134.635 40

E03 3 1 7.2 29.1 35.9 35 40
E06 6 1 14.4 38 44.9 40 45
E08 9 1 21.7 47.1 53.9 50 60
E15 15 2 36.1 65.1 72 70 80

None---14.616.815 20

E03 3 1 3.6 14.6 17.3 15 20
E06 6 1 7.2 19 21.8 20 25
E08 9 1 10.8 23.5 26.3 25 30
E15 15 2 18.0 32.6 35.3 35 40

None---11.813.615 15

E08 9 1 8.7 18.8 21.1 20 25
E15 15 2 14.4 26 28.3 30 30

None---31.537 40 45

E06 4.5 1 12.5 35.6 42.5 40 45
E08 6.8 1 18.9 43.6 50.5 45 60
E15 11.3 2 31.4 59.2 66.1 60 70
E20 15 2 41.6 72 78.9 80 80

None---31.537 40 45

E06 6 1 14.4 38 44.9 40 45
E08 9 1 21.7 47.1 53.9 50 60
E15 15 2 36.1 65.1 72 70 80
E20 20 2 48.1 80.1 87 90 90

None---15.818 20 20

E06 6 1 7.2 19 21.8 20 25
E08 9 1 10.8 23.5 26.3 25 30
E15 15 2 18.0 32.6 35.3 35 40
E20 20 2 24.1 40.1 42.8 45 45

None---12.614.415 15

E08 9 1 8.7 18.8 21.1 20 25
E15 15 2 14.4 26 28.3 30 30
E20 20 2 19.2 32.1 34.3 35 35

None---36.642.150 50

E06 4.5 1 12.5 36.6 42.5 50 50
E08 6.8 1 18.9 43.6 50.5 50 60
E15 11.3 2 31.4 59.2 66.1 60 70
E20 15 2 41.6 72 78.9 80 80
E23 18 2 50.0 82.5 89.3 90 90

None---36.642.150 50

E06 6 1 14.4 38 44.9 50 50
E08 9 1 21.7 47.1 53.9 50 60
E15 15 2 36.1 65.1 72 70 80
E20 20 2 48.1 80.1 87 90 90
E23 24 2 57.7 92.2 99 100 100

None---19.221.425 25

E06 6 1 7.2 19.2 21.8 25 25
E08 9 1 10.8 23.5 26.3 25 30
E15 15 2 18.0 32.6 35.3 35 40
E20 20 2 24.1 40.1 42.8 45 45
E23 24 2 28.9 46.1 48.8 50 50

None-- - 1415.815 20

E08 9 1 8.7 18.8 21.1 20 25
E15 15 2 14.4 26 28.3 30 30
E20 20 2 19.2 32.1 34.3 35 35
E23 24 2 23.1 36.9 39.1 40 40

MCA

(Amps)

Size

Max Fuse2/

2

/

Breaker

3

Size w/

Pwr Exh

(Amps)

3

1

Max Fuse

MCA

1

w/Pwr

Exh

(Amps)

Breaker

(Amps)

22 Johnson Controls Unitary Products

ZU-A3 thru -A5 Hi Static Indoor Blower - With Powered Convenience Outlet

Compressors

Size

(Tons)

-A3
(3)

-A4
(4)

-A5
(5)

Volt

208 9.1 68 14.2 1.5 6.0 5.5 10.0

230 9.1 68 14.2 1.5 6.0 5.5 10.0

460 4.5 34 7 0.8 3.0 2.2 5.0

575 3.8 28 6 0.6 2.4 1.8 4.0

208 11.2 88 17.5 1.5 6.0 5.5 10.0

230 11.2 88 17.5 1.5 6.0 5.5 10.0

460 5.6 44 8.0 0.8 3.0 2.2 5.0

575 4.5 36 7.0 0.6 2.4 1.8 4.0

208 14.1 88 22 1.5 6.8 5.5 10.0

230 14.1 88 22 1.5 6.8 5.5 10.0

460 7.7 55 12 0.8 3.4 2.2 5.0

575 5.1 36 7.5 0.6 2.7 1.8 4.0

(each)

RLA LRA MCC FLA FLA FLA FLA Model kW Stages Amps

1. Minimum Circuit Ampacity.

2. Dual Element, Time Delay Type.

3. HACR type per NEC.

OD Fan
Motors

(each)

Supply
Blower

Motor

Pwr
Exh

Motor

Pwr

Conv

Outlet

Electric Heat Option

None---29.134.635 40

E03 2.3 1 6.4 29.1 34.9 35 40
E06 4.5 1 12.5 35.6 42.5 40 45
E08 6.8 1 18.9 43.6 50.5 45 60
E15 11.3 2 31.4 59.2 66.1 60 70

None---29.134.635 40

E03 3 1 7.2 29.1 35.9 35 40
E06 6 1 14.4 38 44.9 40 45
E08 9 1 21.7 47.1 53.9 50 60
E15 15 2 36.1 65.1 72 70 80

None---14.616.815 20

E03 3 1 3.6 14.6 17.3 15 20
E06 6 1 7.2 19 21.8 20 25
E08 9 1 10.8 23.5 26.3 25 30
E15 15 2 18.0 32.6 35.3 35 40

None---11.813.615 15

E08 9 1 8.7 18.8 21.1 20 25
E15 15 2 14.4 26 28.3 30 30

None---31.537 40 45

E06 4.5 1 12.5 35.6 42.5 40 45
E08 6.8 1 18.9 43.6 50.5 45 60
E15 11.3 2 31.4 59.2 66.1 60 70
E20 15 2 41.6 72 78.9 80 80

None---31.537 40 45

E06 6 1 14.4 38 44.9 40 45
E08 9 1 21.7 47.1 53.9 50 60
E15 15 2 36.1 65.1 72 70 80
E20 20 2 48.1 80.1 87 90 90

None---15.818 20 20

E06 6 1 7.2 19 21.8 20 25
E08 9 1 10.8 23.5 26.3 25 30
E15 15 2 18.0 32.6 35.3 35 40
E20 20 2 24.1 40.1 42.8 45 45

None---12.614.415 15

E08 9 1 8.7 18.8 21.1 20 25
E15 15 2 14.4 26 28.3 30 30
E20 20 2 19.2 32.1 34.3 35 35

None---37.442.950 50

E06 4.5 1 12.5 37.4 43.5 50 50
E08 6.8 1 18.9 44.6 51.5 50 60
E15 11.3 2 31.4 60.2 67.1 70 70
E20 15 2 41.6 73 79.9 80 80
E23 18 2 50.0 83.5 90.3 90 100

None---37.442.950 50

E06 6 1 14.4 39 45.9 50 50
E08 9 1 21.7 48.1 54.9 50 60
E15 15 2 36.1 66.1 73 70 80
E20 20 2 48.1 81.1 88 90 90
E23 24 2 57.7 93.2 100 100 100

None---19.621.825 25

E06 6 1 7.2 19.6 22.3 25 25
E08 9 1 10.8 24 26.8 25 30
E15 15 2 18.0 33.1 35.8 35 40
E20 20 2 24.1 40.6 43.3 45 45
E23 24 2 28.9 46.6 49.3 50 50

None---14.316.115 20

E08 9 1 8.7 19.2 21.5 20 25
E15 15 2 14.4 26.4 28.7 30 30
E20 20 2 19.2 32.4 34.7 35 35
E23 24 2 23.1 37.2 39.5 40 40

MCA

(Amps)

689670-BIM-A-0311

Size

Max Fuse2/

2

/

Breaker

3

Size w/

Pwr Exh

(Amps)

3

1

Max Fuse

MCA

1

w/Pwr

Exh

(Amps)

Breaker

(Amps)

Johnson Controls Unitary Products 23

689670-BIM-A-0311

Table 9: Physical Data
ZU-A3 thru -A5 Single Stage Gas Physical Data

Component

Nominal Tonnage 3.0 4.0 5.0

ARI COOLING PERFORMANCE

Gross Capacity @ ARI A point (MBh) 37000 50000 61000
ARI net capacity (MBh) 36000 48000 58000
EER 11.8 11.8 11.8
SEER 14 14 14
IPLV --­Nominal CFM 1200 1600 2000
System power (KW) 3.05 4.07 4.90
Refrigerant type R-410A R-410A R-410A
Refrigerant charge (lb-oz)

System 1 7-4 6-14 7-12
System 2 ---

ARI HEATING PERFORMANCE

Heating model A06 A08 A11 A06 A08 A11 A08 A11 A16
Heat input (K Btu) 60 80 120 60 80 120 80 120 160
Heat output (K Btu) 49 65 97 49 65 97 65 97 129
AFUE % - - - - - ­Steady state efficiency (%) 81.5 81 81 81.5 81 81 81 81 80.5
No. burners 446446468
No. stages 1 1 1 1 1 1 1 1 1
Temperature Rise Range (ºF) 20-50°F 25-65°F 50-80°F 20-50°F 25-65°F 40-70°F 25-65°F 35-65°F 45-75°F
Gas Limit Setting (ºF) 235°F 200°F 255°F 235°F 200°F 255°F 200°F 245°F 240°F
Gas piping connection (in.) 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4

DIMENSIONS (inches)

Length 89 89 89
Width 595959
Height 42 42 42

OPERATING WT. (lbs.) 723 763 864

COMPRESSORS

Type Recip Recip Recip
Quantity 1 1 1
Unit Capacity Steps (%) 100 100 100

CONDENSER COIL DATA

Face area (Sq. Ft.) 11.9 18.5 12.1
Rows 111
Fins per inch 23 23 23
Tube diameter (in./MM) 1/25 .71/18 .71/18
Circuitry Type 2-pass Microchannel 2-pass Microchannel 2-pass Microchannel

EVAPORATOR COIL DATA

Face area (Sq. Ft.) 8 8 10.6
Rows 333
Fins per inch 15 15 15
Tube diameter 0.375 0.375 0.375
Refrigerant control TXV TXV TXV

ZU-A3 ZU-A4 ZU-A5

Models

24 Johnson Controls Unitary Products

ZU-A3 thru -A5 Single Stage Gas Physical Data (Continued)

689670-BIM-A-0311

Component

ZU-A3 ZU-A4 ZU-A5

Models

Nominal Tonnage 3.0 4.0 5.0

CONDENSER FAN DATA

Quantity of fans 1 1 2
Fan diameter (Inch) 24 24 24
Type Prop Prop Prop
Drive type Direct Direct Direct
Quantity of motors 1 1 2
Motor HP each 1/3 1/3 1/3
No. speeds 1 1 1
RPM 850 850 850
Nominal total CFM 3300 3700 6700

BELT DRIVE EVAP FAN DATA

Quantity 1 1 1
Fan Size (Inch) 12 x 9 12 x 9 12 x 9
Type Centrifugal Centrifugal Centrifugal
Motor Sheave 1VM34 1VL44 1VM34 1VL44 1VL40 1VP56
Blower Sheave AK69 AK69 AK56 AK56 AK61 AK74
Belt A47 A47 A47 A47 A47 A51
Motor HP each 1-1/2 1-1/2 1-1/2 1-1/2 1-1/2 2
RPM 1725 1725 1725 1725 1725 1725
Frame size 56 56 56 56 56 56

FILTERS

Quantity - Size

1. 2 In. Throwaway, Standard, MERV (Minimum Efficiency Reporting Value) 3.

2. 2 In. Pleated, Optional, MERV 7.

3. 4 In. Pleated, Optional, MERV 13.

4 - (24 x 16 x 2)

4 - (24 x 16 x 4)

1,2

3

4 - (24 x 16 x 4)

4 - (24 x 16 x 2)

1,2

3

4 - (24 x 16 x 4)

4 - (24 x 16 x 2)

1,2

3

Johnson Controls Unitary Products 25

689670-BIM-A-0311

ZU-A3 thru -A5 Two Stage Gas Physical Data

Component

ZU-A3 ZU-A4 ZU-A5

Models

Nominal Tonnage 3.0 4.0 5.0

ARI COOLING PERFORMANCE

Gross Capacity @ ARI A point (MBh) 37000 50000 61000
ARI net capacity (MBh) 36000 48000 58000
EER 11.8 11.8 11.8
SEER 14 14 14
IPLV --­Nominal CFM 1200 1600 2000
System power (KW) 3.05 4.07 4.90
Refrigerant type R-410A R-410A R-410A
Refrigerant charge (lb-oz)

System 1 7-4 6-14 7-12
System 2 ---

ARI HEATING PERFORMANCE

Heating model N06 N08 N11 N06 N08 N11 N08 N11 N16
Heat input (K Btu) 60 80 120 60 80 120 80 120 160
Heat output (K Btu) 49 65 97 49 65 97 65 97 129
AFUE % - - - - - ­Steady state efficiency (%) 81.5 81 81 81.5 81 81 81 81 80.5
No. burners 446446468
No. stages 2

1

2

2

2

2

1

2

2

2

2

2

2

2

2

2

2

2
Temperature Rise Range (ºF) 20-50°F 25-65°F 50-80°F 20-50°F 25-65°F 40-70°F 25-65°F 35-65°F 45-75°F
Gas Limit Setting (ºF) 235°F 200°F 255°F 235°F 200°F 255°F 200°F 245°F 240°F
Gas piping connection (in.) 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4

DIMENSIONS (inches)

Length 89 89 89
Width 595959
Height 42 42 42

OPERATING WT. (lbs.) 723 763 864

COMPRESSORS

Type Recip Recip Recip
Quantity 1 1 1
Unit Capacity Steps (%) 100 100 100

CONDENSER COIL DATA

Face area (Sq. Ft.) 11.9 18.5 21.1
Rows 111
Fins per inch 23 23 23
Tube diameter (in./MM) 1/25 .71/18 .71/18
Circuitry Type 2-pass Microchannel 2-pass Microchannel 2-pass Microchannel

EVAPORATOR COIL DATA

Face area (Sq. Ft.) 8 8 10.6
Rows 333
Fins per inch 15 15 15
Tube diameter 0.375 0.375 0.375
Refrigerant control TXV TXV TXV

26 Johnson Controls Unitary Products

ZU-A3 thru -A5 Two Stage Gas Physical Data (Continued)

689670-BIM-A-0311

Component

ZU-A3 ZU-A4 ZU-A5

Models

Nominal Tonnage 3.0 4.0 5.0

CONDENSER FAN DATA

Quantity of fans 1 1 2
Fan diameter (Inch) 24 24 24
Type Prop Prop Prop
Drive type Direct Direct Direct
Quantity of motors 1 1 2
Motor HP each 1/3 1/3 1/3
No. speeds 1 1 1
RPM 850 850 850
Nominal total CFM 3300 3700 6700

BELT DRIVE EVAP FAN DATA

Quantity 1 1 1
Fan Size (Inch) 12 x 9 12 x 9 12 x 9
Type Centrifugal Centrifugal Centrifugal
Motor Sheave 1VM34 1VL44 1VM34 1VL44 1VL40 1VP56
Blower Sheave AK69 AK69 AK56 AK56 AK61 AK74
Belt A47 A47 A47 A47 A47 A51
Motor HP each 1-1/2 1-1/2 1-1/2 1-1/2 1-1/2 2
RPM 1725 1725 1725 1725 1725 1725
Frame size 56 56 56 56 56 56

FILTERS

Quantity - Size

1. 1st Stage Capacity is 75% of Full Capacity.

st

Stage Capacity is 70% of Full Capacity.

2. 1

3. 2 In. Throwaway, Standard, MERV (Minimum Efficiency Reporting Value) 3.

4. 2 In. Pleated, Optional, MERV 7.

5. 4 In. Pleated, Optional, MERV 13.

4 - (24 x 16 x 2)

4 - (24 x 16 x 4)

3,4

5

4 - (24 x 16 x 4)

4 - (24 x 16 x 2)

3,4

5

4 - (24 x 16 x 4)

4 - (24 x 16 x 2)

3,4

5

Optional Electric Heat

The factory-installed heaters are wired for single point power
supply. Power supply need only be brought into the single point
terminal block.

Table 10: Elec tric Heat Minimum Supply Air

Size

(Tons)

-A3
(3)

-A4
(4)

-A5
(5)

Model Voltage

208/230-3-60 960 960 1020 1000 - -

ZU

460-3-60 980 960 960 960 - ­600-3-60 - - 960 960 - -

208/230-3-60 - 1280 1420 1400 1400 -

ZU

460-3-60 - 1400 1400 1400 1400 ­600-3-60 - - 1400 1400 1400 -

208/230-3-60 - 1600 1600 1600 1600 1600

ZU

460-3-60 - 1600 1600 1600 1600 1600
600-3-60 - - 1600 1600 1600 1600

These CSA approved heaters are located within the central
compartment of the unit with the heater elements extending in
to the supply air chamber.

Fuses are supplied, where required, by the factory. Some kW
sizes require fuses and others do not. refer to Table 10 for
minimum CFM limitations and to Table 8 for electrical data.

Minimum Supply Air (CFM)

Heater kW

369152024

Johnson Controls Unitary Products 27

689670-BIM-A-0311

OPTIONAL
COIL
GUARD
SHOWN

OPTIONAL
COIL
GUARD
SHOWN

Optional Gas Heat

These gas-fired heaters have aluminized-steel or optional
stainless steel, tubular heat exchangers with spark ignition.

Gas Piping

Proper sizing of gas piping depends on the cubic feet per hour
of gas flow required, specific gravity of the gas and the length of
run. "National Fuel Gas Code" Z223.1 (in U.S.A.) or the current
Gas Installation Codes CSA-B149.1 (in Canada) should be
followed in all cases unless superseded by local codes or gas
utility requirements. Refer to the Pipe Sizing Table 11. The
heating value of the gas may differ with locality. The value
should be checked with the local gas utility.

Figure 23: Bottom Entry Gas Piping

Figure 22: Side Entry Gas Piping

Table 11: Gas Pipe Sizing - CapacIty of Pipe

Length of

Pipe (ft.)

10 278 520 1050
20 190 350 730
30 152 285 590
40 130 245 500
50 115 215 440
60 105 195 400
70 96 180 370
80 90 170 350
90 84 160 320

100 79 150 305

3/4 in. 1 in. 1-1/4 in.

Nominal Iron Pipe Size

NOTE: Maximum capacity of pipe in cubic feet of gas per hour

based upon a pressure drop of 0.3 inch W.C. and 0.6
specific gravity gas.

NOTE: There may be a local gas utility requirement specifying a

minimum diameter for gas piping. All units require a 3/4
inch pipe connection at the entrance fitting. Line should
not be sized smaller than the entrance fitting size.

28 Johnson Controls Unitary Products

Table 12: Gas Heat Minimum Supply Air

Size

(Tons)

-A3
(3)

-A4
(4)

-A5
(5)

Model Heat Size

ZU

ZU

ZU

Gas Connection

The gas supply line can be routed within the space and roof curb,
exiting through the unit’s basepan. Refer to Figures and 11 for
the gas piping inlet location. Typical supply piping arrangements
are shown in Figures 22 and 23. All pipe nipples, fittings, and the
gas cock are field supplied or may be purchased in UP accessory
kit #1GP0405.

Gas piping recommendations:

1. A drip leg and a ground joint union must be installed in the
gas piping.

2. Where required by local codes, a manual shut-off valve
must be installed outside of the unit.

3. Use wrought iron or steel pipe for all gas lines. Pipe dope
should be applied sparingly to male threads only.

Natural gas may contain some propane. Propane is an
excellent solvent and will quickly dissolve white lead and
most standard commercial compounds. A special pipe
dope must be used when assembling wrought iron or
steel pipe. Shellac based compounds such as Gaskolac
or Stalastic, and compounds such as Rectorseal #5,
Clydes’s or John Crane may be used.

4. All piping should be cleaned of dirt and scale by
hammering on the outside of the pipe and blowing out
loose particles. Before initial start-up, be sure that all gas
lines external to the unit have been purged of air.

5. The gas supply should be a separate line and installed in
accordance with all safety codes as prescribed under
“Limitations”.

6. A 1/8-inch NPT plugged tapping, accessible for test gage
connection, must be installed immediately upstream of the
gas supply connection to the unit.

7. After the gas connections have been completed, open the
main shut-off valve admitting normal gas pressure to the
mains. Check all joints for leaks with soap solution or other
material suitable for the purpose. NEVER USE A FLAME.

689670-BIM-A-0311

Supply Air (CFM)

Heating

Min Max

A06 / N06 890 2220
A08 / N08 915 2370

A11/ N11 1130 1800
A06 / N06 890 2220
A08 / N08 915 2370

A11/ N11 1290 2250
A08 / N08 915 2370
A11 / N11 1380 2570
A16 / N16 1580 2630

FIRE OR EXPLOSION HAZARD
Failure to follow the safety warning exactly could result

in serious injury, death or property damage.
Never test for gas leaks with an open flame. use a

commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage,
personal injury or loss of life.

The furnace and its individual shut-off valve must be
disconnected from the gas supply piping system during
any pressure testing at pressures in excess of 1/2 PSIG.

Pressures greater than 1/2 PSIG will cause gas valve
damage resulting in a hazardous condition. If it is
subjected to a pressure greater than 1/2 PSIG, the gas
valve must be replaced.

The furnace must be isolated from the gas supply piping
system by closing its individual manual shut-off valve
during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2 PSIG.

Threaded joints should be coated with a sealing
compound that is resistant to the action of liquefied
petroleum gases. Do not use Teflon tape.

LP Units, Tanks And Piping

All gas heat units are shipped from the factory equipped for
natural gas use only. The unit may be converted in the field for
use with LP gas with accessory kit model numbers 1NP0454 or
1NP0455.

All LP gas equipment must conform to the safety standards of
the National Fire Protection Association.

Johnson Controls Unitary Products 29

689670-BIM-A-0311

For satisfactory operation, LP gas pressure must be 10.5 inch
W.C. at the unit under full load. Maintaining proper gas
pressure depends on three main factors:

1. The vaporization rate which depends on the temperature of
the liquid and the “wetted surface” area of the container(s).

2. The proper pressure regulation. (Two-stage regulation is
recommended).

3. The pressure drop in the lines between regulators and
between the second stage regulator and the appliance.
Pipe size required will depend on the length of the pipe run
and the total load of all appliances.

Complete information regarding tank sizing for vaporization,
recommended regulator settings, and pipe sizing is available
from most regulator manufacturers and LP gas suppliers.

LP gas is an excellent solvent and will quickly dissolve
white lead and most standard commercial compounds. A
special pipe dope must be used when assembling
wrought iron or steel pipe for LP. Shellac base
compounds such as Gaskolac or Stalastic, and
compounds such as Rectorseal #5, Clyde’s, or John
Crane may be used.

Check all connections for leaks when piping is completed using
a soap solution. NEVER USE A FLAME.

electric heaters are fused and intended for use with single point
power supply.

Smoke Detectors

The use of duct smoke detectors have specific limitations
as established by the National Fire Protection
Association. Duct smoke detectors are; NOT a substitute
for an open area smoke detector, NOT a substitute for
early warning detection, and NOT a replacement for a
building's regular fire detection system. Refer to NFPA
Code 72 and Standard 90A for additional information.

The factory-installed smoke detector will shut down operation of
the unit by interrupting power to the UCB when smoke is
detected within its mounting compartment. The smoke detector
option is available for both supply and/or return air configura­tions. Be aware that the supply air configuration has the sensor
component mounted in the blower section, with its control mod­ule mounted in the return air compartment.

Factory-installed smoke detectors may be subjected to
extreme temperatures during "off" times due to outside air
infiltration. These smoke detectors have an operational
limit of -4°F to 158°F. Smoke detectors installed in areas
that could be outside this range will have to be relocated to
prevent false alarms.

FIRE OR EXPLOSION HAZARD
Failure to follow the safety warning exactly could result

in serious injury, death or property damage.
Never test for gas leaks with an open flame. use a

commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage,
personal injury or loss of life.

Vent And Combustion Air

Venting slots in the heating compartment access panel remove
the need for a combustion air hood. The gas heat flue exhaust
is routed through factory installed exhaust piping with screen. If
necessary, a flue exhaust extension may be installed at the
point of installation.

Options/Accessories

Electric Heat

Electric heaters are available as factory-installed options or
field-installed accessories. Refer to electric heat instructions for
installation. These heaters mount in the heat compartment with
the heating elements extending into the supply air chamber. All

To assure adequate airflow reaches the smoke detector's
sensor, make sure that the holes of the sampling tube
face into the air stream, and that the far-end of the
sampling tube is sealed with the plastic end cap.

In addition, the unit's supply airflow must be adjusted to
provide a pressure differential across the smoke
detector's sampling and exhaust ports of at least 0.01
inches of water and no more than 1.11 inches of water, as
measured by a manometer.

The detector must be tested and maintained on a regular basis
according to NFPA 72 requirements and cleaned at least once
a year. For specific troubleshooting and maintenance
procedures, please refer to the smoke detector's installation
instructions which accompanies the unit.

Motorized Outdoor Damper

The Motorized Outdoor Damper can be a factory installed
option or a field installed accessory. If factory installed, refer to
the instructions included with the outdoor air hood to complete

30 Johnson Controls Unitary Products

689670-BIM-A-0311

the assembly. Field installed Motorized Outdoor Damper
accessories include complete instructions for installation.

Economizer

The Economizer can be a factory installed option or a field
installed accessory. If factory installed, refer to the instructions
included with the outdoor air hood to complete the assembly.
Field installed Economizer accessories include complete
instructions for installation.

There are two Economizer options:

1. Down Flow application with barometric relief hood standard.

2. Horizontal Flow application that requires the purchase of a
barometric relief hood.

Power Exhaust

The Power Exhaust can be a factory installed option or a field
installed accessory. If factory installed, refer to the instructions
included with the outdoor air hood to complete the assembly.
Field installed Power Exhaust accessories include complete
instructions for installation.

The Power Exhaust factory installed option is for Down Flow
application only.

There are two field installed Power Exhaust accessories:

1. Down Flow application.

2. Horizontal Flow application that requires the purchase of a
barometric relief hood.

Rain Hood

All of the hood components, including the filters, the gasketing
and the hardware for assembling, are packaged and located
between the condenser coil section and the main unit cabinet, if
the unit has factory installed options. If field installed
accessories are being installed all parts necessary for the
installation comes in the accessory.

Standard Economizer and Power Exhaust Set Point Adjustments

(Not applicable to INTELLI-Comfort™ or BAS Units)
Remove the top rear access panel from the unit. Locate the

economizer control module, where the following adjustments
will be made.

Extreme care must be exercised in turning all set point,
maximum and minimum damper positioning adjustment
screws to prevent twisting them off.

Minimum Position Adjustment

• Check that the damper blades move smoothly without
binding; carefully turn the Minimum Position Adjust screw

(found on the damper control module) fully clockwise and
then set the thermostat indoor fan switch to the ON
position and then OFF or energize and de-energize
terminals “R” to “G”.

• With the thermostat set to the indoor fan ON position or
terminals “R” to “G” energized, turn the Minimum Position
Adjusting screw (located on the damper control module)
counterclockwise until the desired minimum damper
position has been attained.

Enthalpy Set Point Adjustment

• The enthalpy set point may now be set by selecting the
desired set point shown in the Enthalpy Set Point
Adjustment Figure 24. Adjust as follows:

• For a single enthalpy operation carefully turn the set point
adjusting screw (found on the damper control module) to
the "A", "B", "C" or "D" setting corresponding to the lettered
curve of the Enthalpy Set Point Adjustment Figure 25.

• For a dual enthalpy operation, carefully turn the set point
adjusting screw fully clockwise past the "D" setting.

Power Exhaust Damper Set Point (With Or Without Power
Exhaust)

• With no power exhaust option, adjust the Exhaust Air
Adjustment Screw fully clockwise. This will allow 2nd
stage cooling to operate.

• With power exhaust option, each building pres surization
requirement will be different. The point at which the power
exhaust comes on is determined by the economizer
damper position (Percent Open). The Exhaust Air
Adjustment Screw should be set at the Percent Open of
the economizer damper at which the power exhaust is
needed. It can be set from 0 to 100% damper open.

Indoor Air Quality AQ

Indoor Air Quality (indoor sensor input): Terminal AQ accepts a
+2 to +10 Vdc signal with respect to the (AQ1) terminal. When
the signal is below it's set point, the actuator is allowed to
modulate normally in accordance with the enthalpy and mixed
air sensor inputs. When the AQ signal exceeds it's set point
setting and there is no call for free cooling, the actuator is
proportionately modulated from the 2 to 10 Vdc signal, with 2
Vdc corresponding to full closed and 10 Vdc corresponding to
full open. When there is no call for free cooling, the damper
position is limited by the IAQ Max damper position setting.
When the signal exceeds it's set point (Demand Control
Ventilation Set Point) setting and there is a call for free cooling,
the actuator modulates from the minimum position to the full
open position based on the highest call from either the mixed
air sensor input or the AQ voltage input.

• Optional CO

• Optional CO

Space Sensor Kit Part # 2AQ04700324

2

Sensor Kit Part # 2AQ04700424

2

Replace the top rear access panel on the unit.

Johnson Controls Unitary Products 31

689670-BIM-A-0311

HIGH LIMIT CURVE W7212

N1

N

P1

P

EXH

Set

EXH

Min
Pos

IAQ

Max

IAQ

IAQ
Min

Free
Cool

T

T1

AQ1 AQ

SO+ SO

SR+

SR

A

BC

D

TR TR1

24

Vac

HOT

24

Vac

COM

EF EF1

2

3

4

5

1

+

Exhaust Air
Adjustment

Screw

Exhaust Air LED

Damper Min.

Position

Screw

Indoor Air Quality

Max. Adjustment

Screw

Indoor Air Quality

LED

Indoor Air Quality

Min. Adjustment

Screw

Free Cooling LED

Economizer Enthalpy
Set Point Adjustment

Screw

Figure 24: Enthalpy Set Point Chart

Figure 25: Honeywell Economizer Control W7212
Phasing

ZU units are properly phased at the factory. Check for proper
compressor rotation. If the blower or compressors rotate in the
wrong direction at start-up, the electrical connection to the unit
is misphased. Change the phasing of the Field Line

32 Johnson Controls Unitary Products

Connection at the factory or field supplied disconnect to
obtain proper rotation. (Scroll compressors operate in only one
direction. If the scroll is drawing low amperage, has similar
suction and discharge pressures, or producing a high noise
level, the scroll is misphased.)

689670-BIM-A-0311

A

A

A

B

SPAN LENGTH

DEFL. FORCE

C*

* NEVER LOOSEN

Scroll compressors require proper rotation to operate
correctly. Units are properly phased at the factory. Do
not change the internal wiring to make the blower
condenser fans, or compressor rotate correctly.

Blower Rotation

Check for proper supply air blower rotation. If the blower is
rotating backwards, the line voltage at the unit point of power
connection is misphased (See ‘PHASING’).

Table 13: Supply Air Limitations

Unit Size (Ton) Minimum Maximum

-A3 (3.0) 900 1500

-A4 (4.0) 1200 2000

-A5 (5.0) 1500 2500

Belt Tension

The tension on the belt should be adjusted as shown in Figure 26.

Procedure for adjusting belt tension:

1. Loosen six nuts (top and bottom) A.

2. Adjust by turning (B).

3. Never loosen nuts (C).

4. Use belt tension checker to apply a perpendicular

force to one belt at the midpoint of the span as
shown. Deflection distance of 4mm (5/32”) is

obtained.
To determine the deflection distance from normal
position, use a straight edge from sheave to sheave as

reference line. The recommended deflection force is as
follows:

Tension new belts at the max. deflection force
recommended for the belt section. Check the belt
tension at least two times during the first 24 hours of
operation. Any retensioning should fall between the min.
and max. deflection force values.

5. After adjusting retighten nuts (A).

CFM Static Pressure and Power-Altitude and Temperature
Corrections

The information below should be used to assist in application of
product when being applied at altitudes at or exceeding 1000
feet above sea level.

The air flow rates listed in the standard blower performance
tables are based on standard air at sea level. As the alti tude or
temperature increases, the density of air decreases. In order to
use the indoor blower tables for high altitude applications,
certain corrections are necessary.

A centrifugal fan is a "constant volume" device. This means
that, if the rpm remains constant, the CFM delivered is the
same regardless of the density of the air. However, since the air
at high altitude is less dense, less static pressure will be
generated and less power will be required than a similar
application at sea level. Air density correction factors are shown
in Table 14 and Figure 27.

Figure 26: Belt Adjustment

Johnson Controls Unitary Products 33

689670-BIM-A-0311

0.600

0.650

0.700

0.750

0.800

0.850

0.900

0.950

1.000

1.050

1.100

40 50 60 70 80 90 100

Air Temperature (ºF)

Correction Factor

Sea Level

1000 ft

2000 ft

3000 ft

4000 ft

6000 ft
7000 ft

8000 ft

9000 ft

10000 ft

5000 ft

Table 14: Altitude/Temperature Correction Factors

Air

Temp.

40 1.060 1.022 0.986 0.950 0.916 0.882 0.849 0.818 0.788 0.758 0.729
50 1.039 1.002 0.966 0.931 0.898 0.864 0.832 0.802 0.772 0.743 0.715
60 1.019 0.982 0.948 0.913 0.880 0.848 0.816 0.787 0.757 0.729 0.701
70 1.000 0.964 0.930 0.896 0.864 0.832 0.801 0.772 0.743 0.715 0.688
80 0.982 0.947 0.913 0.880 0.848 0.817 0.787 0.758 0.730 0.702 0.676
90 0.964 0.929 0.897 0.864 0.833 0.802 0.772 0.744 0.716 0.689 0.663

100 0.946 0.912 0.880 0.848 0.817 0.787 0.758 0.730 0.703 0.676 0.651

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Altitude (Ft.)

Figure 27: Altitude/Temperature Correction Factors

The examples below will assist in determining the airflow
performance of the product at altitude.

Example 1: What are the corrected CFM, static pressure, and
BHP at an elevation of 5,000 ft. if the blower performance data
is 6,000 CFM, 1.5 IWC and 4.0 BHP?

Solution: At an elevation of 5,000 ft. the indoor blower will still
deliver 6,000 CFM if the rpm is unchanged. However, Table 13
must be used to determine the static pressure and BHP. Since
no temperature data is given, we will assume an air temperature
of 70°F. Table 15 shows the correction factor to be 0.832.

Corrected static pressure = 1.5 x 0.832 = 1.248 IWC
Corrected BHP = 4.0 x 0.832 = 3.328

Example 2: A system, located at 5,000 feet of elevation, is to
deliver 6,000 CFM at a static pressure of 1.5". Use the unit

34 Johnson Controls Unitary Products

blower tables to select the blower speed and the BHP
requirement.

Solution: As in the example above, no temperature
information is given so 70°F is assumed.

The 1.5" static pressure given is at an elevation of 5,000 ft. The
first step is to convert this static pressure to equivalent sea level
conditions.

Sea level static pressure = 1.5 / .832 = 1.80"

Enter the blower table at 6000 sCFM and static pressure of

1.8". The rpm listed will be the same rpm needed at 5,000 ft.
Suppose that the corresponding BHP listed in the table is 3.2.

This value must be corrected for elevation.

BHP at 5,000 ft. = 3.2 x .832 = 2.66

689670-BIM-A-0311

Drive Selection

1. Determine side or bottom supply duct Application.

2. Determine desired airflow.

3. Calculate or measure the amount of external static pressure.

4. Using the operating point determined from steps 1, 2 & 3, locate this point on the appropriate supply air blower performance
table. (Linear interpolation may be necessary.)

5. Noting the RPM and BHP from step 4, locate the appropriate motor and, or drive.

6. Review the BHP compared to the motor options available. Select the appropriate motor and, or drive.

7. Review the RPM range for the motor options available. Select the appropriate drive if multiple drives are available for the
chosen motor.

8. Determine turns open to obtain the desired operation point.

Example

1. 2400 CFM

2. 1.6 IWC

3. Using the supply air blower performance table below, the following data point was located: 1230 RPM & 1.62 BHP.

4. Using the RPM selection table below, Size X and Model Y is found.

5. 1.62 BHP exceeds the maximum continuous BHP rating of the 1.5 HP motor. The 2 HP motor is required.

6. 1230 RPM is within the range of the 2 HP drives.

7. Using the 2 HP motor and drive, .5 turns open will achieve 1230 RPM.

Airflow Performance

Example Supply Air Blower Performance

Air Flow

(CFM)

2100 759 0.65 819 0.77 881 0.87 943 0.98 1005 1.08 1065 1.18 1121 1.28 1172 1.38 1217 1.48 1254 1.59
2200 778 0.73 838 0.84 900 1.95 962 1.05 1024 1.15 1083 1.25 1139 1.35 1191 1.45 1236 1.56 1273 1.66
2300 797 0.81 857 0.92 919 1.03 981 1.13 1043 1.23 1103 1.33 1159 1.43 1210 1.53 1255 1.64 1292 1.74
2400 817 1.90 877 1.01 939 1.12 1002 1.22 1063 1.32 1123 1.42 1179 1.52 1230 1.62 1275 1.73 1312 1.83

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

1.5 HP & Field Supplied Drive Standard 1.5 HP & Drive Hi Static 2 HP & Drive

Table X: RPM Selection

Size

(Tons)

XY

Model HP

Max

BHP

1.5 1.73 1VL40 AK61 N/A 787 847 908 968 1029 1089
2 2.30 1VP56 AK74 N/A 1035 1084 1134 1183 1232 1281

Motor

Sheave

Available External Static Pressure - IWG

Blower

Sheave

6 Turns

Open

5 Turns

Open

4 Turns

Open

3 Turns

Open

2 Turns

Open

1 Turn

Open

Fully

Closed

Johnson Controls Unitary Products 35

689670-BIM-A-0311

Table 15: A irflow Performance - Side Duct Application
ZU-A3 (3.0 Ton) Side Duct

Air Flow

(CFM)

900 560 0.29 628 0.35 695 0.42 760 0.51 823 0.61 886 0.72 949 0.82 1011 0.92 1073 1.01 1136 1.09
1000 582 0.29 650 0.34 716 0.42 781 0.51 845 0.61 908 0.71 970 0.82 1032 0.92 1095 1.01 1158 1.08
1100 601 0.30 670 0.35 736 0.43 801 0.52 864 0.62 927 0.72 990 0.83 1052 0.93 1114 1.02 1177 1.09
1200 620 0.32 688 0.37 754 0.45 819 0.54 883 0.64 946 0.74 1008 0.85 1070 0.95 1133 1.04 1196 1.11
1300 638 0.35 706 0.40 772 0.48 837 0.57 901 0.67 964 0.77 1026 0.88 1088 0.98 1151 1.06 1214 1.14
1400 655 0.39 724 0.44 790 0.51 855 0.60 918 0.70 981 0.81 1044 0.91 1106 1.01 1168 1.10 1231 1.18
1500 673 0.43 741 0.48 807 0.56 872 0.65 936 0.75 999 0.85 1061 0.96 1124 1.06 1186 1.15 1249 1.22

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

Standard 1.5 HP & Drive Hi Static 1.5 HP & Drive

Available External Static Pressure - IWG

1. Blower performance includes gas heat exchangers and 2” filters. See STATIC RESISTANCE table for additional applications.

2. See RPM SELECTION table to determine desired motor sheave setting and to determine the maximum continuous BHP.

3. kW = BHP x 0.932.

1

1.5 HP & Field Supplied Drive

ZU-A4 (4.0 Ton) Side Duct

Air Flow

(CFM)

1200 620 0.32 688 0.37 754 0.45 819 0.54 883 0.64 946 0.74 1008 0.85 1070 0.95 1133 1.04 1196 1.11
1300 638 0.35 706 0.40 772 0.48 837 0.57 901 0.67 964 0.77 1026 0.88 1088 0.98 1151 1.06 1214 1.14
1400 655 0.39 724 0.44 790 0.51 855 0.60 918 0.70 981 0.81 1044 0.91 1106 1.01 1168 1.10 1231 1.18
1500 673 0.43 741 0.48 807 0.56 872 0.65 936 0.75 999 0.85 1061 0.96 1124 1.06 1186 1.15 1249 1.22
1600 691 0.48 759 0.54 825 0.61 890 0.70 954 0.80 1017 0.90 1079 1.01 1141 1.11 1204 1.20 1267 1.27
1700 709 0.54 777 0.59 843 0.67 908 0.76 972 0.86 1035 0.96 1097 1.07 1160 1.17 1222 1.26 1285 1.33
1800 728 0.60 796 0.66 862 0.73 927 0.82 991 0.92 1053 1.03 1116 1.13 1178 1.23 1241 1.32 1303 1.39
1900 747 0.67 815 0.73 881 0.80 946 0.89 1010 0.99 1073 1.09 1135 1.20 1197 1.30 1260 1.39 1323 1.46
2000 766 0.75 834 0.80 901 0.87 966 0.96 1029 1.06 1092 1.17 1155 1.27 1217 1.37 1279 1.46 - -

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

4

FS

Standard 1.5 HP & Drive Hi Static 1.5 HP & Drive

Available External Static Pressure - IWG

1

1. Blower performance includes gas heat exchangers and 2” filters. See STATIC RESISTANCE table for additional applications.

2. See RPM SELECTION table to determine desired motor sheave setting and to determine the maximum continuous BHP.

3. kW = BHP x 0.932.

4. Field Supplied Drive.

ZU-A5 (5.0 Ton) Side Duct

Air Flow

(CFM)

1500 659 0.35 719 0.46 780 0.57 843 0.67 905 0.77 964 0.87 1020 0.97 1071 1.07 1116 1.17 1154 1.28
1600 675 0.38 735 0.50 796 0.60 859 0.71 920 0.81 980 0.91 1036 1.01 1087 1.11 1132 1.21 1170 1.32
1700 691 0.42 751 0.54 812 0.64 875 0.75 936 0.85 996 0.95 1052 1.05 1103 1.15 1148 1.25 1186 1.36
1800 707 0.47 767 0.58 829 0.69 891 0.79 953 0.90 1012 0.99 1069 1.09 1120 1.20 1165 1.30 1202 1.41
1900 724 0.53 784 0.64 846 0.75 908 0.85 970 0.95 1029 1.05 1085 1.15 1137 1.25 1182 1.35 1219 1.46
2000 741 0.59 801 0.70 863 0.81 925 0.91 987 1.01 1047 1.11 1103 1.21 1154 1.31 1199 1.41 1236 1.52
2100 759 0.65 819 0.77 881 0.87 943 0.98 1005 1.08 1065 1.18 1121 1.28 1172 1.38 1217 1.48 1254 1.59
2200 778 0.73 838 0.84 900 0.95 962 1.05 1024 1.15 1083 1.25 1139 1.35 1191 1.45 1236 1.56 1273 1.66
2300 797 0.81 857 0.92 919 1.03 981 1.13 1043 1.23 1103 1.33 1159 1.43 1210 1.53 1255 1.64 1292 1.74
2400 817 0.90 877 1.01 939 1.12 1002 1.22 1063 1.32 1123 1.42 1179 1.52 1230 1.62 1275 1.73 1312 1.83
2500 838 1.00 898 1.11 960 1.22 1022 1.32 1084 1.42 1144 1.52 1200 1.62 1251 1.72 1296 1.82 1333 1.93

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

1.5 HP & Field Supplied Drive Standard 1.5 HP & Drive Hi Static 2 HP & Drive

Available External Static Pressure - IWG

1. Blower performance includes gas heat exchangers and 2” filters. See STATIC RESISTANCE table for additional applications.

2. See RPM SELECTION table to determine desired motor sheave setting and to determine the maximum continuous BHP.

3. kW = BHP x 0.932.

4. Field Supplied Drive.

1

4

FS

36 Johnson Controls Unitary Products

689670-BIM-A-0311

Table 16: A irflow Performance - Bottom Duct Application
ZU-A3 (3.0 Ton) Bottom Duct

Air Flow

(CFM)

900 605 0.23 671 0.33 738 0.42 804 0.52 869 0.62 933 0.71 995 0.80 1054 0.89 1111 0.98 1164 1.07
1000 621 0.25 688 0.34 754 0.44 820 0.53 885 0.63 949 0.72 1011 0.82 1071 0.91 1127 1.00 1180 1.09
1100 637 0.27 703 0.36 769 0.46 835 0.56 900 0.65 964 0.74 1026 0.84 1086 0.93 1142 1.02 1195 1.11
1200 651 0.30 717 0.39 784 0.49 850 0.58 915 0.68 979 0.77 1041 0.87 1100 0.96 1157 1.05 1210 1.13
1300 666 0.33 732 0.43 799 0.52 865 0.62 930 0.71 994 0.81 1056 0.90 1115 0.99 1172 1.08 1225 1.17
1400 681 0.37 747 0.47 814 0.56 880 0.66 945 0.75 1009 0.85 1071 0.94 1130 1.03 1187 1.12 1240 1.21
1500 697 0.42 763 0.51 830 0.61 896 0.71 961 0.80 1025 0.90 1087 0.99 1146 1.08 1203 1.17 1256 1.26

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

Standard 1.5 HP & Drive Hi Static 1.5 HP & Drive

Available External Static Pressure - IWG

1. Blower performance includes gas heat exchangers and 2” filters. See STATIC RESISTANCE table for additional applications.

2. See RPM SELECTION table to determine desired motor sheave setting and to determine the maximum continuous BHP.

3. kW = BHP x 0.932.

1

1.5 HP & Field Supplied Drive

ZU-A4 (4.0 Ton) Bottom Duct

Air Flow

(CFM)

1200 651 0.30 717 0.39 784 0.49 850 0.58 915 0.68 979 0.77 1041 0.87 1100 0.96 1157 1.05 1210 1.13
1300 666 0.33 732 0.43 799 0.52 865 0.62 930 0.71 994 0.81 1056 0.90 1115 0.99 1172 1.08 1225 1.17
1400 681 0.37 747 0.47 814 0.56 880 0.66 945 0.75 1009 0.85 1071 0.94 1130 1.03 1187 1.12 1240 1.21
1500 697 0.42 763 0.51 830 0.61 896 0.71 961 0.80 1025 0.90 1087 0.99 1146 1.08 1203 1.17 1256 1.26
1600 714 0.47 780 0.57 846 0.66 913 0.76 978 0.86 1042 0.95 1103 1.04 1163 1.14 1220 1.22 1273 1.31
1700 732 0.53 798 0.63 864 0.73 930 0.82 996 0.92 1059 1.01 1121 1.10 1181 1.20 1237 1.29 1291 1.37
1800 751 0.60 817 0.70 883 0.79 950 0.89 1015 0.98 1079 1.08 1140 1.17 1200 1.26 1257 1.35 1310 1.44
1900 771 0.68 837 0.77 904 0.87 970 0.96 1035 1.06 1099 1.15 1161 1.25 1220 1.34 1277 1.43 - ­2000 793 0.75 859 0.85 925 0.95 991 1.04 1056 1.14 1120 1.23 1182 1.32 1242 1.42 1298 1.51 - -

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

4

FS

Standard 1.5 HP & Drive Hi Static 1.5 HP & Drive

Available External Static Pressure - IWG

1

1. Blower performance includes gas heat exchangers and 2” filters. See STATIC RESISTANCE table for additional applications.

2. See RPM SELECTION table to determine desired motor sheave setting and to determine the maximum continuous BHP.

3. kW = BHP x 0.932.

4. Field Supplied Drive.

ZU-A5 (5.0 Ton) Bottom Duct

Air Flow

(CFM)

1500 673 0.47 736 0.54 797 0.63 855 0.72 910 0.82 964 0.92 1016 1.03 1067 1.14 1117 1.25 1166 1.36
1600 693 0.49 756 0.57 817 0.65 874 0.75 930 0.85 984 0.95 1036 1.06 1087 1.17 1137 1.28 1186 1.39
1700 713 0.53 777 0.60 837 0.69 895 0.78 951 0.88 1004 0.98 1057 1.09 1107 1.20 1157 1.31 1207 1.42
1800 734 0.57 797 0.65 858 0.73 916 0.83 971 0.92 1025 1.03 1077 1.14 1128 1.25 1178 1.36 1228 1.47
1900 755 0.62 819 0.70 879 0.79 937 0.88 992 0.98 1046 1.08 1098 1.19 1149 1.30 1199 1.41 1249 1.52
2000 776 0.69 840 0.76 900 0.85 958 0.94 1014 1.04 1067 1.14 1120 1.25 1171 1.36 1221 1.47 1270 1.59
2100 798 0.76 861 0.84 921 0.92 979 1.02 1035 1.11 1089 1.22 1141 1.32 1192 1.44 1242 1.55 1291 1.66
2200 819 0.84 882 0.92 943 1.00 1001 1.10 1056 1.20 1110 1.30 1162 1.41 1213 1.52 1263 1.63 1312 1.74
2300 840 0.93 903 1.01 964 1.10 1022 1.19 1077 1.29 1131 1.39 1183 1.50 1234 1.61 1284 1.72 1334 1.83
2400 861 1.03 925 1.11 985 1.20 1043 1.29 1099 1.39 1152 1.49 1204 1.60 1255 1.71 1305 1.82 1355 1.93
2500 882 1.14 946 1.22 1006 1.30 1064 1.40 1120 1.50 1173 1.60 1226 1.71 1276 1.82 1326 1.93 1376 2.04

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

1.5 HP & Field Supplied Drive Standard 1.5 HP & Drive Hi Static 2 HP & Drive

Available External Static Pressure - IWG

1. Blower performance includes gas heat exchangers and 2” filters. See STATIC RESISTANCE table for additional applications.

2. See RPM SELECTION table to determine desired motor sheave setting and to determine the maximum continuous BHP.

3. kW = BHP x 0.932.

1

3 HP & Field Supplied Drive

Johnson Controls Unitary Products 37

689670-BIM-A-0311

Table 17: RPM Selection

Size

(Tons)

-A3
(3)

-A4
(4)

-A5
(5)

Model HP

ZU

ZU

ZU

1.5 1.5 1VM34 AK69 N/A 531 584 637 690 743 796

1.5 1.5 1VL44 AK69 N/A 796 849 902 955 1008 1062

1.5 1.5 1VM34 AK56 N/A 663 730 796 863 929 995

1.5 1.5 1VL44 AK56 N/A 995 1062 1128 1194 1261 1327

1.5 1.5 1VL40 AK61 N/A 787 847 908 968 1029 1089

Max

BHP

2 2 1VP56 AK74 N/A 1035 1084 1134 1183 1232 1281

Motor

Sheave

Blower

Sheave

6 Turns

Open

5 Turns

Open

4 Turns

Open

3 Turns

Open

2 Turns

Open

1 Turn

Open

Table 18: Indoor Blower Specifications

Size

(Tons)

-A3
(3)

-A4
(4)

-A5
(5)

Model

ZU

ZU

ZU

HP RPM Eff. SF Frame

1-1/2 1725 0.8 1.15 56 2.0 - 3.0 7/8 1VM34 6.5 1 AK69 A47
1-1/2 1725 0.8 1.15 56 3.0 - 4.0 7/8 1VL44 6.5 1 AK69 A47
1-1/2 1725 0.8 1.15 56 2.0 - 3.0 7/8 1VM34 5.2 1 AK56 A47
1-1/2 1725 0.8 1.15 56 3.0 - 4.0 7/8 1VL44 5.2 1 AK56 A47
1-1/2 1725 0.8 1.15 56 2.6 - 3.6 7/8 1VL40 5.7 1 AK61 A47

2 1725 0.8 1.15 56 4.2 - 5.2 7/8 1VP56 7.0 1 AK74 A51

Motor Motor Sheave Blower Sheave

Datum Dia.

(in.)

Bore (in.) Model

Datum Dia.

(in.)

Bore (in.) Model

Table 19: Power Exhaust Specifications

Model Voltage

2PE04703225 208/230-1-60 3/4 1075 1 7.8 5 6.3 10 3800
2PE04703246 460-1-60 3/4 1075 1 3.4 2.2 2.8 5 3800
2PE04703258 575-1-60 3/4 1050 1 2.9 1.5 1.9 4 3800

1. Motors are multi-tapped and factory wired for high speed.

HP RPM

Motor Motor

1

QTY LRA FLA MCA

Fuse Size

CFM @

0.1 ESP

Fully

Closed

Belt

Air Balance

Start the supply air blower motor. Adjust the resistances in both
the supply and the return air duct systems to balance the air
distribution throughout the conditioned space. The job
specifications may require that this balancing be done by
someone other than the equipment installer.

Belt drive blower systems MUST be adjusted to the
specific static and CFM requirements for the application.
The Belt drive blowers are NOT

set at the factory for any
specific static or CFM. Adjustments of the blower speed
and belt tension are REQUIRED

. Verify proper sheave
alignment; tighten blower pulley and motor sheave set
screws after these adjustments. Re-checking set screws
after 10-12 hrs. run time is recommended.

Checking Air Quantity

Method One

1. Remove the dot plugs from the duct panel (for location of
the dot plugs see Figures 12 and 13).

2. Insert eight-inches of 1/4 inch metal tubing into the airflow
on both sides of the indoor coil.

NOTE: The tubes must be inserted and held in a position

perpendicular to the air flow so that velocity pressure
will not affect the static pressure readings.

3. Use an Inclined Manometer or Magnehelic to determine
the pressure drop across a dry evaporator coil. Since the
moisture on an evaporator coil can vary greatly, measuring
the pressure drop across a wet coil under field conditions
could be inaccurate. To assure a dry coil, the compressors
should be de-activated while the test is being run.

NOTE: De-energize the compressors before taking any test

measurements to assure a dry evaporator coil.

4. The CFM through the unit can be determined from the
pressure drop indicated by the manometer by referring to
Figure 28. In order to obtain an accurate measurement, be
certain that the air filters are clean.

5. To adjust Measured CFM to Required CFM, see.

6. After readings have been obtained, remove the tubes and
replace the dot plugs.

7. Tighten blower pulley and motor sheave set screws after
any adjustments. Re-check set screws after 10-12 hrs. run
time is recommended.

38 Johnson Controls Unitary Products

Failure to properly adjust the total system air quantity

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

500 1000 1500 2000 2500 3000

Dry

C

oil

D

elta P (iwg)

Airflow (CFM)

ZU-A3
ZU-A4

ZU-A5

can result in extensive blower damage.

Method Two

1. Drill two 5/16 inch holes, one in the return air duct as close
to the inlet of the unit as possible, and another in the supply
air duct as close to the outlet of the unit as possible.

2. Using the whole drilled in step 1, insert eight inches of 1/4
inch metal tubing into the airflow of the return and supply
air ducts of the unit.

NOTE: The tubes must be inserted and held in position

perpendicular to the airflow so that velocity pressure
will not affect the static pressure readings.

3. Use an Inclined Manometer or Magnehelic to determine
the pressure drop across the unit. This is the External
Static Pressure (ESP). In order to obtain an accurate
measurement, be certain that the air filters are clean.

4. Determine the number of turns the variable motor sheave
is open.

689670-BIM-A-0311

5. Select the correct blower performance table for the unit
from Tables 15 and 16. Tables are presented for side and
downflow configuration.

6. Determine the unit Measured CFM from the Blower
Performance Table, External Static Pressure and the
number of turns the variable motor sheave is open.

7. To adjust Measured CFM to Required CFM, see SUPPLY
AIR DRIVE ADJUSTMENT.

8. After reading has been obtained, remove the tubes and
seal holes.

9. Tighten blower pulley and motor sheave set screws after
any adjustments. Re-check set screws after 10-12 hrs. run
time is recommended.

NOTE: With the addition of field installed accessories repeat

this procedure.

Failure to properly adjust the total system air quantity
can result in extensive blower damage.

Figure 28: Dry Coil Delta P

Johnson Controls Unitary Products 39

689670-BIM-A-0311

Supply Air Drive Adjustment

Before making any blower speed changes review the
installation for any installation errors, leaks or undesirable
systems effects that can result in loss of airflow.

Even small changes in blower speed can result in
substantial changes in static pressure and BHP. BHP
and AMP draw of the blower motor will increase by the
cube of the blower speed. Static pressure will increase
by the square of the blower speed. Only qualified
personnel should make blower speed changes, strictly
adhering to the fan laws.

At unit start-up, the measured CFM may be higher or lower than
the required CFM. To achieve the required CFM, the speed of
the drive may have adjusted by changing the datum diameter
(DD) of the variable pitch motor sheave as described below:

Use the following tables and the DD calculated per the above
equation to adjust the motor variable pitch sheave.

EXAMPLE
A 12.5 ton unit was selected to deliver 4,000 CFM with a 3 HP

motor, but the unit is delivering 3,800 CFM. The variable pitch
motor sheave is set at 2 turns open.

Use the equation to determine the required DD for the new
motor sheave,

Use Table 20 to locate the DD nearest to 4.21 in. Close the
sheave to 1 turn open.

New BHP

3

= (Speed increase)
= (Speed increase)

• BHP at 3,800 CFM

3

• Original BHP
= New BHP
New motor Amps
= (Speed increase)
= (Speed increase)

3

• Amps at 3,800 CFM

3

• Original Amps
= New Amps

Table 20: Mo tor Sheave Datum Diameters

1VM34x7/8

(1-1/2 HP Motor)

Turns Open Datum Diameter Turns Open Datum Diameter Turns Open Datum Diameter Turns Open Datum Diameter

03.004.003.605.2

1/22.91/23.91/23.51/25.1

12.813.813.41 5

1-1/2 2.7 1-1/2 3.7 1-1/2 3.3 1-1/2 4.9

22.623.623.224.8

2-1/2 2.3 2-1/2 3.5 2-1/2 3.1 2-1/2 4.7

32.433.433.034.6

3-1/2 2.3 3-1/2 3.3 3-1/2 2.9 3-1/2 4.5

42.243.242.844.4

4-1/2 2.1 4-1/2 3.1 4-1/2 2.7 4-1/2 4.3

52.053.052.654.2

1VL44x7/8

(1-1/2 HP Motor)

1VL40x7/8

(1-1/2 HP Motor)

1VP56x7/8

(2 HP Motor)

Belt drive blower systems MUST be adjusted to the
specific static and CFM requirements for the application.
The Belt drive blowers are NOT set at the factory for any
specific static or CFM. Adjustments of the blower speed
and belt tension are REQUIRED

. Verify proper sheave
alignment; tighten blower pulley and motor sheave set
screws after these adjustments. Re-checking set screws
after 10-12 hrs. run time is recommended.

40 Johnson Controls Unitary Products

689670-BIM-A-0311

Table 21: A dd ition al Static Resis t ance

Size

(Tons)

-A3 (3)

-A4 (4)

-A5 (5) ZU

Model CFM Cooling Only

ZU

1

Economizer

900 0.05 -0.05 0.01 0.00 0.00 0.00 0.01 0.01 0.01
1000 0.05 -0.03 0.02 0.00 0.00 0.00 0.02 0.02 0.02
1100 0.04 -0.02 0.03 0.01 0.01 0.01 0.02 0.02 0.02
1200 0.04 0.00 0.04 0.01 0.01 0.01 0.02 0.02 0.02
1300 0.03 0.01 0.05 0.01 0.01 0.01 0.03 0.03 0.03
1400 0.03 0.03 0.07 0.02 0.02 0.02 0.03 0.03 0.03
1500 0.03 0.04 0.08 0.02 0.02 0.02 0.04 0.04 0.04
1600 0.02 0.06 0.09 0.02 0.02 0.02 0.04 0.04 0.04
1700 0.02 0.07 0.10 0.03 0.03 0.03 0.05 0.05 0.05
1800 0.01 0.08 0.11 0.03 0.03 0.03 0.05 0.05 0.05
1900 0.01 0.10 0.13 0.04 0.04 0.04 0.06 0.06 0.06
2000 0.00 0.11 0.14 0.04 0.04 0.04 0.07 0.07 0.07
1500 -0.01 0.13 0.07 0.02 0.02 0.02 0.04 0.04 0.04
1600 -0.01 0.14 0.08 0.02 0.02 0.02 0.04 0.04 0.04
1700 -0.01 0.15 0.08 0.03 0.03 0.03 0.05 0.05 0.05
1800 -0.02 0.16 0.09 0.03 0.03 0.03 0.05 0.05 0.05
1900 -0.02 0.17 0.10 0.04 0.04 0.04 0.06 0.06 0.06
2000 -0.02 0.18 0.10 0.04 0.04 0.04 0.07 0.07 0.07
2100 -0.03 0.19 0.11 0.05 0.05 0.05 0.07 0.07 0.07
2200 -0.03 0.20 0.12 0.06 0.06 0.06 0.08 0.08 0.08
2300 -0.04 0.21 0.12 0.06 0.06 0.06 0.09 0.09 0.09
2400 -0.04 0.22 0.13 0.07 0.07 0.07 0.10 0.10 0.10
2500 -0.05 0.23 0.14 0.08 0.08 0.08 0.11 0.11 0.11

2 3

4” Pleated Filter

2

3 6 9 15 20 24

Electric Heat kW

1. Add these values to the available static resistance in the respective Blower Performance Tables.

2. Deduct these values from the available external static pressure shown in the respective Blower Performance Tables.

3. The pressure drop through the economizer is greater for 100% outdoor air than for 100% return air. If the resistance of the return air duct
is less than 0.25 IWG, the unit will deliver less CFM during full economizer operation.

2

Johnson Controls Unitary Products 41

689670-BIM-A-0311

Operation

Cooling Sequence Of Operation

For the ZU series of units, the thermostat makes a circuit
between "R" and "Y1" for the first stage of cooling.

The call is passed to the Unit Control Board (UCB), which
then determines whether the requested operation is available
and, if so, which components to energize.

For gas heating, the UCB monitors the "W1" call but does not
handle the operation of the gas furnace. An ignition control
board controls the gas heater operation. For electric heat units,
the UCB passes the call to the electric heater. In both cases,
when the "W1" call is sensed, the indoor air blower is energized
following a specified heating delay.

If at any time a call for both heating and cooling are present, the
heating operation will be performed. If operating, the cooling
system is halted as with a completion of a call for cooling.
Heating always takes priority.

Continuous Blower

By setting the room thermostat fan switch to "ON," the supply
air blower will operate continuously.

Intermittent Blower

With the room thermostat fan switch set to "AUTO" and the
system switch set to either the "AUTO" or "HEAT" settings, the
blower is energized whenever a cooling or heating operation is
requested. The blower is energized after any specified delay
associated with the operation.

When energized, the indoor blower has a minimum run time of
30 seconds. Additionally, the indoor blower has a delay of 10
seconds between operations.

No Outdoor Air Options

When the thermostat calls for cooling, the low-voltage control
circuit from “R” to “Y1” and “G” is completed. The compressor and
condenser fan motor are energized. After completing the specified
fan on delay for cooling, the UCB will energize the blower motor.

Once the thermostat has been satisfied, it will de-energize Y1. If
the compressor has satisfied its minimum run time, the
compressor and condenser fan de-energize. Otherwise, the
unit operates the cooling system until the minimum run time for
the compressor has been completed. After the compressor de­energizes, the blower is stopped following the elapse of the fan
off delay for cooling.

To be available, a compressor must not be locked-out due to a
high or low-pressure switch or freezestat trip and the anti-short
cycle delay (ASCD) must have elapsed.

Economizer With Single Enthalpy Sensor

When the room thermostat calls for cooling, the low voltage
control circuit from “R” to “G” and “Y1” is completed. The UCB
energizes the blower motor (if the fan switch on th e room
thermostat is set in the “AUTO” position) and drives the
economizer dampers from fully closed to their min imum position.
If the enthalpy of the outdoor air is below the setpoint of the
enthalpy controller (previously determined), “Y1” energize s the
economizer. The dampers will modulate to maintain a constant
supply air temperature as monitored by the discharge air sensor.
If the outdoor air enthalpy is above the setpoint, “Y1 ” en ergi zes
the compressor and condenser fan motor only.

Once the thermostat has been satisfied, it will de-energize “Y1”. If
the compressor has satisfied its minimum run time, the
compressor and condenser fan are de-energized. Otherwise, the
unit operates the cooling system until the minimum run times for
the compressor has been completed. After the compressor de­energizes, the blower is stopped following the elapse of the fan
off delay for cooling, and the economizer damper goes to the
closed position. If the unit is in continues fan operation the
economizer damper goes to the min. position.

Economizer With Dual Enthalpy Sensors

The operation with the dual enthalpy sensors is identical to the
single sensor except that a second enthalpy sensor is mounted
in the return air. This return air sensor allows the economizer to
choose between outdoor air and return air, whichever has the
lowest enthalpy value, to provide maximum operating
efficiency.

Economizer With Power Exhaust

A unit equipped with an economizer (single or dual enthalpy)
and a power exhaust operates as specified above with one
addition. The power exhaust motor is energized 45 seconds
after the actuator position exceeds the exhaust fan set point on
the economizer control. As always, the "R" to "G" connection
provides minimum position but does not provide power exhaust
operation.

Motorized Outdoor Air Dampers

This system operation is the same as the units with no outdoor
air options with one exception. When the "R" to "G" circuit is
complete, the motorized damper drives open to a position set
by the thumbwheel on the damper motor. When the "R" to "G"
circuit is opened, the damper spring returns fully closed.

Cooling Operation Errors

Each cooling system is monitored for operation outside of the
intended parameters. Errors are handled as described below. All
system errors override minimum run times for compressors.

42 Johnson Controls Unitary Products

689670-BIM-A-0311

High-Pressure Limit Switch

During cooling operation, if a high-pressure limit switch opens,
the UCB will de-energize the associated compressor, initiate
the ASCD (Anti-short cycle delay), and, if the other compressor
is idle, stop the condenser fans. If the call for cooling is still
present at the conclusion of the ASCD, the UCB will re-energize
the halted compressor.

Should a high-pressure switch open three times within two
hours of operation, the UCB will lock-out the associated
compressor and flash a code (see Table 27). If the other
compressor is inactive, the condenser fans will be de­energized.

Low-Pressure Limit Switch

The low-pressure limit switch is not monitored during the initial
30 seconds of a cooling system's operation. For the following
30 seconds, the UCB will monitor the low-pressure switch to
ensure it closes. If the low-pressure switch fails to close after
the 30-second monitoring phase, the UCB will de-energize the
associated compressor, initiate the ASCD, and, if the other
compressor is idle, stop the condenser fans.

Once the low-pressure switch has been proven (closed during
the 30-second monitor period described above), the UCB will
monitor the low-pressure limit switch for any openings. If the
low-pressure switch opens for greater than 5 seconds, the UCB
will de-energize the associated compressor, initiate the ASCD,
and, if the other compressor is idle, stop the condenser fans.

If the call for cooling is still present at the conclusion of the
ASCD, the UCB will re-energize the halted compressor.

Should a low-pressure switch open three times within one hour
of operation, the UCB will lock-out the associated compressor
and flash a code (Table 27). If the other compressor is inactive,
the condenser fans will be de-energized.

Freezestat

Low ambient mode operates the compressors in this manner:
10 minutes on, 5 minutes off. The indoor blower is operated
throughout the cycle. The 5-minute off period is necessary to
defrost the indoor coil.

Low ambient mode always begins with compressor operation.
Compressor minimum run time may extend the minutes of
compressor operation. The defrost cycle will begin immediately
following the elapse of the minimum run time.

When operating in low ambient mode, the UCB will not lockout
the compressors due to a freezestat trip. However, a freezestat
trip will de-energize the associated compressor. If the call for
cooling is still present at the end of the ASCD and the freezestat
has closed, the unit will resume operation.

Safety Controls

The unit control board monitors the following inputs for each
cooling system:

1. A suction line freezestat to protect against low evaporator
temperatures due to a low airflow or a low return air
temperature, (opens at 26 ± 5 °F and resets at 38 ± 5°F).

2. A high-pressure switch to protect against excessive
discharge pressures due to a blocked condenser coil or a
condenser motor failure, (opens at 625 ± 25 psig).

3. A low-pressure switch to protect against loss of refrigerant
charge, (opens at 50 ± 5 psig).

The above pressure switches are hard-soldered to the unit. The
refrigeration systems are independently monitored and
controlled. On any fault, only the associated system will be
affected by any safety/preventive action. The other refrigerant
system will continue in operation unless it is affected by the
fault as well.

The unit control board monitors the temperature limit switch of
electric heat units and the temperature limit switch and the gas
valve of gas furnace units.

During cooling operation, if a freezestat opens, the UCB will de­energize the associated compressor, initiate the ASCD, and, if
the other compressor is idle, stop the condenser fans. If the call
for cooling is still present at the conclusion of the ASC D, the
UCB will re-energize the halted compressor.

Should a freezestat open three times within two hours of
operation, the UCB will lock-out the associated compressor and
flash a code (Table 27). If the other compressor is inactive, the
condenser fans will be de-energized.

Low Ambient Cooling

To determine when to operate in low ambient mode, the UCB
has a pair of terminals connected to a temperature-activated
switch set at 45ºF. When the low ambient switch is closed and
the thermostat is calling for cooling, the UCB will operate in the
low ambient mode.

Johnson Controls Unitary Products 43

Compressor Protection

In addition to the external pressure switches, the compressors
also have inherent (internal) protection. If there is an abnormal
temperature rise in a compressor, the protector will open to shut
down the compressor. The UCB incorporates features to
minimize compressor wear and damage. An Anti-Short Cycle
Delay (ASCD) is utilized to prevent operation of a compressor
too soon after its previous run. Additionally, a minimum run time
is imposed any time a compressor is energized.

The ASCD is initiated on unit start-up and on any compressor
reset or lock-out.

Flash Codes

The UCB will initiate a flash code associated with errors within
the system. Refer to UNIT CONTROL BOARD FLASH CODES
Table 27.

689670-BIM-A-0311

Reset

Remove the call for cooling, by raising thermostat setting higher
than the conditioned space temperature. This resets any
pressure or freezestat flash codes.

Electric Heating Sequence Of Operations

The following sequence describes the operation of the electric
heat section.

Two-stage heating:

a. Upon a call for first stage heat by the thermostat, the

heater relay (RA) will be energized. After completing the
specified fan on delay for heating, the UCB will energize
the blower motor. If the second stage of heat is required,
heater relay (RB) will be energized. After completing the
specified fan on delay for heating, the UCB will energize
the blower motor.

b T he thermostat will cycle the electric heat to satisfy the

heating requirements of the conditioned space.

Electric Heat Operation Errors
Temperature Limit

If the UCB senses zero volts from the high temperature limit,
the indoor blower motor is immediately energized.

This limit is monitored regardless of unit operation status, i.e.
the limit is monitored at all times.

If the temperature limit opens three times within one hour, it will
lock-on the indoor blower motor and a flash code is initiated
(See Table 27).

Safety Controls

The UCB monitors the temperature limit switch of electric heat
units.

The control circuit includes the following safety controls:

Limit Switch (Ls)

inadequate supply air flow occurs, thus shutting down the
heater and energizing the blower.

Table 22: Electric Heat Limit Setting

LIMIT

SWITCH

OPENS °F

UNIT (TONS) VOLTAGE

ZU-A3 (3) 208/230

ZU-A4 (4) 208/230

ZU-A5 (5) 208/230

ZU-A3 (3) 480

ZU-A4 (4) 480

ZU-A5 (5) 480

ZU-A3 (3) 600

ZU-A4 (4) 600

ZU-A5 (5) 600

HEATER

kW

3155
6155
9170

15 170

6155

9170
15 170
20 170

6155

9170
15 170
20 170
24 170

3155

6155

9170
15 170

6155

9170
15 170
20 170

6155

9170
15 170
20 170
24 170

9170
15 170

9170
15 170
20 170

9170
15 170
20 170
24 170

This control is located inside the heater compartment and is set
to open at the temperature indicated in the Electric Heat Limit
Setting Table 22. It resets automatically. The limit switch
operates when a high temperature condition, caused by

44 Johnson Controls Unitary Products

689670-BIM-A-0311

Flash Codes

The UCB will initiate a flash code associated with errors within
the system. Refer to UNIT CONTROL BOARD FLASH CODES
Table 27.

Reset

Remove the call for heating by lowering the thermostat setting
lower than the conditioned space temp erature.This resets any
flash codes.

Electric Heat Anticipator Setpoints

It is important that the anticipator setpoint be correct. Too high
of a setting will result in longer heat cycles and a greater
temperature swing in the conditioned space. Reducing the
value below the correct setpoint will give shorter “ON” cycles
and may result in the lowering of the temperature within the
conditioned space. Refer to Table 23 for the required electric
heat anticipator setting.

Table 23: Electric Heat Anticipator Setpoints

SETTING, AMPS

W1 W2

0.13 0.1

Gas Heating Sequence Of Operations

When the thermostat calls for the first stage of heating, the low­voltage control circuit from “R” to “W1” is completed. A call for heat passes through the UCB to the Ignition Control Board (ICB). The UCB monitors the “W1” call and acts upon any call for heat by monitoring the Gas Valve (GV). Once voltage has been sensed at the GV, the UCB will initiate the fan on delay for heating, energizing the indoor blower the specified delay has elapsed.

When the thermostat has been satisfied, heating calls are
ceased. The GV is immediately closed. The blower is de­energized after the fan off delay for heating has elapsed. The
draft motor performs a 30-second post purge.

Ignition Control Board
First Stage Of Heating

When the ICB receives a call for first stage of heating, “W1,” the
draft motor is energized. Once the draft motor has been proven,
a 30-second purge is initiated. At the end of the purge, the GV
is opened, and the spark ignitor is energized for 10 seconds.
The ICB then checks for the presence of flame. If flame is
detected, the ICB enters a flame stabilization period. If flame
was not detected, the GV closes, and a retry operation begins.

During the flame stabilization period, a loss of the flame for 2
seconds will cause the GV to close and the retry operation to
begin. After the flame stabilization period, a loss of flame for 3/4

second will cause the GV to close and the retry operation to
begin.

At the conclusion of the flame stabilization period, the ICB will
operate the gas heat in high fire for an additional 60 seconds
(for a total for 120 seconds of high fire operation). After this 60
seconds, the ICB will then use the call for the second stage of
heat to control second stage operation of the GV.

When “W1” is satisfied, both valves are closed.

Second Stage Of Heating

When the ICB receives a call for the second stage of heating,
“W2,” the ICB conducts a complete first stage ignition
sequence. If this sequence is satisfied, the second main valve
of the GV is opened.

When “W2” is satisfied, the second main valve is closed.

Retry Operation

When a flame is lost or is not detected during an attempt to
achieve ignition, a retry operation occurs. A 30-second purge is
performed between ignition attempts.

If the unit fails after three ignition attempts, the furnace is
locked-out for one hour. The furnace is monitored during this
one-hour period for unsafe conditions.

Recycle Operation

When a flame is lost after the flame stabilization period, a recy­cle operation occurs. If the unit fails after five recycle attempts,
the furnace is locked-out for one hour.

Gas Heating Operation Errors
Lock-Out

A one-hour lockout occurs following three retries or five
recycles. During the one-hour lockout, flame detection, limit
conditions, and main valves are tested. Any improper results
will cause the appropriate action to occur. Recycling the low
voltage power cancels the lock-out.

Temperature Limit

If the UCB senses zero volts from the high temperature limit,
the indoor blower motor is immediately energized. When the
UCB again senses 24 volts from the temperature limit, the draft
motor will perform a 15-second post-purge and the indoor
blower will be de-energized following the elapse of the fan off
delay for heating.

This limit is monitored regardless of unit operation status, i.e.
this limit is monitored at all times.

If the temperature limit opens three times within one hour, it will
lock-on the indoor blower motor and flash code is initiated (See
Table 27).

Johnson Controls Unitary Products 45

689670-BIM-A-0311

Flame Sense

Flame sensing occurs at all times. If “W1” is not present and a
flame is sensed for 2 seconds, the draft motor is energized and
the GV is kept off. The ICB halts any operation until a flame is
not detected. Once the flame detection is lost, the ICB performs
a post-purge. Normal operation is allowed concurrently with the
purge (i.e. this purge can be considered the purge associated
with a call for “W1”).

If “W1” is present, a flame is sensed, but the GV is not
energized, the draft motor is energized until the flame detection
is lost. Normal operation is now allowed.

The flame detection circuitry continually tests itself. If the ICB
finds the flame detection circuitry to be faulty, the ICB will not
permit an ignition sequence and the draft motor is energized. If
this failure should occur during an ignition cycle the failure is
counted as a recycle.

Gas Valve

The UCB and ICB continuously monitor the GV.
If the ICB senses voltage at the GV when not requested, the

ICB will energize the draft motor. The ICB will not operate the
furnace until voltage is no longer sensed at the GV. The draft
motor is stopped when voltage is not sensed at the GV.

Any time the UCB senses voltage at the GV without a call for
heat for a continuous five-minute period, the UCB will lock-on
the indoor blower and a flash code is initiated (Table 27). When
voltage is no longer sensed at the GV, the UCB will de-energize
the indoor blower following the elapse of the fan off delay for
heating.

Safety Controls

The UCB monitors the temperature limit switch of gas heat
units.

The control circuit includes the following safety controls:

Limit Switch (LS)

This control is located inside the gas heat compartment and is
set to open at the temperature indicated in the Unit Physical
Data Table 9. It resets automatically. The limit switch operates
when a high temperature condition, caused by inadequate
supply air flow occurs, thus shutting down the heater and
energizing the blower.

Auxiliary Limit Switch (ALS)

This control is located inside the supply air compartment and is
set to open at the temperature indicated in the Unit Physical
Data Table 9. It resets manually. The limit switch operates
when a high temperature condition, caused by inadequate
supply air flow occurs, thus shutting down the heater and
energizing the blower.

The auxiliary limit switch is wired in series with the limit switch.
As such, the UCB cannot distinguish the auxiliary limit and the
gas heat limit switch operation except the auxiliary is manual
reset. Consequently, the control will respond in the same
manner as outlined above under “Limit Switch”.

The ICB monitors the Pressure and Rollout switches of gas
heat units.

The control circuit includes the following safety controls:

If voltage has been sensed at the GV for at least 15 seconds
during the fan on delay for heating and GV voltage or “W1” is
lost, the indoor blower is forced on for the length of the fan off
delay for heating.

During a call for heat, if the UCB does not sense voltage at the
GV for a continuous five-minute period the UCB will initiate a
flash code (Table 27). The indoor blower motor will not be
locked-on while there is no GV voltage.

Pressure Switch (PS)

Once the draft motor has reached full speed and closes the
pressure switch during a normal ignition sequence, if the
pressure sw opens for 2 seconds, the GV will be de-energized,
the ignition cycle is aborted, and the ICB flashes the
appropriate code. See Table 28 Ignition Control Flash Codes.
The draft motor is energized until the pressure switch closes or
“W1” is lost.

46 Johnson Controls Unitary Products

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Rollout Switch (ROS)

The rollout switch is wired in series with the pressure switch. As
such, the ICB cannot distinguish the rollout switch operation
from that of the pressure switch.

Consequently, the control will only respond in the same manner
as outlined above under “Pressure Switch”. An open rollout will
inhibit the gas valve from actuating.

Internal Microprocessor Failure

If the ICB detects an internal failure, it will cease all outputs,
ignore inputs, and display the proper flash code for control
replacement. The ICB remains in this condition until replaced.

Flash Codes

The ICB will initiate a flash code associated with errors within
the system. Refer to IGNITION CONTROL FLASH CODES
Table 28.

Resets

Remove the call for heating by lowering the thermostat setting
lower than the conditioned space temp er ature. This resets any
flash codes.

Gas Heat Anticipator Setpoints

It is important that the anticipator setpoint be correct. Too high
of a setting will result in longer heat cycles and a greater
temperature swing in the conditioned space. Reducing the
value below the correct setpoint will give shorter “ON cycles
and may result in the lowering of the temperature within the
conditioned space. Refer to Table 24 for the required gas heat
anticipator setting.

Table 24: Gas Heat Anticipator Setpoints

SETTING, AMPS

W1 W2

0.65 0.1

6. Check the unit supply air (CFM).

7. Measure evaporator fan motor's amp draw.

8. Set the room thermostat fan switch to off.

9. Turn unit electrical power off.

Operating Instructions

1. Turn unit electrical power on.
NOTE: Prior to each cooling season, the crankcase heaters

must be energized at least 10 hours before the system
is put into operation.

2. Set the room thermostat setting to lower than the room
temperature.

3. First stage compressors will energize after the built-in time
delay (five minutes).

4. The second stage of the thermostat will energize second
stage compressor if needed.

Post Start Check List

1. Verify proper system pressures for both circuits.

2. Measure the temperature drop across the evaporator coil.

Start-Up (Gas Heat)

Pre-Start Check List

Complete the following checks before starting the unit.

1. Check the type of gas being supplied. Be sure that it is the
same as listed on the unit nameplate.

2. Make sure that the vent outlet and combustion air inlet are
free of any debris or obstruction.

Operating Instructions

Start-Up (Cooling)

Prestart Check List

After installation has been completed:

1. Check the electrical supply voltage being supplied. Be sure
that it is the same as listed on the unit nameplate.

2. Set the room thermostat to the off position.

3. Turn unit electrical power on.

4. Set the room thermostat fan switch to on.

5. Check indoor blower rotation.

• If blower rotation is in the wrong direction. Refer to

Phasing Section in general information section.

Check blower drive belt tension.

Johnson Controls Unitary Products 47

This furnace is equipped with an automatic re-ignition
system. DO NOT attempt to manually light the pilot.

Lighting The Main Burners

1. Turn “OFF” electric power to unit.

2. Turn room thermostat to lowest setting.

3. Turn gas valve counter-clockwise to “ON” position (See
Figure 30).

4. Turn “ON” electric power to unit.

5. If thermostat set temperature is above room temperature,
the main burners will ignite. If a second stage of heat is
called for, the main burners for second stage heat will
ignite for the second stage heat.

689670-BIM-A-0311

Post Start Checklist

After the entire control circuit has been energized and the
heating section is operating, make the following checks:

1. Check for gas leaks in the unit piping as well as the supply
piping.

FIRE OR EXPLOSION HAZARD
Failure to follow the safety warning exactly could result

in serious injury, death or property damage.
Never test for gas leaks with an open flame. use a

commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage,
personal injury or loss of life.

2. Check for correct manifold gas pressures. (See CHECKING
GAS INPUT.)

3. Check the supply gas pressure. It must be within the limits
shown on the rating nameplate. Supply pressure should be
checked with all gas appliances in the building at full fire. At
no time should the standby gas pressure exceed 10.5 in. or
the operating pressure drop below 4.5 in for natural gas
units. If gas pressure is outside these limits, contact the
local gas utility or propane supplier for corrective action.

Shut Down

1. Set the thermostat to the lowest temperature setting.

2. Turn “OFF” all electric power to unit.

3. Open gas heat access panel.

4. Turn gas valve clockwise to “OFF” position (See Figure 30).

Checking Gas Heat Input

This unit has two stages of gas heat. The first stage is 70% of
the full fire input and is considered the minimum input for the
furnace. The intended input for each furnace is shown in
Table 26. The table applies to units operating on 60 Hz power
only.

To determine the rate of gas flow (Second Stage).

1. Turn off all other gas appliances connected to the gas
meter.

2. Turn on the furnace and make sure the thermostat is
calling for Second stage (100% input) heat.

3. Measure the time needed for one revolution of the hand on
the smallest dial on the meter. A typical gas meter has a 1/
2 or a 1 cubic foot test dial.

4. Using the number of seconds it takes for one revolution of
the dial, calculate the cubic feet of gas consumed per hour.
(See example below).

5. If necessary, adjust the high pressure regulator as
discussed in the section “Manifold Gas Pressure
Adjustment”. Be sure not to over-fire the furnace on
Second stage. If in doubt, it is better to leave the Second
stage of the furnace slightly under-fired. Repeat Steps 1-5.

To determine the rate of gas flow (First Stage)

1. Turn off all other gas appliances connected to the gas
meter.

2. Turn on the furnace and make sure the thermostat is
calling for first stage heat.

3. Even when the thermostat is calling for first stage heat, the
unit will light on second stage and will run on Second stage
for 1 minute. Allow this one-minute time period to expire
and be certain the unit is running on first stage.

4. Measure the time needed for one revolution of the hand on
the smallest dial on the meter. A typical gas meter has a 1/
2 or a 1 cubic foot test dial.

5. Using the number of seconds it takes for one revolution of
the dial, calculate the cubic feet of gas consumed per hour
(See example below).

6. If necessary, adjust the low pressure regulator as
discussed in the section “Manifold Gas Pressure
Adjustment”. Be sure not to under-fire the furnace on first
stage. If in doubt, it is better to leave the first stage of the
furnace slightly over-fired (greater than 70% input). Repeat
Steps 1-6.

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Table 25: Gas Rate Cubic Feet Per Hour

Seconds for

One Rev.

10 180 360
12 150 300
14 129 257
16 113 225
18 100 200
20 90 180
22 82 164
24 75 150
26 69 138
28 64 129
30 60 120
32 56 113
34 53 106
36 50 100
38 47 95
40 45 90
42 43 86
44 41 82
46 39 78
48 37 75
50 36 72
52 35 69
54 34 67
56 32 64
58 31 62
60 30 60

Size of Test Dial

1/2 cu. ft. 1 cu. ft.

NOTE: To find the Btu input, multiply the number of cubic feet

of gas consumed per hour by the Btu content of the gas
in your particular locality (contact your gas company for
this information as it varies widely from area to area).

EXAMPLE
By actual measurement, it takes 19 seconds for the hand on a 1

cubic foot dial to make a revolution with a 192,000 Btuh furnace
running. To determine rotations per minute, divide 60 by 19 =

3.16. To calculate rotations per hour, multiply 3.16  60 = 189.6.
Multiply 189.6  1 (0.5 if using a 1/2 cubic foot dial) = 189.6.
Multiply 189.6  (the Btu rating of the gas). For this example,
assume the gas has a Btu rating of 1050 Btu/ft.

3

. The result of
199,000 Btuh is within 5% of the 192,000 Btuh rating of the
furnace.

Manifold Gas Pressure Adjustment

This gas furnace has two heat stages. Therefore, the gas valve
has two adjustment screws located under a plastic protective
cover. The second stage (100% input) adjustment screw is
adjacent to the “HI” marking on the valve and the first stage
(70% input) adjustment screw is located adjacent to the “LO”
marking on the valve (See Figure 30).

Manifold pressure adjustment procedure.
Adjust second stage (100% input) pressure first, then adjust

first stage (70% input) pressure.

1. Turn off all power to the unit.

2. Using the outlet pressure port on the gas valve, connect a
manometer to monitor the manifold pressure.

3. Remove plastic cap covering HI and LO pressure
adjustment screws.

4. Turn on power to the unit.

5. Set thermostat to call for second stage heat and start
furnace.

6. If necessary, using a screwdriver, turn the

second stage
adjustment screw (adjacent to the “HI” marking on the
valve) clockwise to increase manifold pressure or
counterclockwise to decrease manifold pressure. Be sure
not to over-fire the unit on second stage.

7. After the high manifold pressure has been checked, adjust
the thermostat to call for first stage heat.

8. If necessary, using a screwdriver, turn the first stage
adjustment screw (adjacent to the “LO” marking on the
valve) clockwise to increase manifold pressure or
counterclockwise to decrease manifold pressure. Be sure
not to under-fire the unit on first stage.

9. Once pressure has been checked, replace the plastic cap
covering the HI and LO pressure adjustment screws.

NOTE: When using natural gas, the manifold pressure for

second stage (100% input) should be 3.5 IWG ± 0.3.
The manifold pressure for first stage (70% input) when
using natural gas should be 1.8 IWG ± 0.3.

Table 26: Gas Heat Stages

Unit

Size Opt.

A06 4 60 - 60
A08 4 80 - 80
A11 6 120 - 120

-A3
N06 4 45 15 60

N08 4 56 24 80
N11 6 84 36 120
A06 4 60 - 60
A08 4 80 - 80
A11 6 120 - 120

-A4
N06 4 45 15 60

N08 4 56 24 80
N11 6 84 36 120
A08 4 80 - 80
A11 6 120 - 120
A16 8 160 - 160

-A5
N08 4 56 24 80

N11 6 84 36 120
N16 8 112 48 160

# of Burner

Tubes

1st Stage

Input (Mbh)

2nd Stage

Input

(Mbh)

Total
Input

(Mbh)

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HEAT EXCHANGER TUBE

BURNER FLAME

(BLUE ONLY)

IGNITOR

BURNER BRACKET

BURNER

GAS

SUPPLY

PIPE

INLET

PRESSURE

TAP

HIGH & LOW GAS ADJUSTMENT

OUTLET

PRESSURE

TAP

MATE-N-LOCK
CONNECTORS

HI

LO

ON

OFF

MV

C

HI

INLET

PRESSURE

TAP

OUTLET

PRESSURE

TAP

GAS

ADJUSTMENT

ELECTRICAL

TERMINALS

Adjustment Of Temperature Rise

The temperature rise (the difference of temperature between the
return air and the heated air from the furnace) must lie within the
range shown on the CSA rating plate and the data in Table 9.

After the temperature rise has been determined, the CFM can
be calculated as follows:

After about 20 minutes of operation, determine the furnace
temperature rise. Take readings of both the return air and the
heated air in the ducts (about 6 feet from the furnace) where
they will not be affected by radiant heat. Increase the blower
CFM to decrease the temperature rise; decrease the blower
CFM to increase the rise (See SUPPLY AIR DRIVE
ADJUSTMENT).

NOTE: Each gas heat exchanger size has a minimum

allowable CFM. Below this CFM, the limit will open.

Burners/Orifices Inspection/Servicing

Before checking or changing burners, pilot or orifices, CLOSE
MAIN MANUAL SHUT-OFF VALVE AND SHUT OFF ALL
POWER TO THE UNIT.

1. Open the union fitting just upstream of the unit gas valve
and downstream from the main manual shut-off valve in
the gas supply line.

2. Remove the screws holding each end of the manifold to the
manifold supports.

3. Disconnect wiring to the gas valves and spark igniter(s).
Remove the manifold & gas valve assembly. Orifices can
now be inspected and/or replaced.

To service burners, complete step 4.

Figure 30: Typical Two Stage Gas Valve

4. Remove the heat shield on top of the manifold supports.

NOTE: Reverse the above procedure to replace the

Make sure that burners are level and seat at the rear of the gas
orifice.

Figure 29: Typical Flame

50 Johnson Controls Unitary Products

Burners are now accessible for inspection and/or
replacement.

assemblies.

Figure 31: Typical Single Stage Gas Valve

Charging The Unit

All ZU units use Thermal Expansion Devices. Charge the unit to
10° subcooling.

689670-BIM-A-0311

Troubleshooting

Troubleshooting of components may require opening
the electrical control box with the power connected to
the unit. Use extreme care when working with live
circuits! Check the unit nameplate for the correct line
voltage and set the voltmeter to the correct range before
making any connections with line terminals.

When not necessary, shut off all electric power to the
unit prior to any of the following maintenance
procedures so as to prevent personal injury.

Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and
dangerous operation which could cause injury to person
and/or damage unit components. Verify proper
operation after servicing.

On calls for cooling, if the compressors are oper a ti n g bu t th e
supply air blower motor does not energize after a short delay
(the room thermostat fan switch is in the “AUTO” position).

1. Turn the thermostat fan switch to the ON position. If the
supply air blower motor does not energize, go to Step 3.

2. If the blower motor runs with the fan switch in the ON
position but will not run after the compressor has energized
when the fan switch is in the AUTO position, check the
room thermostat for contact between R and G in the AUTO
position during calls for cooling.

3. If the supply air blower motor does not energize when the
fan switch is set to ON, check that line voltage is being
supplied to the contacts of the M3, contactor, and that the
contactor is pulled in. Check for loose wiring between the
contactor and the supply air blower motor.

4. If M3 is pulled in and voltage is supplied to M3, lightly touch
the supply air blower motor housing. If it is hot, the motor
may be off on internal protection. Cancel any thermostat
calls and set the fan switch to AUTO. Wait for the internal
overload to reset. Test again when cool.

5. If M3 is not pulled in, check for 24 volts at the M3 coil. If 24
volts are present at M3 but M3 is not pulled in, replace the
contactor.

6. Failing the above, if there is line voltage supplied at M3, M3
is pulled in, and the supply air blower motor still does not
operate, replace the motor.

7. If 24 volts is not present at M3, check that 24 volts is
present at the UCB supply air blower motor terminal,
“FAN”. If 24 volts is present at the FAN, check for loose
wiring between the UCB and M3.

8. If 24 volts is not present at the “FAN” terminal, check for 24
volts from the room thermostat. If 24 volts are not present
from the room thermostat, check for the following:

a. Proper operation of the room thermostat (contact

between R and G with the fan switch in the ON position
and in the AUTO position during operation calls).

b. Proper wiring between the room thermostat and the

UCB.

c. Loose wiring from the room thermostat to the UCB.

9. If 24 volts is present at the room thermostat but not at the
UCB, check for proper wiring between the thermostat and
the UCB, i.e. that the thermostat G terminal is connected to
the G terminal of the UCB, and for loose wiring.

10. If the thermostat and UCB are properly wired, replace the
UCB.

On a call for cooling, the supply air blower motor is operating
but the compressor is not (the room thermostat fan switch is in
the “AUTO” position).

1. If installed, check the position of the economizer blades. If
the blades are open, the economizer is providing free
cooling and the compressors will not immediately operate.
If both stages of cooling are requested simultaneously and
the economizer provides free cooling, following a short
delay the compressor will be energized unless it is locked
out, unless this option has been disabled through computer
communications.

2. If no economizer is installed or the economizer is not
opening to provide free cooling and the compressor does
not energize on a call for cooling, check for line voltage at
the compressor contactor, M1, and that the contactor is
pulled in. Check for loose wiring between the contactor and
the compressor.

3. If M1 is pulled in and voltage is supplied at M1, lightly touch
the compressor housing. If it is hot, the compressor may be
off on inherent protection. Cancel any calls for cooling and
wait for the internal overload to reset. Test again when
cool.

4. If M1 is not pulled in, check for 24 volts at the M1 coil. If 24
volts are present and M1 is not pulled in, replace the
contactor.

5. Failing the above, if voltage is supplied at M1, M1 is pulled
in, and the compressor still does not operate, replace the
compressor.

6. If 24 volts is not present at M1, check for 24 volts at the
UCB terminal, C1. If 24 volts is present, check for loose
wiring between C1 and the compressor contactor.

7. If 24 volts is not present at the C1 terminal, check for 24
volts from the room thermostat at the UCB Y1 terminal. If
24 volts is not present from the room thermostat, check for
the following:

a. 24 volts at the thermostat Y1 terminal
b. Proper wiring between the room thermostat and the

UCB, i.e. Y1 to Y1, Y2 to Y2

c. Loose wiring from the room thermostat to the UCB.

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8. If 24 volts is present at the UCB Y1 terminal, the
compressor may be out due to an open high-pressure
switch, low-pressure switch, or freezestat. Check for 24
volts at the HPS1, LPS1, and FS1 terminals of the UCB. If
a switch has opened, there should be a voltage potential
between the UCB terminals, e.g. if LPS1 has opened, there
will be a 24-volt potential between the LPS1 terminals.

9. If 24 volts is present at the UCB Y1 terminal and none of
the protection switches have opened, the UCB may have
locked out the compressor for repeat trips. The UCB
should be flashing an alarm code. If not, press and release
the ALARMS button on the UCB. The UCB will flash the
last five alarms on the LED. If the compressor is locked
out, cancel any call for cooling. This will reset any
compressor lock outs.

NOTE: While the above step will reset any lockouts, the

compressor may be held off for the ASCD. See the next
step.

10. If 24 volts is present at the UCB Y1 terminal and none of
the switches are open and the compressor is not locked
out, the UCB may have the compressor in an ASCD.
Check the LED for an indication of an ASCD cycle. The
ASCD should time out within 5 minutes. Press and release
the TEST button to reset all ASCDs.

11. If 24 volts is present at the UCB Y1 terminal and the
compressor is not out due to a protective switch trip, repeat
trip lock out, or ASCD, the economizer terminals of the
UCB may be improperly wired. Check for 24 volts at the Y1
“OUT” terminal of the UCB. If 24 volts is present, trace the
wiring from Y1 “OUT” for incorrect wiring. If 24 volts is not
present at the Y1 “OUT” terminal, the UCB must be
replaced.

12. For units without economizers: If 24 volts is present at the
Y1 OUT terminal, check for 24 volts at the Y1 “ECON”
terminal. If 24 volts is not present, check for loose wiring
from the Y1 “OUT” terminal to the Mate-N-Lock plug, the
jumper in the Mate-N-Lock plug, and in the wiring from the
Mate-N-Lock plug to the Y1 “ECON” terminal.

13. For units with economizers: If 24 volts is present at the Y1
“OUT” terminal, check for 24 volts at the Y1 “ECON”
terminal. If 24 volts is not present, check for loose wiring
from the Y1 “OUT” terminal to the Mate-N-Lock plug, a
poor connection between the UCB and economizer Mate­N-Lock plugs, loose wiring from the Mate-N-Lock plug to
the economizer, back to the Mate-N-Lock plug, and from
the Mate-N-Lock plug to the Y1 “ECON” terminal. If nothing
is found, the economizer actuator may have faulted and is
failing to return the 24-volt “call” to the Y1 “ECON” terminal
even though the economizer is not providing free cooling.
To test, disconnect the Mate-N-Locks and jumper between
the WHITE and YELLOW wires of the UCB’s Mate-N-Lock
plug. If the compressor energizes, there is a fault in the
economizer wiring or actuator.

14. The UCB can be programmed to lock out compressor
operation during free cooling and in low ambient

conditions. These options are not enabled by default. Local
distributors can test the UCB for this programming.

For units with factory installed economizers, the UCB is
programmed to lock out compressor operation when the
LAS set point is reached.

For units without factory installed or with field installed
economizers, the UCB allows compressor operation all the
time. This programming can be checked or changed by the
local distributor.

15. If none of the above correct the error, replace the UCB.

Gas Heat Troubleshooting Guide

Troubleshooting of components may require opening
the electrical control box with the power connected to
the unit. Use extreme care when working with live
circuits! Check the unit nameplate for the correct line
voltage and set the voltmeter to the correct range before
making any connections with line terminals.

When not necessary, shut off all electric power to the
unit prior to any of the following maintenance
procedures so as to prevent personal injury.

Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and
dangerous operation, which could cause injury to person
and/or damage unit components. Verify proper
operation after servicing.

The furnace may shut down on a high temperature
condition during the procedure. If this occurs, the UCB
energize the supply air blower motor until the high
temperature limit has reset. Caution should be used at
all times as the supply air blower may energize
regardless of the room thermostat fan switch position.

On calls for heating, the draft motor operates and the furnace
lights but the supply air blower motor does not energize after a
short delay (the room thermostat fan switch is in “AUTO”
position).

1. Place the thermostat fan switch in the “ON” position. If the
supply air blower motor energizes, go to Step 9.

2. If the supply air blower motor does not energize when the
fan switch is set to “ON,” check that line voltage is being
supplied to the contacts of the M3 contactor, and that the

52 Johnson Controls Unitary Products

689670-BIM-A-0311

contactor is pulled in. Check for loose wiring between the
contactor and the supply air blower motor.

3. If M3 is pulled in and voltage is supplied at M3, lightly touch
the supply air blower motor housing. If it is hot, the motor
may be off on inherent protection. Cancel any thermostat
calls and set the fan switch to “AUTO”, wait for the internal
overload to reset. Test again when cool.

4. If M3 is not pulled in, check for 24 volts at the M3 coil. If 24
volts is present at M3 but M3 is not pulled in, replace the
contactor.

5. Failing the above, if there is line voltage supplied at M3, M3
is pulled in, and the supply air blower motor still does not
operate, replace the motor.

6. If 24 volts is not present at M3, check that 24 volts is
present at the supply air blower motor terminal on the UCB.
If 24 volts is present at the UCB terminal, check for loose
wiring between the UCB and M3.

a. If 24 volts is not present at the UCB supply air blower

motor terminal, check for 24 volts from the room
thermostat. If 24 volts is not present from the room
thermostat, check for the following:

• Proper operation of the room thermostat (contact
between R and G with the fan switch in the “ON” position
and in the “AUTO” position during operation calls.)

• Proper wiring between the room thermostat and the
UCB, and

• Loose wiring from the room thermostat to the UCB

7. If 24 volts is present at the room thermostat but not at the
UCB, check for proper wiring between the thermostat and
the UCB, i.e. that the thermostat G terminal is connected to
the G terminal of the UCB, and for loose wiring.

8. If the thermostat and UCB are properly wired, replace the
UCB.

9. If the blower motor runs with the fan switch in the “ON”
position but does not run shortly after the furnace has
ignited when the fan switch is in the “AUTO” position,
check the room thermostat for contact between R and G
during “W1” calls.

On calls for heating, the supply air blower operates but the draft
motor does not (the room thermostat fan switch is in the
“AUTO” position).

1. The draft motor has inherent protection. If the motor shell is
hot to the touch, wait for the internal overload to reset.

2. If the motor shell is cold with the room thermostat calling
for heat, check for line voltage at the motor leads. If line
voltage is present, replace the draft motor.

3. If line voltage is not present, check for line voltage on the
ignition control at the “inducer” terminal draft motor relay
(DMR or DMC) contacts in the main control box and check
to see if the (DMR or DMC) is pulled in.

The draft motor runs but the furnace does not light and the
spark ignitor does not spark.

1. Check for 24 volts at the spark ignitor from the ignition
control board (ICB). Check the 24-volt wiring from the ICB
to the spark ignitor. Check for 24 volts at the ICB spark
ignitor terminal.

2. Check the ground wiring for the ICB and the gas valve is
intact and making good electrical connection. Check the
ceramic insulator on the spark ignitor for breaks or cracks.
Replace the spark ignitor if damaged.

3. With the draft motor running, check for 24 volts at the
pressure switch terminal on the ICB. If not present, check
for 24 volts on the terminal from the pressure switch. If
present, go to step 4. If 24 volts is not present, the either
pressure or rollout switch is not closed. Or th e draft motor
is not sufficiently evacuating the heat exchanger tubes or
the pressure switch has failed. Check the operation of the
pressure switch. Check the line voltage to the unit; if line
voltage is low, call the local power company. If the problem
persists, the draft motor may need replacement.

4. If the furnace is hot, it may be out on a high temperature
limit open; wait for limit reset.

5. If all are intact replace the ICB.

The draft motor runs and the spark ignitor sparks at the burner,
but the burner does not ignite and a gas odor is not detected at
the draft motor outlet.

1. Check to ensure gas is being supplied to the unit. Confirm
that the gas pressure to the unit is within the proper limits
as described in the “POST START CHECKLIST”.

2. Check the voltage at the gas valve and at the gas valve
terminals on the ICB. Check all wiring between the ICB and
the gas valve. Check to make sure the ground connections
are intact.

3. If 24 volts is present, remove the pilot burner and the
orifice. The removal procedure is described in “BURNER/
ORIFICE INSPECTION/SERVICING.” Inspect the orifice
for obstruction. If it is clear, replace the gas valve.

Main burners light but exhibit erratic flame characteristics.

1. Check the main burner orifices for obstruction and
alignment. The removal procedure is described in
“BURNER/ORIFICE INSPECTION/SERVICING”. Clean or
replace burner orifices and burners as needed.

Johnson Controls Unitary Products 53

689670-BIM-A-0311

C

Unit Flash Codes

Various flash codes are utilized by the unit control board (UCB)
and the ignition control board (ICB) to aid in troubleshooting.
Flash codes are distinguished by the short on and off cycle
used (approximately 200ms on and 200ms off). To show normal
operation, the control boards flashes a 1 second on, 1 second
off “heartbeat” during normal operation. This is to verify that the
UCB and the ICB are functioning correctly. Do not confuse this
with an error flash code. To prevent confusion, a 1-flash, flash
code is not used.

Current alarms or active restrictions are flashed on the UCB
LED.

• LAST ERROR - When this button is pressed and released
one time within five seconds, it flashes the last five flash
codes on the board’s LED. The most recent alarm is
shown first and the oldest alarm is shown last.

When pressed and released twice within a five second
span, the fault history is cleared.

• TEST RESET - When this button is pressed and released
one time within five seconds, any anti-short cycle delays
(ASCD) is by-passed for one cycle.

When this button is pressed twice within five seconds, any
active lockouts are reset.

• COMM SET UP - If the board is to be networked with
other units, this button is used to set the network address.

The first time the button is pressed within five seconds, it
scans the bus, then assigns itself the first available
address {starts at 2}. It then flashes that address one time.

Pressing the button two times within five seconds causes
the control to flash its address.

Pressing the button three times within five seconds forces
the control to reset its address to 1, which is the factory
default.

Current alarms or active restrictions are flashed on the ICB
LED. No history is stored on the ICB.

Fan On And Off Delays

The fan ON and OFF delays can be field adjusted by pressing a
combination of buttons on the UCB.

• Gas Heat Option #1 - Press the LAST ERROR and
TEST RESET buttons simultaneously and then release.
The control flashes three times as it writes a 30 second
delay ON and a 90 second delay OFF to the program.

• Gas Heat Option #2 - Press the COMM SETUP and
TEST RESET buttons simultaneously and then release.
The control flashes four times as it writes a 30 second
delay ON and a 180 second delay OFF to the program.

• Electric Heat - Press and release the COMM SETUP and
LAST ERROR buttons at the same time. The control
flashes twice on the LED as the control writes a 0 second
ON and a 30 second OFF fan delay to the control ’ s
program memory.

Comm Setup

Button

Last Error

Button

Test Reset

Button

ontrol Board

LED

Figure 32: Unit Control Board

54 Johnson Controls Unitary Products

Table 27: Unit Control Board Flash Codes

Flash Code Description

On Steady Control Failure - Replace Control
Heart Beat Normal Operation

1 Flash Not Applicable
2 Flashes Control waiting ASCD
3 Flashes HPS1 - Compressor Lock out
5 Flashes LPS1 - Compressor Lock out
7 Flashes FS1 - Compressor Lock out

Ignition Control Locked Out/

9 Flashes

Ignition Control Failure / Limit Switch Trip / No
Jumper Plug in Heat Section

10 Flashes

11 Flashes

Compressors Locked Out On Low
Outdoor Air Temperature
Compressors Locked Out Because The

Economizer Is Using Free Cooling
13 Flashes Compressor Held Off Due To Low Voltage
14 Flashes EEPROM Storage Failure (Control Failure)

OFF No Power or Control Failure

1. These flash codes do not represent alarms.

1

1

Table 28: Ignition Control Flash Codes

Flashes Fault Conditions Check

Steady On Control Failure Control

Heartbeat Normal Operation

1 Not Applicable
2

3

Pressure Switch
Stuck Closed

Pressure Switch Failed
To Close

4 Limit Switch Open

Flame Present With Gas
Off First Stage Gas Valve

1

1

5

Energized With W1 Off
Second Stage Gas Valve
Energized With First
Stage
Gas Valve Off

6 Ignition Lockout

Steady Off

No Power Or Control
Failure

Pressure Switch
Venter Pressure

Switch
Vent Blocked

Main Limit
AUX Limit

Gas Valve

Gas Flow
Gas Pressure
Gas Valve
Flame Sensor

24VAC or Control

Subject to change without notice. Printed in U.S.A. 689670-BIM-A-0311
Copyright © 2011 by Johnson Controls, Inc. All rights reserved. Supersedes: 527728-BIM-D-1210

Johnson Controls Unitary Products

5005 York Drive

Norman, OK 73069