Honeywell Economizer Controls Technical Reference Manual

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Technical Reference Manual

Design and Application Guide for
Honeywell Economizer Controls

63-8594-02

Table of Contents

Section 1 - Ventilation ...................................................................................1

Indoor Air Quality ...............................................................................................................................................................2

Building-Related Illness .....................................................................................................................................................3

Symptoms of Inadequate Ventilation .................................................................................................................................4

Indoor Air Ventilation Standards .........................................................................................................................................5

Based Demand Control Ventilation .................................................................................................................5

CO

2

Energy Standards ..............................................................................................................................................................6

Ventilation Requirements .................................................................................................................................................7

Air Handler Control Loops ..................................................................................................................................................9

Basic Economizer Control ................................................................................................................................................10

Mixed Air Formulas ..........................................................................................................................................................11

Outside Air Percentage Chart ..........................................................................................................................................12

Example 1: Using the Outside Air Percentage Chart ............................................................................................13

Example 2: Use of Outside Air Chart on a Warm Day ..........................................................................................14

Extra Outside Air Percentage Chart ......................................................................................................................15

Example 3: Minimum Ventilation Adjustment ........................................................................................................16

Example 4: Ventilation Review Questions .............................................................................................................18

Economizer Cycle Definition ............................................................................................................................................20

Single and Two Stage Cooling With Economizer ..................................................................................................21

Section 2 - Enthalpy Theory And Controllers ...........................................23

The Psychrometric Chart .................................................................................................................................................24

Relative Humidity and Saturation .....................................................................................................................................25

Enthalpy ...........................................................................................................................................................................26

Psychrometric Chart of Enthalpy Economizer Control ..........................................................................................27

Single Sensor Enthalpy Control .......................................................................................................................................28

Two Sensor or Differential Enthalpy .................................................................................................................................29

Enthalpy Control with Carbon Dioxide Sensor ................................................................................................................. 30

Section 3 - Types of Analog Economizers ................................................31

H705 ................................................................................................................................................................................32

W7459 .............................................................................................................................................................................33

W6210 and W7210 ..........................................................................................................................................................34

W6215, W7215 and W7460 .............................................................................................................................................35

W7212, W7213 and W7214 .............................................................................................................................................36

W7340 and W7345 ..........................................................................................................................................................37

Analog Economizer Features ...........................................................................................................................................38

Transformer Wiring Requirements for Analog Economizers ............................................................................................39

Section 4 - H705 Economizer Module ........................................................41

H705 Economizer Module ................................................................................................................................................42

H705 Components ...........................................................................................................................................................43

H705 Enthalpy Setpoint ...................................................................................................................................................44

H705 Wiring Diagram .......................................................................................................................................................45

Section 5 - M7XXX Black Motor ..................................................................49

M7215, M7415, M7405 and M8405 Actuators .................................................................................................................50

Honeywell Economizers 63-8594-02 i

Section 6 - W7459 Economizer Module .....................................................53

W7459 Enthalpy Module Components .............................................................................................................................54

W7459A, B, C and D ........................................................................................................................................................56

W7459 Enthalpy Setpoint Chart .......................................................................................................................................57

High Limit Switching .........................................................................................................................................................58

W7459A Wiring Diagram .................................................................................................................................................59

Section 7 - W6210 And W7210 Economizer Modules ...............................63

W7210 Economizer System Components .......................................................................................................................64

W6210 and W7210 Components .....................................................................................................................................65

High Limit Function ................................................................................................................................................65

W7210 Actuator Connections .........................................................................................................................................66

W7210 Wiring Diagrams ..................................................................................................................................................67

Section 8- W6215, W7215 And W7460 Economizer Modules ...................69

W7215 System Components ...........................................................................................................................................70

W6215, W7215 and W7460 Components ........................................................................................................................71

W7215B and W7460B Components ................................................................................................................................71

W6215, W7215, W7460 Inputs and Outputs ....................................................................................................................72

Input and Output Applications ..........................................................................................................................................72

Minimum and Maximum Settings .....................................................................................................................................73

Indoor Air Content Sensor Settings .................................................................................................................................74

Carbon Dioxide Sensor Setup .........................................................................................................................................75

Outdoor Air Content Sensor .............................................................................................................................................76

W6215, W7215 and W7460 Actuator Usage ...................................................................................................................77

W6215, W7215 and W7460 Wiring Diagram ..................................................................................................................78

Section 9 - W7212, W7213 and W7214 Economizer Modules ..................81

W7212 Economizer System Components .......................................................................................................................82

W7212, W7213, and W7214 Components .......................................................................................................................83

DCV Maximum Position Adjustment ......................................................................................................................84

Using Multiple CO2 sensors on the AQ-AQ1 terminals for zones .........................................................................85

Minimum Position Adjustment ...............................................................................................................................85

Dry bulb changeover .............................................................................................................................................86

W7212, W7213, and W7214 Wiring Diagram ..................................................................................................................87

Section 10 - W7340 and W7345 Economizer Module ................................93

W7340 Economizer System Components .......................................................................................................................94

W7340 and W7345 Components .....................................................................................................................................96

W7340 only ...........................................................................................................................................................97

Demand Control Ventilation (DCV) Sensor Input (W7340 only) ............................................................................97

Settings and Adjustment .......................................................................................................................................99

Wiring for W7340 and W7345 ........................................................................................................................................101

Section 11 - W7220 JADE™ Economizer Module ...................................103

W7220 Economizer System Components .....................................................................................................................104

W7220 Components ......................................................................................................................................................106

Wiring Application Examples .........................................................................................................................................109

W7220 (JADE™) Economizer Controller Used with Honeywell Prestige

Alarm Mode for Failed Components on the JADE™ economizer system ...........................................................129

W7220 Personal Computer Tool ....................................................................................................................................134

©

IAQ 2.0 Thermostat ....................................129

Section 12 - Sensors for Economizer Modules .......................................157

Sensor Features ............................................................................................................................................................158

Type of Sensors for Economizer ....................................................................................................................................159

C7150 and C7046 Mixed and Supply Air Sensors .........................................................................................................162

ii Honeywell Economizers 63-8594-02

Mixed or Supply Air Sensor Control Sequence ..............................................................................................................163

Carbon Dioxide Sensor ..................................................................................................................................................163

TM

JADE

Economizer (W7220) Sensors .........................................................................................................................164

Section 13 - Checkout ...............................................................................167

Standard Checkout Procedure .......................................................................................................................................168

Checkout W7212 ...........................................................................................................................................................168

Check out C7400 with W7459, W7210 and W7212 .......................................................................................................170

Check out for W7220 JADE

TM

Economizer ...................................................................................................................172

Section 14 - Simulator for W7212 .............................................................173

Section 15 - Demo for W7220 ...................................................................177

Section 16 – Economizer Savings Estimator .........................................181

Section 17 - Retrofit and Upgrades ..........................................................183

Replacement of W7459Axxx and M7415Axxx with W7220A1000 (JADETM) and M7215A1008 ................................188

Replacement of W7212Axxx with W7220A1000 (JADE

Replacement of W7210Axxx with W7220A1000 (JADE

Replacement of W859F with W7220A1000 (JADE

Replacement of W957G with W7220A1000 (JADE

W957G Replaced with W7220 and M7285A1045 Mod Motor .............................................................................198

Cross Reference ............................................................................................................................................................199

W7220 JADE

TM

Y-Pack Table .......................................................................................................................................203

TM

) ..........................................................................................191

TM

TM

) ..........................................................................................193

) and M7285A1045 .....................................................................195

TM

) and M7285A1045 ....................................................................197

Section 18 - Appendix ...............................................................................207

Glossary .........................................................................................................................................................................207

Accessories for the M74XX Series Actuators ................................................................................................................210

Accessories for the W7220 JADE

TM

Economizer Module .............................................................................................211

Honeywell Economizers 63-8594-02 iii

iv Honeywell Economizers 63-8594-02

Section 1 - Ventilation

M23621

MIXED AIR SECTION

O.A.

FILTERS

EX.
AIR

DAMPER

DAMPER

DAMPER

Section 1 - Ventilation

1 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

Indoor Air Quality

The characteristics of the indoor climate of a building, including the gaseous
composition, temperature, relative humidity, and airborne contaminants.

The Arab oil embargo of 1974 caused many
building designers to begin implementing
energy cost reduction measures. One of these
measures was to seal up the building shell to
reducing exfiltration of indoor air and the
resultant heat loss. Energy costs were
reduced but there was a significant negative
side effect that was not detected until 1988:
Indoor Air Quality. Many buildings constructed
prior to 1974 had sufficient leakage through
poorly sealed windows and doors to
adequately ventilate the building. Construction

methods used between 1974 and 1988
substantially reduced this leakage. As a result
many buildings constructed between 1974 and
1988 are not adequately ventilated for the
occupants.

As the energy costs continue to rise into the
beginning of the 21st century, building
managers are seeking ways to reduce the
energy usage in new and existing buildings
and continue to provide a healthy environment
for the building occupants.

Honeywell Economizers 63-8594-02 2

Section 1 - Ventilation

Healthy Air

Building-Related Illness

A diagnosable illness with identifiable symptoms whose cause can be
directly attributed to airborne pollutants within a building such as
Legionnaires disease or hypersensitivity pnuemonitis.

The American Society of Heating,
Refrigeration, and Air Conditioning Engineers
(ASHRAE) are engineers in the HVAC
industry who establish standards for the
mechanical equipment used to heat, cool and
ventilate buildings. Many local, state, national
and international buildings codes are based
on these standards. ASHRAE Standard

62.1,Ventilation for Acceptable Indoor Air
Quality, is the ventilation standard for
commercial buildings. It states “indoor air
quality is acceptable when there are no known

contaminants at concentrations determined to
be harmful to building occupants, as
determined by cognizant authorities, and
when a substantial majority (80% or more) of
those persons exposed to the indoor air do not
express dissatisfaction with its quality.” This
standard sets minimum outdoor air ventilation
rates and requires other measures intended to
provide indoor air quality that is both
acceptable to human occupants and
minimizes negative effects on health.

3 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

Headaches

Dizziness

Symptoms of Inadequate Ventilation

Drowsiness

Fatigue

Nausea

Eye Irritation

Causes of poor indoor air quality are not
always caused by the design of the building.
Poor or improper maintenance such as
outdoor air dampers that are blocked open or
completely closed, defective damper actuators
or incorrectly set or malfunctioning controls
may also cause inadequate ventilation. Many
maintenance people respond to occupant
complaints with only temperature in mind. If
the room is within the acceptable temperature

Respiratory Irritation

range of 68 to 78°F. (20 to 26°C) it is
perceived that no adjustments are necessary.
The occupants may have many of the
symptoms listed above but do not have the
knowledge to request “open the outside air
damper” or “increase the volume of supply air
to this room.” It is incumbent on the
knowledgeable HVAC service person to
recognize inadequate ventilation when it is
encountered.

Honeywell Economizers 63-8594-02 4

Indoor Air Ventilation Standards

Section 1 - Ventilation

ASHRAE is continually updating the
ventilation standard (ASHRAE 62.1) to provide
guidelines for design and maintenance of
buildings. These standards are recommended
guidelines only and are not legal
requirements. However many state and local
codes use the ASHRAE standards as the
basis for building codes for new construction
and building occupancy. They also form a
basis for litigation in indoor air quality lawsuits.

Some measurements and gases referred to in
the standards may not be familiar to the
average person in the HVAC industry.
However the majority of the information
contained in these standards is very clearly
stated. Everyone in the HVAC industry should
be knowledgeable about the contents of these
standards.

The ventilation standard states a minimum
outdoor air ventilation rate required per person
per type of environment in Cubic Feet per
Minute (cfm). The ventilation requirement
varies between occupied and unoccupied
periods. Outdoor air dampers are set to a
minimum position based on the maximum
occupancy level for the space. To save energy
the ASHRAE 62.1 standard also allows
ventilation to be based on a CO

sensor input

2

that determines occupancy. This is commonly
referred to as CO

-based demand control

2

ventilation (DCV).

CO2 Based Demand Control
Ventilation

CO2 is a fairly dependable indicator of the
concentration of the odorous bioeffluents

exhaled by human beings. Therefore we can
use CO2 concentration levels in a space to

determine the human occupancy and reduce

outdoor air intake when the space is not
occupied to the maximum design occupancy
level. CO

-based DCV is an energy

2

conservation measure; its purpose is to
reduce outdoor air intake rates and the energy
required to condition the outdoor air when
spaces are not occupied at maximum design
densities.

For those who do not want to read an
engineering standard, ASHRAE offers a user
manual that:

• offers information on the intent and
application of Standard 62.1

• provides sample calculations and examples.

• provides useful reference materials.

• gives guidance to building operation and
maintenance personnel.

Standard 62.1 Ventilation

for Acceptable Indoor Air Quality

(ANSI Approved)

The Standard and User's Manual can be
ordered from:

ASHRAE Publications Sales
1791 Tullie Circle, N.E.
Atlanta, GA 30329 or

www.ashrae.org

5 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

Energy Standards

There are four ASHRAE standards that affect
energy use in buildings: Standard 90.1,
Standard 90.2, Standard 100 and Standard

189.

Standard 90.1

Energy Efficient Design of New
Buildings covers all buildings except low-rise
residential for new design and build. It has
been used for all buildings in the past due to
the lack of detail in Standard 100.

Standard 90.2 Energy Efficient Desin of New
Low-Rise Buildings covers low-rise residential
buildings and has lacked detail in the past.

Standard 100 Energy Efficiency in Existing
Buildings is the energy standard for existing
buildings including residential. It was revised
in 2012 to include compliance requirements,
energy use analysis methods and energy
targets, operation and maintenance and
energy audit requirements for existing
buildings for energy efficiency. There is also
an extensive list of Energy Efficiency
Measures that can be incorporated into
existing buildings for energy efficiency.

Standard 189

Design of High-Performance
Green Buildings except Low-Rise Residential
Buildings – developed in conjunction with the
US Green Buildings Council that goes beyond
the requirements of Standard 90.1 for “green”
buildings.

The standards are used as the basis for many
federal, state and local jurisdictions as the
energy code. If a state does not use the
ASHRAE standards for the basis of the codes,
they will use the International Energy Code
Council (IECC) code.

In addition to the standards, ASHRAE has
developed a series of publications designed to
provide recommendations for achieving
energy savings over the minimum code
requirements of Standard 90.1 The guides
were developed in collaboration with The
American Institute of Architects (AIA), the
Illuminating Engineering Society of North
America (IES), the US Green Building Council
(USGBC) and the U.S. Dept of Energy (DOE).
All guides are free for download at the
ASHRAE website.

Honeywell Economizers 63-8594-02 6

Ventilation Requirements

M23621A

MIXED AIR SECTION

O.A.

FILTERS

EX.
AIR

DAMPER

DAMPER

DAMPER

Section 1 - Ventilation

Ventilation is defined as the process of
bringing outside air into a building. The four
major reasons for ventilation are:

1. To ensure a healthy atmosphere for the

occupants. Ventilation is used to dilute
indoor contaminants and provide fresh air
for breathing.

2. To pressurize the building. Positive

pressure inside a building prevents
infiltration of unconditioned and unfiltered
outside air through openings.

3. To provide atmospheric cooling. Bringing

in cool outside air is more energy efficient
and less costly than using mechanical
cooling equipment.

4. To replace air that is being exhausted.

The term for this is make-up air.
Whenever air is exhausted, replacement
air must be provided.

ventilation system. Section 6 of ASHRAE 62.1
offers two procedures designers can use to
determine ventilation rates, the Ventilation
Rate Procedure (VRP) and the Indoor Air
Quality Procedure (IAQP).

The VRP method is based on typical spaces
and usage, the rates are intended to dilute and
exhaust bioeffluents from occupants and
building contaminants to satisfy the 80% of the
occupants of the space. There are two
sources of contaminants in a space that
ventilation is intended to reduce: Occupants
and their activities (e.g., use of office
equipment) and Off-gassing from building
materials. The ventilation rate in the breathing
zone (Vbz) required for both people related

sources (Vp) and building related sources (Va)
is:

Vbz = Vp + V

a

Vp and Va both have two components; Vp is
the number of people in the space (Pz) times
the occupant comfort factor Rp (minimum
ventilation rate determined by extensive

studies for occupant comfort based on activity
level in the space) and Va is the area of the

space (Az) times the building component
factor Ra (minimum ventilation rate
determined by extensive studies for occupant

comfort based on type of space). Therefore
ventilation required in the breathing zone
becomes:

The air controls in the mixing section of a
HVAC unit are used to maintain a minimum
ventilation volume at all times. This is in
addition to controlling the dampers for
atmospheric cooling.

Determining the amount of ventilation required
for a space is probably one of the hardest
tasks an engineer faces in the design of the

Vbz = RpPz + RaA

z

Rp and Ra values are found in ASHRAE 62.1
User’s manual (Table 6-A) and ASHRAE 62.1

Standard.

The outdoor air or recirculated air may be
cleaned using a filter or air cleaner but the
outdoor air ventilation rates cannot be reduced
below the rate determined by the above
formula.

7 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

The IAQP method is used for spaces where
the designers target a specific contaminant
and control the concentration level of the
contaminant. This method has two
requirements: Maintain concentration of
specific contaminant(s) below target
concentration limits and achieve a design
target of perceived indoor air quality
acceptability. The IAQP method allows
ventilation rates to be lower than the rates
required by the VRP method if it can be
demonstrated the resulting air quality can
meet the required criteria.

The IAQP procedure has 4 steps:

• Identify the contaminants of concern.

• Determine acceptable concentration of
contaminant(s).

• Specify the perceived indoor air quality
criteria.

• Apply an acceptable design approach to
achieve the performance criteria.

Additional information on ventilation and the
two methods used to determine the ventilation
rates can be found in ANSI/ASHRAE Standard

62.1 and in the User’s manual for ANSI/

ASHRAE Standard 62.1. Both documents are
available on the ASHRAE website at
http://resourcecenter.ashrae.org/store/ashrae/

Example using the VRP method: Office space
of 6600 sq. feet with maximum occupancy of 7

persons per 1000 ft2.

Vbz = RpPz + RaAz where
Rp = 5 cfm per person
(Table 6-A ASHRAE 62.1 User’s Manual)
Pz = 7 person per 1000 ft2 x A

z

Ra = 0.06 cfm per ft2

(Table 6-A ASHRAE 62.1 User’s Manual)

Az = 6600 ft2.

Vbz = 5 ft3 / min/person x 7 persons/1000 ft2 x

6600 ft2 + 0.06 ft3/ min/ft2 x 6600 ft

2

= 231 cfm + 396 cfm
=627 cfm

For a single zone system V
ventilation) is the same as V

(outdoor

OT

. For multiple

bz

zone systems a zone air distribution system
effectiveness (E) factor needs to be used in
the calculation of the V

. See ASHRAE

OT

Standard 62.1 for method.

In our example during maximum occupancy
the ventilation is 627 cfm. When the
occupancy rate is less than the maximum
occupancy, the ventilation rate can be
adjusted to a lower occupancy and the
ventilation increased as the CO

level in the

2

space increases. This can be done following
these steps:

• Calculate the VOT.

• Use Vbz = RpPz + RaAz, where Pz = 0. This
is the new ventilation rate Vat (the area
building based component).

• Add a CO2 sensor to the space.

• Adjust the CO2 maximum to the Vbz (for
maximum occupancy).

• Adjust the minimum position for occupancy
for Va.

In our example the Vbz ventilation is 627 cfm
and the minimum position (Va) is 396 cfm.
Using a CO2 sensor for Demand Control
Ventilation, the new minimum position is set

for 396 cfm and the maximum damper position
for occupancy ventilation is 627 cfm. When
one person enters the space or the
commercial thermostat goes into occupancy
mode, the outdoor air dampers will open to
bring in 396 cfm of outdoor air. As space
occupancy increases, the CO2 level will

increase and the outdoor air dampers will
modulate open to the maximum of 627 cfm of
outdoor air.

NOTE: When the commercial thermostat calls

for free cooling using an economizer,
the dampers are still allowed to
override the DCV maximum position
for ventilation and open the damper
100% open for maximum free cooling.

Honeywell Economizers 63-8594-02 8

Section 1 - Ventilation

Air Handler Control Loops

DAMPER

EX.
AIR

RETURN AIR
FROM ROOM

O.A.

DAMPER

MIXED
AIR

MIXED AIR

SECTION

There are typically four sections of an air
handler. The Mixed Air Section is where
return air and outside air are combined
(mixed). Note some systems’ fans may be
100% return air or 100% outside air and will
not have a mixed air section.

The Conditioning Section commonly
contains filtration, heating, cooling and
humidification. The filters and heating and
cooling coils are located in the conditioning
section of the air handler.

DAMPER

FILTERS

HEATING COIL

SUPPLY
AIR TO
BUILDING

COOLING COIL

CONDITIONING

SECTION

FAN

FAN

SECTION

TERMINAL

SECTION

M23889A

In the Fan Section on the air handler shown
there is a supply fan. On other air handlers
there may be a return or exhaust fan. The
supply fan on this unit is referred to as a pull­through because it is located on the outlet of
the coils. If it were located in front of the coils
then it would be a push-through fan.

The Terminal Section is composed of all the
components between the central fan and the
zones.

9 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

BUILDING

IS HIGHER THAN 70˚F (21 C)

EXHAUST
AIR

Basic Economizer Control

DAMPER

RETURN AIR
FROM ROOM

DAMPER

DAMPER
MOTOR

DAMPER
LINKAGE

OUTSIDE
AIR

120

F

110

130

100

140

90

15

80

16

70

100

80

120

60

40

140

°F

PROPORTIONAL
MINIMUM POSITION
CONTROL FOR
OUTSIDE AIR
DAMPERS

ECONOMIZER TWO-POSITION
HIGH LIMIT. CLOSES OUTSIDE
AIR DAMPERS TO MINIMUM WHEN
OUTSIDE AIR TEMPERATURE

170

60

180

Shown is the most basic temperature based
economizer control configuration. An
averaging element mixed air controller with
the sensing element is located in the duct
before the cooling or heating coils and
maintains the mixed air at 55°F (13°C). A two
position limit controller with sensing element in
outdoor air is used to close the outside air
dampers to a minimum position if the outdoor
air temperature is too warm to use for cooling.

There is a minimum position control on most
air handlers. The function of this control is to
ensure proper ventilation. The control provides
adjustable damper positioning between 0 and
100%. The outdoor damper position must be
set for minimum ventilation requirements
based on building occupancy as defined by
state or local code.

TR

TR1

BC

S

+

O

A

D

H705

S

R

+

5

2

1

ENTHALPY

4

3

X

CONTROL

D

6

SUPPLY
AIR TO

120

F

110

130

100

140

90

15

80

16

70

170

60

180

PROPORTIONAL MIXED
AIR CONTROLLER.
SETPOINT 55˚F (13 C)

M23916A

NOTE: A setting of 25% does not produce

25% airflow because the flow through
dampers is nonlinear.

It is important to know how much outside air is
being brought into a building through the
outdoor dampers on the air handlers. When
the return and mixed air temperatures can be
measured there is a formula used to calculate
the settings that will provide the desired
quantity of outside air.

Using the formula Vbz = Vp we know the total
ventilation and volume required. A second

formula is used to calculate the mixed air
temperature when the outside air temperature,
the return air temperature and the required
percentage of outside air are known.

Honeywell Economizers 63-8594-02 10

Mixed Air Formulas

M23917A

MIXED
AIR
SENSOR

ECONOMIZER

“OA”

“MA”

“RA”

C7400S
SENSOR

MS3103
ACTUATOR

COMMERCIAL
THERMOSTAT

Section 1 - Ventilation

Return Air

Temperat ure

Return Air

Temperat ure

_

_

Mixed Air

Temperature

Outdoor Air

Temperature

Formula for Measuring the Percentage of Outside Air in an Air Handler.

This formula is used to determine the
percentage of outside air (by volume) being
brought into a building from the outside. The
OA dampers can be adjusted by measuring
the MA, OA and RA to balance the correct
Vbz. It is a test that should be conducted

during routine maintenance to ensure that the

Return Air

Temperature

X

% of

Return

Air

Outside Air

+

Temperature

Formula for Adjusting the Minimum Position Control.

x 100% =

Volume (%) of

Outside Air

correct percentage of ventilation is being
provided. Note the fan must be running with
the panels on the unit to take these
measurements. Drill a hole in the side of the
unit and insert temperature probe to measure
the MA temperature. The hole must be sealed
when measurements are completed.

X

% of

Outside

Air

Temperature

=

of Mixed Air

This formula is used to make adjustments to
the mixed air controls. In ASHRAE 62.1 there
are two components of the percent of outdoor
air ventilation required, the human component
and the buildings effluent component. The
rates in the standard are based on the type of
human activity normally performed in the
building. For example: the base rate for office
buildings is 5 cfm per person and the building

effluent rate is 0.06 cfm per square foot of
space. Initially only two temperatures are
measured, return and outside air. The
minimum position control is then adjusted until
the mixed air temperature is equal to the result
of the formula. For design requirements for
CFM per person for all building types, refer to
ASHRAE standard 62.1 section 6 and/or local
or state building codes.

11 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

OUTSIDE AIR TEMPERATURE

MIXED and RETURN AIR TEMPERATURES

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

%

O
U

T
S

I

D

E

A

I

R

%

O
U

T
S

I

D

E

A

I

R

49 C

120 F

43

110

38

100

32
90

27
80

21
70

16
60

10
50

4

40

-1

30

-7

20

-12
10

-18
0

-23

-10

-29 C

-20 F

120 F

49 C

110

43

100

38

90
32

80
27

70
21

60
16

50
10

40

4

30

-1

20

-7

10

-12

0

-18

-10

-23

-20 F

-29 C

M25274A

Outside Air Percentage Chart

This chart can also be used for measuring the
percentage of outside air on an air handler.
The same three temperatures are measured
per the formulas on the preceding page. Lines
are drawn on the chart using a ruler. As with
the formulas this chart is most effective if there
is at least a 10 degree F difference between
the return and outside air. This will typically
require either a warm or cold day rather than
moderate weather. It is more accurate to
measure outside air percentage on a day

Honeywell Economizers 63-8594-02 12

when the outside temperature is 10°F (-12°C)
rather than on a day when it is 70°F (21°C). If
the temperature difference between the return
and outside air is only a few degrees, a small
error in measurements can alter the results by
as much as 50% using this method. If the
temperature difference is 40 or 50°F (22 or
28°C) small errors in measurement do not
substantially affect the results of the
calculations.

Example 1: Using the Outside Air Percentage Chart

OUTSIDE AIR TEMPERATURE

MIXED and RETURN AIR TEMPERATURES

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

%

O
U

T

S

I

D

E

A

I

R

%

O
U
T

S

I
D
E

A

I
R

49 C

120 F

43

110

38

100

32
90

27
80

21
70

16
60

10
50

4

40

-1

30

-7

20

-12
10

-18
0

-23

-10

-29 C

-20 F

120 F

49 C

110

43

100

38

90
32

80
27

70
21

60
16

50
10

40

4

30

-1

20

-7

10

-12

0

-18

-10

-23

-20 F

-29 C

Draw a line straight
down from the mixed air
temperature till it
intersects the line that
was just drawn.

Draw a line from the return
air on top to the outside air on
the bottom.

Measure the outside air temperature.

At the point of

intersection draw a

line to the left till the

percentage of outside

air is indicated.

Measure the mixed air
temperature. This should be
done in 4 or more locations and
averaged.

6

4

3

70 F (21 C)

1

Measure the
return air
temperature.

2

5

RETURN AIR TEMP

MIXED AIR TEMP

OUTSIDE AIR TEMP

OUTSIDE

AIR

CHART

59 F

(15 C)

25 F (-4 C)

M25275A

Section 1 - Ventilation

1. Measure the return air temperature.

2. Measure the outside air temperature.

3. Draw a line from the return air

temperature to the outside air
temperature.

4. Measure the mixed air temperature in

multiple locations and determine the
average.

5. Draw a line down from the mixed air

temperature to the point where it
intersects the first line.

6. Draw a line from the point of intersection

to the outside air percentage on the left
side of the chart.

According to the results from this chart this air
handler is supplied with 26% outside air. If the
total supply volume is 20,000 cubic feet per

minute (cfm) (566 m3/min) then:

0.26 X 20,000 cfm of total supply air equals
5,200 cfm of outside air (147 m3/min).

This indicates that when the measurements
were done on this air handler the total volume
of outside air in the mixed air was 5,200 cfm of

outside air (147 m3/min).

13 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

OUTSIDE AIR TEMPERATURE

MIXED and RETURN AIR TEMPERATURES

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

%

O
U

T
S

I

D

E

A

I

R

%

O
U

T
S

I

D

E

A

I

R

49 C

120 F

43

110

38

100

32
90

27
80

21
70

16
60

10
50

4

40

-1

30

-7

20

-12
10

-18
0

-23

-10

-29 C

-20 F

120 F

49 C

110

43

100

38

90
32

80
27

70
21

60
16

50
10

40

4

30

-1

20

-7

10

-12

0

-18

-10

-23

-20 F

-29 C

Measure the return air

temperature.

1

Measure the
outside air
temperature.

2

Draw a line

from the return

air on top to the

outside air on

the bottom.

3

Measure the mixed
air temperature.
This should be
done in 4 or more
locations and
averaged.

4

Draw a line straight down from the

mixed air temperature till it intersects

the line that was just drawn.

At the point of

intersection draw a

line to the left till

the percentage of

outside air is

indicated.

6

71 F (22 C)

RETURN AIR TEMP

MIXED AIR TEMP

OUTSIDE AIR TEMP

OUTSIDE

AIR

CHART

75 F

(24 C)

84 F (29 C)

5

M25276A

Example 2: Use of Outside Air Chart on a Warm Day

The chart can also be used on a warm day
when the outside air temperature exceeds
both the return and the mixed air
temperatures. The first line drawn will slant in

a different direction. Once again it is best to do
this test when there is a minimum of 10
degrees F difference between the outside and
return air.

Honeywell Economizers 63-8594-02 14

Extra Outside Air Percentage Chart

Section 1 - Ventilation

OUTSIDE

AIR

CHART

C 92-

F 02-

01-

32-

0

81-

01

21-

7-

02

1-

03

4

04

MIXED AIR TEMP

OUTSIDE AIR TEMP

R

I

%08

%09

%001

RETURN AIR TEMP

O

A

%07

D

E

%06

S

I

%05

U

T

%03

%04

%

%0

%01

%02

C 92-

F 02-

32-

01-

0

81-

MIXED and RETURN AIR TEMPERATURES

01

21-

7-

02

1-

03

4

04

OUTSIDE AIR TEMPERATURE

05

01

06

61

07

12

08

72

09

23

83

001

34

011

C 94

F 021

%06

%07

%08

%09

%001

R

A

I

E

D

01

05

61

06

12

07

72

08

23

09

83

001

34

011

C 94

F 021

%0

%01

%02

%03

%04

%05

O

U

T

S

I

%

M25277A

15 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

A

Example 3: Minimum Ventilation Adjustment

EXHAUST
AIR

OUTSIDE

IR

30˚F (-1 C)

DAMPER

1. Specifications:

Office space - 100,000 ft

2

Air handler capacity 20,000 cfm
(566 m3/min.)
People in area - 250

2. Ventilation (VOT) required:

= 250 x 5 cfm + 0.06 cfm/ft2 x 100,000 ft
= 1250 cfm + 6000 cfm
= 7250 cfm

Where Vat = 0.06 cfm/ft2 x 100,000 ft2.
Therefore Vat = 6000 cfm

DAMPER

2

RETURN
AIR
73˚F (23 C)

M23910

3. Ventilation percentage:

7250 cfm (205.3 m3/min)/20,000 cfm
(570 m3/min)

VOT maximum position= 36%

6000 cfm (169.9 m3/min)/20,000 cfm
(570 m3/min)

VOT Minimum position= 30%

4. Measure the return air temperature:

73°F (23°C).

5. Measure the outside air temperature:

30°F (-1°C).

This example shows a procedure for adjusting
the DCV maximum and minimum positions.

Honeywell Economizers 63-8594-02 16

M23918A

SUPPLY

ADJUST THIS SETTING

OUTSIDE
AIR
30˚F (-1 C)

RETURN

AIR
73˚F (23 C)

Section 1 - Ventilation

FILTERS

Return Air

Temperature

X

+

S

COMMERCIAL
THERMOSTAT

% of

Return

Air

Outside Air

+

Temperature

SUPPLY OR
MIXED AIR
SENSOR

X

COILS

FAN

% of

Outside

Air

UNTIL THE MIXED AIR
IS 62.5˚F (17 C)

AIR

Temperature

=

of Mixed Air

6. Use the mixed air temperature formula or the graph to determine the Demand Control

Ventilation maximum MAT:

73°F (23°C) X 64% + 30°F (-1°C) X 36% =

Temperature of

Mixed Air

46.7°F (8.2°C) + 10.8°F (-11.8°C) 57.5°F (14.2°C)

7. Use the mixed air temperature formula or the graph to determine the minimum position MAT:

73°F (23°C) X 60% + 30°F (-1°C) X 30% =

43.8°F (8.2°C) + 12°F (-11°C) 55.8°F (13.2°C)

8. Close the outside air dampers. The

method used for this depends upon the
controller being used.

9. When using analog economizers, turn the
DCV maximum position control (pot) until
the measured mixed air temperature is

57.5°F (14.2°C). When using the JADETM
controller, go to the set point menu and
adjust the Vent max setting and the up
and down arrows on the keypad.

10. Mark this setting on the control as being

11. Close the outside air dampers. On the

analog economizers, turn the minimum
position control (pot) until the measured
mixed air temp is 55.8 °F (13.2°C). When

using the JADETM controller, go to the set
point menu and adjust the Vent min
setting using the up and down arrows on
the keypad.

12. Mark this setting on the control as being
30% outdoor air.

Temperature of

Mixed Air

36% outdoor air.

17 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

A

Example 4: Ventilation Review Questions

EXHAUST
AIR

DAMPER

OUTSIDE

IR

21˚F (-6 C)

1. Specifications:

Office space - 200,000 ft2.
Air handler capacity - 30,000 cfm
(849 m3/min)
People in area - 350

2. Ventilation required:

=350 x 5 cfm per person + 0.06 cfm/ft2 x
200,000 ft

2

=1750 cfm + 12,000 cfm
=13750 cfm

RETURN
AIR
68˚F (20 C)

30,000 CFM

3

MIN.)

(849 M

M23920

4. Measure the return air temperature:

68°F (20°C)

5. Measure the outside air temperature:

21°F (-6°C)

This is the air handler for an office building
with 350 people maximum occupancy.
Complete the required steps in the procedure
to adjust the controls for the correct volume of
ventilation.

3. Ventilation percentage:

13750 cfm (389.4 m3/min)/30,000 cfm
(849 m3/min)

Honeywell Economizers 63-8594-02 18

M23919B

SUPPLY

OUTSIDE
AIR
21˚F (-6 C)

RETURN

AIR
68˚F (20 C)

Section 1 - Ventilation

FILTERS

+

S

SUPPLY OR
MIXED AIR
SENSOR

ADJUST THIS SETTING
UNTIL THE MIXED AIR
IS ___˚F (___ C)

% of

Return Air

Temperature

X

Return Air

COMMERCIAL
THERMOSTAT

% of

Outside Air

+

Temperature

CONTROLLER

X

Outside Air

6. Use the mixed air temperature formula or the graph:

68°F (20°C) X ____% + 21°F (-6°C) X ____% =

_____°F (____°C) + _____°F (_____C) _____°F (____°C)

AIR

Temperature

=

of Mixed Air

Temperature of

Mixed Air

NOTE: Note use this formula to determine

DCV maximum MAT and Minimum
position MAT.

7. Close the outside air dampers to the
minimum position.
The method used for this depends upon
the controller being used.

8. On analog economizers, turn the DCV
maximum control (potentiometer) until the
measured mixed air temperature is
_____°F (_____°C). When using the

JADETM controller, go to the set point

menu and adjust the Vent max setting
using the up and down arrows on the
keypad.

9. Mark this setting on the control as being
36% outdoor air.

10. On analog economizers, turn the
minimum position until the measured
mixed air temperature is _____°F

(_____°C). When using the JADETM
controller, go to the set point menu and
adjust the Vent min setting using the up
and down arrows on the keypad.

11. Mark this setting on the control as being
_____% outdoor air.

12. Restore all settings and setpoints.

19 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

Economizer Cycle Definition

ECONOMIZER CONTROLLER

SINGLE STAGE COOLING

FIRST
STAGE COOL

Y1

SECOND

Y2

STAGE COOL

COMMERCIAL THERMOSTAT

On a First Call for Cooling From
Commercial Thermostat (Y1)

Controller signal is routed to the economizer
logic module.

IF THE OUTDOOR AIR IS SUITABLE FOR
FREE COOLING:

YES

OUTSIDE
AIR COOL?

OPEN OUTSIDE

NO

AIR DAMPER

MECHANICAL
COOL 1

COMPRESSOR

M13816A

hold the temperature between -1F and +1F of
the MAT setpoint. For example if the MAT is
set to 53F, the damper will hold between 52F
and 54F.

When the mixed or supply air goes below 50°F
(10°C) the damper is modulated towards

closed (52°F for JADETM in our example).

With analog economizers the actuator
modulates the outdoor damper open until the
room temperature is cool enough to satisfy the
call for cooling and maintain the mixed or
discharge air between 50 and 55°F (10 and

13°C). With the JADETM controller the actuator
modulates the OA damper open to maintain
the MAT setpoint. The MAT default is 53F with
a 2F differential. The MAT setpoint can be
changed in the menu using the up and down

arrows on the JADETM.

When the mixed or discharge air is between
50 and 55°F (10 and 13°C) the actuator will
hold damper position with analog

economizers, with JADETM the actuator will

Honeywell Economizers 63-8594-02 20

When the mixed or supply air goes above
56°F (13°C) the damper is modulated towards

open (54°F for JADE

TM

in our example).

For the analog economizers the MAT setpoint
is not adjustable, the range can be changed

using external resistance. For the JADETM, the
MAT is adjustable between 38°F and 70°F.

IF THE OUTDOOR AIR IS NOT SUITABLE
FOR FREE COOLING:

The first stage of the cooling compressor is
turned on and the dampers are set to
minimum for occupancy requirements (Vat if

using DCV, VOT if no DCV).

Single and Two Stage Cooling With Economizer

Y2

Y1

SECOND
STAGE COOL

FIRST
STAGE COOL

OUTSIDE
AIR COOL?

YES

NO

OPEN OUTSIDE
AIR DAMPER

COMPRESSORS

MECHANICAL
COOL 1

M13817A

TWO STAGE COOLING

MECHANICAL
COOL 2

COMMERCIAL THERMOSTAT

ECONOMIZER CONTROLLER

Section 1 - Ventilation

On a Call for Second Stage Cooling

Controller signal is routed to the economizer
logic module.

IF THE OUTDOOR AIR IS SUITABLE FOR
FREE COOLING AND THE OUTSIDE AIR
DAMPERS ARE OPEN:

The economizer logic turns on the first stage
of mechanical cooling for the second stage of
cooling required by the commercial
thermostat. With JADETM the actuator drives
the OA damper wide open to try to satisfy the
call for second stage of cooling. If OA
dampers are 100% open and call for second
stage is not satisfied then the JADETM will turn
on the second stage mechanical cooling and
the OA damper will remain wide open.

NOTE: JADETM has an option in the

Advanced setup menu "STG3 DLY"
which is a delay after the stage 2 for

cooling has been active for a
programmed amount of time. If the
space has not been satisfied after the
programmed amount of time, the
JADETM turns on the 2nd stage of
mechanical cooling to allow 3 stages
of cooling, 1 economizer and 2
mechanical. This feature can also be
turned off.

IF THE OUTDOOR AIR IS NOT SUITABLE
FOR FREE COOLING:

The first stage cooling compressor is on, and
the logic module turns on the second stage of
mechanical cooling.

NOTE: A commercial thermostat with a

minimum of two stages of cooling is
required. The first stage must be
available for economizing if outside air
is suitable.The OA dampers must be
opened completely on a second call
for cooling before the mechanical
cooling is turned on.

21 Honeywell Economizers 63-8594-02

Section 1 - Ventilation

Honeywell Economizers 63-8594-02 22

Section 2 - Enthalpy Theory And Controllers

40 F

4 C

50 F

10 C

60 F

16 C

70 F

21 C

80 F

27 C

90 F

32 C

100 F

38 C

110 F

43 C

120 F

49 C

35 F

2 C

45 F

7 C

55 F

13 C

65 F

18 C

75 F

24 C

85 F

29 C

95 F

35 C

105 F

41 C

115 F

46 C

F 0 9

) C 2 3 (

B L U B T E W

F 5 8

) C 9 2 (

B L U B T E W

F 0 8

) C 7 2 (

B L U B T E W

F 5 7

) C 4 2 (

B L U B T E W

F 0 6

) C 6 1 (

B L U B T E W

F 5 5

) C 3 1 (

B L U B T E W

F 0 5

) C 0 1 (

B L U B T E W

5 4

F

(

7

) C

B L U B T E W

0 4

F

(

4

) C

B L U B T E W

5 3

F

(

2

) C

B L U B T E W

H R % 0 8

H R % 0 7

H R % 0 3

H R % 0 4

H R % 0 5

H R % 0 6

H R % 0 9

H R % 0 1

H R % 0 2

H R % 0 0 1 - N O I T A R U T A S

F 0 7

) C 1 2 (

B L U B T E W

F 5 6

) C 8 1 (

B L U B T E W

DRY BULB TEMPERATURES

15

BTU/LB

34.8 k­J/kg

20 BTU/LB

46.4 k-J/kg

25 BTU/LB

58 k-J/kg

30 BTU/LB

69.7 k-J/kg

35 BTU/LB

81.4 k-J/kg

40 BTU/LB

92.8 k-J/kg

45 BTU/LB

104.5 k-J/kg

50 BTU/LB

116 k-J/kg

M25280

Section 2 - Enthalpy Theory And Controllers

23 Honeywell Economizers 63-8594-02

Section 2 - Enthalpy Theory And Controllers

40 F

4 C

50 F

10 C

60 F

16 C

70 F

21 C

80 F

27 C

90 F

32 C

100 F

38 C

110 F

43 C

120 F

49 C

35 F

2 C

45 F

7 C

55 F

13 C

65 F

18 C

75 F

24 C

85 F

29 C

95 F

35 C

105 F

41 C

115 F

46 C

F 0 9

) C 2 3 (

B L U B T E W

F 5 8

) C 9 2 (

B L U B T E W

F 0 8

) C 7 2 (

B L U B T E W

F 5 7

) C 4 2 (

B L U B T E W

F 0 6

) C 6 1 (

B L U B T E W

F 5 5

) C 3 1 (

B L U B T E W

F 0 5

) C 0 1 (

B L U B T E W

5 4

F

(

7

) C

B L U B T E W

0 4

F

(

4

) C

B L U B T E W

5 3

F

(

2

) C

B L U B T E W

H R % 0 8

H R % 0 7

H R % 0 3

H R % 0 4

H R % 0 5

H R % 0 6

H R % 0 9

H R % 0 1

H R % 0 2

H R % 0 0 1 - N O I T A R U T A S

F 0 7

) C 1 2 (

B L U B T E W

F 5 6

) C 8 1 (

B L U B T E W

DRY BULB TEMPERATURES

M25278

The Psychrometric Chart

This is a psychrometric chart. To use the chart
effectively the thermodynamic properties of air
must be known. Some common terms are:

Dry Bulb Temperature

The temperature read directly on an ordinary
thermometer.

Wet Bulb Temperature

The temperature read on a thermometer
whose bulb is encased in a wet wick and with
air blown across the wick at 900 ft. per minute

(274 meters per minute). The evaporation of
the water causes the temperature to drop, this
may also be referred to as the “evaporation
effect.” When the temperature stops falling
that is the wet bulb temperature. The sling
psychrometer is a common instrument used to
determine the wet bulb temperature although
there are other methods now available.

Dry bulb and wet bulb are the two most readily
measurable variables on the chart and when
known can be used to determine all other
properties on the psychrometric chart.

63-8594-02 Honeywell Economizers 24