McQuay AZR User Manual

Catalog UV1620

AAF-HermanNelson Classroom Unit Ventilators

Models AZQ, AZR, AZU Self-Contained Floor Units with R-410A Refrigerant

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Nomenclature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

AAF-HermanNelson Classroom Unit Ventilators . . . . . . . . . . . 4

The Model AZ Floor Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Features & Benefits. . . . . . . . . . . . . . . . . . . . . . . . . 6

GentleFlo Delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

The Right Amount of Fresh Air and Cooling. . . . . . . . . . . . . . . 7

Precise Temperature and Dehumidification Control. . . . . . . . . 7

Low Installation Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Easy To Maintain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Built To Last . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

MicroTech II Controls . . . . . . . . . . . . . . . . . . . . . . 13

MicroTech II Controls For Superior Performance, Easy Integra-

tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Control Modes and Functions . . . . . . . . . . . . . . . . . . . . . . . . 14

System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Wall Louvers & Grilles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

VentiMatic™ Shutter Room Exhaust Ventilation . . . . . . . . . . 25

Storage Cabinets, Sink & Bubbler . . . . . . . . . . . . . . . . . . . . . 26

End Panels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Application Considerations . . . . . . . . . . . . . . . . . 27

Why Classrooms Overheat . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Meeting IBC Seismic Requirements. . . . . . . . . . . . . . . . . . . . 31

Face & Bypass Temperature Control. . . . . . . . . . . . . . . . . . . 32

Modulating Valve Temperature Control . . . . . . . . . . . . . . . . . 34

Wall Sleeve Arrangements. . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Unit Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Quick Selection Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Selection Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Hot Water Heating Selection. . . . . . . . . . . . . . . . . . . . . . . . . 45

Steam Heating Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Engineering Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Valve Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Face and Bypass End-Of-Cycle Valve Sizing & Piping . . . . 50

Modulating Valve Sizing & Piping. . . . . . . . . . . . . . . . . . . . . 51

Steam Valve Sizing & Piping . . . . . . . . . . . . . . . . . . . . . . . . 52

Details & Dimensions . . . . . . . . . . . . . . . . . . . . . . 54

Coil Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Model AZ Self Contained Unit Dimensions, 024. . . . . . . . . . 57

Model AZ Self Contained Unit Dimensions, 036. . . . . . . . . . 58

Model AZ Self Contained Unit Dimensions, 044, 054. . . . . . 59

End Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Valve Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Wall Intake Louvers & Grilles . . . . . . . . . . . . . . . . . . . . . . . . 62

VentiMatic Shutter Assembly . . . . . . . . . . . . . . . . . . . . . . . . 63

Sink & Bubbler Cabinet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Filler Sections & Utility Compartment . . . . . . . . . . . . . . . . . . 65

Shelf Storage Cabinets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Typical MicroTech II Wiring Diagrams . . . . . . . . . . . . . . . . . 68

Guide Specifications . . . . . . . . . . . . . . . . . . . . . . . 71

AAF-HermanNelson Unit Ventilator Model AZ Guide Specifica-

tions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

McQuay is a registered trademark and MicroTech II, Digital Ready, GentleFlo, ServiceTools,

Microsoft is a registered trademark and Windows is a trademark of Microsoft Corporation.

and Protocol Selectability are trademarks of McQuay International.

Introduction

Nomenclature

UC0246AZU G 65 B1Z

Product Category U = Unit Ventilator

Product Identifier

ZQ = SC - a/c Face & Bypass

Heating, Ultra Quiet

ZU = SC - a/c Valve Heating,

Ultra Quiet

ZR = SC - a/c Valve Reheat

Design Series 6 = F-Series

Nominal Capacity 024 = 24000 BTUH 036 = 36000 BTUH 044 = 44000 BTUH 054 = 54000 BTUH

Voltage C = 208V, 60Hz, 1Ø D = 208V, 60Hz, 3Ø G = 230V, 60Hz, 1Ø H = 230V, 60Hz, 3Ø K = 460V, 60Hz, 3Ø

Cooling Coil Options G = Direct Expansion H = Direct Expansion with Refrigerant Relief Valve

Heating Options 00 = None 12 = Low Electric Heat, 3-Element 13 = High Electric Heat, 6-Element 65 = 1 Row Hot Water 66 = 2 Row Hot Water 68 = Steam, Low Capacity 69 = Steam, High Capacity

Hand Orientation Z = Not Applicable

Control Options B1 = Basic Stand-Alone w/o TC B2 = Basic Stand-Alone Master w/o TC B3 = Basic Stand-Alone Slave w/o TC B4 = Basic BACnet MS/TP w/o TC B5 = Basic LonMark SCC w/o TC B6 = Basic Metasys N2 Open w/o TC B7 = Basic Stand-Alone w/ TC B8 = Basic Stand-Alone Master w/ TC B9 = Basic Stand-Alone w/o TC w/CO2 BA = Basic Stand-Alone Master w/o TC w/CO2 BB = Basic Stand-Alone Slave w/o TC w/CO2 BC = Basic BACnet MS/TP w/o TC w/CO2 BD = Basic LonMark SCC w/o TC w/CO2 BE = Basic Metasys N2 Open w/o TC w/CO2 BF = Basic Stand-Alone w/ TC w/CO2 BG = Basic Stand-Alone Master w/ TC w/CO2

AL 22 G BC1

Product Style 1 = Product Style 1

SKU Type B = Std. Delivery C = Ext. Delivery

Color I = Antique Ivory W = Off White B = Putty Beige G = Soft Gray

Power Connection G = Box with Switch

Return Air/Outdoor Air 22 = Return Air Front,

Outdoor Air Rear

Discharge AL = 16 5/8" Top Bar

Control Options (continued) E1 = Expanded Stand-Alone w/o TC E2 = Expanded Stand-Alone Master w/o TC E3 = Expanded Stand-Alone Slave w/o TC E4 = Expanded BACnet MS/TP w/o TC E5 = Expanded LonMark SCC w/o TC E6 = Expanded Metasys N2 Open w/o TC E7 = Expanded Stand-Alone w/ TC E8 = Expanded Stand-Alone Master w/ TC E9 = Expanded Stand-Alone w/o TC w/CO2 EA = Expanded Stand-Alone Master w/o TC w/CO2 EB = Expanded Stand-Alone Slave w/o TC w/CO2 EC = Expanded BACnet MS/TP w/o TC w/CO2 ED = Expanded LonMark SCC w/o TC w/CO2 EE = Expanded Metasys N2 Open w/o TC w/CO2 EF = Expanded Stand-Alone w/ TC w/CO2 EG = Expanded Stand-Alone Master w/ TC w/CO2 L1 = Leading Stand-Alone w/o TC L2 = Leading Stand-Alone Master w/o TC L3 = Leading Stand-Alone Slave w/o TC L4 = Leading BACnet MS/TP w/o TC L5 = Leading LonMark SCC w/o TC L6 = Leading Metasys N2 Open w/o TC L7 = Leading Stand-Alone w/ TC L8 = Leading Stand-Alone Master w/ TC L9 = Leading Stand-Alone w/o TC w/CO2 LA = Leading Stand-Alone Master w/o TC w/CO2 LB = Leading Stand-Alone Slave w/o TC w/CO2 LC = Leading BACnet MS/TP w/o TC w/CO2 LD = Leading LonMark SCC w/o TC w/CO2 LE = Leading Metasys N2 Open w/o TC w/CO2 LF = Leading Stand-Alone w/ TC w/CO2 LG = Leading Stand-Alone Master w/ TC w/CO2 44 = Electromech w/2-Pos Damper for Remote T'Sta 45 = Electromech w/2-Pos Damper w/Unit Mtd. ACO 46 = Electromech w/2-Pos Damper w/Unit Mtd. MCO

Grille Unit

AAF-HermanNelson Model AZ Unit Ventilators 3

Introduction

AAF-HermanNelson Classroom Unit Ventilators

For more than 89 years, schools have relied on AAF-HermanNelson unit ventilators to keep classrooms comfortable. Students learn more readily in a quiet, wellventilated environment. That’s why Herman Nelson invented the unit ventilator and why we remain committed to meeting the changing requirements of schools with the highest quality products available.

We realize that keeping expenditures down is a high

iority for school administrators and school boards.

p AAF-HermanNelson unit ventilators are inexpensive to install and operate, and they are designed and built to provide decades of trouble-free service.

Built To Last

Our proven institutional design can withstand the rigors of the classroom environment. It features an extra-sturdy chassis and double-wall damper on the inside; scuffresistant finishes and tamper prevention features on the outside. In fact, many units installed over 30 years ago continue to provide quiet, reliable classroom comfort.

Heavy Duty Frame Construction

AAF-HermanNelson’s exclusive, unitized welded frame is far superior to the fastener-type construction used by other manufacturers. Loosened fasteners can cause vibration, rattles and sagging panels.

Other design features that promote trouble-free

per

ation and long life include:

• A corrosion-resistant, galvanized-steel frame.

• Extra-strength, steel-bar disc

• Heavy-gauge-metal cabinet access panels and doors.

• An extra-str

ength pipe tunnel that stiffens the structure

while adding aerodynamic air flow within the unit.

• Hidden reinforcement that provides additional built-in ort for the top section as well as better support for

supp the fan deck assembly.

harge grille.

igid exterior that is strong enough to support

• A r main

tenance personnel without fear of damaging the

unit.

Rugged Exterior Finish

The superior finish of the unit ventilator cabinet fosters long-lasting beauty as well as resistance to abuse and corrosion. We apply the very highest standards at every step of the finishing process to provide lasting quality:

• Exter

ior cabinet panels are fabricated from high-

qua

lity, furniture grade steel with no sharp edges.

• A specially formulated, environmentally friendly,

ermosetting urethane powder is applied

th electrostatically to the exterior panels. This film is oven-cured to provide correct chemical cross-linking and to obtain maximum scuff- and mar-resistance.

he top of the unit is finished with a textured, non-glare

• T and

scuff-resistant, charcoal bronze electrost atic pa int. End and front panels are available in a pleasing array of architectural colors.

he Oxford brown steel kickplate is coated and baked

• T with a

thermosetting urethane powder paint to blend with floor moldings and provide years of trouble-free service.

h unit is painstakingly inspected before

• Eac then encapsulated in a clear plastic bag, surrounded by an extra-heavy-duty cardboard box and secured to a skid to help provide damage-free shipment.

MicroTech II Control For Superior Performance, Easy Integration

AAF-HermanNelson unit ventilators can be equipped with MicroTech II™ unit controllers for superior performance. Factory integrated and tested controller, sensor, actuator and unit options promote quick, reliable start-up and minimize costly field commissioning. Our Protocol Selectability feature provides easy, low-cost integration into most building automation systems. Select BACnet communications to communicate control and monitoring information to your BAS, without the need for costly gateways. Unit controllers are L the optional L

, LonTalk® or Metasys® N2 Open

ONWORKS

communication module.

ONMARK

certified with

boxing,

4 McQuay Catalog 1620

Introduction

The Model AZ Floor Unit

Our Model AZ is a vertical, floor-standing unit that utilizes refrigerant for cooling, and hot water, steam or electric heat for heating. The Model AZ also can be supplied as a cooling/ventilating unit only.

The Model AZ is just right for new construction and for

etrofit applications. Older buildings with baseboard

r radiant heat or other hydronic heating systems can be easily adapted to work efficiently with Model AZ units. The major features of this model are shown below and described in more detail on the following pages.

1 Welded One-Piece Chassis offers

superior strength, durability, and vibration reduction.

2 Unique Draw-Thru Design provides

uniform air distribution across the coil for even discharge air temperatures.

3 Quiet, Aerodynamic Fans utilize

GentleFlo technology for exceptionally quiet unit operation.

4 Modular Fan Section improves

balance, alignment and simplifies maintenance.

Fan Motor Located Out Of Air Stream

and away from heating coil

reduces heat exposure to prolong life.

6 Outside Air/Return Air Damper &

Linkage Provides superior mixture of

outdoor air and room air for precise temperature control.

7 MicroTech II Controls provide

superior comfort control and easy integration into the building automation system of your choice.

8 Advanced Heat Transfer Coil

design provides extra capacity.

9 Sturdy Cabinet Construction

includes hidden reinforcement, a non-glare textured surface, and a tough, scuff- and mar-resistant finish to make the top sturdy enough to support maintenance personnel.

10 Sectionalized Front Access Panels

provide easy access to unit interior. Panels are easily removed by a single person. Front side panels can be removed while unit is running.

11 Two Hinged To p Access Doors

provide easy access to the motor, electrical, and refrigeration components..

12 Sampling Chamber for unit-

mounted sensor provides accurate sensing of room temperature.

13 Optional Adjustable Caster (Left

and Right Ends).

14 Insulated Double-Wall Outdoor Air

Damper seals tightly without

twisting.

15 Full-leng t h Air Filt er is efficient and

easy to replace. All air delivered to classroom is filtered.

16 Corrosion Proof Sloped Drain Pan. 17 Tamper Resistant Fasteners on

Access Panels

AAF-HermanNelson Model AZ Unit Ventilators 5

Features & Benefits

GentleFlo Delivery

AAF-HermanNelson unit ventilators are engineered and manufactured to deliver quiet, continuous comfort. We developed our GentleFlo™ air moving syst em to minimize operating sound levels—even as demands for more fresh air require units to operate longer and work harder. GentleFlo featur es include:

wheels are large, wide and rotate at a low speed

• Fan to red

uce fan sound levels. They are impact-resistant and carefully balanced to provide consistent performance.

fset, aerodynamic fan wheel blades move air

• Of ef

ficiently (Figure 1).

• Precision tolerances help reduce flow and pr es su re turbulence, resulting

in lower sound levels.

• Fan housings incorporate the latest logarithmic-

ansion technology for smoother, quieter air flow

exp (Figure 2).

Figure 1. GentleFlo Fan Technology

Expanded discharge air opening

• A large, expanded discharge opening minimizes air resistance, further lowering sound levels.

• Modular fan construction contributes to equal outlet

locities and promotes quiet operation.

• Fan shafts are of ground and polish ed steel to

ize deflections and provide consistent, long-term

minim operation.

• Fan assemblies are balanced before unit assembly,

en tested after assembly (and rebalanced if

th necessary) to provide stable, quiet operation.

Figure 2. GentleFlo Reduces Turbulence

Minimal

Offset aerodynamic blades

Logarithmic expansion housing

Precision Tolerances

6 McQuay Catalog 1620

GentleFlo fan blade design

turbulence

Typical fan blade design

High turbulence

Features & Benefits

The Right Amount of Fresh Air and Cooling

AAF-HermanNelson unit ventilators deliver required amounts of fresh air to meet ventilation requirement s and added cooling capacity to maintain consistent comfort for students and teachers. Our Economizer Operation, Demand Control Ventilation (DCV) and Part Load, Variable Air options allow you to mat ch cla ssr oo m comfort requirements even more closely, and reduce operating costs.

at your school is

This means that you can be confiden meeting ventilation standards for Indoor Air Quality and that your students are receiving adequate air to be attentive to instruction. At the same time, you are saving money in early morning hours, between classes or after hours when classrooms are heated and cooled but not always fully occupied.

Economizer Operation

It is well recognized that cooling, not heating, is the main thermal challenge in school classrooms. The typical classroom is cooled by outdoor air over half the time, even in cold climates. It is therefore essential that unit ventilators efficiently deliver outdoor air when classroom conditions call for “free” or economizer cooling.

With AAF-HermanNelson unit ventilators, you can have

tdoor air whenever it is needed. Economize r operatio n

o is facilitated by the outdoor air damper, which automatically adjusts the above-minimum outside air position to provide free cooling when the outdoor air temperature is appropriate (Figure 3). On unit s equippe d with MicroTech II controls, three levels of economizer

rol are available (see See “Economizer Modes” on

con page 14).

Figure 3. Full Economizer Mode

100% Outdoor Air Into Classroom

Condenser Section

Face & Bypass Damper

Room Air Damper

t th

Filter

Outdoor Air Damper

Outdoor Air

Part-Load Variable Air Control

Part Load Variable Air control can be used in conjunction with face and bypass damper temperature control to automatically adjust the unit ventilator fan speed based upon the room load and the room temperat ure. This MicroTech II control option provides higher latent cooling capabilities and quieter operation during non-peak load periods by basing indoor fan speed upon room load. Lower fan speeds in conjunction with our GentleFlo fan technology contributes to a very quiet classroom environment.

Room-temperature PI control loops determine the speed

e fan, wh

of th also provides a built-in delay to prevent overshooting for better comfort control. The outdoor air damper’s minimum-air position is adjusted with the fan speed to bring in a constant amount of fresh air.

ich varies according to the room load. It

Precise Temperature and Dehumidification Control

AAF-HermanNelson unit ventilators provide precise temperature and dehumidification control to keep students and teachers comfortable while making maximum use of “free” outdoor-air cooling to reduce operating costs. They utilize a draw-thru fan design that contributes to even heat transfer and provides uniform discharge air temperatures into the classroom. MicroTech II active dehumidification control strategies and 2-stage compressor operation, provide precise control of temperature and humidity levels under both part-load and full-load conditions.

Draw-Thru Design For Even Discharge Temperatures

The AAF-HermanNelson Draw-Thru design sets our unit ventilators apart from most competitive models. With this system, fans draw air through the entire heat transfer element (Figure 4) rather than blowing it through highly concentrated areas of the coil element. The result is

re uniform discharge air temperatures into the

m classroom and more efficient unit ventilator operation.

AAF-HermanNelson Model AZ Unit Ventilators 7

Features & Benefits

Figure 4. Draw-Thru Design Provides Even Discharge Air

Uniform Discharge Air (Shaded)

Motor

Fans

Condenser

Face & Bypass Design For Better Temperature Control

When coupled with our draw-thru design, face and bypass damper air control offers optimal temperature control in heating. That’s because indoor and out d oo r air streams can be separated until it is optimal to mix them.

Figure 5. Draw-Thru Vs. Blow-Thru Design

Coil

Filter

RA/OA Divider

Room Air

Outdoor Air

Blow-Thru Design

Face & Bypass Damper

Room Air Damper

Room Air

AAF-HermanNelson Draw-Thru Design

Coil

Outdoor Air Damper

Outdoor Air

Active Dehumidification (Reheat)

In high-humidity applications where valve-controlled, reheat units are used, the Active Dehumidification Control (ADC) sequence should be considered. With the Leading Edge Microtech II controls, an inside humiditst at compares indoor humidity (enthalpy) with outdoor humidity to determine the economizer position.

During excessive humidity conditions

, a humidity

sensor directs the unit to continue cooling p ast the room setpoint to remove moisture. Hydronic heat or electric heat is then used to reheat the discharge air to maintain acceptable room temperatures.

Increased Coil Freeze Protection

AAF-HermanNelson units equipped with face and bypass damper control, provide extra protection from coil freeze-up, because there is a constant flow of hot water

through the coil, and water that is flowing typically does not freeze. Additionally, all AAF-HermanNelson units feature a double-walled, insulated outdoor air damper with airtight mohair seals to prevent unwanted coil air from entering the unit.

Furthermore, a low-temperature freezestat is factory inst

alled on

all units with hydronic coils. Its serpentine capillary tube senses temperatures across the leaving air side of the coil, allowing the unit controller to react quickly to low-temperature conditions.

Figure 6. Freezestat

Freezestat

Capillary Tube

Low Installation Costs

Perfect For Both New & Retrofit Applications

New construction installations are easily accomplished with AAF-HermanNelson unit ventilators because they avoid the added cost and space required for expensive duct work. Further savings can be realized because piping installations use less space than duct systems. This is important in existing buildings and also in new construction where floor-to-floor heights can be reduced, saving on overall building costs.

Retrofit installations are economical because new units

pically

ty Using AAF-HermanNelson unit ventilators, central equipment, such as chillers, can be sized smaller using building diversity. This results in a low capital-cost system.

Built In Flexibility

AAF-HermanNelson unit ventilators include features that make them easy to set up and reconfigure as needed to meet special requirements. These features include:

• Built-In Wire Race A built-in meta

fit the same space occupied by existing ones.

l wire race runs from one end of the unit to the other to provide extra protection for wires and protect them from unit air.

8 McQuay Catalog 1620

Features & Benefits

Figure 7.

Condenser casters ease

installation. Optional indoor

casters can be adjusted.

Condenser Casters and Optional Unit Casters

Controls Flexibility

Multiple control options—including MicroTech II controls with our Protocol Selectability feature—provide easy , low cost integration of AAF-HermanNelson unit ventilators into the building automation system of your choice (See “MicroTech II Controls” on page 13) . You can also operate these units individually or in a master-servant

rol configuration.

con With MicroTech II controls, you can select BACnet,

alk or Metasys N2 communications to communicate

LonT control and monitoring information to your BAS, without

need for costly gateways. Unit controllers are

the

ONMARK certified with the optional LONWORKS

L communication module.

Then consider how AAF-HermanNelson unit ventilators, locate

d in each classroom, take advantage of these

realities to lower operating costs:

• They provide individual classroom control and comfort.

• They can be cycled on

when the room is occupied and

cycled off when it is not.

• They bring in fresh air from directly outside the ssroom for high indoor air quality.

cla

• During most of the school year, they use outdoor air to

ep classrooms comfortable without the expense of

ke mechanical cooling.

MicroTech II Control Options Further Reduce Operating Costs

Many of the MicroTech III control options available with AAF-HermanNelson unit ventilators can further reduce operating costs. For example:

• Economizer Operation Econ

automatically adjusts the above-minimum outside air position to provide free cooling when the outdoor air temperature is appropriate.

• Demand Control Ventilation By usin

monitor the actual occupancy pattern in a room, the system can allow code-specific levels of outdoor air to be delivered when needed without costly overventilation during periods of low or intermittent occupancy (Figure 8).

omizer operation

g CO

levels to

Low Operating Costs

Schools consume more than 10% of the total energy expended in the United States for comfort heating and cooling of buildings. As energy costs increase, educators are placed in a difficult position: caught between rising costs, lower budgets and the requirements to raise educational standards.

e system exists for

Fortunately, the technology an schools to take control of their energy expenditures wh ile providing a comfortable environment for learning. And that system is the AAF-HermanNelson unit ventilator.

Consider these realities of school environments:

• Most

heating energy in schools is expended to heat

occupied spaces. Because lights, computers and

students give off considerable heat, occupied spaces require little supplemental heat.

• The

removal

of heat is usually required in occupied classrooms, even when outside temperatures are moderately cold (i.e., 35-40°F).

d th

Figure 8. Energy Savings with Demand Control Ventilation

100%

Energy Savings

with DCV

Unoccupied

20%

DCV's fresh air for indoor air quality

6:00 8:00 10:00 12:00 2:00 4:00 6:00 8:00 10:00

School Hours

Cleaning

After Hours

Unoccupied

• Occupancy Mode Operation Units can be

programmed to operate only sparingly during unoccupied periods and at night to conserve energy.

Two Stage Compressor

Air conditioning units are usually sized for worse case conditions. During high load requirement the unit will operate in high fan speed and high compressor capacity. Most of the time there is not a full load on the compressor. Operation in lower load will be at medium or

AAF-HermanNelson Model AZ Unit Ventilators 9

Features & Benefits

low fan speeds which will be at the lower displacement compressor stage. The two stage compressor will remain at low speed until more cooling is required. With the twostage compressor, these units will run on lower fan speeds most of the time improving comfort through better humidity control and quieter operation, while minimizing issues with over-sizing.

ors operate at

Other units utilizing single stage compres full compressor capacity all of the time regardless of fan speed.

Easy To Maintain

Fan Deck

The fan deck’s rotating element has one large, selfaligning, oilable end bearing for smoother operation.

Figure 9. Long-Life Bearings

Long Life Bearing

Even “permanently” lubricated motors are supplied with recommended lubrication charts calling for lubrication every seven years. Maintenance instructions of the motor manufacturer should be followed clo sely.

Heavy-Duty Discharge Grille

The discharge grille on the top of the unit is made from extra-strength steel bar stock, promoting long life (Figure 10). It can be removed to facilitate cleaning fans and fan housings.

Figure 10. Heavy-Duty Steel Discharge Grille

Internal Fan Deck Components

Unlike with many competitive models, the motor in AAF-HermanNelson unit ventilators is separate from the fan assembly and is located out of the airstream at the end of the fan shaft—away from the hot coil—for easier maintenance and removal. Locating the motor away from the coil (Figure 11) has the added benefit of extending motor life. Our direct-coupled motor and self-aligning

r mount facilitate motor change-out. The motor

mo comes with a molex plug that fits all sizes and further simplifies removal.

Figure 11. Fan Deck

Aerodynamic Fans

Modular

Fan Deck

Heavy-Duty

Discharge Grille

Motor Located

Out of Airstream

Filter

10 McQuay Catalog 1620

Features & Benefits

Tamper-Resistant Fasteners

Front panels and top access doors are held in place by tamper-resistant, positive-positioning fasteners. They are quickly removed or opened with the proper tool, but deter unauthorized access to the unit’s interior (Figure 12).

Sectionalized Access Panels And Doors

All units have three separate front panels and hinged top access doors, sized for convenient handling by a single person (Figure 12). The result is easy , t argeted access to the component that needs servicing:

wo end panels provide easy access to piping,

• T te

mperature control components and the fan switch. Unlike units with full-length front panels, these can be removed without disturbing the normal operation of the unit.

ged top access doors provide easy access into the

• Hin end c

ompartments to facilitate convenient servicing of

the motor, electrical, and refrigeration components.

• Center front panel provides easy access to the filter

d fan shaft bearing (size 048 only).

Filter

Three filter types are offered:

• Units come standard with a single-use filter which is

signed to be used once and discarded.

• Optional, permanent metal filters are available and can

removed for cleaning and reused numerous times.

• Renewable media filters, which consist of a heavy-

uty, painted-metal structural frame and renewable

d media.

Figure 12. Easy Access With Tamper-Resistant Fasteners

Tamper Resistant

Fasteners

Tamper Resistant

Fasteners

Discharge

Grille

Tamper Resistant

Fasteners

Tamper Resistant

Fasteners

Removeable

Filter

AAF-HermanNelson Model AZ Unit Ventilators 11

Features & Benefits

Built To Last

Durable, Energy Efficient Fan Motors

AAF-HermanNelson unit ventilators are equipped with 1 15/60/1 NEMA motors that feature low operating curr ent and wattage (Figure 13).

Figure 13.

Additional features of these motors include:

• Split-capacitor (PSC) design with au thermal-overload protection.

• No brushes, contacts or centrifugal starting switches— the mo

• A built-in, decoupled isolation system to reduce tran

• A multi-tap, auto-transformer (Fi multiple fan motor speed control through the speed switch. The which allows stocking of one motor (school districtwide) for various voltage applications.

Figure 14. Multi-Tap Auto-Transformer

Energy-Efficient Fan Motor

Energy Efficient NEMA Motor

Decoupled Isolation System

tomatic reset and

st common causes of motor failure.

smission of vibrations for quieter operation.

gure 14) provides

motor is independent of supply voltage,

Nylon damper bearings foster quiet, maintenance-free operation.

Additional features include:

have

• Face and bypass dampers

a twist-free reinforced aluminum construction for durability. Aluminum is used because it is lightweight and noncorrosive, resulting in low torque and easy movement.

• Outdoor air dampers ar

made of galvanized steel to inhibit corrosion, with double-wall welded construction for rigidity and encapsulated insulation (Figure 15). Additional insulation is provided on the exterior of the

oor air damper blade and on the outdoor air entry

out portion of the unit.

Figure 15.

Wool Mohair End Seal

Outdoor Damper Seals Out Cold Weather

Turned Metal Damper Blade

Turned Metal Damper Stop

Full-Length Wool Mohair Damper

Additional Insulation

Wool Mohair End Seal

• Room air dampers are free-floating and designed to prevent intermittent gusts of cold air from blowing directly into the classroom on windy days (Figure 16). They are constructed of aluminum with built-in rigidity.

metal forming technique that is employed resists

The twisting and incorporates a full-length counter weight for easy rotation. The simple principle of an area exposed to a force is used to automatically close the damper, rather than open it, when gusts of cold air occur.

Figure 16.

Room Air Damper Auto-Closed By Wind Gusts

Wind Gust

Durable Damper Design

All dampers in AAF-HermanNelson Unit Ventilators use the turned-metal principle on their long closing edges (Figure 15). Positive sealing is provided by embedding

the edge into wool mohair (no met There are no plastic gaskets to become brittle with time, sag with heat or age, or require a difficult slot fit to seal.

12 McQuay Catalog 1620

l to metal contact).

MicroTech II Controls

MicroTech II Controls For Superior Performance, Easy Integration

AAF-HermanNelson unit ventilators equipped with MicroTech II unit controllers can

ovide superior performance

pr and easy integration into your building automation system of choice. MicroTech II benefits include:

actory integrated and tested

• F controller, sensor, actuator and unit options promote quick, reliable start-up and minimize costly field commissioning.

h-performance features and advanced control

• Hig options can quickly pay for themselves in saved energy costs and more comfortable classrooms.

• Select

from three control levels: stand-alone, master-

servant or network control.

network control applications, our Protocol

• For Selectability feature provides easy, low-cost integration of AAF-HermanNelson unit ventilators into most building automation systems.

• Flexible BAS

network communication options guard against controls obsolescence, keeping MicroTech II controls viable for the life of your AAF-HermanNelson equipment.

Three Control Levels

MicroTech II unit controllers provide the flexibility to operate AAF-HermanNelson unit ventilators on any of three levels:

• As st

• I

• Co

Stand-Alone Control

When operating in stand-alone mode, the MicroTech II controller performs complete room temperature and ventilation control. Units can be operated in occupied, unoccupied, stand-by, or bypass (tenant override) modes. Occupied/unoccupied changeover can be accomplished:

• Man

• Automa

and-alone units, with control either at the unit or

from a wall sensor.

n a master-servant relationship, where serv an t un its

follow the master unit for some or all functions.

ntrolled as part of a network using a centralized

building automation system.

ually by a unit-mounted occupied/unoccupied

switch.

tically by a unit-mounted occupied/unoccupied

time clock.

tomatically by a remote-mounted time clock that

• Au operates unit-mounted day/night relays.

If a school has more than one zone, separate, remote time clocks ar

e used to regulate each zone. In this case, the remote-mounted time clock energizes or deenergizes an external, 24-volt or 120-volt control circuit which operates the unit-mounted day/night relays in that zone.

Master-Servant Control

Designate the master and servant units and we will factory configure and install the controllers so they are set up for a local peer-to-peer network between units (leaving only the network wiring between these units to be field installed).

Servant units can be field-configured to be dependent or

ependent as follows:

ind

pendent servant units follow the master unit

• De

completely. They are ideal for large spaces that have even loads across the space (such as some libraries).

dependent servant units (default) use master

• In

setpoints and servant sensors. The servant follows the master unit modes, such as heat or cool, but has the flexibility to provide the conditioning required for its area within the space. Independent servant units perform better in spaces where loads vary from one area of the space to the other (such as stairwells or cafeterias).

Network Control

MicroTech II unit controllers provide easy integration into your building automation system of choice. All factoryinstalled options are handled by the unit controller. This simplifies the transmission of monitoring and setpoint data to the building automation system.

You select BACnet, LonTalk or Metasys N2 Open

unications to communicate control and monitoring

comm information to your BAS, without the need for costly gateways (see “Optional Communication Modules” on page 19). Unit controllers are L optional L

ONWORKS communication module.

ONMARK certified with the

Flexible network communication options via our Protocol

tability feature help you avoid control obsolescence

Selec over the life of your AAF-HermanNelson equipment.

AAF-HermanNelson Model AZ Unit Ventilators 13

MicroTech II Controls

Control Modes and Functions

AAF-HermanNelson unit ventilators equipped with MicroTech II unit controllers can be programmed to

perate in a variety of modes based on the current

o situation in the room and the status of the unit ventilator. Changes in mode can be triggered manually, via network signals, by sensor readings, or by date and time. External inputs and outputs can be used to change modes, communicate data to network contr ols or change the functional operation of the unit.

Occupancy Modes

MicroTech II unit controllers can be set up to change modes based on room occupancy. Four different occupancy modes are provided, as described below.

Occupied Mode

This is the normal daytime operation mode. The controller maintains a room set point using the out side air capability and other functions.

Note: For non-school applications, the unit can also be

configured to cycle the fan in response to the room load. In this case, the fan would normally be in the Off Mode until heating or cooling is required. The outside air damper is always closed when the fan is off. When the fan starts, the outside air damper opens to the required position, usually minimum position.

Economizer Modes

Economizer operation is facilitated by the outdoor air damper, which automa tically adjust s the above-minimum outside air position to provide free cooling when the outdoor air temperature is appropriate. Three levels of economizer control are available:

Basic Economizer Operation: The MicroTech II

controller compares the inside and outs ide temperatures. If the temperature comparison is satisfactory, then freeair economizer operation is used to cool the space. Reheat units also come configured with an indoor humidity sensor.

Expanded Economizer Operation: In addition to

comparing inside and outside temperatures, outdoor relative humidity is measured to calculate outside air enthalpy. Free economizer operation is used to cool the space. This helps to minimize the entrance of humid outside air.

Leading-Edge Economizer Operation: The MicroTech II

controller compares both indoor and outdoor temperatures and indoor and outdoor relative humidities to determine if free economizer operation can cool the space with non-humid outside air. This is a true enthalpy economizer.

Unoccupied Mode

This is the night setback operating mode, in which the unit responds to a new room set point and cycles to maintain the condition. The fan comes on when heating or cooling is needed and runs until the load is satisfied. The outdoor air damper is closed during this mode. When a cooling load is satisfied by a refrigerant system, the compressor is de-energized and the unit ventilator indoor fan continues to run for a fixed period of time to remove coldness from the evaporator coil.

Stand By Mode

In this mode, the unit maintains the occupied mode set point temperature with the outdoor air damper closed. The fan runs continuously unless it is configured to cycle in response to the load.

Bypass Mode

This is a tenant override operating mode in which the unit is placed back into the Occupied Mode for a predetermined time. The default is 120 minutes. Settings can be made in 1-minute increments from 1 minute to 240 minutes through ServiceTools™ (see page 23) or a network.

Night Purge Mode

Under this mode, the unit is configured to purge the room space for one hour for various reasons (odor or fume removal, drying, etc.).During Night Purge the outside air damper is open full and the fan is run on high speed. No “normal” heating or cooling takes place (the emergency heat set point is maintained) and the exhaust fan, if the room is so equipped, is signaled to turn on.

Freeze Prevention Mode

This mode helps protect the unit ventilator from freezing air conditions. Control functions vary depending on the type of temperature control used by the unit, as follows:

Face and Bypass Control Units

Upon sensing a potential freezing air tempera tu re condition leaving the heating coil, the unit will protect itself by shutting the outside air damper and opening the EOC valve. The fan continues to run to remove the cold air. Once accomp lished, the freezestat is reset, the outside air damper opens to the minimum position and the unit commences its normal mode of operation.

14 McQuay Catalog 1620

MicroTech II Controls

Valve Control Units

Upon sensing a potential freezing air temperature condition leaving the heating coil, the unit will automatically protect itself by shutting the outside air damper and opening the hot water valve to a mini mum of 50% (more if required to heat the room). The fan speed will be staged down to low speed and then turned off. When the freezestat is reset, the outside air damper opens to the minimum position and the fan runs at low speed for a minimum of 10 minutes. It then will stage up if needed to satisfy the room set point. This reduces the potential to overheat a room recovering from a potential freeze condition.

Note: Valve selection and coil sizing is critical for proper

operation. Face and bypass control is recommended for proper freeze protection.

Emergency Heat Mode

If the unit is left in a mode that does not normally allow heating (such as Off, Fan Only, Cool, or Night Purge) and the room temperature falls below 55°F, the unit will heat the space to above 55°F and then return to the previously set mode of operation. This mode of operation can be field configured and/or be disabled.

External Input Functions

The unit ventilator controller is provided with three (3) binary inputs that allow a single set of dry contacts to be used as a signal to it. Input signal choices are described below. Multiple units can be connected to a single set of dry contacts.

Note: Not all of the functions listed can be used at the same

time. The unit ventilator controller is provided with configuration parameters that can be adjusted to select which function will be used for these inputs where multiple functions are indicated below. For wiring examples see installation manual IM 747: MicroTech II Unit V

entilator Controller.

Unoccupied Input Signal

This input signals the unit ventilator controller to go into unoccupied or occupied mode. When the contact s close, the unit ventilator controller goes into unoccupied mode; when the contacts open, it goes into occupied mode. Additional variables can affect occupancy mode and override this binary input. See “Occupancy Modes” on page 14.

Dewpoint/Humidity Input Signal (Optional)

This input signals the unit ventilator controller to go into active dehumidification mode. When the contacts close (high humidity) the controller will go into active

dehumidification; when the contacts open (low hu midity) it will stop active dehumidification.

Remote Shutdown Input Signal

This input signals the unit ventilator controller to go into shutdown mode. When the contact s close, the controller goes into shutdown mode; when the contacts open, it returns to normal operation.

Ventilation Lockout Input Signal

This input signals the unit ventilator controller to close the outdoor air damper. When the contacts close (ventilation lockout signal) the controller closes the outdoor damper; when the contacts open, it returns to normal outdoor damper operation.

Exhaust Interlock Input Signal

This input signals the unit ventilator controller that an exhaust fan within the space has been energized. The controller then repositions the outdoor air damper to a user-adjustable minimum position. When the contacts close (exhaust fan on signal) the controller uses the value defined by the Exhaust Interlock OA Damper Min Position Setpoint as the new minimum outdoor air damper position regardless of the indoor air fan speed. When the contacts open, it returns to normal outdoor damper operation.

External Output Functions

The unit ventilator controller is provided with three (3) binary outputs to perform the functions described below. These are relay type outputs that are intended to be used with signal level voltages only (24 VAC max).

Note: Not all of the functions listed can be used at the same

time. The unit ventilator controller is provided with configuration parameters that can be adjusted to select which function will be used for these outputs when multiple functions are indicated below. For wiring examples, see installation manual IM 747: MicroTech II Uni

t Ventilator Controller.

Lights On/Off Signal

This relay output provides one set of NO dry contacts that can be used to signal the operation of the room lights. When the unit ventilator controller is in occupied, standby or bypass occupancy modes, the relay output will signal the lights on (contacts closed); when the controller is in unoccupied occupancy mode the relay output will signal the lights off (contacts open).

AAF-HermanNelson Model AZ Unit Ventilators 15

MicroTech II Controls

Fault Signal

This relay output provides NO, NC, and Common connections that can be used to signal a fault condition. When a fault exists, the unit ventilator controller energizes this relay output. When the fault or faults are cleared, it de-energizes this relay output.

Exhaust Fan On/Off Signal

This relay output provides one set of NO dry contacts that can be used to signal the operation of an exhaust fan. When the outdoor air damper opens more than the Energize Exhaust Fan OA Damper Setpoint, the relay output will signal the exhaust fan on (contacts closed). When the outdoor damper closes below this setpoint, th e relay output will signal the exhaust fan off (contacts open).

Auxiliary Heat Signal

This relay output provides one set of NO dry contacts that can be used to operate an auxiliary heat device. The unit ventilator controller by default is configured to operate a NO auxiliary heat device (de-energize when heat is required) such as a wet heat valve actuator with a spring setup to open upon power failure. However, the Auxiliary Heat Configuration variable can be used to set the controller to use an NC auxiliary heat device (energize when heat is required) such as electric heat.

fan operation under normal operating conditions, in conjunction with our GentleFlo fan technology contributes to a very quiet classroom environment.

Demand-Controlled Ventilation (Optional)

AAF-HermanNelson unit ventilators can be equipped to use input from a CO based on actual occupancy instead of a fixed design occupancy. This Demand Controlled Ventilation (DCV) system monitors the amount of CO students and teachers so that enough fresh o utdoor air is introduced to maintain good air quality. The system is designed to achieve a target ventilation rate (e.g., 15 cfm/person) based on actual occupancy.

By using DCV to monitor the actual occup a ncy pattern in

oom, the system can allow code-specific levels of

a r outdoor air to be delivered when needed. Unnecessary over-ventilation is avoided during periods of low or intermittent occupancy.

With DCV you can be confident that your school is

eting ventilation standards for Indoor Air Quality and

me that your students are receiving adequate air to be attentive to instruction. At the same time, you are saving money in early morning hours, in between classes, or after hours when classrooms are heated and cooled but not always fully occupied.

Acceptance By Codes And Standards

controller to ventilate the space

produced by

Advanced Control Options

MicroTech II controls make possible a number of advanced control options that can quickly pay for themselves in saved energy costs and more comforta ble classrooms, as described below .

Part Load Variable Air Control

Part Load Variable Air control can be used in conjunction with face and bypass damper temperature control to automatically adjust the unit ventilator fa n spee d ba se d upon the room load and the room-temperature PI control loop. This MicroTech II control option provides higher latent cooling capabilities and quieter operation during non-peak load periods by basing indoor fan speed upon room load.

During low-load or normal operation (about 60% of the time) the fan will operate increases to an intermediate demand, the fan will automatically shift to the medium-speed setting. Under near-design or design-load conditions, the fan will operate on high speed. A built-in, 10-minute delay helps minimize awareness of fan speed changes. Low-speed

on low speed. When the load

ASHRAE Standard 62-2004 Ventilation for Indoor Air Quality recognizes CO controlling ventilation based on occupancy. The ASHRAE standard has been referenced or adopted by most regional and local building codes. This standard references ventilation on a per-person basis.

Using CO amount of outside air delivered into a room but will maintain the per-person rate. For example, if a classroom is designed for 30 students, the ventilation rate is 450 cfm (30 students X 15 cfm/student) . However, when there are only ten students in the classroom, the CO

X 15 cfm/student). A minimum base ventilation rate (typically 20% of design levels) is provided when in the occupied mode. This provides outdoor air to offset any interior source contamination while allowing for proper space pressurization.

control will sometimes lower the absolute

control will adjust ventilation to 150 cfm (10 students

based DCV as a means of

Active Dehumidification Control (Reheat)

In high-humidity applications where valve-controlled, reheat units are used, the Active Dehumidification Control (ADC) sequence should be considered. During

16 McQuay Catalog 1620

MicroTech II Controls

excessive humidity conditions, a humidity sensor directs the unit to continue cooling past the room setpoint to remove excess moisture. Hydronic heat or electric heat is then used to reheat the discharge air to maintain acceptable room temperatures.

MicroTech II controls minimize th

e amount of reheat needed to maintain relative humidity below a preset limit. Reheat is used only when required and in the most energy-efficient manner possible.

Active Dehumidification comes standard on units

quipped with MicroTech II controls, a reheat

figuration and valve-control temperature modulation.

con The MicroTech ADC humidity sensor is unit-mounted. It issues a signal proportional to the classroom’s humidity level (unlike humidistats which issue an open-close signal). This enables a control sequence that manages both the temperature and the relative humidity.

When the relative humidity exceeds a preset value, the

efrigerant cooling activates to dehumidify the mixture of

r outdoor and return air entering the cooling coil. The reheat modulating water valve then opens, or electric heat is engaged, to reheat the air leaving the cooling coil, as required to maintain the classroom setpoint.

Active dehumidification starts when the indoor relative

umidity exceeds the preset relative humidity upper

h setpoint and continues until the room humidity falls 5% below the endpoint. During active dehumidification, economizer operation is disabled (and the outdoor air damper is reset to its minimum position) unless the outdoor air temperature is below 55°F. It is maintained until dehumidification is completed. When the indoor humidity level is satisfied, the MicroTech II controller

reverts to its normal sequences to satisfy the classroom temperature setpoint.

DX System Control

The unit ventilator controller is configured to operate the compressor as secondary (mechanical) cooling when economizer cooling is available, and as primary cooling when economizer cooling is not available. Additional DX control features include:

Compressor Envelope: This helps protect the

compressor from adverse operating conditions that can cause damage and or shortened compressor life. It ends compressor operation if coil temperatures exceed the defined operating envelope.

Compressor Cooling Lockout: The unit ventilator

controller is configured to lock out compressor cooling when the outdoor air temperature falls below the compressor cooling lock out setpoint. Below this temperature setpoint only economizer cooling will be available.

Minimum On And Off Time: The unit ventilator controller

is provided with minimum-on and minimum-off timers to prevent adverse compressor cycling (3-minutes default).

Compressor Start Delay Variable: This variable is

intended to be adjusted as part of the start-up procedure for each unit. It is used to prevent multiple unit compressors from starting at the same time af ter a power failure or after an unoccupied-to-occupied changeover. Each unit should be configured at start-up with a slightly different (random) delay, or groups of units should be provided with different delays.

AAF-HermanNelson Model AZ Unit Ventilators 17

MicroTech II Controls

System Components

The main components of the MicroTech II system are:

• The Unit Ventilator Controller (UVC)

• The Local User Interface (LUI)

• Optional plug-in network communication modules

In ad

dition, unit ventilators equipped with MicroTech II

rollers feature factory-mounted sensors and

cont actuators for system control and feedback.

Unit Ventilator Controller

The MicroTech II UVC is a DDC, microprocessor-based controller designed to provide sophisticated comfort control of an economizer-equipped AAF-HermanNelson unit ventilator. In addition to normal operating control, it provides alarm monitoring and alarm-specific component shutdown if critical system conditions occur. Each UVC is factory wired, factory programmed and factory run-tested for the specific unit ventilator model and configuration ordered by the customer.

Figure 17. MicroTech II Control Board

Terminal Connections

Plug-In Control Module

Figure 18. User Interface To uc h Pad

The User Interface has individual touch-sensitive printed circuit board mounted buttons, and comes with a built-in menu structure (Hidden Key and Password Protected) to change many of the common operating variables.

Four Operating Mode States

Four different user operating mode st ates can be chosen on the LUI:

Heat: Heating and economizer operation only. Cool: Cooling and economizer operation only. Fan Only: Fan only operation.

Local User Interface

A built-in LUI touch pad with digital LED Display is located in the right hand compartment below the top rig ht access door. In addition to the Operating Mode States and Fan Functions, the Touch Pad will digitally display:

he room set point temperature.

• T

• The current room temperature.

• Any fault code for quick diagnostics at the unit.

Auto: The unit automatically switches between heating,

cooling and economizer operation to satisfy the room load conditions. The current unit state is also displayed.

Four Fan States

Four fan states are provided on all units: high, medium low and Auto speed modulation. The Auto speed function (part load, variable air) varies the fan speed automatically to meet the room load whether the unit is in heating, cooling or economizer mode.

All this is accomplished with NEMA frame motor. A built-i n 10-minute delay helps minimize awareness of speed changes. During low-load or normal operation (about 60% of the time) the fan will operate at low speed. The low speed operation, along with GentleFlo fan technology, contributes to a very quiet classroom environment.

When the load increases to an intermediate demand, the

cally shifts to the medium speed setting. At

fan automat near-design or design-load conditions the fan will operate on high speed.

With four fan states and GentleFlo fan technology, there

o need to oversize units or worry about

is uncomfortable conditions.

a standard, single-speed

18 McQuay Catalog 1620

MicroTech II Controls

Optional Communication Modules

Optional communication modules provide control and monitoring information to your building automation system without the need for costly gateways. Available communication protocols include BACnet, LonTalk and Metasys N2 Open. The communication modules for each are described below.

Figure 19. Typical 2" x 4" Communication Module

BACnet MS/TP Communication Module

This module allows the UVC to inter-operate with systems that use the BACnet (MS/TP) protocol with a conformance level of 3. It meets the requirements of the ANSI/ASHRAE 135-1995 standard for BACnet systems.

LONWORKS SCC Communication Module

This module supports the LONWORKS SCC (Space Comfort Communication) profile number 8500-10. Unit controllers are LonMark certified with this optional

ONWORKS communication module.

Metasys™ N2 Communication Module

This module provides N2 Open network communication capability to the UVC for communication with Johnson Metasys systems.

Sensors

The UVC is configured to use passive Positive Temperature Coefficient (PTC) unit-mounted and wallmounted sensors. These sensors vary their input resistance to the UVC as the sensed temperature changes.

Figure 20. Wall-Mounted Temperature Sensors

Standard Expanded

Standard Sensor: This sensor has no remote setpoint

adjustment capability.

Expanded Sensor: This sensor has a remote room

setpoint adjustment of ±3°F (±1.5°C) from the room setpoint established on the unit ventilator’s local user interface touch pad. Five temperature settings are provided on each side of center.

Humidity Sensors

On units equipped with humidity sensors, the UVC is configured to use a 0-100% RH, 0 VDC, capacitive humidity se

nsor. Humidity sensors are available as unitmounted only. The humidity sensors are used with units capable of active dehumidification, or with units using an outdoor enthalpy economizer or an indoor/outdoor enthalpy economizer.

CO2 Sensor for Demand Controlled Ventilation

On units equipped for Demand Controlled Ventilation (DCV) the UVC is configured to use a 0-2000 PPM, 0-10 VDC, single beam absorption infrared gas sensor. CO

sensors are available as unit mounted only. An air collection probe (pitot tube and filter) is installed in the return air of the unit.

Figure 21. CO2 Sensor For Demand Control Ventilation

Remote Wall-Mounted Temperature Sensors

MicroTech II unit ventilators offer three choices for remote wall-mounted room sensors (Figure 20). Each has a tenant override capability and comes with an international, quick-

AAF-HermanNelson Model AZ Unit Ventilators 19

fastening connection capability.

MicroTech II Controls

MicroTech II Sensor and Component Locations

Figure 22. MicroTech II Sensor and Component Locations

1 MicroTech II Unit Ventilator Controller (UVC):

(Located Beneath the Local User Interface Panel). Factory mounted and run tested, microprocessorbased DDC control device capable of complete, Stand-alone unit control, Master/Slave control, or incorporated into a building-wide network using an optional plug-in communication module. The UVC supports up to 6 analog inputs, 12 binary inputs, and 9 binary outputs. The UVC expansion board supports up to 4 additional analog inputs and 8 additional binary outputs. Master/Slave units have the controller factory configured for a local peer-to-peer network between these units (network wiring between thes e units needs to be field installed). Optional network

communication is provided via plug-in communication modules that connect directly to the UVC.

2 Communication Modules (optional): (Lo

Beneath the Local User Interface Panel). Plug -in network communication module that is attached to the UVC via a 12-pin header and 4 locking standoffs. Available communication modules:

ing Automation and Control Netw

• Build net™) Master Slave/Token Passing

ork (BAC-

(MS/TP) Allows the UVC to inter-operate with systems that use the BACnet (MS/TP) protocol with a conformance level of 3. Meets the requirements of ANSI/

AE 135-1995 s

ASHR

tandard for BACnet systems.

ated

20 McQuay Catalog 1620

MicroTech II Controls

• LONWORKS™ compliant Space Comfort Controller

(SCC) – Supports the L

ONWORKS SCC profile num-

ber 8500-10.

etasys™ N2 Open – Provides N2 Open network

• M communication capability to the UVC.

3 Local User Interface (LUI):

The LUI provides a unit mounted interface which indicates the current unit operating state and can be used to adjust the unit ventilator operating parameters (operating mode, temperature set points, fan speed, and occupancy mode). The LUI features a 2-digit display, 7 keys (1 key is hidden), and 9 individual LED indicators.

4 Tenant Override Switch Pr

ovides a contact closure that causes the unit to enter the “Occupied” operating mode for a set time period (default = 120 minutes).

5Time Clock (

optional on stand-alone units only) Factory mounted 7 day/24 hour, digital time clock with up to 20 programs to sequence the unit ventilator through occupied and unoccupied modes in accordance with a user programmed time schedule.

6 External Signal Connection Plugs: (L

ocated Beneath the Local User Interface Panel). Three multipin plugs are factory provided and pre-wired with amp plug connections that plug into the wall sleeve. Provided for field wiring of :

ote Wall Mounted Temperature Sensor

• Rem

(optional accessory).

rnal Input Signals (by others): unoccupied,

• Exte

remote shutdown, ventilation lockout, dew point/ humidity (night time operation) or exhaust interlock signals.

rnal Output Options (by others): lights on/off,

• Exte

fault indication signal, exhaust fan on/off or au xiliary heat signal.

Note: Not all external signal options can be used

simultaneously and may not be available on all software models. Refer to the “UVC Input and Output Tables” in IM 747 for available options.

7 Motor Speed Transformer: (Located Beneath the

Local User Interface Panel). Multi-tap autotransformer provides multiple fan motor speed control through the LUI.

8 Unit Main Power “On-Off” Switch (not shown):

Shipped

with the wall sleeve accessory, the “On-Off” switch disconnects the main power to the unit for servicing or when the unit is to be shut down for an extended period of time.

9 Fuse(s) - Fa

n motor and controls have the hot line(s)

protected by factory installed cartridge type fuse(s).

10 Control Transformer - (L

ocated Beneath the Local User Interface Panel). 75 VA 24-volt NEC Class 2 transformer for 24 volt power supply.

11 Outdoor Air/Return Air Damper Actuator -

Direct coupled, floating point (tristate) actuator that spring returns the outdoor air damper to the closed position upon a loss of power.

12 Face and Bypass Damper Actuator - Direc

t coupled, floating point (tristate) actuator that is nonspring returned (Model AZQ only , other unit s are valve control).

13 Hydronic Coil Low Air T

emperature Limit (T6

freezestat) – Factory installed on all units with hydronic (water) coils. The T6 freezestat cuts out at 38ºF (+/- 3ºF) and automatically resets at 45ºF (+/3ºF).

14 Indoor, Direct Expansion (DX) Coil Refrigerant

emperature Sensor – The sensor is installed on the

unit ventilator’s indoor refrigerant coil on the right hand side of the coil “u-bend”. It is used to sense low refrigerant temperatures on the indoor coil.

15 Outdoor, Direct Expansion (DX) Coil Refrigerant

emperature Sensor - The sensor is installed on the

unit ventilator’s outdoor refrigerant coil on the right hand side of the coil “u-bend”. It is used to sense the refrigerant temperature on the outdoor coil.

16 Room Temperature Sensor - Th

e unit mounted sensor is located in the sampling chamber (front, center section) where room air is continuously drawn through for prompt response to temperature changes in the room. A remote wall mounted temperature sensor is available for remote room temperature sensing. (optional).

17 Discharge Air Temperature Sensor – The

sensor is located on the second fan from the right to sense discharge air temperatures.

18 Outdoor Air Temperature Sensor –

The sensor is located in the outdoor air section of the unit before the outdoor air damper. With network applications, the unit mounted sensor can be overridden by a remote sensor through the network.

19 Outdoor Air Humidity Sensor (o

ptional, standard with expanded and leading edge controls) - Unit mounted humidity sensor for units using expanded outdoor enthalpy economizer or Le ad ing Edge in doo r/ outdoor, true enthalpy comparison economizer. The sensor is located in the outdoor air section of the unit before the outdoor air damper. With network applications, the unit mounted sensor can be overridden by a remote sensor through the network.

AAF-HermanNelson Model AZ Unit Ventilators 21

MicroTech II Controls

20 Room Humidity Sensor (optional, standard with

expanded controls) – Unit mounted humidity sensor for units capable of passive or active dehumidification (Reheat) or with units using Leading Edge indoor/ outdoor, true enthalpy comparison economizer. The sensor is located in the sampling chamber (front, center panel) where room air is continuously drawn through for fast response to humidity changes in the room. With network applications, the unit mounted sensor can be overridden by a remote sensor thro ugh the network.

(

21 CO2 Sensor

optional) – Unit mounted, single beam absorption infrared gas sensor with a sensing range of 0 – 2000 ppm and voltage output of 0 to 10 VDC (100 ohm output impedance). The pitot tube sensing device is located in the unit ventilator's return air stream. The optional CO2 sensor is used with the UVC's Demand Control Ventilation feature to vary the amount of outside air based on actual room occupancy. With network applications, the unit mounted sensor can be overridden by a re mote sensor through the network.

22 Control Valve(s) (n

shown) – Optional accessory valve(s) may be either 2-position "End of Cycle" (model AZQ) or modulating (model AZU and AZR), to control the quantity of water through the coil. Available in 2-way or 3-way configurations. Spring return actuators are required for all hot water and steam heating valves. All heating valves are normally open.

Outdoor Air/Return Air Damper (OAD) Actuator

The UVC is configured to operate a floating-point (tristate) direct-coupled actuator for the outdoor air damper. This actuator provides spring-return operation upon loss of power for positive close-off of the outdoor air damper. To determine damper position, the UVC uses a separate, factory-preset, configurable setting for each actuator's stroke time.

Figure 24. Outdoor Air Damper Actuator

2-Position End-of-Cycle Valve Actuators (Optional)

On units equipped with 2-way or 3-way, end-of-cycle (EOC) valves, the UVC is configured to operate 2position End-Of-Cycle (EOC) valve actuators (Figure 25). Spring return actuator s are used fo r all End of Cycle (EOC) valves. All wet heat EOC valves are

rmally open.

Figure 25. End of Cycle Valve Actuator

Actuators

Face & Bypass Damper Actuator

On units equipped with face & bypass damper control, the UVC is configured to operate a floating-point (tristate), direct-coupled, face & bypass damper actuato r . To determine the modulating damper position, the controller uses a separate, factory-preset, configurable setting for each actuator's stroke time.

Figure 23. Face & Bypass Damper Actuator

22 McQuay Catalog 1620

MicroTech II Controls

Modulating Valve Actuators (Optional)

On units equipped with modulating valves, the UVC is configured to operate floating-point (tri-state) actuators for modulating 2- way and 3-way valves (Figure 26).

Figure 26. Modulating Valve Actuator

2-Way Valve 3-Way Valve

Spring return actuators are used for all modulating valves. All wet heat valves are normally open.

To determine modulating valve position

the UVC uses a separate factory preset, configurable setting for each actuator's stroke time. For accuracy of actuator positioning, the UVC is provided with an overdrive feature for the 0% and 100% positions and a periodic (12-hour) auto-zero PI control loop for each modulating actuator.

Optional Time Clock For Stand-Alone Units

As an option, stand-alone, non-servant un it ventilators can be factory-equipped with a unit-mount ed, di g ital, 24hour/7-day time clock with 20 programs (Figure 27). The clock is factory-wired to automatically o

ccupied or unoccupied mode based upon its schedule.

Features of this clock include:

• Large keys with circular programming for easy

hedule setup

• An LCD disp

lay

• Manual 3-way override (On/Auto/Off)

• Capacitor backup to retain pr ogram memory during

wer outages.

place the unit into

Figure 27. Optional Time Clock

ServiceTools™

ServiceTools for MicroT ech II Unit Ventilators is a CD containing software for operation on a personal computer. This software provides a visual schematic of the unit, a pictorial representation of the sequence of operation and enables the service technician to:

onitor equipment operation.

• M

• Configure network communications.

• Diagnose unit operating problems.

• Download application code and configure the unit.

is software is a purchased tool for service technicians

and will run

on PCs with Windows 2000 (SP2), and NT4.0 (SP6) and XP (SP1) operating systems. This tool is highly recommended for startup and servicing. (It may be required for startup and/or servicing, depending upon unit integration and other requirement s.) It has no BAS functions, such as scheduling or trending, and it cannot serve as a Work Station Monitoring package.

ServiceTools comes with a service cable having two

rface conn

inte

ections:

• A 12-pin connection to the main control board.

• A 3-pin connection to the optional communication

ules.

mod

98 (Second Edition),

AAF-HermanNelson Model AZ Unit Ventilators 23

+ 53 hidden pages