McQuay AVF Installation Manual

MicroTech

Unit Ventilator Controller

AAF-HermanN elson Classroom Unit Ventilator Model AVS, AVH, Floor Mounted Model AVF, AHF, Ceiling Mounted

Program UV7: Chilled Water Cooling Only

Chilled Water Cooling and Electric Heating

Operation Manual

OM 107-1

Group: Unit V entilator Part No.: 106101801 Date: July 1999

Table of Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Software ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Chilled Water Cooling Only, Valve Control . . . . . . . . . . 2

Description of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Occupied or Tenant Override Operating Mode . . . . . . 3

Unoccupied Operating Mode . . . . . . . . . . . . . . . . . . . . 3

Discharge Air Low Limit Control . . . . . . . . . . . . . . . . . 3

Safeties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Sequence Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Chilled Water Cooling Only, Damper Control . . . . . . . . 5

Description of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Occupied or Tenant Override Operating Mode . . . . . . 5

Unoccupied Operating Mode . . . . . . . . . . . . . . . . . . . . 5

Discharge Air Low Limit Control . . . . . . . . . . . . . . . . . 5

Chilled Water Cooling and Electric

Heating, Valve Control . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Description of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Occupied or Tenant Override Operating Mode . . . . . . 7

Unoccupied Operating Mode . . . . . . . . . . . . . . . . . . . . 8

Discharge Air Low Limit Control . . . . . . . . . . . . . . . . . 8

Safeties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Sequence Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Chilled Water Cooling and Electric

Heating, Damper Control . . . . . . . . . . . . . . . . . . . . . . . 10

Description of Operation . . . . . . . . . . . . . . . . . . . . . . . . . 10

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Occupied or Tenant Override Operating Mode . . . . . 10

Unoccupied Operating Mode . . . . . . . . . . . . . . . . . . . 10

Discharge Air Low Limit Control . . . . . . . . . . . . . . . . 11

Sequence Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Sequence Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Introduction

This manual describes the sequences of operation for MicroTech controlled AAF-HermanNelson Unit V entilators equipped with chilled water cooling and electric hating, or chilled water cooling only. Unit Ventilators with these heating and cooling configurations could be AAF-HermanNelson models AVV, AVS, AHF or AHV. Regardless of

General Information

Software ID

The Unit Ventilator Controller software must be compatible with the Unit V entilator heating and cooling configuration. The softw are is identified by a program code and “software model” number printed on a small label attached to the controller. Models AVV, AVS, AHF, or AHV with chilled water cooling only or both chilled water cooling and electric heating use program UV7***. The first wild card character defines the UVC communication type as follows: S = stand-alone , M = master/slav e, and N = network code. The last two wild card char acters denote the software version (numeric) and revision lev el (alphabetical) respectiv ely . Progr am UV7*** comprises four software models: MDL15 through MDL18. Each software model is for a diff erent unit configuration. Refer to Table 1.

Table 1. Program UV7 Unit Ventilator Configurations

Program Software Model Configuration Description

MDL15 Chilled Water Only, Valve Control

UV7***

MDL16 Chilled Water Only, Damper Control MDL17 Chilled Water and Electric Heat, Valve Control MDL18 Chilled Water and Electric Heat, Damper Control

the AAF model type, the Unit Ventilator Controller (UVC) provided with these units uses program UV7***.

For more information on the MicroTech Unit Ventilator Controller, refer to Bulletin No. IM613, “MicroTech Unit Ventilator Controller.”

Setpoints

Most UVC setpoints are either “hardware” or “software” adjustable. Hardware adjustable means there is an on-board potentiometer used for adjustment. Software adjustable means a PC equipped with Monitor software and proper cable connection is required to make an adjustment. Default software adjustable v alues are shown on the sequence charts. Hardware adjustable values sho wn on the charts are for example only. Several UVC setpoints are defined b y offsets relative to other setpoints. Table 2 summarizes these setpoints and offsets.

Table 2. UVC Setpoints

Setpoint

Description Abbreviation Defined By Label

Occupied cooling setpoint OCS Hardware setpoint Room Setpoint -Ventilation cooling setpoint VCS Software offset (below OCS) Vent Clg Offset 2oF Occupied heating setpoint OHS Software offset (below OCS) Occ RmT Spt Difl 6oF Unoccupied heating setpoint UHS Hardware offset (below OHS) Unoccupied cooling setpoint UCS Hardware offset (above OCS) Ventilation cooling lockout VCLO Software setpoint OAT Vent Clg Lkout 64oF Ventilation cooling discharge air low limit VCLL Software setpoint DAT Vent Clg Low 55oF Chilled water cooling discharge air low limit CWLL Software setpoint DAT CW Clg Low 45oF Outdoor air lockout OALO Software setpoint OALO Setpoint 35oF

Unocc Offset --

Chilled Water Cooling Only, Valve Control

Description of Operation

Definitions

Control T emperature

In order to maintain more stable room temperature control, the MicroTech Unit Ventilator Controller (UVC) uses the concept of a “Control Temperature.” During the occupied or tenant override operating modes, the Control T emperature is a weighted v alue equal to 19/20 room temperature and 1/20 discharge air temperature. During the unoccupied operating mode, the Control Temperature is set equal to the room temperature.

OM 107-1 / Page 2 (Rev. 7/99)

Setpoint Abbreviations

OCS Occupied cooling setpoint VCS Ventilation cooling setpoint OHS Occupied heating setpoint UHS Unoccupied heating setpoint UCS Unoccupied cooling setpoint VCLO Ventilation cooling outdoor air lockout setpoint VCLL Ventilation cooling discharge air low limit setpoint CWLL Chilled water cooling discharge air low limit setpoint OALO Outdoor air lockout setpoint

Software ID

Program: UV7*** Software Model: MDL15

Default

Value

Occupied or Tenant Override Operating Mode

The supply fan will run continually in the occupied or tenant override operating modes.

When the UVC is first energized it will perform a self-calibration procedure upon the OA damper and valv e actuators. The calibr ation procedure will take approximately 5-minutes to perf orm during which time the supply fan will not operate.

An outdoor air lockout setpoint has been provided to force the OA damper closed when the OA temperature goes below the OALO setpoint (software adjustable).The OALO setpoint must not be set below the freeze point of the liquid being used within the building water loop. In order to lower the OALO setpoint below the default value glycol must be added to the building water loop in sufficient concentration to ensure freezing will not occur. However, the O ALO setpoint can be lowered if steam heat is used.

If provided, the optional exhaust fan output will energize when the OA damper opens and de-energize when the OA damper closes.

If provided, the optional ventilation lock out feature can ov erride UVC temperature control and keep the OA damper closed as required.

If provided, the optional auxiliary heat output will operate a normally open device. The auxiliary output will energize (close the device) when the Control Temperature is above the OHS. The auxiliary output will de-energize (open the device) when the Control Temperature is

F below the OHS.

3 The same UVC output is used for both the auxiliary heat output

feature and the exhaust f an output f eature. Therefore, both features cannot be used together.

Note: When switching from unoccupied-to-occupied mode the OA damper will remain closed for the first 5-minutes of occupied operation.

Morning Start

If the space is cool and heating is required, the outdoor air (OA) damper will remain closed and room air will be circulated until the Control Temperature rises to within 3 will be opened to minimum position.

If the space is warm and cooling is required, the unit will operate as described in “Cooling Operation” below. If the outdoor air is not suitable for free cooling, the OA damper will remain closed until the Control Temperature falls to within 3 will be opened to minimum position.

Cooling Operation

When the Control Temperature is greater than the OHS setpoint and less than the VCS setpoint, the OA damper will be held at its minim um position setpoint (hardware adjustable). As the Control Temperature rises and cooling becomes necessary, the UVC will decide whether the outdoor air is suitable for free cooling by comparing the outdoor air temperature (dry bulb) to the VCLO setpoint.

If the OA temperature is less than or equal to the VCLO setpoint, the economizer will modulate as required to maintain the VCS setpoint (default = 2

F less than OCS). The Control Temperature will rise if the outdoor air is too warm to satisfy the cooling load. If the OA damper is more than 85% open, the chilled water valve will modulate as required to maintain the OCS setpoint.

If the OA temperature is warmer than the VCLO setpoint, the chilled water valve will modulate as required to maintain the OCS setpoint. The OA damper will be held to the minimum position setpoint, except when the Control Temperature is 3 unlikely situation, the OA damper will be closed.

As the Control Temperature falls, the chilled water valve will modulate closed. If the v alve is less than 15% open when the Control T emperature falls below the VCS setpoint, the OA damper will modulate closed.

Note: Regardless of the economizer state, its operation is subject to discharge air low limit control.

F of the OHS setpoint. Then it

F of the OCS setpoint. Then it

F or more above the OCS. In this

Heating Operation

The OA damper will maintain its minimum position when the Control Temperature is within 3 Temperature falls to 3

Certified Drawing

F of the OHS setpoint. If the Control

F or more below the OHS, the OA damper

will be closed and room air will be circulated.

Unoccupied Operating Mode

The outdoor air damper will always be closed when the unit is in the unoccupied operating mode. The indoor fan will remain off when the unit is in the unoccupied operating mode unless heating or cooling are required (see note below).

Note: During the unoccupied mode, if the fan remains off continually for 60-minutes, it will start and run for 5-minutes.

Cooling Operation

If the Control Temperature rises to the UCS setpoint, the chilled water valve will be fully opened and the fan will be energized.

When the Control Temperature falls 1 the fan will be de-energized. When it f alls 2

F below the UCS setpoint,

the valve will be closed.

Heating Operation

If the Control Temperature falls below the UHS setpoint, the fan will be energized and room air will be circulated.

The fan will be de-energized when the Control Temperature rises above the UHS setpoint.

Discharge Air Low Limit Control

There are two discharge air low limit functions: the “CW cooling” low limit and the “vent cooling” low limit. The vent cooling low limit function prevents the discharge air (D A) temperature from falling below the VCLL setpoint whenever chilled water cooling is not necessary; when chilled water cooling is necessary , the vent cooling low limit function is disabled. The CW cooling low limit function prevents the DA temperature from falling below the lower CWLL setpoint whene ver the unit is in the chilled water cooling mode (chilled water valv e > 15% open).

Vent Cooling Low Limit (CW Cooling Inactive)

If the DA temperature f alls below the VCLL setpoint, the OA damper will modulate toward fully closed. When the DA temper ature rises to the VCLL setpoint, normal operation will resume.

CW Low Limit (CW Cooling Active)

If the DA temperature falls below the CWLL setpoint, the chilled water valve will be closed.

If the DA temperature rises abov e the CWLL setpoint before the actual valve position is less than 15% open, normal operation will resume.

If the DA temperature remains below the CWLL setpoint until the actual valve position is less than 15% open (unlikely), the O A damper will be closed by the vent cooling low limit function (see above).

Safeties

Low Water Coil Leaving Air Temperature

A normally closed low temperature switch is provided to detect low leaving air temperature conditions on the indoor air coil. The low temperature switch cut out is 38 When the UVC detects the possibility of low leaving air temperatures for longer then 5-seconds (fixed), the following will occur:

• The OA damper is closed

• The chilled water valv e is opened to 25% if the DA temperature is above the VCLL setpoint

• The chilled water valve is opened to 100% if the D A temperature is less than or equal to the VCLL setpoint

When the alarm conditions are gone, the fault will automatically reset.

F +/– 2 and the cut in is 45oF +/– 2.

OM 107-1 / Page 3 (Rev. 7/99)

Sequence Charts

12345678901234

123

The following charts graphically summarize the expected sequences of operation for this Unit Ventilator configuration. The charts are all based upon factory default setpoints. The output states indicated on the charts will typically exist for a particular control temperature, howev er, e xceptions will occur when other control features are active or when alarm conditions exist or when factory defaults are changed. Brief descriptions of the control feature exceptions are noted on the

Outdoor Air Temperature Dependent Functions

charts. Refer to bulletin No. IM613, “MicroTech Unit Ventilator Controller” for more information.

Software ID

Program: UV7*** Software Model: MDL015

Outdoor Air Temperature (

UVC

Function

Indicated

State

Notes

OALO VCLO

34 35 36 63 64 65

Economizer Cooling Available 1,3,4 Outdoor Air Lockout Available 2

Indicated state (default setpoints)

Indicated state dependent on differential (default setpoints)

Outdoor Air Temperature Dependent Function Notes:

1. Economizer cooling will be unavailable when OA is above VCLO

2. OA lockout feature is enabled from the factory in UV Model 15, when enabled the O A damper will be forced closed if O A temperature is below OALO

3. In very humid locations VCLO can be lowered to limit the economizer function

4. In locations where humidity is of no concern, VCLO can be raised slightly to allow additional economizer cooling

Occupied Mode

1234567890123

UVC

Output

Indicated

State

Notes

Cooling Valv e Modulating 2,6

Economizer 1,2,4

OA Damper Minimum Pos. 1,3,5

Control T emper ature (

OHS VCS OCS

64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81

Closed 1,3,5

234

Indicated state (default setpoints)

Indicated state dependent on differential (default setpoints)

Indicated state dependent on OA

234

temperature (default setpoints)

Occupied Mode Notes:

1. The vent cooling discharge air low limit function can affect OA damper position

2. In economizer mode, when cooling is required, the OA damper must be greater than 85% open before hydronic cooling is enabled

3. Control temperature can affect OA damper operation

4. Valve must be less than 15% open before OA damper will begin closing

5. The outdoor air lockout option, if enabled, can affect OA damper position

6. Valve operation can be affected by the CW low limit function

Unoccupied Mode

Control T emper ature (

UVC

Output

Cooling Valv e Fully Open 1 Indoor Fan Off 2

Indicated state (default setpoints)

Unoccupied Mode Notes:

1. Valve operation can be affected by the CW low limit function

2. The indoor fan will remain off in unoccupied mode when heating and cooling are not required

Indicated

State

Notes

Indicated state dependent on differential (default setpoints)

UHS UCS

58 59 60 61 62 84 85 86 87

OM 107-1 / Page 4 (Rev. 7/99)

+ 8 hidden pages