Installation Manual
Single Duct VAV Terminals
Model(s): MQTHI5
IM 1093
Group: Controls
Part Number: IM 1093
Date: September 2010
Supersedes: New
© 2010 McQuay International
Table of Contents
Table of Contents..................................................................................................................2
Revision History....................................................................................................................................3
Limited Warranty..................................................................................................................................3
Installation .............................................................................................................................5
Receiving Inspection.........................................................................................................................5
Hanging/Installation Requirements.............................................................................................. ..... 5
Minimum clearance For Access........................................................................................................7
Connecting Ductwork ....................................................................................................................... 7
Field Electrical Wiring......................................................................................................................7
MQTHI5 Single Duct Terminal Units With Electric Heat................................................................ 7
MQTHI5 Single Duct Terminal Units With Hot Water Coils .......................................................... 8
Controls.............................................................................................................................................8
Labeling ............................................................................................................................................8
MQTHI5 Flow Sensor.......................................................................................................................8
Troubleshooting....................................................................................................................9
Investigating Noise Complaints........................................................................................................9
Discharge Noise................................................................................................................ ................ 9
Radiated Noise..................................................................................................................................9
Controls.............................................................................................................................................9
Electric Duct Heater..........................................................................................................................9
Specific Electric Heat Troubleshooting Procedures:.......................................................................10
2 IM 1093
Revision History
IM 1093 Date: October 2010 Initial release
Reference Documents
Number Company Title Source
ANSI/ASHRAE
135-2001
OM 1092 McQuay International
American Society of Heating,
Refrigerating and AirConditioning Engineers
BACnet® - A Data Communication Protocol for Building
Automation and Control Networks
Operators Manual, Delivered VAV Systems
www.ashrae.org
www.mcquay.com
ED 15126 McQuay International Maverick™ I Unit Controller Protocol Information, BACnet
ED 15113-2 McQuay International BACnet Protocol Implementation Conformance Statement
ED 15112-7 McQuay International BACnet and LONWORKS Protocol Information for Rooftop
and LONWORKS® Networks
(PICS) for MicroTech III Applied Air Handling Unit
Controller
and Self-Contained Units with MicroTech III Controls
Limited Warranty
Consult your local McQuay Representative for warranty details. Refer to Form 933-43285Y. To find your
local McQuay Representative, go to www.mcquay.com
Notice
Copyright © 2010 McQuay International, Minneapolis MN. All rights reserved throughout the world.
McQuay International reserves the right to change any information contained herein without prior notice. The user
is responsible for determining whether this software is appropriate for his or her application.
® ™ The following are trade names or registered trademarks of their respective companies: BACnet from the
American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.; L
Corporation; Windows and Internet Explorer from Microsoft Corporation; Maverick, RoofPak and McQuay from
McQuay International. L
.
ONWORKS from Echelon
www.mcquay.com
www.mcquay.com
www.mcquay.com
IM 1093 3
Introduction
Hazard Identification Messages
!
Dangers indicate a hazardous situation which will result in death or serious injury if not
avoided.
!
WARNING
Warnings indicate potentially hazardous situations, which can result in property damage,
severe personal injury, or death if not avoided.
!
CAUTION
Cautions indicate potentially hazardous situations, which can result in personal injury or
equipment damage if not avoided.
! WARNING
Electric shock hazard. Can cause personal injury or equipment damage.
This equipment must be properly grounded. Connections and service to the MicroTech III Air
Handling Unit Controller must be performed only by personnel knowledgeable in the operation of
the equipment being controlled.
!
CAUTION
Static sensitive components. Can cause equipment damage.
Discharge any static electrical charge by touching the bare metal inside the control panel before
performing any service work. Never unplug cables, circuit board terminal blocks, or power plugs
while power is applied to the panel.
NOTICE
This equipment generates, uses and can radiate radio frequency energy and, if not installed and
used in accordance with this instruction manual, may cause interference to radio communications.
It has been tested and found to comply with the limits for a Class A digital device, pursuant to part
15 of the FCC rules. These limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a commercial environment. Operation of this
equipment in a residential area is likely to cause harmful interference in which case the user will
be required to correct the interference at his or her own expense. McQuay International
disclaims any liability resulting from any interference or for the correction thereof.
DANGER
4 IM 1093
Installation
Receiving Inspection
Prior to removing the shipping material, visually inspect the packing materials. There should be a
black plastic strip wrapped in the clear plastic shrink wrap. If this black plastic strip is missing,
the shipment may have been repacked by the shipper and you should make note of this on the
shipping documents and inform the delivering carrier. After unpacking the terminal, check it for
shipping damage. If any shipping damage is found, report it immediately to the delivering carrier.
Store units in a clean, dry location prior to installation. Units with controls are not recommended
for use in ambient temperatures greater than 95°F. For protection of controls, do not store in
ambient temperatures greater than 135°F. Caution: Do not use the flow sensor, connecting tubing,
or damper shaft as a lift point. Damage to the flow sensor or controls may result.
Hanging/Installation Requirements
Unless local building codes require hangers, the smaller size basic single duct terminals may be
light enough to be supported by the ductwork itself. However, when accessory modules, such as
DDC controls, hot water coils, or sound attenuators are included, the single duct terminal should
be supported directly. Straps screwed directly into the side of the terminal, trapeze hangers, or the
method prescribed for the rectangular duct on the job specifications may be used (See Figure
1and Figure 2). The MQTHI5 Single Duct Terminal is not suitable for outdoor use.
Important: If equipped with pneum
pneumatic controls must be mounted right side up. The single duct unit must be level within + or
– 10 degrees of horizontal, both parallel to the air flow and at the right angle of air flow. The
control side of the terminal is labeled with an arrow indicating UP. Unless otherwise noted, most
analog and digital controls may be installed in any orientation. Check with the local McQuay
representative for verification.
atic controls, the orientation of the terminal is critical. The
IM 1093 5
Figure 1: Strap-Hangers
Figure 2: Trapeze-Hangers
!
CAUTION
Cautions indicate potentially hazardous situations, which can result in personal
injury or equipment damage if not avoided.
The equipment is heavy and counted in the ceiling. Use caution and follow OSHA and
SMACNA installation guidelines.
6 IM 1093
Minimum clearance For Access
Single Duct Air Terminals require sufficient to allow servicing of the actuator, controls and single electric
power hook-up (if applicable). Horizontal clearance requirements are dependent upon access panel
dimensions which are indicated on the appropriate submittals (for control panel enclosure access a
minimum of 18" is recommended. See the appropriate submittal for control panel location). NOTE: These
clearance recommendations are not meant to preclude NEC requirements or local building codes.
Connecting Ductwork
Slip each inlet duct over the inlet collar of the terminal. Fasten and seal the connection by the method
prescribed by the job specification. The diameter of the inlet duct "D" in inches must be equal to the listed
size of the terminal; e.g. a duct that actually measures 8 inches must be fitted to a size 8 terminal. The inlet
collar of the terminal is made 1/8 inch smaller than listed size in order to fit inside the duct.
Note: Do not insert duct work inside the inlet collar of the assembly.
Inlet duct should be installed in accordance with SMACNA guidelines. If a single point electronic velocity
sensor is installed, it is recommended that the installer provide three to five diameters of straight duct at the
terminal inlet. The outlet end of the terminal is designed for use with slip and drive duct connections
(flanged outlets optional). A rectangular duct the size of the terminal outlet should be attached.
Field Electrical Wiring
All field wiring must comply with the local codes and with the National Electrical Code (ANSI/NFPA 70-
2002).
When applicable, electrical, control and piping diagrams are shown on labels attached to the exterior of the
single duct unit.
Use copper conductors only!
All terminal units must be properly grounded per NEC 424-14 and 250.
Always check product label for voltage and current data to determine the proper wire size and current
protection.
The control cabinet contains live electrical parts! Contacting these parts with the power applied may cause
serious injury or death. The control cover must be closed prior to applying electric power to the unit.
These recommendations are not meant to preclude NEC requirements or local building codes that may be
applicable, which are the responsibility of the installing contractor.
Electric shock hazard. Can cause personal injury or equipment damage.
This equipment must be properly grounded. Connections and service to the MicroTech III
Chiller Unit Controller must be performed only by personnel knowledgeable in the
operation of the equipment being controlled.
! WARNING
MQTHI5 Single Duct Terminal Units with Electric Heat
Always inspect the electric coils for damage prior to installing the single duct unit.
All electric heaters if provided by McQuay are balanced by kW per stage. The installing electrician should
rotate these heater stages by phase in order to help balance the building electric load.
See above wiring instructions.
The "up" orientation must be followed.
IM 1093 7
! WARNING
Electric shock hazard. Can cause personal injury or equipment damage.
This equipment must be properly grounded. Connections and service to the MicroTech III
Chiller Unit Controller must be performed only by personnel knowledgeable in the
operation of the equipment being controlled.
MQTHI5 Single Duct Terminal Units with Hot Water Coils
Always inspect the hot water coils for damage prior to installing the single du ct unit.
CAUTION: The copper tubing should not be used as lift points.
The hot water coil casing is field insulated.
The hot water coils do not have a drip pan and are not suitable for use as cooling coils.
Controls
Detailed information regarding connection, start-up and operating procedures for controls provided by
McQuay are available from your local McQuay representative. For information on controls by other
manufacturers, contact that manufacturer’s local branch or dealer.
Important: Units with digital controls, if factory programmed, incorporate specific communication
addresses. Installing the terminal in a different location than noted on unit label and building plans may
result in excessive start-up labor.
!
CAUTION
Static sensitive components. Can cause equipment damage.
Discharge any static electrical charge by touching the bare metal inside the control panel
before performing any service work. Never unplug cables, circuit board terminal blocks,
or power plugs while power is applied to the panel.
Labeling
MQTHI5 Single Duct Air Terminals are shipped from the factory with up to seven different information
labels (not all labels pertain to all single duct units depending upon the type of insulation and the final ship
to state).
1) Control Label – affixed to the single duct terminal casing. Shows piping/wiring diagram and control
sequence number and fusing (if applicable).
2) Calibration Label – affixed to the single duct terminal casing. Shows air flow calibration data and
control settings (if applicable).
3) I.D. Label – affixed to the single duct terminal casing. Shows tagging information, customer order
number, ETL Logo, etc.
4) ARI Certification Label on Single Duct Terminal Unit – identifies applicable industry test standard
and certifies unit is in compliance.
5) ARI Certification Label on Hot Water Coils – identifies applicable industry test standard and certifies
hot
water coil compliance (if hot water coils is ordered as an accessory).
6) Fiberglass Label – identifies insulation type for units sh ipped to California.
7) Orientation label – identifies the proper air flow direction and the top of the unit.
MQTHI5 Flow Sensor
MQTHI5 Single Duct Air Terminals are shipped with a factory-installed pressure differential flow sensor
installed. See
Figure 3, for the calibration curve.
8 IM 1093
Troubleshooting
Investigating Noise Complaints
Noise from a terminal can be due to a variety of conditions, and can be difficult to eliminate. The first step
is to isolate the type, source and direction. Generally, noise heard at the air outlet is considered a discharge
type. Noise heard through the ceiling is considered a radiated noise. For detailed information concerning
noise transmission in buildings see ARI Standard 885-2008E, titled Procedure For Estimating Occupied
Space Sound Levels In The Application Of Air Terminals And Air Outlets.
Discharge Noise
Discharge noise is usually caused by high static or little to no internal duct lining downstream of the
terminal. It can sometimes be caused by the air outlet itself. Air outlet generated sounds can be reduced by
reducing flow or increasing air outlet size. Reducing static pressure, or flow, or adding additional
attenuation materials will reduce discharge sounds from the terminal unit. Sometimes, moving the flex duct
between the terminal and air outlet so the air must make an additional turn will help with the discharge
sound.
Radiated Noise
Radiated noise is most commonly associated with fan powered terminal units.
Controls
Contact your McQuay representative for information concerning controls provided by McQuay. For
controls provided by others, contact the local control representative for assistance.
Electric shock hazard. Can cause personal injury or equipment damage.
This equipment must be properly grounded. Connections and service to the MicroTech III
Chiller Unit Controller must be performed only by personnel knowledgeable in the
operation of the equipment being controlled.
Static sensitive components. Can cause equipment damage.
Discharge any static electrical charge by touching the bare metal inside the control panel
before performing any service work. Never unplug cables, circuit board terminal blocks,
or power plugs while power is applied to the panel.
Electric Duct Heater
If the heater does not operate:
Check electric power into the unit, and verify that the wiring agrees with the label diagram located on
the terminal unit casing.
Verify that the unit is installed properly (i.e., according to the air flow orientation label). Review the
wiring diagram supplied with the heater to verify the field wiring is correct and of the proper gauge
and that the heater is properly grounded.
If the heater cycles on and off:
Verify that the airflow is uniformly distributed across the face of the heater. Check for obstructions in
the duct, or insufficient air flow (CFM) (see label for minimum CFM).
! WARNING
!
CAUTION
IM 1093 9
If conditioned space fails to warm-up:
Make certain that the heater controls and the thermostat are compatible and wired properly. Relocate
the thermostat if it is located in a position that is too warm.
If conditioned space overheats:
Make certain that the heater controls and the thermostat are compatible and wired properly. Relocate
the thermostat if it is located in a position that is too cool. Verify that the air distribution to the space
is appropriate for the required thermal load.
! WARNING
Electric shock hazard. Can cause personal injury or equipment damage.
This equipment must be properly grounded. Connections and service to the MicroTech III
Chiller Unit Controller must be performed only by personnel knowledgeable in the
operation of the equipment being controlled.
Specific Electric Heat Troubleshooting Procedures:
Warning: On all troubleshooting that requires you to work inside the heater wiring casing, disconnect
power first! Jumpers are used for diagnostic purposes only – remove all jumpers prior to returning unit to
operation.
Possible Cause Solution
Power not properly
connected to the heater.
Disconnect switch,
toggle switch, or circuit
breaker set to OFF
Power fuses are blown
or circuit breakers have
tripped.
Manual reset switch
has been tripped.
Air static switch is not
engaging.
Automatic reset switch
bad.
Step controller Jumper out each step of the step controller. If contactor engages, the trouble is in the step controller.
With a voltmeter, check the power wiring terminals to insure the proper voltage is available to the
element side of the power terminal block or to the field side of the disconnect switch, power fusing,
or circuit breakers. If proper voltage is not present, check the terminal studs for proper wiring and
check the power source for power.
Set switch circuit breakers to the ON position.
Replace fuses with the same type and amperage as those provided with the heater, or reset circuit
breaker by first setting the breaker to the OFF position, and then resetting it to the ON position. With
an ammeter, check amperage draw on the power lines. For heaters with fusing, amperage draw should
not exceed the fuse. For heaters with circuit breakers, amperage should not exceed the rated value. If
the amperage draw is excessive, check the power supply as described above for proper voltage. If the
fuse/circuit breaker trips upon application of power, check for a short. If no short is present and the
power supply wiring/voltage is correct, contact the factory for further assistance.
Push manual reset button. Manual reset is usually located in the control cabinet near the bottom of the
been tripped. element header.
Jumper out the air static switch by connecting the lead attached to the normally open stud, to the
normally closed stud. If heater operates, the problem may be the air static switch. Disconnect the
pneumatic tubing from the pitot tube located in the control cabinet. Attach a magnehelic gauge to the
pitot tube. Available static pressure at the pitot tube should be <= -0.03" S.P. or >= +0.03" S.P. If the
available static pressure is in the dead band between these two ranges, the switch will not engage and
some method must be devised to increase the available static pressure. If sufficient static pressure is
available, check to insure the
pneumatic tube is connected to the correct port of the switch. For negative pressure, connect to the
low port. For positive pressure, connect to the high port. If the air static switch still fails to operate,
contact the factory for a replacement switch.
Allow the duct temperature to cool below 90°F. If the heater does not operate, jumper out the
automatic reset switch. If the heater now operates, contact the factory for a replacement switch.
Manual reset switch Allow the duct temperature to cool below 90°F. If the heater does not operate, do
the following:
• On heaters with the manual reset installed in the power wiring, jumper out the manual reset switch.
If the heater now operates, contact the factory for a replacement switch.
• On heaters with the manual reset located in the backup contactor circuit, jumper out the manual
reset switch. If the backup contactor now engages, contact the factory for a replacement switch. If the
backup contactor fails to operate, the problem is in the backup contactor holding coils. Use an
ohmmeter to check the continuity of the holding coils.
Contact the factory for a replacement of any contactor with faulty holding coils.
10 IM 1093
malfunction. Refer to the literature provided with the step controller for proper power and wiring. If wiring appears
SCR controller
malfunction.
POSSIBLE CAUSE SOLUTION
Insufficient air flow
across the heating
elements
to be correct, contact the factory for assistance.
Refer to the literature provided with the SCR controller for proper power and wiring. If wiring
appears to be correct, contact the factory for assistance.
Possible: Nuisance Tripping of Reset Switchs
The minimum allowable air flow across the heating coils is 70 CFM/kW. Unless this minimum air
flow is met, the leaving air temperature will be greater than the set point of the high temperature limit
switches. This will cause nuisance tripping of the reset switches. Reset the minimum air flow across
the coils to the minimum listed value. If further assistance is needed, contact the factory
Figure 3: MI Flow Sensor Calibration Chart
IM 1093 11
This document contains the most current product information as of this printing. For the most current product
information, please go to www.mcquay.com. All McQuay equipment is sold pursuant to McQuay’s Standard
Terms and Conditions of Sale and Limited Warranty.
www.mcquay.com
800-432-1342
12 IM 1093
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