Mammoth 800, 5500 CFM User Manual
VHC
!
Energy Recovery Ventilators with Enthalpy Wheels and
Integrated Heating and Cooling
Installation, Operation and Maintenance
Capacity: 800 to 5,500 cfm
Model: VHC-36, VHC-42, VHC-50
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause injury or death. Read the installation, operation and maintenance instructions in this
appendix thoroughly before installing or servicing this
equipment.
IMPORTANT
The use of this appendix is specically intended for a
qualied installation and service agency. A qualied installation and service agency must perform all installation and
service of these appliances.
MAMM-VHC-IOM-1A (January 2013)
Table of Contents
Table of Contents .................................................................................................................................................................2
Nomenclature .......................................................................................................................................................................3
Safety Considerations ..........................................................................................................................................................4
General Information ..............................................................................................................................................................4
Unit Application Limitations ............................................................................................................................................4
Installation ............................................................................................................................................................................4
Unit Location Requirements ...........................................................................................................................................4
Roofcurbs Supplied by Mammoth (External Applications Only) ..................................................................................... 5
Roofcurbs Supplied by Others .......................................................................................................................................6
Rigging and Placing the Unit ..........................................................................................................................................6
Field Fabricated Ductwork ..............................................................................................................................................6
Hood Installation .............................................................................................................................................................7
Access Panels ................................................................................................................................................................ 7
Internal Packaging ..........................................................................................................................................................7
Electrical Connections .................................................................................................................................................... 8
Water Source Heat Pump (WSHP) Water Piping and Connections .............................................................................10
Condensate Drain Trap ................................................................................................................................................10
Start-up ...............................................................................................................................................................................11
Pre Start-up Procedure ................................................................................................................................................11
Start-up Procedure .......................................................................................................................................................11
Optional Controls and Accessory Sequence and Interlocks ........................................................................................12
Frost Control .................................................................................................................................................................13
Airow Balancing .......................................................................................................................................................... 14
Service................................................................................................................................................................................15
Quarterly Maintenance .................................................................................................................................................15
Annual Maintenance .....................................................................................................................................................15
Coils .............................................................................................................................................................................15
Testing and Replacement of the Damper Actuator ......................................................................................................16
Motor and Blower Removal – Down, Side and End Supply/Exhaust ...........................................................................16
Motor and Blower Service – Down, Side and End Supply/Exhaust .............................................................................16
Belt Tension Adjustment ..............................................................................................................................................17
Plenum Fan and Motor Removal ..................................................................................................................................17
Plenum Fan and Motor Service .................................................................................................................................... 18
Cassette Removal ........................................................................................................................................................18
Cassette Service ..........................................................................................................................................................19
Appendix A: Service Clearance Dimensions ...................................................................................................................... 20
Appendix B: Hood Installation ............................................................................................................................................21
Appendix C: Rigging Drawing.............................................................................................................................................22
Appendix D: Equipment Data .............................................................................................................................................23
Appendix E: Electrical Data ................................................................................................................................................ 24
Appendix F: Terminal Control Diagrams ............................................................................................................................27
Appendix G: Standard Field Wiring (FW) Terminals ..........................................................................................................30
Appendix H: VHC-36, 42 and 50 Start-up Report and Checklist ........................................................................................ 31
Appendix I: Troubleshooting ...............................................................................................................................................35
Appendix J: Electric Heating Coil and Controls Information ............................................................................................... 37
Appendix K: Water Line Field Mounted Options and Accessories .....................................................................................39
Appendix L: Enthalpy Wheel Pressure Drop vs. Flow Formulae and Curves ...................................................................47
Manufacturer reserves the right to discontinue or change specications or designs without notice or obligation.
MAMM-VHC-IOM-1A (JANUARY 2013)
2
Nomenclature
VHC-XX
Ventilator
with heating
and cooling
Nominal wheel
diameter
– 36
– 42
– 50
©Mammoth Inc. 2012. All rights reserved throughout the world.
Illustrations cover the general appearance of Mammoth products at the time of publication and Mammoth reserves the
right to make changes in design and construction at any time without notice.
™® The following are trademarks or registered trademarks of their respective companies: Tefzel from DuPont.
MAMM-VHC-IOM-1A (JANUARY 2013)
3
Safety Considerations
!
!
!
Warning, Caution and Important notes appear throughout
this manual in specic and appropriate locations to alert Installing Contractors and maintenance or service personnel
of potential safety hazards, possible equipment damage or
to alert personnel of special procedures or instructions that
must be followed as outlined below.
WARNING
Identies an instruction which, if not followed, might cause
serious personal injuries including possibility of death.
CAUTION
Identies an instruction which, if not followed, might severely damage the unit, its components, the assembly or
nal installation.
General Information
These ventilators can provide 100% outdoor air ventilation or, depending on options selected, varying amounts of
recirculation between the exhaust and supply airstreams.
The VHCs use an enthalpy wheel for total energy recovery which provides superior efciency in hot and humid
climates. These models are also effective in cold climates
and use various types of frost control or defrost to ensure
IMPORTANT
Indicates supplementary information needed to fully complete an instruction or installation.
Hazards may exist within this equipment because it contains electrical and numerous moving components. Only
qualied service personnel should install or service this
equipment. Untrained personnel may perform basic maintenance such as maintaining lters. Observe precautions
marked in literature and on labels attached to the unit. Follow all safety codes.
WARNING
Disconnect the main power switch to the unit before performing service or maintenance. Electric shock can cause
personal injury or death.
proper operation when the outside temperatures are extremely low. Units intended for rooftop installations must
be installed on a factory or eld supplied roofcurb. This
manual contains information on optional components that
may or may not be included with this unit. Refer to the submittals for options that pertain to this unit.
Unit Application Limitations
WARNING
Mammoth equipment is not designed to be used for temporary heating, cooling and/or ventilation during construction.
Using Mammoth units for temporary ventilation during
construction constitutes a violation of Mammoth warranty
terms which indicate that the unit warranty would be void
“…if equipment is misapplied or if any alterations are made
to the basic design or operating requirements as listed
on the original order and shipped from the factory unless
Installation
Unit Location Requirements
Consult local building codes and electrical codes for special installation requirements and note additional requirements listed in this manual. In choosing the installation
location of the unit, consider the following factors:
approval is received in writing from Mammoth” Fine dust,
larger particulate matter, solvents, varnishes and other
chemicals may cause lter clogging and elevated cabinet
pressures, higher power consumption and possible irreparable damage to the desiccant material of the enthalpy
wheel, which could reduce energy recovery performance of
the wheel and also reduce the heat transfer effectiveness
of other components. Potential damages include, but are
not limited to, these examples.
• The unit should be installed to allow easy access for
maintenance and for systems operation. See the service clearance dimensions in Appendix A.
• When possible, mount the unit over an unused area
such as a hallway. Although fans and motors are
mounted on vibration isolators or are dynamically
MAMM-VHC-IOM-1A (JANUARY 2013)
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balanced, the unit will be even less perceptible if positioned away from busy ofces.
• Locate the unit in an area requiring the least amount
of ductwork and direction changes to allow optimum
performance, to reduce pressure loss and to use less
electricity to achieve proper ventilation. Ductwork
must be in accordance with ducting mechanical rules
to prevent sound issues and system effects.
• The fresh air intake hood must be positioned away
from sources of contamination such as hot chimneys
or kitchen exhaust vents.
• Fresh air intake must also be positioned in a direction
opposite to that of prevailing winds to reduce entry of
snow or rain.
• The unit should be mounted on a level foundation to
allow condensation to ow into internal drains. The
foundation must provide adequate continuous support
to minimize deection of the unit base frame to not
more than 1/16” [1.6 mm] over entire length. In addition to these recommendations, a Structural Engineer
Roofcurbs Supplied by Mammoth (External Applications Only)
must be involved to properly size supporting structural
elements.
• When mounting the unit indoors, if drain connections
are required, mount the unit on a housekeeping pad
of sufcient height to allow for drain trap height and
condensate lines to slope toward the building drain.
• When mounting the unit on a roofcurb check the
height from the nished roof to the bottom of the
intake hood. Consult with Local Authorities or your
building code for minimal intake hood height for the
water-tight height from and above the nished roof
and in snow prone areas, the buildup of snow, to determine the height of the roofcurb. Mammoth optional
roofcurbs measure 18” [457 mm] in height. If additional height is required from the nished roof to the
top of the roofcurb, to the bottom of the intake hood
or if other than level, custom height roofcurbs must be
ordered.
Roofcurbs supplied by Mammoth should be mounted as
follows:
• The roofcurb is shipped knocked-down with assembly
hardware and instructions provided. The roofcurb
must be eld erected, assembled and set in place by
the Installing Contractor.
• Roofcurb dimensions are submitted with the unit mechanical drawings which can also be found in the unit
control panel pocket or by calling Technical Support
personnel from the Mammoth factory.
• After the roofcurb has been assembled, ensure that
the roofcurb dimensions suit the unit for which it is
designated.
• The cross members must be positioned as per the
roofcurb drawing to properly support the ductwork
plenums for bottom vertical return and supply connections and for stability.
• Ensure that the assembled roofcurb is square, plumb
and level to within 1/16” [1.6 mm] over the entire
length. The building structure must provide continuous structural support to the full perimeter of the
roofcurb and all cross members requiring support.
The roofcurb may be shimmed as required to provide
continuous support.
• The roofcurb must be fastened to the building structure.
• The Installing Contractor is responsible for making the roofcurb water-tight by caulking all roofcurb
joints.
IMPORTANT
The following items must be completed prior to setting the
unit on the roofcurb:
• The roofcurb roong must be completed including
insulation, cant strip, ashing and counter-ashing.
• Vertical ductwork must be attached to the roofcurb
cross members and building structure, not to the
unit. See the mechanical drawings for information on
roofcurb installation, recommended ductwork attachment and dimensions.
• If there is no building roof access underneath the
unit and drain or piping connections must be made
(in the roong), it is recommended to do so before
unit installation using the appropriate materials provided by the Installing Contractor.
• Remove the length of 3/8” x 1½” [9.5 mm x 38 mm]
polyvinyl gasket strip with adhesive backing supplied
with the unit and apply a continuous strip to the top
perimeter of the roofcurb and duct opening connections for an air and water-tight seal.
IMPORTANT
The gasket between the unit and the roofcurb is critical for
an air and water-tight seal. An improperly applied gasket
can result in air and water leakage and poor unit performance. Position the unit with equal spacing all around between the roofcurb and inside unit base rail using ½” [13
mm] wood shims as it is being lowered.
MAMM-VHC-IOM-1A (JANUARY 2013)
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Roofcurbs Supplied by Others
Roofcurbs supplied by others must be designed with the
same dimensions and cross member arrangement as per
Mammoth roofcurb drawings and must be designed to
evenly withstand perimeter and cross section static loads.
Rigging and Placing the Unit
Inspect the equipment exterior and interior for damage
and for shipped loose parts. Ensure there is no damage to
internal components such as fans, motors, dampers, enthalpy wheel, insulation and structures. File a claim with the
shipping company if the unit is damaged. Check the packing slip against all items received. If any items are missing,
sign the carrier’s bill of lading with the notation “Shipment
Received Less Item #___.”
IMPORTANT
The hoods for these units are not installed from the factory and must be installed on site. They should be installed after the unit is installed. Hoods are shipped on top
of the unit. When rigging the unit, make sure the hoods
are secured and are not damaged by the spreader bars.
See Appendix B for hood installation.
IMPORTANT
Mammoth is not liable for any damages, costs or other issues arising from roofcurbs supplied by others.
Spreader bars are required to prevent damage to the roof
ange. Rollers may be used to move the unit across the
roof. Lifting holes are provided in the base rails as shown in
Appendix C. Refer to submittal documents for overall unit
dimensions and Appendix D for unit weights.
CAUTION
All panels must be in place when rigging.
Field Fabricated Ductwork
On vertical discharge units, secure all ducts to the roofcurb
and building structure. Do not secure ductwork to the unit.
For unit and duct opening sizes see submittal drawings.
Insulate and weatherproof all external ductwork, joints and
roof openings with counter-ashing and mastic in accordance with applicable codes. Ductwork running through
roof decks must comply with local re codes. Ducts passing through unconditioned spaces must be insulated and
covered with a vapor barrier. Flexible connectors should
be installed close to the unit in the duct leading to occupied
spaces to minimize noise transmission.
Duct Design Considerations
The discharge ductwork immediately downstream from the
fan is critical for successful applications. Poorly designed
ductwork can degrade fan performance and contributes to
excessive pressure drop and noise.
When designing ductwork in the eld, it is important to
use a straight discharge duct of the correct dimensions to
obtain maximum fan performance. The straight section of
ductwork helps the airow to develop a uniform velocity
prole as it exits the fan and allows the velocity pressure to
recover into static pressure. See Figure 1.
Centrifugal fan
Figure 1: Duct design
For 100% recovery of velocity pressure into static pressure, the straight portion of the discharge duct must be at
least 2.5 times the discharge diameter to the length of the
straight portion of ductwork.
As an example of how to size the straight portion of duct,
assume the fan has a 13.5”x 9.5” discharge outlet = 0.89
Cutoff
100% effective duct length
2½ diameters at 2,500 FPM
Discharge duct
IMPORTANT
This information is referenced from AMCA Fans and Systems Publication 201.
ft2.
MAMM-VHC-IOM-1A (JANUARY 2013)
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Refer to Table 1 for the effect of undersized equivalent duct
diameter.
Table 1: Effect of Undersized Equivalent Duct Diameter
Pressure
recovery
12%
No Duct
Effective
Duct
0% 50% 80% 90% 100%
25%
Effective
Duct
50%
Effective
Duct
100%
Effective
Duct
Hood Installation
Calculate Equivalent Duct Diameter
The equivalent duct diameter of the fan outlet.
= (4ab + n)
= (4 x 13.5 x 9.5)
n
= 12.75
= ~13
So the straight duct length required would be:
= 2.5 x 13
= 32.5” long [2.7 feet]
0.5
0.5
Intake and exhaust hoods for these models are shipped
separately from the unit. To install hoods see Appendix B.
A quick connect for the damper motors is provided to con-
Access Panels
Handles for lift off exterior access panels with screw door
fasteners are provided but must be installed on site. Handles and fasteners are secured inside the unit.
Internal Packaging
Open access doors or panels and remove all packaging
from the unit. Note that there is packaging for wheel support during shipping. Removal of all packaging is critical.
nect to the main body of the unit. Make sure that all screws
are secured to maintain proper support and keep seals
water-tight.
IMPORTANT
Securing door fasteners too tightly has negative effects on
the door gasket and should be avoided.
MAMM-VHC-IOM-1A (JANUARY 2013)
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Electrical Connections
!
WARNING
When installed, the appliance must be electrically
grounded in accordance with local codes or, in the absence of local codes, with the National Electrical Code,
ANSI/NFPA70, and/or the Canadian Electrical Code CSA
C22.1. Unit cabinet must have an uninterrupted, unbroken
electrical ground to minimize the possibility of personal
injury if an electrical fault should occur. Failure to follow
this warning could result in the Installer being liable for
personal injury of others.
Power Supply
Units are available in all voltages and phases. Please see
Appendix E for electrical data. These units may or may not
have a factory installed disconnect switch. If disconnect is
eld supplied, provide a disconnect as per local electrical
codes and NEC. Use copper conductors only.
All eld wiring must comply with NEC and local requirements. In Canada, electrical connections must be in accordance with CSA C22.1 Canadian Electrical Code Part One.
Units equipped with electric preheaters and/or post heaters
have either single-point or two-point power connections.
See Appendix E, submittal data and/or nameplate to de-
termine which. All units equipped with two-point electric
heaters require two-point power connection—one to the
unit control panel and one to the electric heater fed from a
single eld supplied disconnect.
Field Connection
A high voltage connection hole is located on the outside of
the unit with knock-out; see submittal drawings for location.
A eld installed disconnect switch must use a liquid-tight
connector between the disconnect switch and the outside
panel of the unit eliminating any water penetration into the
control box. A wiring diagram is located within the control
panel area of the unit.
A low voltage Field Wiring (FW) interface is provided near
the control Panel (PNL) terminals for shipped loose or eld
supplied controls, sensors or interlock connections. The
location of the eld wiring and panel terminals may vary
depending upon options selected as illustrated in Figure 2.
The low voltage eld wiring entry is made through the side
of the unit below the input power supply connection (see
Appendix G) which runs through the outside casing and
requires a liquid-tight connector or conduit to avoid water
penetration.
Installer must provide wiring for controls that are supplied
optionally and shipped loose or eld supplied. All eld supplied low voltage wiring must be Class 2. Mark the Field
Wiring terminals schematic (Appendix G) with the connections completed and leave with the unit for start-up and
service.
Units will require a start contact interlock from a remote
time clock, light sensor, occupancy sensor, manual selector switch or remotely through BACnet from a Building
Management System (BMS) depending on ventilation
control scheduling mode required. Select required interlock and ventilation control scheduling mode from description below.
See Appendix F and Appendix G for wiring terminal con-
trol diagram examples and standard Field Wiring (FW) terminal and interlock connections available.
Units Supplied with DDC Control Package
The DDC control package enables stand alone operation of the VHC unit and includes a factory installed, programmed and run tested stand alone microprocessor
based controller, all necessary sensors and interfaces to
provide control of optional post conditioning functions. See
the VHC-36, 42 and 50 DDC Control Package Manual
(VCES-DDC-IOM-1 (500020459)) for overview, installation
and start-up.
An intelligent programmable interface device (BacStat II)
with built in room sensor is included for communication,
display, setpoint control and to allow for servicing and is
shipped loose for eld wiring and installation at the unit or
remotely. Determine required location for installation and
connect using two twisted pair cables, the rst for power
connection. The LinkNet cable needs to be balanced 100
to 120 ohm nominal impedance twisted shielded pair cable,
nominal capacitance of 16 PF/FT or lower.
Units Supplied with an Electro-mechanical
Controls (EMC) Package
The EMC controls package or dry contact control option
include: all relays, motor starters, motor overloads, damper
actuators, heating and cooling initiate contacts and selected option pickup points. All necessary connections are
wired to a terminal strip in the control panel for eld wiring
connections to a Building Management System (BMS), for
eld supplied DDC or standard controls and thermostats.
See the Control Contractor’s ow and wiring schematics
for connection details.
Ventilation Control Scheduling Modes
Occupied Ventilation (Ov)
If the occupancy contact closes or a jumper is placed
across terminals FW 304–305 this will enable the unit to
run in 100% fresh air mode. Free cooling and defrost will
initiate based on the setpoint.
Unoccupied Recirculation (Ur)
If the unoccupied recirculation contact closes or a jumper
is placed across terminals FW 305–306 the unit will turn off
unless there is a call for heating/cooling or dehumidication
across the heating/cooling or dehumidication contacts.
MAMM-VHC-IOM-1A (JANUARY 2013)
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This must come from an optional thermostat or humidistat.
The unit will run in recirc mode upon a call.
Occupied Recirculation (Or) (DDC Control Package
only)
If the occupied recirculation contact closes or a jumper is
placed across terminals, heat wheel starts (not in free cooling), defrost recirculation damper closes (if equipped), outside and exhaust air dampers (if equipped) begin to open;
after outside air damper opens fully the supply blower
starts; after exhaust air damper opens fully the exhaust
blower starts, the occupied recirculation damper opens and
outside and exhaust dampers modulate to the minimum
setpoints.
Unoccupied (Un)
If the contact opens or jumper removed on any of the terminals 304, 305, 306, 307 or 308 the unit will turn off.
PNL
PNL
FW
FW
Figure 2: Possible terminal strip locations in electrical panel
MAMM-VHC-IOM-1A (JANUARY 2013)
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Water Source Heat Pump (WSHP) Water Piping and Connections
[76 mm]
Before connecting piping to the unit, the water supply line
and return line must be ushed to eliminate the foreign
material. In low temperature applications, the water supply
line and return line should be insulated to prevent condensate and antifreeze solution should be used to protect
water-to-refrigerant heat exchanger from freezing damage.
See submittal drawings for water piping connection location. The concentration of water/glycol solution depends
on the eld application. On open loop systems, a water
strainer (16–20 mesh minimum, 20–40 mesh best) is recommended to be installed in the water inlet line to the unit
to eliminate contaminants and it must be used for units
having water-to-refrigerant brazed plate heat exchanger.
A water ow switch is recommended to be installed in line
to prevent possible freeze-up due to loss of water ow.
An air vent must be installed on the high side of the water
line to discharge the non-condensable air in order to avoid
Condensate Drain Trap
Cooling coil drain pan is provided with a 1¼” MPT drain
connection. A drain trap and condensate line of equal size
must be eld provided on the drain connection to prevent
air or sewer gases from being pulled into the unit caused
by the negative (suction) pressure and forcing water out of
the pan into the unit.
A label with recommended trap height is provided on the
unit as per Figure 3.
Condensate drain must be trapped as shown.
Refer to IOM for further instructions and maintenance.
Le drain de condensation doit être fabriqué et intallé tel que
le croquis ci-bas. Voir le manuel d’installation,
opération et maintenance pour instructions.
Curb
6.578”
[167.08 mm]
support
3.375”
[85.73 mm]
6.0” [191 mm]
minimum
unexpected high head pressure and poor cooling/heating
performance. Manual shut-off valves are recommended to
be installed for the convenience of future service.
A circuit balancing valve with pressure and temperature
gauge connections is recommended to be installed in the
water line for balancing and service.
See Appendix K for water line eld mounted options and
accessories.
CAUTION
In areas where scaling can become serious, a periodic
cleaning for the water-to-refrigerant heat exchanger is
recommended. Standard water coil cleaning procedure
should be followed which must be done by a qualied service mechanic.
The trap height allows for the maximum suction pressure
after the cooling coil with intake damper, dirty pre and nal
high efciency lters, high efciency heat wheel plus 1” w.c.
per ASHRAE guidelines for outdoor units with intake hood
or indoor unit with up to 0.5” w.c. external static intake duct.
Slope the drain lines downward in direction of ow 1/8 inch
per foot referring to local codes for proper drainage requirements. Installing a plug for cleaning of the trap is recommended. Prime the trap by lling with water before start-up.
Winterize the drain line before freezing on outdoor units.
Check and clear drains annually at start of cooling season. Drainage problems can occur should drains be inactive and dry out, or due to reduced water ow caused
by buildup of algae. Regular maintenance will prevent
these from occurring.
Unit baserail
Curb
Figure 3: Condensate drain trap label
MAMM-VHC-IOM-1A (JANUARY 2013)
3.0”
minimum
PN 500005436
10
Start-up
Pre Start-up Procedure
Before requesting start-up, check that the installation is
complete and unit is ready. Complete the pre start-up
check list below and in the Appendix H for each unit as
items are checked.
1. Set the electrical disconnect to the ‘Off’ position.
2. Check the unit for obstructive packaging, objects near
or in blowers, dampers, heat wheel, etc. Remove all
red tie down bolts on fan assemblies and heat wheel if
so equipped.
3. Check that the fans and heat wheel are rotating
freely.
4. Check blower wheels and drive set screws. Tighten if
required.
5. Check belt alignment and tension.
6. Check that the air lters are installed and clean. Replace if necessary.
7. Check coils (if equipped) if ns have been damaged
in transit or construction and are clean. Straighten ns
with n comb and clean coil if required.
8. Check the refrigerant components and piping that they
are in good condition and have no damage or leaks
from shipping or installation.
9. Check that the water strainer has been installed for a
WSHP with a brazed heat exchanger.
10. Check that ductwork is connected and complete.
11. Check that condensate drain connections have been
trapped, installed correctly and lled.
12. Check that all shipped loose or eld supplied components have been correctly installed and wired and that
start interlocks have been completed for the ventilation
control desired.
13. Check that the standard eld wiring (FW) terminal
diagram has been marked up accordingly and left with
the unit.
14. Check that all power supplies and control wiring have
been inspected and approved by the Local Authorities
having jurisdiction.
15. Check all factory and eld wiring connections for tightness. Tighten if necessary.
16. Check that all fuses are properly installed in holders.
17. Check the voltage at the disconnect switch against the
nameplate and against phase-to-phase readings on
three-phase. If the voltage is not within 10% of rated
or 2% of phase-to-phase, have the condition corrected
before continuing start-up.
18. Check that all eld piping and venting installation and
connections for the heating and cooling options have
been completed and test.
19. Set the heating and cooling enable switches to the
‘Off’ position.
Start-up Procedure
To ensure proper operation of each unit, qualied personnel should perform the start-up and complete the checklist
below and the start-up report in Appendix H for permanent
record. A completed checklist will provide valuable information for personnel performing future maintenance.
IMPORTANT
A completed copy must be sent back to the factory for
warranty validation and for factory assistance.
All units are factory run tested. Blowers, heat wheel and
compressors (if equipped) are set up to run correct when
power is connected. If any one blower is running backwards or compressor is making loud noises disconnect
power and switch two leads (on three-phase power) to ensure proper rotation and avoid damage.
If units are equipped with compressors power must be
turned on for 24 hours prior to a call for cooling, for the
compressor crank case heaters to be energizing to prevent
possible damage.
The BacStat II interface module (if equipped with DDC control package and mounted remotely) may be temporarily
connected at the unit for checkout. Ensure it is connected
to the Net 2 contacts otherwise it will not give readings.
1. Before proceeding complete the pre start-up checklist.
2. Check that all access panels or doors are closed.
3. Turn the main disconnect to the ‘On’ position.
4. Set the timer, selector switch or BMS contact to the
ventilation control scheduling mode selected and
check operation according to sequence. Only one of
the following modes selected can have their contacts
closed or jumped.
a. Occupied ventilation (Ov): With the occupancy
contact closed or a jumper placed across terminals, heat wheel starts (not in free cooling), defrost recirculation damper closes (if equipped),
outside and exhaust air dampers open fully,
the supply blower starts and after exhaust air
damper opens fully, the exhaust blower starts.
b. Unoccupied recirculation (Ur): With the unoc-
cupied recirculation contact closed or a jumper
MAMM-VHC-IOM-1A (JANUARY 2013)
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placed across terminals, heat wheel stops,
defrost recirculation damper opens, outside
and exhaust air dampers (if equipped) begin to
close and supply blower starts.
c. Occupied recirculation (Or) (DDC control pack-
age only): With the occupied recirculation
contact closed or a jumper placed across terminals, heat wheel starts (not in free cooling), defrost recirculation damper closes (if equipped),
outside air damper (if equipped) opens. After
outside air damper opens supply blower starts,
exhaust air damper (if equipped) opens; after
exhaust air damper opens, exhaust blower
starts, occupied recirculation damper opens,
outside and exhaust air dampers modulate to
the damper minimum setpoints.
5. Check that dampers are operating properly.
6. Check that blowers and heat wheel are rotating in the
correct direction.
7. For occupied recirculation scheduling mode the outside air and exhaust air dampers must be adjusted
during start-up to achieve the required outside and exhaust air volumes. See Airow Balancing for further
information.
8. Re-check the voltage at the disconnect switch against
the nameplate and against phase-to-phase readings on three-phase with all blowers operating. If the
voltage is not within 10% of rated or 2% of phase-tophase have the condition corrected before continuing
start-up.
9. Check amperage draw to each motor on each
phase against motor nameplate FLA. If signicantly
different, check ductwork static and/or take corrective action.
10. Before activating the compressor on WSHP units, are
water shut-off valves open and is water circulating
through the water-to-refrigerant heat exchanger.
11. Enable cooling and check if the sound of the compressor is normal or if there is excessive vibration.
12. Check all eld and factory refrigerant and water piping
connections for leaks and correct.
13. Enable heating options, see start-up and check out instructions in Appendix J for electric coil and complete.
14. Check the operation of the control options provided
on the unit. A functional description is provided below
and in the VHC-36, 42 and 50 DDC Control Package
Manual.
15. Check the setpoints on the DDC Points Reference,
adjust and record changes as required.
16. When unit has achieved steady state take measurements and complete the readings section of the start-
up report in Appendix H and send copy of the start-up
report to Mammoth to validate warranty. Maintain a
copy of the report at the unit for future reference.
Optional Controls and Accessory Sequence and Interlocks
Free Cooling
Power connected, unit ventilating, free cooling call. Wheel
stops rotating.
Variable Speed Setpoint Free Cooling
Power connected, unit ventilating. Wheel modulates to
keep discharge temperature air at setpoint.
Unit Fault
An external unit fault can be initiated by removing the
dry contact jumper to the eld wire terminal in the control
panel. This contact is normally closed and requires an
open contact to initiate a fault and shut down the unit.
Dirty Filter Sensor
The VHCs can be equipped with dirty lter sensors which
monitor the pressure across the lters and close the contacts when the lters become restricted with dirt. Field
wired connections can be made to the terminal interface
MAMM-VHC-IOM-1A (JANUARY 2013)
for both the supply and exhaust lter sensors (electro-mechanical controls [EMC] units only).
Remote Fan Control
Remote fan control can be achieved by connecting dry
contacts to the terminal interface (during occupied or unoccupied recirculation). These controls could also be the
following: SPDT switch, dehumidistat, CO2 sensor, light sensor, heat sensor, timer, Building Management System, etc.
CO2 Ventilation Control
VHCs can be directly controlled by a CO2 controller (accessory or eld supplied) that can be connected to the supply
and exhaust high speed contact terminals (VFD units only).
As the CO2 levels exceed acceptable limits, dry contacts
close raising high speed fan ventilation. See Appendix F,
CO2 Ventilation Control. Alternatively a eld supplied CO2
controller output can be connected to the BMS which can
then be connected to the supply and exhaust fan modulating signal input terminals (VFD units only). As the CO2
12
levels rise and fall the BMS must modulate the signal to
the supply and exhaust fans to change the ventilation rate
proportionally. See Appendix G. The minimum VFD speed
is factory default set to 40 Hertz.
Smoke Detector
VHCs can be equipped with a duct mount smoke detector
which will monitor the air when passing through the duct
system into the unit. When sufcient smoke is detected, an
alarm condition is activated. By connecting the occupied
terminals to the NC alarm auxiliary contacts on the duct
sensor, an alarm condition will open the auxiliary contact
and stop operation of the VHC. Locate in a normally occupied area of premises. Recommended for compliance to
NFPA-90A and IMC code 606.
Cooling Override (DDC Controls Units Only)
These terminals are available for a room or return air summer thermostat. All thermostats are eld installed and wired.
Dehumidication (DDC Controls Units Only)
IMPORTANT
Removal of dry contacts that close on high speed terminals is required for VFDs to modulate.
These terminals are available for a room or return air dehumidistat. All dehumidistats are eld installed and wired.
Heating Override (DDC Controls Units Only)
These terminals are available for a room or return air winter
thermostat. All thermostats are eld installed and wired.
For standard eld wiring terminals diagram, refer to Appen-
dix G.
Frost Control
During cold temperatures, defrost and frost prevention are
controlled by the unit’s integrated controls as follows.
Preheat will prevent frost formation on the enthalpy wheel
to maintain proper operation and provide continuous ventilation and make-up air. This prevention occurs when a preheater is energized to maintain an outdoor air temperature
higher or when the wheel speed is reduced to maintain an
exhaust air temperature higher than minimum required for
the enthalpy wheel to operate frost free.
The requirement for frost control is based upon the outdoor
air temperature and humidity content of the return air. In
areas where the winter outdoor air condition falls below 5°F
[−15°C] or the return air relative humidity is above 30%,
frost control is probably required.
Preheat Frost Prevention
Preheat frost prevention is an outdoor air temperature
controlled function that allows for continuous ventilation by
ensuring a minimum enthalpy wheel entering air temperature of 5° F [−15°C]. The temperature sensor is located between the open wire electric heating coil and the enthalpy
wheel. The electric heating coil is selectable in 1 kW increments and available in two-stage, four-stage or SCR control. With staged control, one stage cycles to maintain 5°
F [−15°C] temperature to the enthalpy wheel as the other
stages are continuously on as the outdoor air temperature
drops. If the selected kW is insufcient, based upon the
entered design conditions, selection software automatically
adjusts the minimum kW required to maintain the minimum
wheel entering air temperature.
Non-defrost
No frost control is required in areas where the winter outdoor air condition stays above 5°F [−15°C] and the return
air humidity level is below 30%.
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!
Airow Balancing
IMPORTANT
On initial power up, the unit will perform a system check
and operate at high speed for ve seconds.
For proper performance the unit must operate and be
balanced at the design supply and exhaust airow rates.
Permanent or temporarily eld supplied and installed ow
measuring stations (FMS) can be used to measure airow
or by using other ASHRAE suggested methods. Where
space is limited in the outdoor air or exhaust air ducts
for measurements, pressure drop readings can be taken
across the enthalpy wheel rotor and airow extrapolated
from the curves in Appendix L for the wheel effectiveness
category or thickness. Heat recovery performance is tested
in accordance to AHRI Standard 1060 and is accurate to
within +/− 5% if there is no dirt buildup in the heat recovery
wheel rotor.
When FMS are used it is important to locate it in the “warm
side” ductwork to minimize the effects of differences in air
density especially during cold outside conditions. Air density variations can affect the FMS by more than 15%. The
FMS should be located downstream from straight sections
of duct and not immediately after fans or obstructions that
will cause turbulent ow.
coils or reheat to protect building systems must be eld
provided.
Setting Flow Rate
Units supplied with belt driven double width double inlet
fans have an adjustable motor sheave factory set at the
midpoint of travel at rpm for the ow rate and external static
specied. With optional VFD driven motors this factory setting is at 60 Hz. For 100% outdoor and exhaust, ow rate
should be balanced with motors operating at high speed
and at 60 Hz by adjusting the motor sheave pitch diameter.
The VFD can be used for ne tuning depending on sequence.
With the optional direct driven plenum supply fan the VFD
is used for speed setting and balancing at the required
Hertz.
With the optional internal bypass the airow rate may be
reduced. Consult the factory for setting the ow rate during
internal bypass.
WARNING
Disconnect the main power switch to the unit before performing service and maintenance procedures.
Imbalanced airow may cause supply air temperatures
to be below freezing. Adequate freeze protection such as
glycol or low limit temperature protection for downstream
MAMM-VHC-IOM-1A (JANUARY 2013)
14
Service
Quarterly Maintenance
Quarterly maintenance (every three months) should include:
Air Filters
The standard medium efciency lters and optional high efciency lters are disposable and should be replaced every
three months. More frequent replacement may be required
under extremely dirty operating conditions.
To replace the lters, open the lter access door, grasp the
lters and pull straight out. The lters will slide completely
Annual Maintenance
Annual maintenance should include:
Aluminum Enthalpy Wheel
No cleaning of the enthalpy wheel is required as it is
self-cleaning due to the opposing airows. If it is desired
to clean the enthalpy wheel, use low pressure air or a
vacuum. Wash the cassette panels with a soft cloth and
mild cleaning solution. Visually inspect the cassette brush
seals (shown in Figure 4), perimeter seal and drive belt
for proper operation.
out of the unit. Slide the new lters into the frame and close
the lter access door.
Cassette Panels and Interior of Unit
Remove the lters from the unit. Wipe the foil faced insulation, or the optional interior galvanized liner, surfaces
and cassette panels with a soft cloth and mild cleaning
solution.
System Operation Check
Verication of all control modes should be checked to ensure proper operation. Refer to Start-up section.
Rotor
Brush seal
Fans
Blower wheels and fan housing should be checked for dirt
buildup. If they are dirty, it will be necessary to remove the
blower assembly to clean the dust out through the fan mouth.
Dirt on the surface of the coil reduces its ability to transfer
heat which lowers the efciency of the unit, resulting in
poor air quality and expensive operating costs. Because
of the condensate on the coil, the dirt often becomes wet
and contributes to the growth of microbial organisms.
Negligence in maintenance may result in serious health
related indoor air quality problems.
The coil should be kept clean for maximum performance.
To achieve maximum efciency, clean the coil often during
periods of high demand or when dirty conditions prevail.
Mammoth recommends cleaning the coil a minimum of
once per year to prevent dirt buildup in the coil ns where
it may not be visible.
Coil ns can be cleaned by using steam with detergent, hot
water spray or a commercial chemical coil cleaner. After
cleaning the coil, be sure to rinse thoroughly.
Figure 4: System operation check
Coils
Cleaning Procedure
CAUTION
Do not use acidic chemical coil cleaners. Do not use alkaline chemical coil cleaners with a pH value greater than
8.5 or lower than 6 (after mixing) without using an alu-
minum corrosion inhibitor in the cleaning solution. Using
these types of cleaners may result in unit damage.
1. Shut down the unit by closing the main disconnect
at the power inlet.
2. Open panels or doors to gain access to both sides of
the coil section.
3. Remove soft debris from both sides of the coil with a
soft brush.
MAMM-VHC-IOM-1A (JANUARY 2013)
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