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 specically intended for a
qualied installation and service agency. A qualied 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

Airow 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 specications or designs without notice or obligation.

MAMM-VHC-IOM-1A (JANUARY 2013)

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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)

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Safety Considerations

!

!

!

Warning, Caution and Important notes appear throughout
this manual in specic 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

Identies an instruction which, if not followed, might cause
serious personal injuries including possibility of death.

CAUTION

Identies 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 efciency 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
qualied 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

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balanced, the unit will be even less perceptible if posi­tioned away from busy ofces.

• 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 deection 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 sufcient 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 roong 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 roong), 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.

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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 airow to develop a uniform velocity
prole 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.

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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.

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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 dehumidication
across the heating/cooling or dehumidication 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 qualied ser­vice mechanic.

The trap height allows for the maximum suction pressure
after the cooling coil with intake damper, dirty pre and nal
high efciency lters, high efciency 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, qualied 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)

11

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 Airow 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 signicantly
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 sufcient 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.

Dehumidication (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 insufcient, 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%.

MAMM-VHC-IOM-1A (JANUARY 2013)

13

!

Airow 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 airow rates.
Permanent or temporarily eld supplied and installed ow
measuring stations (FMS) can be used to measure airow
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 airow 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
specied. 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 airow 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 airow 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 efciency lters and optional high ef­ciency 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 airows. 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

Verication 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 efciency 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 efciency, 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)

15

WARNING

!

Disconnect the main power switch to the unit before per­forming service and maintenance procedures.

4. Using a steam cleaning machine, clean the leaving
airside of the coil rst (going downward) then clean the
entering airside. Use a block-off to prevent the steam
from penetrating a dry section of the unit.

5. Allow the unit to dry thoroughly before restoring power.

Testing and Replacement of the Damper Actuator

6. Damaged coil ns (excluding brazed aluminum)
should be straightened by using a n comb.

7. Close all panels and doors once the coil is dry.

8. Restore electrical power to the unit.

After disconnecting the power from the unit, determine
if the actuator is defective. Disconnect the 24 volt power
source. Connect the actuator directly to a 24 volt power
source with an appropriate cable. If the damper operates
correctly, the problem is either in the wiring connections
or main circuit board.

Motor and Blower Removal – Down, Side and End Supply/Exhaust

Disconnect the four-wire service connector from the
motor (#1, Figure 5). Loosen the four bolts (#2, Figure

5) and all screws that fasten the blower to the ex collar.

Motor and Blower Service – Down, Side and End Supply/Exhaust

The belt tension is adjusted by the positioning of the ro­tating motor base plate. Loosen the two adjustment bolts
(#4, Figure 5) on the base plate. Rotate the motor and
base plate to achieve the maximum belt deection as
described under belt tension adjustment below. Tighten
the adjustment bolts (#4, Figure 5). Verify that the
sheave and pulley faces are still parallel. The fan rpm
can be adjusted to achieve the design airow by setting
the adjustable sheave on the motor shaft. The pulley set
screw torque setting is 110 in.-lbs to 130 in.-lbs.

If the actuator does not work, it must be replaced. Loosen
the nuts on the jack shaft clamp and remove the actua­tor. Tighten the clamp on the damper jack shaft. Test for
proper operation.

Slide the fan assembly out of the unit. The fan assembly
may have to be lifted over the fan assembly plate bolts
(#3, Figure 5).

Figure 5: Motor and blower orientation for down, side and
end supply/exhaust options

MAMM-VHC-IOM-1A (JANUARY 2013)

16

!

Belt Tension Adjustment

!

WARNING

Disconnect the main power switch to the unit before per­forming service and maintenance procedures.

1. Measure the belt span with a span scale (see Figure

6).

2. Divide the belt span by 64 to determine the belt deec­tion needed to check tension.

3. Set the O-ring on the span scale to the required de­ection value.

4. Set the small O-ring at zero on the force scale.

5. Place the scale end of the tension checker squarely
on one belt at the center of the belt span. Apply force
on the plunger until the bottom of the large O-ring is
even with the top of the next belt or until it is even with
a straight edge laid across the sheaves.

6. Read the force scale under the small O-ring to
determine the force required to give the needed
deection.

7. Compare the force scale reading in Step 6 with the
correct value for the belt style and cross section. The
force scale reading should be between the minimum
and maximum values shown in Table 2.

8. If the deection value is below the minimum, tighten
the belts. If the deection value is above the maxi­mum, loosen the belts. The tension on new belts

Plunger with

deflection force scale (lbs)

Small O-ring Large O-ring

Body with deflection

distance scale (inches)

Figure 6: Belt tension adjustment

Table 2: Recommended Deection Force

V-belt

Cross

Sec-

tion

Small

Sheave

Diameter

Range

Recommended Deection Force

(lbs)

Initial

Installation

Re-tensioned

Maximum Minimum

3.0” to 3.4” 3.3 2.9 2.2

3.6” to 4.2” 3.5 3.1 2.4

A

4.6” to 6.0” 3.7 3.3 2.5

4.6” to 5.4” 6.0 5.1 4.0

B

5.6” to 7.4” 6.3 5.5 4.2

8.6” to 9.4” 6.6 5.7 4.4

should be checked during the rst day of operation, at
the end of the rst week and monthly thereafter.

Belt Span

Force

Deflection

Plenum Fan and Motor Removal

Disconnect the four-wire service connector between the
motor and the VFD (#1, Figure 7). Remove the four bolts
(#2, Figure 7) and slide the motor and plenum fan past the
inlet cone, then lift out of the unit. A 1¾” socket is required
to remove the fan from the motor shaft.

WARNING

No lubrication is necessary during servicing.

MAMM-VHC-IOM-1A (JANUARY 2013)

17

Plenum Fan and Motor Service

!

!

!

WARNING

Disconnect the main power switch to the unit before per­forming service and maintenance procedures.

Both motor shaft and fan bore must be completely free of
paint, grease, oil and dirt. If necessary, clean the surfaces
with non-petroleum based solvent, such as isopropyl alco­hol. Insert the bushing into the fan, making sure the mating
hub is ush against the shoulder at the ats. Position the
assembly at the desired location on the motor shaft and
hand tighten nut (clockwise) until the assembly becomes
snug on the shaft.

WARNING

Do not hammer or use any type of impact to force the
bushing along the shaft.

WARNING

The shaft must fully engage the shaft gripping area of the
bushing.

Using a torque wrench and a 1¾” socket, tighten the nut to
the proper installation torque. See Table 3 for torque value.

Table 3: Torque Value

Shaft Size ft-lb

5/8” to 3/4” 100

13/16” to 1” 125

1-1/16” to 1¼” 167

Fan should overlap inlet cone by 3/8” [9 mm] and have a
clearance of 1/16” [2 mm]. Motor/fan assembly position is
adjustable by loosening the four bolts (#3, Figure 7) and
sliding shelf forwards and back.

Figure 7: Plenum fan and motor

Cassette Removal

After disconnecting the power from the unit, open the ser­vice door for the cassette access. Disconnect the service
connector between the motor and the control box. Remove
the exhaust lters and slide the cassette out of the unit.

MAMM-VHC-IOM-1A (JANUARY 2013)

Take care to not damage the rotor face or any of the cas­sette seals. Proper support must be provided so the cas­sette is not dropped.

18

Cassette Service

!

WARNING

Disconnect the main power switch to the unit before per­forming service and maintenance procedures.

Perimeter Seal Replacement

CAUTION

When handling the enthalpy wheel, ensure not to damage
the face of the wheel.

To replace the perimeter seal, the enthalpy wheel must be
removed from the frame. Disconnect the service connector
to the drive motor of the enthalpy wheel cassette. Remove
the cassette from the unit and stand the assembly on the
oor or roof. Remove the dust cap (#1, Figure 8) from the
bearing on the drive motor side of the cassette. Remove
the bolt (#2, Figure 8) from the end of the wheel shaft with
a socket or wrench on the drive motor side. Repeat this
procedure for the other side of the cassette assembly. Re­move the four bolts (#3, Figure 8) with a socket or wrench.
Remove the beam and bearing assembly from the end of
the wheel shaft. Loosen the four Nyloc nuts (#1, Figure 9)
holding the drive motor using a socket or wrench. Rotate
the drive motor in the slots to loosen the drive belt and
remove the belt. Lift the enthalpy wheel out of the frame
with assistance and set aside. Remove the perimeter seal
halves (#4, Figure 8) from the cassette frame assembly.
Install the two new perimeter seal halves by pressing them
into place, cutting to the correct length as is necessary. The
perimeter seals are non-adjustable. Complete the installa­tion by reversing the above procedure.

Face Seal Replacement and Adjustment

CAUTION

When handling the enthalpy wheel, ensure not to damage
the face of the wheel.

To replace the face seals, the cassette assembly must be
removed from the unit. Disconnect the service connector
to the drive motor of the enthalpy wheel cassette. Remove
the cassette from the unit and stand the assembly up on
the oor or roof. Remove the screws holding the face seals
(#5, Figure 8). Replace the two seals (supply and exhaust
sides), cutting to length as required. Adjust the seals in the
slots so that the brush just touches the face of the wheel.
Complete the installation by reversing the above proce­dure.

Enthalpy Wheel Drive Belt Replacement
and Tensioning Adjustment

CAUTION

When handling the enthalpy wheel, ensure not to damage
the face of the wheel.

The enthalpy wheel drive belt can be tightened by slid­ing the cassette assembly only part way out of the unit.
Disconnect the service connector to the drive motor of
the enthalpy wheel cassette. Slide the cassette assembly
out of the unit enough to access the drive motor. Loosen
the four Nyloc nuts (#1, Figure 9) holding the drive motor
using a socket or wrench. Rotate the drive motor to loosen
the belt and replace the belt if necessary. Rotate the drive
motor in the slots to tighten the drive belt. Secure the motor
in its new location by tightening the four Nyloc nuts (#1,
Figure 8). Complete the installation by reversing the above
procedure.

Figure 8: Cassette and drive

Figure 9: Tension adjustment

MAMM-VHC-IOM-1A (JANUARY 2013)

19

Appendix A: Service Clearance Dimensions

34.0”
[864]

Reverse cassette

removal

Exhaust
blower

Defrost or
unoccupied
recirc
damper

34.0”
[864]

**46.0”

[1,168]

* Clearance for enthalpy wheel removal.
** Clearance for S-OA intake hood.

Supply filters

Electric
preheat

34.0”
[864]

Enthalpy wheel

Standard cassette

removal

Figure A1: VHC with water source heat pump (WSHP)

*56.0”
[1,422]

Occupied

recirc or

return

damper

Cooling/heating
coil

*56.0”
[1,422]

Power line input
control wiring

36.0”
[914]

Water inlet
and outlet
connections

WSHP
Module

Supply
blower

CompressorCompressor

Control box

Coaxial coil

Exhaust filters

Electric
post heat

Note: All dimensions in [ ] are millimeters.

MAMM-VHC-IOM-1A (JANUARY 2013)

20

Appendix B: Hood Installation

Figure B1: Outdoor VHC hood installation

IMPORTANT

Complete wire connections between the unit and the hood by matching the correct wire colors on the actuator with the wire
colors on the schematic.

MAMM-VHC-IOM-1A (JANUARY 2013)

21

Appendix C: Rigging Drawing

Spreader bars

Figure C1: VHC rigging

MAMM-VHC-IOM-1A (JANUARY 2013)

22

Appendix D: Equipment Data

Table D1: VHC-36, 42 and 50 Equipment Data

VHC-36 VHC-42 VHC-50

Fans

Supply type – Belt drive, ODP

Wheel type Forward curved Forward curved Forward curved

Bearing Pillow block Pillow block Pillow block

Motor (HP) 0.5 to 5 0.5 to 5 1 to 10

Supply type – Direct drive, ODP

Wheel type Backward inclined airfoil Backward inclined airfoil Backward inclined airfoil

Motor (HP) 0.5 to 5 0.5 to 5 1 to 10

Exhaust type – Belt drive, ODP

Wheel type Forward curved Forward curved Forward curved

Bearing Pillow block Pillow block Pillow block

Motor (HP) 0.5 to 5 0.5 to 5 1 to 10

Energy Recovery Module

4” wheel depth medium efciency

Wheel size 36” x 4” [914 x 102 mm] 42” x 4” [1,067 x 102mm] 50” x 4” [1,270 x 102 mm]

Cassette size

6” wheel depth standard efciency

Wheel size 36” x 6” [914 x 152 mm] 42” x 6” [1,067 x 152 mm] 50” x 6” [1,270 x 152 mm]

Cassette size

8” wheel depth high efciency

Wheel size 36” x 8” [914 x 203 mm] 42” x 8” [1,067 x 203 mm] 50” x 8” [1,270 x 203 mm]

Cassette size

Wheel substrate Aluminum Aluminum Aluminum

Wheel desiccant Silica gel Silica gel Silica gel

Wheel performance 0.20 to 0.90” w.g. 0.20 to 0.90” w.g. 0.30 to 1.00” w.g.

Filters

Supply and return

2” [51 mm] MEF
(MERV 7 30–35%)
4” [102 mm] MEF
(MERV 7 30–35%)

Supply only

4” [102 mm] prelter
MEF (MERV 7 30–35%)
4” [102 mm] prelter
HEF (MERV 14 80–85%)

Maximum Weight

Base unit, no heating or cooling 1,800 lbs [818 kg] 2,000 lbs [909 kg] 2,200 lbs [1,000 kg]

WSHP – add 590 lbs [268 kg] 755 lbs [343 kg] 890 lbs [405 kg]

Max unit 2,884 lbs [1,311 kg] 3,351 lbs [1,523 kg] 3,850 lbs [1,750 kg]

Roofcurb – add 210 lbs [95 kg] 250 lbs [114 kg] 270 lbs [123 kg]

40” x 40” x 4.5”
[1,016 x 1,016 x 114 mm]

40” x 40” x 6.5”
[1,016 x 1,016 x 165 mm]

40” x 40” x 8.5”
[1,016 x 1,016 x 216 mm]

1 of 20” x 20” [508 x 508 mm] &
1 of 16” x 20” [406 x 508 mm]
1 of 20” x 20” [508 x 508 mm] &
1 of 16” x 20” [406 x 508 mm]

1 of 20” x 20 “ [508 x 508 mm] &
1 of 16” x 20” [406 x 508 mm]
1 of 20” x 20” [508 x 508 mm] &
1 of 16” x 20” [406 x 508 mm]

46” x 46” x 4.5”
[1,168 x 1,168 x 114 mm]

46” x 46” x 6.5”
[1,168 x 1,168 x 165 mm]

46” x 46” x 8.5”
[1,168 x 1,168 x 216 mm]

1 of 18” x 24” [457 x 610 mm] &
1 of 24” x 24” [610 x 610 mm]
1 of 18” x 24” [457 x 610 mm] &
1 of 24” x 24” [610 x 610 mm]

1 of 18” x 24” [457 x 610 mm] &
1 of 24” x 24” [610 x 610 mm]
1 of 18” x 24” [457 x 610 mm] &
1 of 24” x 24” [610 x 610 mm]

54” x 54” x 4.5”
[1,372 x 1,372 x 114 mm]

54” x 54” 6.5”
[1,372 x 1,372 x 165 mm]

54” x 54” x 8.5”
[1,372 x 1,372 x 216 mm]

4 of 16” x 24” [406 x 635 mm]

4 of 16” x 24” [406 x 635 mm]

4 of 16” x 25” [406 x 635 mm]

4 of 16” x 25” [406 x 635 mm]

MAMM-VHC-IOM-1A (JANUARY 2013)

23

Appendix E: Electrical Data

!

Table E1: Full Load Amperage (FLA)

HP

0.5 4.5 4.0 1.8 2.2 1.1 0.9

0.75 5.4 6.0 2.7 2.7 1.4 1.1

1.0 6.8 7.0 3.4 3.4 1.7 1.4

1.5 10.2 10.2 5.0 5.0 2.5 2.0

2.0 14.0 14.0 6.4 6.0 3.0 2.4

3.0 17.8 17.0 10.6 10.6 4.8 3.4

5.0 22.0 22.0 15.3 12.8 6.4 5.1

7.5 32.0 32.0 25.0 19.2 9.6 7.8

10.0 29.3 26.8 13.4 10.3

208/1/60 230/1/60 208/3/60 230/3/60 460/3/60 575/3/60

Blower Motor

Wheel Drive Motor and Controls

2.4 2.2 2.4 2.2 1.1 0.9

The blower motor FLA values show in in the above table are for one motor only.

Voltage

Electric Preheat and Post Heat Calculation

FLA = W / (1.73 x voltage)

IMPORTANT

Electric preheaters and post heaters range from 1 to 120
kW (see below for heater limitations) and actual FLA values
of individual heaters will vary based upon the size, tem­perature rise and voltage. Consult the factory for actual FLA
values. All electric heaters require three-phase voltage.

WARNING

All units equipped with two-point electric post heaters
require two-point power connections, one to the control
panel and one to the electric heater fed from a eld sup­plied single disconnect.

CAUTION

All electrical installations and wiring require correct wire
gauge sizing and protection according to local building codes.

Electric Preheaters and Post Heaters

Electric preheaters and post heaters are available in:

• Single-point or two-point power connection

• Two-stage, four-stage* or SCR control

IMPORTANT

Four-stage electric post heaters are only available with
kW ratings higher than 10 kW.

Electric Heater Performance Calculations

Temperature Rise (°F) = kW x 3,160
cfm

kW = cfm x temperature rise (°F)
3,160

Electric single point preheaters and post heaters have the
following limitations:

• 208 VAC – 24 kW maximum

• 230 VAC – 27 kW maximum

• 460 VAC – 67 kW maximium

• 575 VAC – 84 kW maximum

Table E2: Electric Preheater and Post Heater Limitations

VHC-36 up to

VAC

50 kW

24 24 24

208

50 70 120

27 27 27

230

50 70 120

50 70 67

460

50 70 120

50 70 84

575

50 70 120

Shaded areas – single-point post heater limitations
White areas – two-point post heater limitations

VHC-42 up to
70 kW

VHC-50 up to
120 kW

• 1 kW increments for all three-phase voltages.

MAMM-VHC-IOM-1A (JANUARY 2013)

24

Table E3: Compressor Run Load Amperage (RLA)

Water Cooled Single Circuit

2 Two-stage 16.7 11.2 4.5 3.7

3 Two-stage 16.7 13.5 6.1

4 Two-stage 23.0 17.6 9.2

5 VRC

®

20.4 9.7

6 VRC 23.2 11.2

8 VRC 24.0 12.6

10 VRC 33.3 17.9 12.8

12 VRC 48.1 18.6 14.7

14 VRC 51.3 23.1 19.9

16 VRC 55.8 26.9 23.7

Water Cooled Dual Circuit

6

8

10

12

14

16

21

Crossed out areas indicate unavailable compressor selection.
Values indicated are for single compressor only.

On/off 13.2 6.0

VRC 11.7 6.2

On/off 14.5 6.2

VRC 17.9 7.8

On/off 20.5 9.6

VRC 20.4 9.7

On/off 23.2 10.6

VRC 23.2 11.2

On/off 25.0 14.7

VRC 24.0 12.6

On/off 29.5 14.7

VRC 24.0 12.6

On/off 33.3 17.9 12.8

VRC 33.3 17.9 12.8

MAMM-VHC-IOM-1A (JANUARY 2013)

25

Table E4:

For Dual Circuit On/off Units

6 tons Two 3 ton on/off compressors

8 tons Two 4 ton on/off compressors

10 tons Two 5 ton on/off compressors

12 tons Two 6 ton on/off compressors

14 tons Two 7 ton on/off compressors

16 tons Two 8 ton on/off compressors

21 tons Two 10 ton on/off compressors

For Dual Circuit VRC® Units

6 tons

8 tons

10 tons

12 tons

14 tons

16 tons

21 tons

One 3 ton on/off compressor
One 3 ton VRC compressor
One 4 ton on/off compressor
One 4 ton VRC compressor
One 5 ton on/off compressor
One 5 ton VRC compressor
One 6 ton on/off compressor
One 6 ton VRC compressor
One 7 ton on/off compressor
One 7 ton VRC compressor
One 8 ton on/off compressor
One 8 ton VRC compressor
One 10 ton on/off compressor
One 10 ton VRC compressor

Minimum Current Ampacity (MCA)
Calculation

1.25 x FLA of larger hp motor or compressor = _____

1.25 x heater FLA = + _____
Sum of all other motors FLA = + _____
Wheel drive motor and standard controls FLA = + _____
Calculated total MCA = _____

Finding the Actual MOP Value

From the calculated MOP value, select the next smallest
value of protection from the Standard Overcurrent Protec­tion chart below to get the actual MOP value (maximum
value of overcurrent device).

IMPORTANT

If this method leads to an actual MOP value being smaller
than the calculated total MCA, then a larger value must
rather be selected, such that the actual MOP is at least
equal to the calculated total MCA.

Table E5: Standard Overcurrent Protection

3 40 250

4 45 300

5 50 350

6 60 400

7 70 450

8 80 500

9 90 600

10 100 650

12 110 700

15 125 750

20 150 800

25 175 850

30 200 900

35 225 1,000

Maximum Overcurrent Protection (MOP)
Calculation

2.25 x FLA of larger hp motor or compressor = _____
Electric heater FLA = + _____
Sum of all other motors FLA = + _____
Wheel drive motor and standard controls FLA = + _____
Calculated total MCA = _____
Actual MOP (from Table E5) = _____

MAMM-VHC-IOM-1A (JANUARY 2013)

26

Appendix F: Terminal Control Diagrams

Occupied Ventilation

Occupied ventilation is achieved by closing the occupancy
contact to the terminal interface shown in Figure F1. These
terminals require a dry contact which could be provided by
a number of types of controls such as a timer, light sensor,
occupancy sensor, Building Management System or other.
The unit will not operate unless these contacts are closed.

301
302

OCCUPANCY

CR

CONTACT

Note: This is the only
connection needed to
start single-speed units.

304
305
305
306
307
308
320
321
322
323
324
325
374
375
376
377

12

9

6

234

5

1

301
302
304
305
305
306
307
308
320
321
322
323
324
325
326
327
328
329

Figure F2: Occupied ventilation for DDC controls package
and electro-mechanical controls (EMC)

Figure F1: Occupied ventilation for DDC controls package
and electro-mechanical controls (EMC)

Occupied Timer Sensor

Occupied ventilation is achieved by connection to the
terminal interface shown in Figure F2. These terminals re­quire a dry contact which could be provided by a number of
types of controls such as a timer, light sensor, occupancy
sensor, Building Management System, or other. The unit
will not operate unless these contacts are closed.

IMPORTANT

DDC units can be turned on/off through software.

Unoccupied Recirculation

Supply fan recirculation for heating and cooling can be
achieved by connecting dry contact controls to the terminal
interface provided in the control panel area. This terminal
requires a dry contact closure from a eld provided and
wired device.

301
302
304
305

UNOCCUPIED RECIRCULATION

CR

CONTACT (OPTIONAL)

305
306
307
308
320
321
322
323
324
325
326
327
328
329

MAMM-VHC-IOM-1A (JANUARY 2013)

Figure 10: Unoccupied recirculation for DDC controls units

27

301

301
302
304
305
305
306
307
308
320
321
322
323
324
325
374
375
376
377

302
304

UNOCCUPIED

CR

RECIRCULATION
CONTACT (OPTIONAL)

305
305
306
307
308
320
321
322
323
324
325
326
327
328
329

Figure F3: Unoccupied recirculation for electro-mechanical
controls (EMC) units

VFD High Speed Control

High speed fan control can be achieved by connecting dry
contact controls to the eld wired (FW) terminals 374 and
375 for the supply fan and 376 and 377 for the exhaust fan.
Only VFD units have the high speed option. These controls
could also be the following: DPST switch, dehumidistat,

CO2 sensor, light sensor, heat sensor, timer, Building Man-

agement System, etc.

301
302
304
305
305
306
307
308
320
321
322
323
324
325
374
375
376
377

OCCUPANCY

CR

CONTACT

SUPPLY BLOWER

CR

HIGH SPEED CONTACT

EXHAUST BLOWER

CR

HIGH SPEED CONTACT

Figure F4: VFD high speed control

MAMM-VHC-IOM-1A (JANUARY 2013)

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 Figure F5.
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 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.

IMPORTANT

Removal of dry contacts that close on high speed termi­nals is required for VFDs to modulate.

TB-1

TB-2

TB-1

TB-2

TB-3

RELAY CR1

TB-4

HIGH SPEED

CONTROL

TB-5

Figure F5: CO2 ventilation control

OCCUPANCY

CR

CONTACT

HIGH SPEED
CONTROL (SUPPLY BLOWER)

3

RELAY CR1

5

4

RELAY CR1

6

HIGH SPEED
CONTROL (EXHAUST BLOWER)

28

Smoke Detector

Locate in a normally occupied area of premises. Recom­mended for compliance to NFPA-90A and IMC Code 606.

VHCs can be equipped with a duct mount smoke detector
which will monitor the air when passing through the duct
system into the VHC. When sufcient smoke is detected,
an alarm condition is activated. By connecting the occupied
timer/sensor contacts to the NC alarm auxiliary contacts on
the duct sensor, an alarm condition will open the auxiliary
contact and stop operation of the VHC.

IMPORTANT

This wiring conguration cannot be used on DDC units
that are scheduled on/off through software.

1 2 15 16

24V 24V NC C

301
302
410
411

IMPORTANT

On DDC units, there is no dirty lter sensor output to con­nect to. Rather, the dirty lter sensor is connected to the
DDC controller and will display a dirty lter alarm on the
BacStat II (user interface) when it senses the lter is dirty.

301
302
304
305
305
306
307
308

24 VAC+ OUTPUTS

20 VA MAXIMUM

DIRTY SUPPLY FILTER

DIRTY EXHAUST FILTER

320
321
322
323
324
325
326
327
328
329

Figure F6: Smoke detector

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 for
both the supply and exhaust lter sensors.

Figure F7: Dirty lter control

MAMM-VHC-IOM-1A (JANUARY 2013)

29

Appendix G: Standard Field Wiring (FW) Terminals

Control Field Wiring (FW)

Low voltage terminal control consists of the following:

Electro-mechanical Controls (EMC) Unit

Inputs

• Occupied ventilation timer/sensor

– Dry contact

• Occupied recirculation (if equipped)

– Dry contact

• Unoccupied recirculation (if equipped)

– Dry contact

• Unit fault

– Dry contact

• Cooling stage 1 (if equipped)

– Dry contact

• Cooling stage 2 (if equipped)

– Dry contact

• Heat enable (if equipped)

– Dry contact

• Modulating heat (if equipped)

– 0 to 10 VDC

• Reheat valve on/off 1 (if equipped)

– Dry contact

• Reheat valve on/off 2 (if equipped)

– Dry contact

• Reheat valve modulating (if equipped)

– 0 to 10 VDC

• Modulating supply motor speed (if equipped)

– 0 to 10 VDC

• Modulating exhaust motor speed (if equipped)

– 0 to 10 VDC

Outputs

• Supply fan on

• Exhaust fan on

• External unit fault

• Defrost on (if equipped with recirculation or exhaust

only defrost options)

• Free cooling on (if equipped with free cooling option)

• Wheel failure (if equipped with wheel rotation sensor
option)

• Dirty supply lters (if equipped with dirty lter sensor
option)

• Dirty exhaust lters (if equipped with dirty lter sensor
option)

• Cooling on (if equipped with cooling)

24 VAC+

24 VAC−

OCCUPANCY

CR

CONTACT

CR

UNOCCUPIED RECIRCULATION
CONTACT (OPTIONAL)

COOLING STAGE 1

CR

COOLING STAGE 2

CR

CONTACT (OPTIONAL)

GAS HEAT ENABLE

CR

CONTACT (OPTIONAL)

SCR ELECTRIC POSTHEAT (0–10 VDC+) (OPTIONAL)

SCR ELECTRIC POSTHEAT (0–10 VDC−) (OPTIONAL)

SCR ELECTRIC POSTHEAT (SHIELD) (OPTIONAL)

REHEAT VALVE 1

CR

CONTACT (OPTIONAL)

REHEAT VALVE 2

CR

CONTACT (OPTIONAL)

24 VAC+

OUTPUTS

MAXIMUM

HOT GAS REHEAT MODULATING (0–10 VDC+) (OPTIONAL)

HOT GAS REHEAT MODULATING (0–10 VDC−) (OPTIONAL)

SUPPLY BLOWER MODULATING (0–10 VDC+) (OPTIONAL)

SUPPLY BLOWER MODULATING (0–10 VDC−) (OPTIONAL)

SUPPLY BLOWER MODULATING (SHIELD) (OPTIONAL)

EXHAUST BLOWER MODULATING (0–10 VDC+) (OPTIONAL)

EXHAUST BLOWER MODULATING (0–10 VDC−) (OPTIONAL)

EXHAUST BLOWER MODULATING (SHIELD) (OPTIONAL)

FREE COOLING ON (OPTIONAL)

DIRTY SUPPLY FILTER (OPTIONAL)

DIRTY EXHAUST FILTER (OPTIONAL)

WHEEL FAILURE (OPTIONAL)

SUPPLY BLOWER ON

EXHAUST BLOWER ON

COIL LOW LIMIT (OPTIONAL)

CR

20 VA

CR

CR

ELECTRIC HEAT STAGE 3

CR

CONTACT (OPTIONAL)

ELECTRIC HEAT STAGE 4

CR

CONTACT (OPTIONAL)

COOLING STAGE 1 (ON) (OPTIONAL)

HEATING (ON) (OPTIONAL)

GAS HEAT MODULATING (0–10 VDC−) (OPTIONAL)

GAS HEAT MODULATING (0–10 VDC+) (OPTIONAL)

COOLING STAGE 2 (ON) (OPTIONAL)

COMPRESSOR ONE STATUS (OPTIONAL)

COMPRESSOR TWO STATUS (OPTIONAL)

CR

CR

CR

CONTACT (OPTIONAL)

GAS HEAT STAGE 2
(OPTIONAL)

SCR ELECTRIC HEAT ENABLE
CONTACT (OPTIONAL)

ELECTRIC HEAT STAGE 1

CR

CONTACT (OPTIONAL)

ELECTRIC HEAT STAGE 2
CONTACT (OPTIONAL)

SUPPLY BLOWER HIGH SPEED
CONTACT (OPTIONAL)

EXHAUST BLOWER HIGH SPEED
CONTACT (OPTIONAL)

UNIT FAULT

Figure G1: Electro-mechanical controls (EMC)

301
302
304A
304
305
305
306
307
308
309
310
311
312
313
314
315
320
321
322
324
325
326
329
352
353
354
355
356
357
358
359
360
361
362
363
364
368
370
371
372

373
374
375
376
377
410
411
501
502

502-S
503
504-S
504

IMPORTANT

All output controls are 24 VAC unless otherwise indicated.

MAMM-VHC-IOM-1A (JANUARY 2013)

30

Appendix H: VHC-36, 42 and 50 Start-up Report and Checklist

IMPORTANT

• Complete this form for each unit and email, fax or
mail to Mammoth immediately after start-up to vali­date warranty and to provide valuable information for
personnel performing future maintenance or for fac­tory assistance to address below.

• Read the Installation, Operation and Maintenance
Instructions Manual and the VHC-36, 42 and 50
DDC Control Package Manual (if equipped) before
proceeding.

• Leave a copy of this report with the owner and at the
unit for future reference and permanent record.

• To ensure proper operation of each unit qualied
personnel should perform the start-up, complete the
checklist and report.

• 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 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.

Mammoth Inc.

13200 Pioneer Trail, Suite 150
Eden Prairie, MN 55347-4125
Phone: [phone]

Fax: [phone]

Unit Identication Information

Project: _______________________________________
Model Number: _________________________________
Serial Number: __________________________________
Tag: __________________________________________
Jobsite Contact: _________________________________
Job Name: _____________________________________
Job Address: ___________________________________
Telephone: _____________________________________
Email: _________________________________________

Table H1: Pre Start-up Checklist

Checklist Item Yes N/A

1 Is the electrical disconnect set to the ‘Off’ position?
2 Have obstructive packaging, objects, tie downs on fans and heat wheel been removed?
3 Are fans and heat wheel rotating freely?
4 Are fan wheels and drive set screws tight?
5 Are belt alignment and tension correct?
6 Are air lters installed, clean or replaced?
7 Have coils been checked for n damage and dirt, straightened and cleaned?
8 Are refrigerant components and piping in good conditions, no damage or leaks caused by shipment or installation?

9 Has a water strainer been installed for WSHP with brazed heat exchanger?
10 Is ductwork connected and complete?
11 Are condensate drain connections trapped, installed correctly and lled?

Are all shipped loose or eld supplied components correctly installed and wired and are the start interlocks com-

12

pleted for the ventilation control desired?

13 Has the eld wiring (FW) terminal diagram been marked up accordingly and left with the unit?
14 Has power supply and control wiring been inspected and approved by the Local Authorities?
15 Have factory and eld wiring connections been checked and tightened?
16 Are all fuses properly installed in holders?
17 Is voltage at the disconnect switch within 10% of nameplate and phase-to-phase readings within 2% of nameplate?
18 Are eld piping and venting installation and connections for heating and cooling options completed and tested?
19 Are heating and cooling enable switches set to the ‘Off’ position?

MAMM-VHC-IOM-1A (JANUARY 2013)

31

Serial Number: __________________________________

Table H2: Start-up Checklist

Checklist Item Yes N/A

1 Before proceeding, complete the pre start-up checklist.

2 Close all access panels or doors.

3 Turn the main disconnect to the ‘On’ position.

Set the timer, selector switch or BMS to close the contact for the scheduling mode desired and check opera­tion and sequence.

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
(if equipped) begin to open; after outside air damper opens fully the blower starts and after the exhaust air
damper opens fully the exhaust blower starts.

Unoccupied recirculation (Ur): With the unoccupied recirculation contact closed or a jumper placed across ter-

4

minals, heat wheel stops, defrost recirculation damper opens, outside and exhaust air dampers (if equipped)
begin to close and supply blower starts.

Occupied recirculation (Or) (DDC controls package 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 Are dampers operating properly?

6 Are fans and heat wheel rotating in the correct direction?

For occupied recirculation mode adjust outside air and exhaust air damper positioner to achieve the required

7

air volume.
Re-check the voltage at the disconnect switch against the nameplate and against phase-to-phase readings on

8

three-phase with all blowers operating. If the voltage is not within 10% of rated or 2% of phase-to-phase have
the condition corrected before continuing start-up.
Check amperage draw to each motor on each phase against motor nameplate FLA. If signicantly different

9

check ductwork static and/or take corrective action.
Before activating the compressor on WSHP units, are water shut-off valves open and is water circulating

10

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.

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 readings section of start-up report.

MAMM-VHC-IOM-1A (JANUARY 2013)

32

Start-up Readings

• Allow unit to reach steady state before taking readings.

• Complete based on options included with the unit.

Table H3: Start-up Readings

Mode of Operation Heating Cooling

Nameplate voltage

Power supply

Power supply
with all loads

connected

Airside

WSHP
waterside

Voltage at discon­nect no motors

Voltage at full load L1/L2/L3

Supply fan

Exhaust fan

Condenser fan #1 amp draw – L1/L2/L3
Condenser fan #2 amp draw – L1/L2/L3

Airow CFM

Temperature °F
db/wb

Static pressure

inches w.c.

US GPM
Entering temperature – °F
Leaving temperature – °F
Entering pressure – PSI
Leaving pressure – PSI

L1–L2
L2–L3
L1–L3

Fan load amps
Amp draw L1/L2/L3
Overload amp setting
RPM
Hertz
Full load amps
Am draw L1/L2/L3
Overload amp setting
RPM
Hertz

Supply
Exhaust
Occupied recirculation
Outdoor entering
Supply enthalpy wheel entering
Supply enthalpy wheel leaving
Cooling coil leaving
Heating coil leaving
Reheat coil leaving
Supply leaving
Return entering
Exhaust enthalpy wheel leaving

Outdoor duct

Supply enthalpy wheel entering
Supply enthalpy wheel leaving
Supply fan entering
Supply duct
Return duct
Exhaust enthalpy wheel entering
Exhaust enthalpy wheel leaving
Exhaust duct

Serial Number: __________________________________

MAMM-VHC-IOM-1A (JANUARY 2013)

33

Table H3: Start-up Readings

Circuit #1

Compressor
refrigerant

side

Circuit #2

Stage 1 2 3 4 5 6

Electric
heating

Amp draw – L1
Amp draw – L2
Amp drave – L3

Serial Number: __________________________________

Mode of Operation Heating Cooling

Discharge pressure – PSI
Suction pressure – PSI
Discharge temperature – °F
Suction temperature – °F
Superheat – °F
Subcooling – °F

Site glass oil level

Site glass clear __Yes __No
Amps – L1/L2/L3
Discharge pressure – PSI
Suction pressure – PSI
Discharge temperature – °F
Suction temperature – °F
Superheat – °F
Subcooling – °F

Site glass oil level

Site glass clear __Yes __No
Amps – L1/L2/L3

__½ __¾
__F

__½ __¾
__F

This unit has been checked out and started according
with the above procedures and completed forms and is
operating satisfactorily. After 24 hours of satisfactory op­eration, shut down the unit and check all foundation bolts,
shaft bearings, drive set screws, valve train and terminals.
Tighten where required.

Additional Comments: ____________________________

______________________________________________

______________________________________________

______________________________________________

______________________________________________

______________________________________________

______________________________________________

MAMM-VHC-IOM-1A (JANUARY 2013)

Start-up

By ___________________________________________
Company Name ________________________________
Date __________________________________________
Email _________________________________________
Telephone _____________________________________

34

Appendix I: Troubleshooting

Table I1: VHC-36, 42 and 50 Troubleshooting

Problem Cause Solutions

Unit will not turn on.

Unit will not turn off.

Air from supply diffusers too cold. Imbalance of supply and exhaust air.

Unit makes an annoying noise.

Enthalpy wheel freezing.

Enthalpy wheel not running.

Motor and blower not functioning.

Only supply fan will turn on.

Only exhaust fan will turn on.

Damper will not open.

Damper opens when it should be
closed.

Compressor will not turn.

Occupancy contact open. Check external wiring.
Unoccupied recirc contact open. Check the wiring in the control panel.
Occupancy contact closed. Check the external wiring.
Unoccupied recirc contact closed. Check the wiring on the control panel.

Check lters and heat exchanger for blockage.
Check balance of airows.
Install post heat module.

Blower wheel out of alignment.

Enthalpy wheel wiper seal not func­tioning properly.

Imbalance of supply and exhaust air.

Defrost damper not functioning. Check for operation of damper actuator.
Preheater not functioning. Check for operation of damper actuator.
Unit is in free cooling. Check jumper wire for proper operation.
Unit is in recirc defrost. Check unit circuit breaker.
Drive motor capacitor failure. Check motor electrical connections.

Drive motor failure.

Drive motor relay in control box. Check relay wiring.
Drive belt. Check for drive belt derailment off drive pulley or failure.
Drive pulley. Check for securely fastened pulley on motor shaft.
Electrical supply interrupted. Check unit circuit breaker.
Fan motor capacitor. Check motor electrical connections.
Fan motor failure. Check capacitor connections.
Fan motor contactor failure. Check contactor wiring. Check contactor operation.
Fan drive belt. Check for a tripped overload relay.

Fan drive pulleys.

Unit is in recirc defrost (recirc units). Wait until unit is out of defrost.

Unit is in unoccupied recirc (recirc

units).

Damper end switch not made.

Unit is in defrost (exhaust units).
Motor wiring incorrect.

Damper end switch not made. Check exhaust air damper for proper wiring.
Electrical supply interrupted. Check wiring on damper actuator.
Defrost relay in control box. Check relay wiring. Check relay operation.

Wires are reversed. Reverse wires #2 and #3 on damper actuator.

No power.

Wiring is incorrect. Verify if compressor is wired correctly.
Controlled temperature lower (cool­ing) or higher (heating) than thermo­stat setting.
Compressor failed. Replace compressor.

Remove the motor/blower assembly.
Adjust blower wheel.

Check for proper seal operation.

Check lters and heat exchanger for blockage.
Check balance of airows.

Check capacitor connections. Check motor operation
with a new capacitor.

Check for securely fastened pulley(s) on motor or fan
shaft(s). Set screw setting at 100 in-lbs to 130 in-lbs.

Check external wiring.

Check outdoor air damper for proper wiring.
Check that the end switch is making.

Check connection to motor.

Ensure main disconnect is on and measure main termi­nal block for voltage.

Adjust thermostat setting.

MAMM-VHC-IOM-1A (JANUARY 2013)

35

Table I1: VHC-36, 42 and 50 Troubleshooting

Problem Cause Solutions

Check if voltage is too low, wiring is incorrect, wire
gauge is sized correctly; replace blown fuse.
See solution for high pressure switch open and low
pressure switch open.
Reverse any two phases on the three-phase com­pressor.

Compressor runs but stops quickly.

Compressor makes an abnormal
sound.

Overload, fuse burnout.

Low or high pressure switch acti­vated.

Reverse scroll operation.

Compressor quality issue. Replace compressor.

Excessive compressor vibration. Compressor screw is loose. Tighten the screw.
Compressor is running but there is
no pressure buildup.

Compressor system is normal but
amps are too high.

High pressure switch is open in cool­ing operation.

Scroll reverse operation.

Incorrect compressor voltage. Replace with correct voltage compressor.

Lack of water ow (WSHP).

Water ow rate is too small (WSHP).

Condenser is too dirty (AC system). Clean condenser coil.
Refrigerant overcharge. Charge correct amount of refrigerant.

Non-condensable air accumulates in
the coaxial coil.

Reverse any two phases on the three-phase com­pressor.

Check if the motorized water valve is opening complete­ly and conrm loop water pumps are running.
Check if pump sized correctly. If water strainer is in­stalled in line, check if strainer is too dirty.

Vacuum system, recharge refrigerant.

Coaxial coil scaled. Clean coaxial coil.

Check if wiring is correct, replace any failed compo­nents.
Check outside air damper operation and replace actua­tor if failed.

Check if components (coil, wheel, lter) are too dirty,
motor is running at low speed or not and check if there

High pressure switch is open in heat­ing operation.

Supply fan failure.

Outside air damper not open.

Dx coil is too dirty. Clean Dx coil.

Supply airow is too small.

is too much pressure loss in supply duct.

Refrigerant overcharge. Charge correct amount of refrigerant.
TXV failed in closed position. Replace TXV.
Supply blower failure. Replace TXV or lter drier.

Low pressure switch is open in cool­ing operation.

Insufcient supply airow.

Loss of refrigerant charge.

Check if components (coil, wheel, lter) are too dirty,
motor is running at low speed or not and check if there
is too much pressure loss in supply duct.
Check and repair any leaks in the piping and rell
refrigerant.

TXV failed in closed position. Replace TXV.
Blocked TXV or lter drier. Replace TXV or lter drier.

Check if motorized water valve is opening completely
and conrm loop water pumps are running.
Check if pump is sized correctly or if water strainer is
blocked.

Consult factory for operation out of application range.

Check and repair any leaks in the piping and rell
refrigerant.

Low pressure switch is open in heat­ing operation.

Lack of water ow (WSHP).

Insufcient water ow (WSHP).

Water entering temperature too low
(WSHP).

Loss of refrigerant charge.

MAMM-VHC-IOM-1A (JANUARY 2013)

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Appendix J: Electric Heating Coil and Controls Information

This electric heating coil module covered by this appendix
is a component of a “Listed” product, subject to the guide­lines of application as designated by the Certifying Agency
and outlined in the appliance Manufacturer’s installation
and operation instructions.

The information provided in this appendix applies to the
electric heating coil module, installed in the appliance and
to its operation, maintenance and service. Refer to the ap­pliance manufacturer’s instructions for information related
to all other components.

1 – Mechanical Installation of Electric Coil
Heaters

1.1 Handling

1.1.1 Remove the shipping covers just before installa­tion.

1.1.2 Inspect the heater carefully and report any dam­age to the manufacturer.

Do not install a damaged heater.

1.2 Installation

Heater Position

1.2.1 The axis of the duct must always be perpendicular
to the face of the heater.

1.2.2 The heating elements must always be installed
horizontally.

Model SC or ST (Slip-in Type)

1.2.3 Cut an opening in the side of the duct.

1.2.4 Slip the heater into the duct until the hole is com­pletely covered by anges around the heater.

1.2.5 Fasten the heater to the duct with sheet metal
screws and seal openings with a suitable sealing
compound.

1.2.6 If the heater is heavy, use additional hangers to
support the heater.

Model FC or FT (Flanged Type)

1.2.7 Flange both ends of the duct outwards on three
sides to match the heater’s anges.

1.2.8 Fasten the heater to the duct with sheet metal
screws (for heavy heaters, use nuts and bolts and
additional hangers to support the heater).

IMPORTANT

• Do not install spray humidiers upstream of duct.
Install it downstream instead.

• Do not cover the control box with thermal insulating
materials.

• Use special air intake louvers of weatherproof con­struction for preheat duct heaters to avoid intake of
water or snow particles.

• Make sure that motorized damper blades are not
blocked with snow or dirt. Inspect the dampers regu­larly to ensure a suitable airow.

1.2.9 Seal openings with a suitable sealing compound.

2 – Electrical Installation of Electric Coil
Heaters

2.1 Disconnect Power Source

Disconnect all power sources before opening the control
box and working within.

2.2 Read Nameplate

Read the nameplate carefully and consult wiring diagram
before starting to wire.

2.3 Supply Wires

Use only wires suitable for 167°F [75°C]. Wires shall be
sized according to the Canadian Electrical Code require­ments. All wires must be brought in through knock-outs.

2.4 Disconnecting Means

Install a disconnect switch close to the heater according to
the code unless a disconnect switch is already built into the
heater.

2.5 Control Circuit Wiring

Use Class 2 wiring for control circuit connections to the
duct heater.

2.6 Magnetic Contactors

If magnetic contactors are mounted outside of the duct
heater, use only contactors approved for:

• 250,000 operations when controlled by auto-reset
thermal cut-out (A) and by other switching devices in
series with this cut-out (thermostat, step controller,
airow switch, etc.).

• 100,000 operations when controlled by auto-reset
thermal cut-out (A) alone.

• 100,000 operations when controlled by auto-reset
thermal cut-out (A) plus manual reset cut-out in series
(A & M).

• 6,000 operations when controlled by manual reset
cutout (M) alone.

2.7 External Controls Ratings

Rating of external control devices shall be suitable for han­dling the VA ratings as marked on the nameplate; other­wise, a backup relay must be used.

2.8 Airow Interlock

Heaters are generally supplied with one extra terminal
marked for fan interlock or air sensing device connection.
Remove jumper between terminals I and C before con­necting the fan interlock. Select a suitable airow sensing
device of the differential pressure sensing type, with snap
acting contacts. A slow make, slow brake device may
cause undue cycling and in some instances chattering of
the contactors. When fresh air dampers are used, make

MAMM-VHC-IOM-1A (JANUARY 2013)

37

sure the heater is properly interlocked to prevent it from
being energized before the damper is fully open.

3 – Operating Electric Coil Heaters

3.1 Minimum Airow

Ensure that sufcient airow as marked on the name­plate is passing through the heater. Airow should be
evenly distributed across the entire face of the heater.
Use air turning vane at duct elbows and splitter damper
at duct branch-offs to streamline the airow in the heater.
Use suitable airow sensing device or interlock the
heater with fan. An insufcient airow will lead to the
opening of the auto-reset thermal cut-out or damage to
the heating elements.

3.2 Warning

The air owing through the duct where the heater is in­stalled shall not contain any combustible particles, nor any
ammable vapor or gas.

3.3 Air Temperature

The air temperature should not exceed 120°F [49°C] at the
heater outlet.

3.4 Minimum Static Pressure and Air Direction

The heater is protected by a differential pressure switch.
To keep the contact of this switch closed, it is necessary to
maintain a minimum total pressure of 0.07” of water for a
constant ow.

3.5 Manual Reset Thermal Cut-out

This protection device is standard on all heaters of less
than 300 volt and 30 kW and is optional on all other heat­ers. Please check the auto-reset thermal cut-out before re­setting the manual thermal cut-out. If any defect has been
detected in the auto-reset thermal cut-out, it will be neces­sary to replace it before resetting the manual reset thermal
cut-out.

Two weeks after start-up, all electric connections to
contactors should be checked and tightened up. Before
each heating season, check the resistance between the
heating elements and ground. It is also recommended
to check the electrical connections to heating elements,
magnetic contactors and main power lugs. This inspection
is recommended monthly during the rst four months of
operation. After that, two inspections per heating season
are sufcient.

4.3 Checkpoints

• Check all fuses.

• Check the resistance to ground for each circuit.

• Check the resistance phase-to-phase for each circuit.

• Check the tightening of connections at all contactors

and heating elements.

• Check all contactors.

4.4 Off-season Maintenance

Where tubular heating elements are used, it is strongly rec­ommended that you start the heating system from time to
time. This precaution will prevent moisture from percolating
through the terminal gaskets into the heating element and
accumulating in the insulating powder. Should a heater be
shut off for a long period, we recommend that you check
carefully the resistance to ground for each circuit. It is im­portant not to power a heater when too low a resistance
to ground has been measured. It is also recommended to
pay attention to any other heater operating in normal condi­tions. Control components such as step controllers or mod­ulating valves (SCR) should be maintained and checked
according to respective Manufacturer’s instructions. Any
defective components should be replaced only with identi­cal original parts.

4 – Maintenance

All electric coil heaters have been designed to operate long
term without problems. Those responsible for equipment
and maintenance should be aware of the following sugges­tions.

4.1 Visual Inspection

It is strongly recommended to complete a periodic inspec­tion. This precautionary step will help to keep your instal­lations operating well. Note these eventual rst signs of
problems:

• Accumulation of dust on the heating elements.

• Signs of overheating on the heater frame.

• Traces of water or rust on the control box.

4.2 Electrical Inspection

MAMM-VHC-IOM-1A (JANUARY 2013)

38

Appendix K: Water Line Field Mounted Options and Accessories

IMPORTANT

• Water source heat pump external water supply and
return piping shall be in accordance with National
and Local Codes. Line sizing, pressure limiting
devices, backow preventers, strainers, valves,
ow temperature and pressure measuring, freeze
protection and all other safety or control piping
requirements for system operation are the sole re­sponsibility of the Installing Contractor and/or Design
Engineer.

• Some external piping components and control inter­locks are offered as an option or accessory for partly
eld and factory installation and are summarized in
Table K1. A detailed functional description follows.

• On open loop systems, a eld supplied and installed
water strainer (16–20 mesh minimum) is recom­mended in the water inlet or supply line to the unit to
eliminate contaminants and must be used for 14, 16
and 21 ton dual circuit WSHP units which utilize a
brazed plate heat exchanger condenser.

• Air vents must be eld installed on the high side
of the water supply or inlet line to discharge the
noncondensable air in order to avoid unexpected
high head pressure and poor cooling/heating perfor­mance.

• Manual shut-off valves in supply and return water
lines are recommended to be eld installed for isola­tion and service.

• A circuit balancing valve with pressure and tempera­ture gauge connections is recommended to be eld
supplied and installed for balancing and service. The
water supply must be sized for the minimum ow as
indicated on the submittals.

• Prior to connection of condensing water supply, ver­ify water pressure is less than the maximum pres­sure for components in the water line. To prevent
injury or death due to instantaneous release of high
pressure water, relief valves should be eld supplied
and installed in system water piping.

• Maximum working pressure, pressure drop or Cv
factors for condenser and optional or accessory
components are given in tables below.

Table K1: WSHP Water Line Option or Accessory

Function Field Installed Factory Installed

Head
pressure

control

Water
shut-off

Freeze
protection

Three-way water
control valve with
modulating actuator

Two-way water shut-off
valve with on/off actua-

tor

Water ow switch

Head pressure control
DDC program logic
Refrigerant pressure

transducer

Water on/off control
DDC program logic

Unit on/off control DDC
program logic
Water outlet tempera-

ture sensor

Functional Descriptions

Head Pressure Control

A three-way modulating head pressure control valve is re­quired to maintain stable operation of the refrigeration sys­tems when operated on ground loop water systems when
the design water temperature is below 65°F in the cooling
mode. A refrigerant pressure sensor on the compressor
discharge is used to modulate the water ow to the con­denser using a 2 to 10 VDC signal to articially keep the
compressor discharge pressure at a high enough operat­ing condition to prevent the low pressure refrigerant switch
from tripping.

The three-way modulating head pressure control valve
consists of a 24 VAC NEMA 1 or 2 modulating actua­tor with a temperature rating of −22°F to 122°F [−30°C
to 50°C], nickel plated forged brass valve with stainless
steel ball, stem and replaceable valve cartridge assembly
which is an option and must be externally eld mounted.
For outdoor applications a NEMA 4x rated actuator must
be installed. The hydronic valves are intended for use in a
normal indoor/outdoor environment for hot or cold water
or glycol solutions to 60% concentration with a medium
temperature rating of 0°F to 212°F [−18°C to 100°C]. The
valve and actuator are preassembled for 100% ow to the
coil with minimum of 2 VDC signal. The refrigerant pres­sure sensor is internally factory mounted, prewired and
programmed for the DDC to control the three-way valve. A
6 foot coiled wiring harness is factory supplied with the unit,
located in the compressor compartment for eld extension
and wiring to the actuator.

See Table K2 for three-way valve sizing and performance
data. Dimensions, technical and installation data follow.
See the wiring schematic for connection and the VHC-36,
42 and 50 DDC Control Package Manual for sequencing
information.

Water Shut-off

A two-way motorized on/off water shut-off valve is required
to isolate water owing through both the economizer coil (if
equipped) and water-to-refrigerant condenser for conser­vation when the unit is off. The water shut-off valve must
be placed upstream of the economizer coil and three-way
economizer control valve and the three-way modulating
head pressure control valve (if equipped). The motorized
water valve must open 90 seconds prior to compressor
start-up and remain open ve seconds after the compres­sor is shut off.

The two-way motorized water shut-off valve is an acces­sory item and consists of a 24 VAC NEMA 1 or 2 on/off ac­tuator with a temperature rating of −22°F to 122° F [−30°C
to 50°C], nickel plated forged brass valve and replaceable
valve cartridge assembly which is an accessory and must
be externally eld mounted. For outdoor applications a

MAMM-VHC-IOM-1A (JANUARY 2013)

39

NEMA 4x rated actuator must be installed. The hydronic
valves are intended for use in a normal indoor/outdoor en­vironment for hot or cold water or glycol solutions to 60%
concentration with a medium temperature rating of 0°F to
212°F [−18°C to 100°C]. The actuator must be eld wired
to the standard eld wiring (FW) terminals #435, 436 and
437 depending on valve size. The valve and actuator are
preassembled for 0% ow to the coil when the unit does
not require heating or cooling.

See Table K3 for two-way valve sizing, performance data
and dimensions; installation and technical data is included
with accessory parts. See the wiring schematic for connec­tion information.

Table K2: Three-way Valve Sizing and Performance Data

Tons

2 6 4.3 400 3.0 600 ½

3 9 9.2 400 3.0 600 ½

4 12 3.0 400 4.7 600 ¾

5 15 5.0 400 7.4 600 ¾

6 18 7.0 400 7.4 600 1

8 24 7.7 400 7.4 600 1

10 30 4.3 400 10.0 400 1¼

12 36 7.0 100 19.0 400 1¼

14 42 6.0 400 19.0 400 1¼

*Maximum close off pressure 200 psi.

Minimum US

GPM

Condenser Pressure

Drop (PSI)

Freeze Protection

A water ow switch and a temperature sensor as an op­tion and mounted on the water return or leaving side of the
condenser are used to monitor the presence or absence
of ow and the water temperature which will shut down
the compressor and unit for freeze protection. The ow
switch also features an adjustment which allows the user
to change the switch from normally open (NO) to normally
closed (NC).

The temperature sensor is factory mounted and wired in­ternally. The ow switch must be externally eld mounted
in the leaving or return water line and eld wired to the
standard eld wiring (FW) terminal strip as per wiring sche­matic. See performance, dimensions and installation data
at the end of this appendix.

Condenser

Maximum

Pressure (PSI)

Three-way Head Pressure Control Valve

C

v

Maximum Pressure

(PSI)*

Size FPT

Table K3: Two-way Valve Sizing and Performance Data

Tons

2 6 4.3 400 24 600 ¾

3 9 9.2 400 24 600 ¾

4 12 3.0 400 24 600 ¾

5 15 5.0 400 24 600 ¾

6 18 7.0 400 19 400 1¼

8 24 7.7 400 19 400 1¼

10 30 4.3 400 19 400 1¼

12 36 7.0 100 37 400 1½

*Maximum close off pressure 200 psi.

MAMM-VHC-IOM-1A (JANUARY 2013)

Minimum US

GPM

Condenser Pressure

Drop (PSI)

Condenser

Maximum

Pressure (PSI)

Two-way Water Shut-off Valve

C

v

Maximum Pressure

(PSI)*

Size FPT

40

Table K4: Three-way Technical Data

Service Chilled or hot water, 60% glycol

A-port B-port

Flow characteristic

Equal percent­age

Action 90° rotation
Sizes ½”, ¾”, 1”, 1¼”, 1½”, 2”
Type of end tting NPT female ends
Materials

Body Forged brass, nickel plated
Ball and stem Stainless steel
Seats PTFE
Characterizing disc Tefzel

®

Packing 2 EPDM O-rings, lubricated

Body pressure rating 600 PSI 400 PSI

½”–1” 1¼”–2”
Media temperature range 0°F to 212°F [−18°C to 100°C]
Close off pressure – 200
PSI
Maximum differential pres­sure (∆P)

Leakage

½”–2”

30 PSI for typical applications

A to AB B to AB

0% <2%

A-port B-port
Cv rating

See product chart

for values

Modied for con­stant common
port ow

70% of A to AB
Cv

Table K5: Indoor Three-way Valve Actuator Technical and
Dimensional Data (2 to 5 tons)

Control On/off, oating point
Nominal voltage 24 VAC 50/60 Hz
Nominal voltage range 19.2–28.8 VAC
Power consumption 1 W
Transformer sizing 1 VA (Class 2 power source)

Screw terminals accessible after

Electrical connection

Input impedance 0.36kΩ
Angle of rotation 90°
Position indication Integrated into handle
Manual override Push down handle

Running time

Humidity 5–95% non-condensing
Ambient temperature −22° to 122°F [−30°C to 50°C]
Storage temperature −40°F to 176°F [−40°C to 80°C]
Housing NEMA 1/IP40
Housing rating UL94-5V (B)

Agency listing*

Noise level Max. 35 db (A)
Quality standard ISO 9001

*Rated impulse voltage 330V, control pollution degree 2, type of action 1

removal of small cover (3 feet, 10
feet, 16 feet cables optional)

90 seconds at 60 Hz, 108 seconds
at 50 Hz

cULusa ac. to UL60730-1A/-2- 14,
CAN/CSA E60730-1, CSA C22.2
No. 24-93, CE acc. to 89/336/EEC

2.50”

[63.5 mm]

2.82”

[71.6 mm]

B

C

3.25”

[82.6 mm]

A

Figure K1: Indoor three-way valve actuator (2 to 5 tons)

Table 4: Indoor Three-way Valve Dimensions (2 to 5 tons)

Value Nominal Size Dimensions (Inches [mm])

Inches DN [mm] A B C

½” 15 mm 2.41” [61.1] 1.39” [35.2] 1.20” [30.6]
½” 15 mm 2.38” [60.4] 1.72” [43.7] 1.26” [32.1]
¾” 20 mm 2.73” [69.3] 1.81” [45.9] 1.45” [36.8]

MAMM-VHC-IOM-1A (JANUARY 2013)

41

Table K6: Outdoor Three-way Valve Actuator Technical

C

and Dimensional Data (2 to 5 tons)

Control 2–10 VDC, 4–20 mA

Power supply

Power consumption

Transformer sizing 5 VA (Class 2 power source)
Electrical connection Screw terminal (for 26–14 GA wire)
Overload protection Electronic throughout 0° to 95° rotation
Input impedance 100 kΩ [0.1 mA], 500Ω
Angle of rotation 90°, adjustable with mechanical stop
Direction of rotation Reversible with switch
Position indication Visual pointer
Manual override External push button

Running time

Humidity 100% RH
Ambient temperature −22°F to 122°F [−30°C to 50°C]
Storage temperature −40°F to 176°F [−40°C to 80°C]

Housing type

Housing material Polypropylene

Agency listings

Quality standard ISO 9001

2.99”

[76 mm]

0.62” [16 mm]

B

24 VAC ± 20% 50/60 Hz

24 VDC ± 10%

Running Holding

2.5 W 0.4 W

95 seconds constant independent

of load

UL Type 4X/NEMA 4X/IP66 and

IP67

cULus acc. to UL 60730-1A/- 2-14,

CAN/CSA E60730-1, CSA C22.2

No. 24-93, CE acc. to 89/336/EEC

9.76”

[248 mm]

9.21”

[234 mm]

5.28”

[134 mm]

1.0”

[25.5 mm]

Table K2: Indoor Three-way Valve Actuator Technical and
Dimensional Data (6 to 8 tons)

Power supply

Power consumption

Transformer sizing

Electrical connection

Overload protection

Operating range Y
Feedback output U
Input impedance
Angle of rotation
Direction of rotation
Position of indication
Manual override
Running time

LRB24-SR

LRX24-SR

Humidity

Ambient temperature
Storage temperature
Housing
Housing material

Agency listings

Noise level
Quality standard

Electrical connection

2.6”

[66 mm]

24 VAC ± 20% 50/60 Hz
24 VDC ± 10%
Running Holding

1.5 W 0.4 W
3 VA (Class 2 power source)
½” conduit connector 18 GA, ple­num rated cable 3 feet [1 m]
_3 ft [1 m] _10 ft [3 m] _16 ft [5 m]
Electronic throughout 0° to 95°

rotation

2–10 VDC, 4–20 mA
1–10 VDC, max. 0.5 mA
100Ω [0.1 mA], 500Ω
90° adjustable with mechanical stop
Reversible with protected switch
Handle
External push button
Constant independent of load

95 seconds

_150 sec. _95 sec. _60 sec.
_45 sec. _35 sec.
5% to 95% RH non-condensing (EN

60760-1)

−22°F to 122°F [−30°C to 50°C]

−40°F to 176°F [−40°C to 80°C]
NEMA 2/IP54
UL94-5VA
cULus acc. to UL60730-1A/-2- 14,
CAN/CSA E60730-1, CSA C22.2
No. 24-93, CE acc. to 9/336/EEC
<35 db (A)

ISO 9001

Screw terminal (for 26–14 GA wire)
protected (NEMA 2/IP20)

7.97” [200 mm]

C

A

Figure K2: Outdoor three-way valve actuator (2 to 5 tons)

Table K1: Outdoor Three-way Valve Dimensions (2 to 5 tons)

Value Nominal Size Dimensions (Inches [mm])

Inches DN [mm] A B C

½” 15 mm 2.41” [61.1] 1.39” [35.2] 1.20” [30.6]
½” 15 mm 2.38” [60.4] 1.72” [43.7] 1.26” [32.1]
¾” 20 mm 2.73” [69.3] 1.81” [45.9] 1.45” [36.8]

1” 25 mm 3.09” [78.4] 1.81” [45.9] 1.56” [39.8]

MAMM-VHC-IOM-1A (JANUARY 2013)

3.22”

[82 mm]

B

1.69”

[42 mm]

A

[59.4 mm]

Figure K3: Indoor three-way valve actuator (6 to 8 tons)

Table K3: Indoor Three-way Valve Dimensions (6 to 8 tons)

Value Nominal Size Dimensions (Inches [mm])

Inches DN [mm] A B C

½” 15 mm 2.41” [61.1] 1.39” [35.2] 1.20” [30.6]
½” 15 mm 2.38” [60.4] 1.72” [43.7] 1.26” [32.1]
¾” 20 mm 2.73” [69.3] 1.81” [45.9] 1.45” [36.8]

1” 25 mm 3.09” [78.4] 1.81” [45.9] 1.56” [39.8]

2.34”

42

[134 mm]

Table K4: Outdoor Three-way Valve Actuator Technical
and Dimensional Data (6 to 8 tons)

Power supply

Power consumption

Transformer sizing 5 VA (Class 2 power source)
Electrical connection Screw terminal (for 26–14 GA wire)

Overload protection

Operating range Y 2–10 VDC, 4–20 mA
Input impedance 600Ω
Angle of rotation 90° adjustable with mechanical stop
Direction of rotation Reversible with switch
Position indication Visual pointer
Manual override External push button

Running time

Humidity 100% RH
Ambient temperature −22°F to 122°F [−30°C to 50°C]
Storage temperature −40°F to 176°F [−40°C to 80°C]
Housing type UL Type 4X/NEMA 4X/IP66 & IP67
Housing material Polypropylene

Agency listings†

Quality standard ISO 9001

† Rated impulse voltage 800V, type of action 1, control population
degree 3.

2.99”

[76 mm]

0.62” [16 mm]

B

C

24 VAC ± 20% 50/60 Hz

24 VDC ± 10%

Running Holding

2.5 W 0.4 W

Electronic throughout 0° to 95°

rotation

95 seconds constant independent

of load

cULus acc. to UL60730-1A/-2-

14,CAN/CSA E60730-1, CSA C22.2

No. 24-93, CE acc. to 89/336/EEC

9.76”

[248 mm]

9.21”

[234 mm]

1.0”

[25.5 mm]

A

Figure K4: Outdoor three-way valve actuator (6 to 8 tons)

5.28”

Table K6: Indoor Three-way Valve Actuator Technical and
Dimensional Data (10 to 21 tons)

Power supply

Power consumption

Transformer sizing 3 VA (Class 2 power source)

Electrical connection

Overload protection

Operating range Y 2–10 VDC, 4–20 mA
Feedback output U 1–10 VDC, max. 0.5 mA
Input impedance 100Ω [0.1 mA], 500Ω
Angle of rotation 90° adjustable with mechanical stop
Torque 180 in-lb [20 Nm]
Direction of rotation Reversible with switch
Position indication Handle
Manual override External push button

Running time

Humidity

Ambient temperature −22°F to 122°F [−30°C to 50°C]
Storage temperature −40°F to 176°F [−40°C to 80°C]
Housing NEMA 2/IP54
Housing material UL94-5VA

Agency listings†

Noise level <45 db (A)
Quality standard ISO 9001

† Rated impulse voltage 800V, control pollution degree 3, type of action1
(1.B for -S models)

3.46”

[88 mm]

3.3”

[84 mm]

B

24 VAC ± 20% 50/60 Hz
24 VDC ± 10%
Running Holding

2.5 W 0.4 W

½” conduit connector 18 GA ple­num rated cable
_3 ft [1 m] _10 ft [3 m] _16 ft [5 m]
Electronic throughout 0° to 95°

rotation

95 seconds constant independent

of load
5% to 95% RH non-condensing
(EN 60730-1)

cULus acc. to UL60730-1A/-2­14,CAN/CSA E60730-1, CSA C22.2
No. 24-93, CE acc. to 89/336/EEC

8.5” [216 mm]

1.35”

[35 mm]

2.49”

[63.4 mm]

Table K5: Outdoor Three-way Valve Dimensions
(6 to 8 tons)

Value Nominal Size Dimensions (Inches [mm])

Inches DN [mm] A B C

1¼” 32 mm 3.96” [100.6] 2.21” [56.2] 2.14” [54.3]
1½” 40 mm 4.39” [111.6] 2.45” [62.2] 2.33” [59.1]

2” 50 mm 4.90” [124.5] 2.68” [68.0] 2.60” [66.0]

MAMM-VHC-IOM-1A (JANUARY 2013)

C

A

Figure K5: Indoor three-way valve actuator (10 to 21 tons)

Table K7: Indoor Three-way Valve Dimensions (10 to 21
tons)

Value Nominal Size Dimensions (Inches [mm])

Inches DN [mm] A B C

1¼” 32 mm 3.96” [100.6] 2.21” [56.2] 2.14” [54.3]
1½” 40 mm 4.39” [111.6] 2.45” [62.2] 2.33” [59.1]

2” 50 mm 4.90” [124.5] 2.68” [68.0] 2.60” [66.0]

43

Table K8: Outdoor Three-way Valve Actuator Technical
and Dimensional Data (10 to 21 tons)

Power supply

Power consumption

Transformer sizing 5 VA (Class 2 power source)

Electrical connection

Overload protection

Operating range Y 2–10 VDC, 4–20 mA
Feedback output U 1–10 VDC, max. 0.5 mA
Input impedance 100Ω [0.1 mA], 500Ω

Angle of rotation

Torque 160 in-lb [16 Nm]
Direction of rotation Reversible with switch
Position indication Pointer
Manual override External push button

Running time

Humidity

Ambient temperature −22°F to 122°F [−30°C to 50°C]
Storage temperature −40°F to 176°F [−40°C to 80°C]
Housing IP66/67 UL Type 4X, NEMA 4X
Housing material UL94-5VA

Agency listings†

Noise level <45 db (A)
Servicing Maintenance free
Quality standard ISO 9001
Weight 3.3 lbs [1.5 kg]

† Rated impulse voltage 800V, type of action 1, control pollution degree 3

24 VAC ± 20% 50/60 Hz

24 VDC ± 10%

Running Holding

2.5 W 0.4 W

Screw termianl (for 26–14 GA wire)

½” conduit connector

Electronic throughout 0° to 95°

rotation

Max 95° adjustable with mechani-

cal stop

95 seconds constant independent

of load

5% to 95% RH non-condensing

(EN 60730-1)

cULus acc. to UL60730-1A/-2-

14,CAN/CSA E60730-1, CSA C22.2

No. 24-93, CE acc. to 89/336/EEC

Table K9: Outdoor Three-way Valve Dimensions
(10 to 21 tons)

Value Nominal Size Dimensions (Inches [mm])

Inches DN [mm] A B C

1¼” 32 mm 3.96” [100.6] 2.21” [56.2] 2.14” [54.3]
1½” 40 mm 4.39” [111.6] 2.45” [62.2] 2.33” [59.1]

2” 50 mm 4.90” [124.5] 2.68” [68.0] 2.60” [66.0]

Table K10: Actuator Specications

Torque 162 in-lbs [18 Nm]

Angle of rotation

95° (adjustable with mechanical

stops)

Fits shaft diameter 9/16”...3/4”

Manual override External push button

Direction of rotation External switch

Dimensions

10.66” x 5.28” x 4.88”
[271 x 134 x 124 mm]

Electrical connection Terminal strip

Overload connection Electronic throughout rotation

Add on: 1 or 2 SPDT, 3A (0.5A

Auxiliary switch(es)

inductive) at 250V one switch
adjustable 25° to 85°

Housing specications NEMA 4/4X, IP66/IP67

cULus according to UL 30730-

Agency listings

1A/- 2-14, CAN/CSA E60730­1:02, CE according to 2004/108/
EC and 2006/95/EC

Control shaft length

Minimum ¾”

Maximum 2¼”

B

AM..N4

1.52”

2.01”

4.88”

5.15”

9.56”

10.66”

1.10”

5.28”

0.21”

5.52”

4.41”

9/10”...3/4”

3/8”...9/10”

9/10”...3/4”

Figure K6: Outdoor three-way valve actuator (10 to 21 tons)

MAMM-VHC-IOM-1A (JANUARY 2013)

C

Figure K7: Actuator

A

44

Water Valve Piping Arrangement

option

ABAAAB

A AB 0%AB 100%

Two-way valves
should be installed
with the disc
upstream.

Flow direction

AAB

Belimo

A

AA

%A

It is important to follow the proper piping arrangement for
both two-way and three-way water valves. Incorrect piping
arrangements will damage the unit. The eld piping sche­matic is illustrated below.

Correct Piping

1 input, 2 outputs

Return

Refrigerant components

Access valve

P

Switch low optional
pressure valve kit

Pressure transducer factory
mounted at compressor
discharge port

Scroll compressor

Access valves

Crank case heater

P

Switch high
pressure

Pressure
transducer

P

T

Unit water inlet

Unit water outlet

Head pressure
control valve
option

Modulating
three-way valve

C

Flow
switch

H

J

On/off valve
accessory

Motorized valve
water shut-off

B

B

Field mounted

Strainer

Water inlet

Water inlet

K

A

Figure K8: Water valve piping arrangement

For Two-way Valve

Two-way valves should be installed in accordance to the
arrow direction marked on the valve body for the water inlet
or supply line. Two-way valves should be installed with the
disc upstream. If installed with disc downstream, ow curve
will be deeper. If installed “backwards” it is not necessary to
remove and change. No damage or control problems will
occur.

Figure K9: Two-way valve arrangement

Coil

B

Supply

A

AB

Figure K11: Correct three-way diverting valve piping

Incorrect Piping

1 input, 2 outputs

Return

Coil

A

Supply

B

AB

Figure K12: Incorrect three-way diverting valve piping

Valve and Actuator Installation

Mount the valve directly in the pipe where the assembly will
not block the system vent or other components. Do not grip
the actuator while making and tightening up plumbing con­nections. Either hold valve body in your hand or attach ad­justable wrench across the hexagonal or at faces on the
valve body. If assembling valve train on bench, take care

For Three-way Valve

Three-way valves must be installed with the ‘AB’ marked
or common port to the supply water line, the ‘A’ marked
or control port to the coil and the ‘B’ marked, ‘Bypass’ or
middle port to the return water line.

CAUTION

If the valve is piped incorrectly, it must be re-piped as it
may restrict ow and cause damage to the unit.

Diverting

AAB

The A-port must
be piped to the coil
to maintain proper
control.

Figure K10: Three-way valve arrangement

MAMM-VHC-IOM-1A (JANUARY 2013)

B

A

AB 100

B

B

A

B 0%

B

AB 70%AB 0%

B

Figure K13: Valve installation

not to deform the body with a vise.

45

A

A-AB = 100%

!

2-7/16” [62 mm]

3

1

A-AB = 100%

CCW

4 x 90°

2

AB

5

B

4

B-AB = 0%

A

AB

One screw attaches

1

actuator to valve

Four actuator mounting

2

positions

3

Two-way flow pattern

Three-way flow pattern

4

(mixing shown)

Top of valve stem indicates

5

direction of flow
(Flow A to AB shown)

Note: For diverting flow, flow
enters in AB and diverts
to A and B ports.

CCW

Figure K14: Valve and actuator assembly and installation

Water Flow Switch

Flow Switch Dimensions

¼ (6) travel to
normally closed
position

(2) 22 AWG Leadwires
18 (460) long

1/8 NPT – switch shown
in normally open position

Lower body

7/8 hex

½ NPTM

Figure K15: Valve and actuator assembly and installation

Flow Switch Installation

The ow switch must be externally eld mounted in the
leaving or outlet water line. Before installation, the ow
switch vane must be trimmed for the size of piping being
used. A full size, trimmable stainless steel vane is provided
with a removable laminate template. This template is cali­brated for brass or ductile iron reducing tee and forged
steel straight tee/brushing combination which allows for
eld installation in pipeline from ½” to 2” diameter. See
Table K11 for approximate actuation and deactivation val­ues.

1. Carefully unpack the ow switch and remove any
packing material from the lower housing. Trim the
vane at the appropriate mark for the size of piping
being used.

2¼” [57 mm]

1” [25 mm]

2-7/8” [73 mm]

Vane

WARNING

Mechanical shock or vibration can cause permanent
damage to the switch. Avoid dropping the unit on hard
surfaces.

2. Apply thread tape or sealant to the ½” male NPT
mounting threads and install the ow switch in the sys­tem piping with the arrow on the side pointing in the
direction of ow.

3. The ow switch must be eld wired to the standard
eld wiring (FW) terminal strip as per wiring schematic
for 24 VAC.

4. Avoid exceeding any of the maximum electrical ratings
which can lead to failure.

5. After installation, set the switch action to normally
open or normally closed. To change the switching
from normally open to normally closed, loosen, but
do not remove the two screws on the top cap. Slide
the reed switch assembly to expose the switch ac­tion selected. Tighten screws when adjustment is

Table K11: Flow Switch Performance Data Table

Cold Water Flow Rates –

Approximate Actuation/Deactuation

Pipe Trim NO NC

½” L

¾” J

1” H

1¼” E

1½” C

2” Full

GPM upper, LPM lower

complete.

2.6/2.3 2.6/2.5

9.8/8.7 9.8/9.5

3.1/2.7 3.1/2.8

11.7/10.2 11.7/10.6

4.8/4.5 4.8/4.4

18.2/17.0 18.2/16.7

6.2/5.6 6.1/5.6

23.5/21.2 23.1/21.2

8.2/7.7 8.2/7.7

31.0/29.1 31.0/29.1

9.5/9.1 9.5/9.0

36.0/34.4 36.0/34.1

MAMM-VHC-IOM-1A (JANUARY 2013)

46

Appendix L: Enthalpy Wheel Pressure Drop vs. Flow Formulae and

Curves

Enthalpy Wheel Pressure Drop vs. Flow

Formula

Flow in cfm = pressure drop measured in ” w.c. / pressure
drop coefcient based on enthalpy wheel size

Table L1: Enthalpy Wheel Pressure Drop Coefcient

Enthalpy Wheel Size

(diameter x depth in inches)

Pressure Drop

Coefcient

36 x 4 0.00029551

36 x 6 0.00032675

36 x 8 0.00038283

42 x 4 0.00021504

42 x 6 0.00023397

42 x 8 0.00027220

50 x 4 0.00014783

50 x 6 0.00016034

50 x 8 0.00018639

Enthalpy Wheel Pressure Drop vs. cfm

Curves (based on wheel diameter x depth
(inches))

1.0

0.9

0.8

0.7

0.6

0.5

0.4

Pressure Drop [in. w.g.]

0.3

0.2

0.1

0.0
0 500 1,000 1,500 2,000 2,500 3,000

Airflow [cfm]

Figure L1: Pressure drop – 36” enthalpy wheel diameter

36” x 8” (High)

36”x 6” (Standard)

36” x 4” (Medium)

1.0

0.9

0.8

0.7

0.6

0.5

0.4

Pressure Drop [in. w.g.]

0.3

0.2

0.1

0.0
0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000

Airflow [cfm]

42” x 8” (High)

42”x 6” (Standard)

42” x 4” (Medium)

Figure L2: Pressure drop – 42” enthalpy wheel diameter

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

Pressure Drop [in. w.g.]

0.3

0.2

0.1

0.0
0 1,000 2,000 3,000 5,000 6,0004,000

Airflow [cfm]

50” x 8” (High)

50”x 6” (Standard)

50” x 4” (Medium)

Figure L3: Pressure drop – 50” enthalpy wheel diameter

MAMM-VHC-IOM-1A (JANUARY 2013)

47

[email protected]
www.mammoth-inc.com

Mammoth, Inc. has a policy of continuous improvement and reserves

the right to change design and specications without notice.

©2013 Mammoth, Inc.

MAMM-VHC-IOM-1A

January 2013