MrCool Signature Series User manual

Signature Series
MMBV*E Modular Blower
Please read this manual carefully before installation and keep it for future reference.
Due to updates and constantly improving performance, the information and instructions within this
manual are subject to change without notice. Please visit www.mrcool.com/documentation to
ensure you have the latest version of this manual.
Version Date: 04-21-21
Installation Manual

Save these instructions for future reference
INSTALLATION INSTRUCTIONS
Signature Series Modular Blower
Manufactured By:
MRCOOL®,LLC
48 Remington Way
Hickory, KY 42051
This manual must be left with the homeowner for future reference.
This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in
manuals, be alert to the potential for personal injury or death.
Table of Contents
Installation ...................................................................2
Condensate Drain Connection ....................................4
Electrical Wiring...........................................................5
Setup ...........................................................................6
Sequence of Operation................................................8
System Check .............................................................9
Replacement Parts....................................................10
Maintenance..............................................................10
................................................11
Improper installation, adjustment, service, or
maintenance can cause injury or property damage.
Refer to this manual. For assistance or additional
agency.
WARNING
The information contained in this manual is intended
safety procedures and equipped with the proper tools
and test instruments. Failure to carefully read and follow
all instructions in this manual can result in equipment
malfunction, property damage, personal injury, and/or
death.
WARNING
Disconnect all power supplies to both the indoor
blower section and outdoor section before making any
electrical connections or servicing the system. More
than one disconnect switch may be required to de-
energize the equipment. Hazardous voltage can cause
severe personal injury or death.
WARNING
Inspection of Shipment
Upon receipt of equipment, carefully inspect it for possible
shipping damage. If damage is found, it should be noted
on the carrier’s freight bill. Take special care to examine
the unit inside the carton if the carton is damaged. Any
concealed damage discovered should be reported to the
last carrier immediately, preferably in writing, and should
include a request for inspection by the carrier’s agent.
If any damages are discovered and reported to the carrier
DO NOT INSTALL THE UNIT, as claim may be denied.
ordered.
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Installation
This modular blower is designed for ease of installation
applications. The units are shipped from the factory
completely assembled. Accessories may also be ordered
installations only.
Read the entire instruction manual before starting the
installation. Several of the installation steps can be done
prior to setting the unit in place and doing this can save
time and simplify installation. Do not remove the cabinet
knockouts until it has been determined which knockouts
will need to be removed for the installation. Determining
which knockouts to remove will depend on the application
and in some cases preference.
These instructions are intended to be a general guideline
and do not supersede any local or national codes.
Installation must conform with the local building codes and
with the latest editions of the National Electric Code or
Canadian Electric Code.
Improper installations not following these instructions
can result in unsatisfactory operation and/or dangerous
conditions and may void the unit warranty.
General Information
The modular blower furnace may be used with optional
matching furnace coil cabinets in upflow, counterflow, or
horizontal applications (see Figure 3 for acceptable
system configurations). Tie-plates and the necessary
hardware are packaged with the blower sections to
connect the furnace and coil section cabinets together.
be removed from inside any threaded drain pan hole to
which a drain line is to be connected. Use care when
removing the web so as to not damage the coil.
To avoid property damage caused by condensate drain
separate drain line to the outside under any indoor electric
building codes apply, install per those codes.
Select the best position which suits the installation site
conditions. Take into consideration required clearances,
space, routing requirements for refrigerant line, condensate
These electric furnaces are completely factory assembled
and all components are performance tested. Each unit
consists of a blower assembly, optional refrigerant coil,
Knockouts are provided for electrical power wiring
entrance.
When used on cooling applications, excessive sweating
may occur when unit is installed in a very humid space.
If installed in an unconditioned space, sealant should be
applied around the power wires, control wires, refrigerant
tubing, and condensate lines where they enter the cabinet.
Power wires should be sealed on the inside where they
exit the conduit opening. Sealant is required to prevent air
leakage into and condensate from forming inside the unit,
control box, and on electrical controls.
The unit must be installed in such a way as to allow
free access to the coil compartment and blower/control
compartment.
The unit must be installed in a level position to ensure
proper condensate drainage. Make sure unit is level in
both directions within 1/8”.
Units with circuit breakers installed in the vertical position
must have breaker switch position “ON” in the up position
and switch position “OFF” in the down position. This
Electric Codes requirements.
The modular blower may be converted for vertical downflow
applications. The circuit breaker(s) must be rotated 180°.
units with circuit breakers installed in the vertical position
must have circuit breakers installed so that the breaker
switch “ON” position and marking is up, and “OFF” position
and marking is down.
All electric furnaces installed with a mating coil section must
follow the instructions listed below for proper condensate
drainage. It is recommended that the auxiliary drain be
connected to a drain line for all units. If the auxiliary drain
is not connected, it must be plugged with provided cap. For
and routed to a drain.
Horizontal Installations
Horizontal installations can be left or right hand. Adequate
support must be provided to insure cabinet integrity.
Ensure that there is adequate room to remove service
and access panels if installing in the horizontal position.
horizontal coil installations.
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Maintain all required clearances to combustible surfaces
as stated on the unit rating plate.
Supply and return ductwork must be adequately sized to
meet the system’s air requirements and static pressure
capabilities. Ductwork should be insulated with a minimum
of 1” thick insulation with a vapor barrier in conditioned
areas or 2” minimum in unconditioned areas. Connect
Sheet metal ductwork run in unconditioned spaces must
be insulated and covered with a vapor barrier. Fibrous
ductwork may be used if constructed and installed in
accordance with SMACNA Construction Standard on
Fibrous Glass Ducts. Check local codes for requirements
on ductwork and insulation.
Duct system must be designed within the range of external
static pressure the unit is designed to operate against. It
accessories, etc. are accounted for in total resistance.
the unit around the blower outlet.
opening provided around the blower outlet and should be
installed as recommended in ASHRAE or ACCA Manual D.
The plenum forms an extension of the blower housing and
minimizes air expansion losses from the blower.
If an elbow is included in the plenum close to the unit, it
must not be smaller than the dimensions of the supply duct
Non-Ducted Return Closet Installation
The cabinet can be installed in a closet with a false bottom
to form a return air plenum or be installed with a return
air plenum under the unit. Louvers or return air grilles are
without a ducted return to single story buildings.
• Install louvers in a closet. Use the free area of louver or
grille to determine the size opening required to provide
the free area for metal louvers or grilles.
• If the free area is not known, assume a 25% free area
for wood or a 75% free area for metal louvers or grilles.
• If the return air plenum is used, the return air grille
should be immediately in front of the opening in the
When not installed in front of the opening, there must be
adequate clearance around the unit to allow for the free
Nominal Tons Air
Conditioning & Nominal Air
Flow
Square Inch Surface Area & Nominal Size Minimum Return Air Free
Area
Disposable Filters Washable Filters
Up through 2 ton
800 - 900 CFM
432 sq. in.
20 in x 25 in
260 sq. in.
15 in x 20 in 260 sq. in.
2-1/2 ton
900 - 1000 CFM
480 sq. in.
20 in x 30 in
288 sq. in.
14 in x 25 in 288 sq. in.
3 tons
1300 - 1500 CFM
576 sq. in.
14 in x 25 in (2)
346 sq. in.
16 in x 25 in 346 sq. in.
3-1/2 tons
1300 - 1500 CFM
672 sq. in.
16 in x 25 in (2)
404 sq. in.
20 in x 25 in 404 sq. in.
4 tons
1500 - 1700 CFM
768 sq. in.
20 in x 25 in (2)
461 sq. in.
20 in x 25 in 461 sq. in.
5 tons
1900 - 2100 CFM
960 sq. in.
20 in x 30 in (2)
576 sq. in.
24 in x 25 in 576 sq. in.
Table 1. Recommended Remote Filter Sizes
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Condensate Drain Connection
Do not operate unit without a drain trap. The condensate
drain is on the negative pressure side of the blower;
therefore, air being pulled through the condensate line
will prevent positive drainage without a proper trap.
from inside any threaded drain pan hole to which a
drain line is to be connected. Use care when removing
the web so as to not damage the coil.
with the bottom of the inside of pan. Auxiliary connection
is raised above the bottom of the inside of the pan. Plastic
web covering 3/4” auxiliary connection must be broken
out if used. Do not get primary and auxiliary connections
interchanged.
connections on the drain pan.
The unit is provided with 3/4” FPT condensate drain
connections.
• Connect the drain lines to the appropriate drain pan
• Secondary drain connections should be connected to
a separate drainage system.
• Install a trap in the drain line below the bottom of the
drain pan and pitch the drain lines down from the coil at
least 1/4” per foot of run. Horizontal runs over 15’ long
must also have an anti-siphon air vent (stand pipe),
installed ahead of the horizontal run. An extremely
long horizontal run may require an oversized drain line
to eliminate air trapping.
• Route to the outside or to an appropriate drain. Check
local codes before connecting drain line to an existing
drainage system.
• Insulate drain lines where sweating could cause water
damage.
• The removal of cabinet knockouts required for drain
connections can be made much easier with the indoor
coil assembly removed from the cabinet.
• Install drain lines so they do not block service access
coil, or blower removal and service access.
• Make sure unit is level or pitched slightly toward
primary drain connection so that drain pan will empty
completely without water standing in pan.
• Install a 2” trap in the primary drain line as close to the
unit as practical. Make sure that the top of the trap is
below connection to the drain pan to allow complete
drainage of pan.
• Auxiliary drain (if used) should be run to a place
where it would be noticeable if it becomes operational.
Occupant should be warned that a problem exists if
water should begin running from the auxiliary drain
line.
• Test condensate drain pan and drain line after
installation is complete. Pour several quarts of water
to make sure drain pan is draining completely, no leaks
from the termination of the primary drain line.
Unit Drain Connection
Positive Liquid Seal Required
1 in Minimum
12 in
Maximum
Figure 1. Typical Condensate Drain Connection
the outside of the building, is required in all installations
locations, local codes may require an auxiliary drain pan
for any horizontal installation.
CAUTION
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3 in Minimum

Electrical Wiring
Turn off electric power at the fuse box or service panel
before making any electrical connections and ensure a
proper ground connection is made before connecting
line voltage. Failure to do so can result in property
damage, personal injury, or death.
WARNING
Electrical Code recommendations, local codes, and
applicable requirements of UL; or in accordance with
the Canadian Electrical Code, local codes, and CSA
Standards. Power wiring, disconnecting means, and over-
current protection are to be supplied by the installer. See he
unit rating plate for unit maximum over-current protection,
minimum circuit ampacity, and operating voltage. The
power supply must be sized and protected according to
require grounding of each circuit to lug(s) provided in unit.
Use copper conductors only.
NOTE
The unit must be grounded with separate ground
connector(s). See the electrical connection diagrams
High voltage pigtail wiring connections are included in the
unit. For systems requiring additional electric heat, this
plug-in harness will be discarded and the high voltage
kit. Low voltage control wiring are pigtail leads located
outside the cabinet and are color coded to match the
connection called out on the wiring schematic.
These units are designed for operation with a 208-240 volt
single phase, 60 cycle, AC power supply. The units are
internally factory wired for 240 volt installation. If 208 volt
installation is desired, it will be necessary to change the
black transformer lead in the blower cabinet control box to
the 208V terminal on the transformer.
The variable speed motor in the modular blower
influx of current when power is applied. Power is to
remain applied to the motor except during servicing.
Remove AC power before plugging or unplugging the
input power to the motor. Do not install blower relays
that interrupt line voltage to the motor.
IMPORTANT
Variable Speed Features
The modular blower is equipped with a variable speed
of external static pressures. The variable speed blower
offers the following comfort features:
Soft Start
When called into operation, the variable speed motor will
slowly ramp up to normal operating speed. This eliminates
the noise and discomfort that results caused by the initial
blast of air encountered with standard electric furnaces.
It can take up to 7.5 minutes to reach normal operating
speed.
Continuous Blower Operation
The comfort level of the living space can be enhanced
when using this feature by allowing continuous circulation
of air in between calls for cooling or heating. The circulation
minimum).
For situations where humidity control is a problem, the
variable speed motor can be enabled to operate at a 10%
by connecting to a standard humidity control that is
normally closed and opens on humidity rise.
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Setup
coil should be between 350 – 450 CFM per ton of cooling
outdoor unit. If the electric furnace is to be used with
smaller tonnage outdoor equipment, the variable speed
changing the motor control board (refer to Table 2. Variable
Speed Motor Application).
The cooling blower speed must be set to provide a
outdoor cooling capacity.
IMPORTANT
Variable Speed Motor
Locate the motor control board in the blower control box.
Set the HEAT and COOL CFM taps by moving the board
jumpers to the A, B, C, or D positions (see Figure 2) based
on the information found in Table 2. Variable Speed Motor
Application. The ADJUST tap on the control board can be
used to raise or lower the table CFMs. The (+) tap will raise
the table CFM by 10%, and the (–) tap will lower the table
CFM by 12%.
IMPORTANT: When changing the control taps, the
high voltage must be off in order for the new settings to
take effect.
DEHUMIDIFY
CUT TO ENABLE
COOL
HEATADJUST
NORM A
B
C
D
A
B
C
D
(+)
(–)
TEST
D1
Figure 2. Motor Board Taps and Dehumidify Resistor
This model is designed for use with heat pumps as
well as air conditioning systems. The motor control
board needs to sense a signal on the “O” thermostat
wire in order to use cooling delay timing. For a straight
air conditioning system, connect the “O” wire to the 24
volt “R” wire.
also features LED indicators that display operating mode,
signals for emergency heat (EM), aux. heat (W1), reversing
valve (O), compressor stage 1 (Y1), compressor stage 2
(Y2), and blower (G) are all indicated by lit LED’s on this
board. If a humidistat is used, the dehumidify LED will light
when the humidistat opens and the motor runs at reduced
for each 100 CFM. For example: if the operating CFM is
Special note for units equipped with a humidistat: If
using a humidistat, the dehumidify resistor located on the
bottom right of the control board must be removed (see
Figure 2).
The HUM terminal on the board must be connected to
the Normally Closed contact of the humidistat so that the
board senses an open circuit on high humidity.
Application Table
The versatility of the variable speed motor enables the
performance of the modular blower to be tailored to the
different modes of operation encountered in heating and
cooling. All modular blowers are capable of operation
a modular
the control board taps and the thermostat (see Table 2.
Variable Speed Motor Application). Before beginning the
setup, become familiar with the information found in this
table.
The data in the application table is categorized by unit size
and mode of operation. Use the information provided to
determine the CFM taps needed for cooling and heating.
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Control Board Taps
Model Mode
Thermostat Cool Heat
HUM EM W1 O Y2/
Y1 G A B C D A B C D
CFM CFM
MMBV08BE
Cont. Blower X 500 400 350 350
Cooling ** X X 1000 800 700 600
Heating X 1000 800 700 600
Aux. Heat X X *** *** *** *** 1000 800 700 600
Emer. Heat X X *** *** *** *** 1000 800 700 600
MMBV12BE
Cont. Blower X 600 500 400 350
Cooling ** X X 1200 1000 800 600
Heating X 1200 1000 800 600
Aux. Heat X X *** *** *** *** 1200 1100* 1100* 1100*
Emer. Heat X X *** *** *** *** 1200 1100* 1100* 1100*
MMBV16CE
Cont. Blower X 800 700 600 500
Cooling ** X X 1600 1400 1200 1000
Heating X 1600 1400 1200 1000
Aux. Heat X X *** *** *** *** 1600 1400 1200* 1100*
Emer. Heat X X *** *** *** *** 1600 1400 1200* 1100*
MMBV20DE
Cont. Blower X 900 800 700 600
Cooling ** X X 1800 1600 1400 1200
Heating X 1800 1600 1400 1200
Aux. Heat X X *** *** *** *** 1800 1600 1400 1200*
Emer. Heat X X *** *** *** *** 1800 1600 1400 1200*
* This CFM is not approved for use with highest kW heater size.
.
At the end of a call for cooling there is a blower delay of 1 minute.
Table 2. Variable Speed Motor Application
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Sequence of Operation
Cooling (cooling only or heat pump)
Single Stage Cooling
For single stage cooling, Y1 and Y2 need to be jumpered.
When the thermostat calls for cooling, the circuit between R
and G is completed, and the blower relay is energized. The
Normally Open contacts close, causing the indoor blower
motor to operate. The circuit between R and Y is also
completed; this circuit closes the contactor in the outdoor
unit starting the compressor and outdoor fan motor. Circuit
R and O energizes the reversing valve switching it to the
cooling position. (The reversing valve remains energized
as long as selector switch is in the COOL position.)
Two Stage Cooling
On a call for 1st stage cooling, the thermostat closes R
to Y. In 1st stage cooling, the blower runs at 70% of the
the thermostat closes R to Y2. In 2nd stage cooling, the
Heating (electric heat only)
When the thermostat calls for heat, the circuit between R
and W is completed, and the heater sequencer is energized.
A time delay follows before the heating elements and the
indoor blower motor come on. Units with a second heat
W on the thermostat sub-base or connected to a second
stage on the sub-base.
Heating (heat pump)
When the thermostat calls for heat, the circuits between R
and Y and R and G are completed. Circuit R-Y energizes
the contactor starting the outdoor fan motor and the
compressor. Circuit R and G energizes the blower relay
starting the indoor blower motor.
If the room temperature should continue to fall, the
circuit between R and W1 is completed by the second
stage heat room thermostat. Circuit R-W1 energizes
a heat sequencer. The completed circuit will energize
supplemental electric heat. Units with a second heater
W1 on the thermostat or connected to a second heating
stage W2 on the thermostat sub-base.
Emergency Heat (heating heat pump)
If selector switch on thermostat is set to the emergency
heat position, the heat pump will be locked out of the
heating circuit, and all heating will be electric heat. A jumper
should be placed between W2 and E on the thermostat
sub-base so that the electric heat control will transfer to the
blower to cycle on and off with the electric heat when the
fan switch is in the AUTO position.
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System Check
Pre-start Check
• Is unit properly located, level, secure, and serviceable?
• Has an auxiliary pan been provided under the unit
ceiling?
• Have all webs been carefully removed from the drain
connections that are being used?
• Has the condensate line been properly sized, run,
trapped, pitched, and tested?
• Is the ductwork correctly sized, run, taped, and
insulated?
• Have all cabinet openings and wiring been sealed?
•
•
• Has the indoor/outdoor unit application been reviewed
for proper motor dip switch settings?
• Is the wiring tight, correct, and to the wiring diagram?
• Is the unit properly grounded and protected (fused)?
• Is the thermostat correctly wired, level, and in a good
location?
• Is the unit circuit breaker(s) rotated properly – ON up/
OFF down?
• Are all access panels in place and secure?
Refer to outdoor unit installation instructions for system
start-up instructions and refrigerant charging instructions.
coil should be between 350 – 450 CFM per ton of cooling
outdoor unit. If the electric furnace is to be used with
smaller tonnage outdoor equipment, the variable speed
changing the motor control board (refer to Table 2. Variable
Speed Motor Application).
Electric Heater
To check the electric heater operation:
1. Set thermostat to call for auxiliary heat (approximately
5° F above ambient temperature). The indoor blower
and auxiliary heat should come on together. Allow a
minimum of 3 minutes for all sequencers to cycle on.
2. Set the thermostat so it does not call for heat. Allow up
to 5 minutes for all sequencers to cycle off.
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Replacement Parts
Use only original equipment service parts when repairing
these products. These parts include but are not limited
to: circuit breakers, heater controls, heater limit controls,
heater elements, motor, blower relay, control transformer,
blower wheel, indoor coil, and sheet metal parts.
When ordering replacement parts, it is necessary to order
by part number and include with the order the complete
model number and serial number (see unit data plate).
Refer to the parts list for unit component part numbers.
Maintenance
Air Filters
to protect the coil, blower, and internal parts from
excessive dirt and dust.
IMPORTANT
of inadequate heating or cooling performance. Replace
soaking in mild detergent and rinsing with cold water.
properly sized for it.
Owner Record
Furnace Model # Serial # Installation Date:
Installed By:
Dealer:
Address:
Telephone # License #
Contact Person:
Other Equipment Installed:
Equipment Type:
Model # Serial # Installation Date:
Equipment Type:
Model # Serial # Installation Date:
Equipment Type:
Model # Serial # Installation Date:
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Left to Right
Airflow
Right to Left
Airflow
Upflow
Counterflow
Horizontal
Figure 3.
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Figure 4. Wiring Diagram for
Variable Speed Blower
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Figure 5. Field Connections
Heat Pump with Electric Heat
Electric
FurnaceThermostat Heat Pump
R R
R
C1 C1
C
W2 EM
W1 W1
W
O O
O
Y2 Y2
Y/Y2
Y1 Y1
Y1
G G
Only for 2-Stage
Electric Heat
2-Stage System only;
for single-stage systems,
jumper Y1 to Y2
Air Conditioning with or without Electric Heat
Electric
FurnaceThermostat
Air
Condensing
Unit
R R
O
C C1
C
W2 EM
W1 W1
Y2 Y2
Y1 Y1
Y1
G G
2nd Stage Electric
Heat if used
1st Stage Electric
Heat if used
2-Stage System only;
for single-stage systems,
jumper Y1 to Y2
Connect O to R for proper
cooling blower delay
Y/Y2
Heat Only
Electric
FurnaceThermostat
R R
C C1
W2 EM
W1 W1
G G
2nd Stage
Electric Heat
if wired
Connect common wired to thermostat only if required. See thermostat instructions.
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Signature Series
Please read this manual carefully before installation and keep it for future reference.
Consult with the sales agency or manufacturer for details.