Unico M Series User manual

The information on the following pages is to help the in-
staller save time, provide the best possible installation and
ensure continuous trouble-free operation.
These instructions apply to the Unico M-Series air han-
dler units. For heat pump coils, refer to Bulletin 30-24 for
additional instructions. Installation instructions for the air
distribution system are covered in Bulletin 30-05. Before
beginning any installation a detailed system layout must
be done in accordance with the System Sizing and Layout
Procedure, Bulletin 40-40 and the Component Layout In-
structions, Bulletin 40-30.
Do not attempt to install or startup unit without first read-
ing and understanding the appropriate sections in this
manual.
Before operating, be sure the unit is properly grounded.
Installation should be in accordance with all local codes
and regulations and with the National Board of Fire Un-
derwriters regulations. In case of conflict, local codes take
precedence.
All electrical wiring should be in accordance with the lat-
est edition of the National Electrical Code and all local
codes and regulations. The unit is safety certified to UL
1995 and listed with ETL.
Always install a secondary drain pan when an overflow of
condensate could cause damage.
This manual does not always include the latest revision
letter when referring to UPC part numbers. Refer to the
latest Price List and Spec Sheets for the current UPC re-
vision letter. For example, in UPC-00xthe ‘x’ indicates
the latest revision.
The Unico System is a complete indoor comfort system
that includes an indoor air handling unit and small duct
system. The air handler and duct system were designed to
operate together to provide the proper airflow in every in-
stallation. The conditioned air is supplied through a series
of 2-inch ducts as a stream of air that entrains and mixes
the room air. This process of aspiration produces a more
even temperature distribution in the room.
The Unico 'M' Modular Series air-handling units consist
of various modules that are easily latched together. The
modules can be arranged in a vertical-up-flow, vertical-
counter-flow and horizontal-flow configuration. They can
be combined as a heating-only, cooling-only, or heating
and cooling air handler unit. See Fig. 1.

Bulletin 30-20 —Page 2
© Copyright 2014, Unico, Inc.
All insulated Unico System modules feature closed-cell
insulation for improved sound attenuation. There is no ex-
posed fiberglass insulation.
Each module is available in four sizes: 2430, 3036, 3642,
and 4860. There are three basic modules: a blower mod-
ule, a cooling module, and a heating module. The blower
module includes the blower wheel, blower housing, mo-
tor, and electrical control box. The cooling module in-
cludes a cooling-only refrigerant coil, a heat pump coil, or
a chilled water coil. The heating module is supplied as an
empty cabinet with room for a slide-in hot water coil.
The modules can be arranged to provide only the options
needed as shown in Figure 1 (with details on pages 26 and
27). Heating-only systems require the blower module, the
heating module, and a hot water coil. Cooling-only sys-
tems include the blower module and a cooling module.
For heating and cooling all the modules are combined
with coils. The system may even be used for ventilation-
only, using just the blower module.
Unico designed and built blowers feature direct drive mo-
tors or EC motors and are located in the air stream. Each
blower wheel is balanced to Unico specifications. The
blowers feature a quick twist-and-lock motor mount for
easy maintenance (see page 16). The motorized blower
assembly consists of the motor, which is mounted to the
inlet ring, and the wheel, which is mounted to the motor
shaft.
Other options and modules are also available to add addi-
tional features or to simplify installation. These include an
electric duct heater, multiple return plenum, and a vertical
plenum stand. Please refer to the latest Unico Catalog for
information on these and other options.
All modules are inspected prior to shipping and are care-
fully packaged in individual cartons. Inspect all cartons
prior to unpacking. Notify carrier of any damage.
Open each carton to remove the modules. Inspect unit for
visible signs of concealed damage and notify carrier of
any such damage.
All materials are sold FOB Factory and it is the responsi-
bility of the consignee to file any claims with the deliver-
ing carrier for materials received in damaged condition.
Locate the air handler to minimize the number of plenum
elbows and fittings while keeping the supply duct runs as
short as possible. (See Bulletin 40-30, Component Duct
Layout Design). Provide minimum clearance on both
sides for servicing the unit as shown in Fig. 2.
Heating and Cooling
Horizontal
Flow
Vertical
Counter-Flow
Vertical
Up-Flow
IL00010d.CVN
Heating Only Cooling Only
Normal Air Inlet/Outlet Optional Air Inlet
Blower Module`
Spacer Module
Cooling Module
Vertical Plenum
Module (with Hot
Water Coil)
Vertical Plenum
Module (without Hot
Water Coil)
Spacer Module
Heating Module
(with Hot Water Coil)
Heating and Cooling (M4860)

Bulletin 30-20 —Page 3
© Copyright 2014, Unico, Inc.
If installing the unit in an attic, avoid placing the unit
above a bed. The ideal location is above a central hall, a
closet, a bathroom, or any normally unoccupied space.
The unit can also be installed in a closet, crawlspace, or
basement. If the local codes allow, the unit may be in-
stalled in the garage provided the ductwork is well sealed,
especially the return duct. Although the unit is not de-
signed for outdoor use, it may be located outside provided
adequate weather protection is used; typically a roof in-
stallation requires mounting on blocks with a sheet metal
cover or cap to protect the unit from rain and extreme
weather conditions.
Be sure to position the return air box and filter near the
unit allowing at least one 90° bend in the return duct for
proper acoustical performance (refer to figure 3 for a typ-
ical horizontal attic installation). The section on Return
Air Ducts in the manual provides more details.
All modules except the 4860 cooling module are designed
to fit through a 14-inch (356 mm) opening, typical of a
joist spaced at 16-inch (406 mm) center distance. The
4860 module requires an 18.5-inch (470 mm) opening. If
no access is provided, an opening must be cut. It is sug-
gested to use the opening required for the return air box,
especially in an attic installation. The opening for the re-
turn air box is listed in Table 1. If the joists or studs are
less than 16-inches (406-mm) center-to-center or running
the wrong direction it will be necessary to cut and header
the joists.
The Unico EC motor includes an electronic circuit board
that is sensitive to overheating if the air temperatures sur-
rounding the motor are above a certain value. The motor
will not function above its maximum operating tempera-
ture and will have some reduction in motor life between
the maximum operating temperature and the recom-
mended temperature limit. Depending on the application,
this may or may not be acceptable.
38
 
38

12

38

12

38

12

38

12

Cooling
Module
(MCxxxxx)
Blower
Module
(MBxxxxx)
Heating
Module
(MHxxxxx)Return Air Adapter
(UPC 104-xxxx)Band (supplied with return air box)
Return Air Duct
(UPC-04-xx-1)
Return Air Box
(UPC-01-xxxx-1)
Plenum
Adapter
(UPC 61-xxxx)
Isolation
Pads
Secondary
Drain Pan
(UPC 20 or 24)
Platform
Typical 10 foot (3.6 m) Return Duct
Use at least one 90° bend.
IL00039c.CVS
Control
Box
Band

Bulletin 30-20 —Page 4
© Copyright 2014, Unico, Inc.
For maximum
motor life, we recommend that the Unico EC motor be
limited to applications with less than 130°F (54°C) air
temperature. Therefore, the Unico EC motor can be used
with all heat pump and electric heating applications with-
out problem. It may also be installed with a hot water coil
with air temperature leaving the coil less than 130°F
(54°C). This is generally with water temperature less than
135°F (57°C) but it depends on the water and air flow.
Consult the hot water coil specifications to determine air
temperatures based on water flow and air flow rate.
The abso-
lute limit for the motor is 158°F (70°C) air temperature at
which point the motor will automatically begin to slow
down. The motor may be used in applications with air
temperature around the motor between 130 to 150°F (54
to 65°C), typical for boiler systems with water tempera-
tures between 135 and 160°F (57 to 70°C). However, ex-
pect the life of the motor to be reduced by as much as
50%. In most applications, with unit operating intermit-
tently, the amount of time that the motor operates in heat-
ing is very small so the reduction in motor life will not be
significant. Only for extended continuous heating appli-
cations, will the reduction be noticeable. The reduction in
motor life can be minimized by using setback boiler tem-
peratures while operating with maximum airflow at the
highest water temperatures.
The units may be assembled either horizontally or verti-
cally. Refer to Fig. 1 for your particular flow arrangement.
Assemble the units’two modules at a time. If you use a
refrigerant coil, the anti-frost switch wires must be routed
to the control box as you connect the modules.
Remove the coil access
panel and unravel the anti-frost switch wires. If you use a
heating module, feed the wires under the hot water coil
support channel. Then feed the wires through the bushing
in the motor partition panel. After routing the wires
through each module, connect the modules together.
To fasten the modules
together tilt the units to insert the connection flange over
the mating flange as shown in Fig. 4. It may be necessary
to squeeze the units together as you are inserting the
flange to compress the rubber gaskets. If the hook flange
has a small gap, use a large flat bladed screwdriver to pry
the gap apart. Secure the modules together with the
latches, compressing the gasket further.
Most systems are installed in the horizontal configuration,
with the air going from right to left when looking at the
connections (as shown in figure 1). All the modules are
factory set for horizontal airflow. It is not recommended
to flip the cooling module to reverse the flow direction of
the air. When connecting the modules be sure to arrange
the heating module on the inlet (return) side of the cooling
module.
The 4860 cooling module also includes a spacer module
which has a small drip shelf (shipped loose) that must be
installed on the air exit side of the drain pan (shown in
figure 5).
When installing the heat module or return air plenum
module upstream of the cooling module, it is necessary to
first install a hook flange to the bottom of the cooling coil
(Figure 6).
IL00009.CVS

Bulletin 30-20 —Page 5
© Copyright 2014, Unico, Inc.
Figure 6. Hook flange location.
As shown in figure 1, the modular system can also be con-
figured for vertical up-flow or down-flow. The arrange-
ment of modules is different so be sure to follow these
instructions.
In most cases connecting the modules is straight forward
–just use the arrangement shown in figure 1. However, if
you are using a 2430, 3036 or 3642 cooling module, the
top access panel of the cooling module will need to be
repositioned as shown in figure 7.
For vertical up-flow the return air may enter through the
bottom or side return opening of the 2430, 3036 or 3642
cooling module although the bottom opening is preferred.
The 4860 cooling only has one return opening for either
horizontal or vertical applications. The 4860 drain pan is
‘L’ shaped and will work properly when the module is
turned 90 degrees.
For vertical up-flow installations, we recommend using
the vertical return plenum module (MV module). The
spacer shown in figure 1 is included with the MV module
(except for the 4860 unit, where it is included with the
cooling module). If you are not using the MV module for
the 2430, 3036 or 3642, you will need to use the vertical
conversion kit, which includes the extra panels needed.
You will also need to provide a field fabricated mount for
the unit.
The vertical plenum module includes a filter and a space
for a hot water coil. If the unit is installed in an area where
water may cause damage, be sure to set the unit inside a
drain pan.
The return air opening for the vertical plenum module is
in the front. If connecting to a flexible duct, you will need
the return air adapter. The return air adapter attaches to
the front of the return plenum module using latches,
which need to be moved from the top to the sides as shown
below.
IL00302.CNV
Reposition Latches
to sides of Module
UPC-104-xxxx
Return Air
Adapter
Airflow
Cooling Module Return Air
Plenum
or
Heating-
Module
Hook Flange
(shipped loose with MR or MH unit)
Latch Hook
(shipped loose with MR module)
IL00220a.CNV
Filler Panel
(Item A)
Install first
IL00301d.CNV
1
Remove
Latches
Move
1Top panel
Remove
Bottom panel
Remove
Drip Plate
Install new
Panel
MV Vertical Heat
Module
AIRFLOW
UPC-104
Return Air Adapter
Typical Vertical
System Layout
Gasket Tape
(Shipped Loose)
IL00303.CNV

Bulletin 30-20 —Page 6
© Copyright 2014, Unico, Inc.
Position the base, either the vertical module or a field fab-
ricated unit, where desired. Then set the cooling module
on top of the base as shown in Figure 9. Use gasket tape
under the cooling cabinet to prevent air leaks.
Then set the spacer section on top of the coil, securing it
with the corner brackets as shown in Figure 10. The
blower module goes on top. The blower module can be
turned 180 degrees to position the motor to the other side,
or top position the blower discharge towards the front.
Heating-Only Systems For heating-only systems, the
installation is similar to the cooling-only or heating-and-
cooling system, except that the cooling module is re-
moved from the system.
For the 2430, 3036 and 3642 systems, use a vertical spacer
kit such that the spacer overhangs the back of the vertical
plenum and the filter access is not covered over.
Blower
Module
Return Air
Adapter
Airflow
Corner
Bracket
(2 plcs)
Attach
both
corner
brackets
(not used
on 4860)
Vertical
Heating
Module
ReturnAir
Adapter
Airflow
Latches
(shipped
loose)
Note: Attach Latches and Latch keepers to appropriate
modules on opposite side (not shown)
Gasket Tape
(applied to top
of MV module)
Cooling
Module
Latch Keeper
(shipped loose)
Blower
Module
ReturnAir
Adapter
Airflow

Bulletin 30-20 —Page 7
© Copyright 2014, Unico, Inc.
The control box is shipped
with the blower module. It can be installed on either the
discharge side of the blower cabinet, on top, or on the bot-
tom of the blower cabinet, depending on what is most con-
venient.
To install, first remove the two knockouts on the side or
top of the cabinet, where it will be installed. Mount the
control box using four (4) sheet metal screws as shown in
Figure 12. Connect the wiring as required in the wiring
section and the control box manual.
Figure 12. Mounting the Control Box.
Where an over-
flow of condensate could cause water damage, a second-
ary drain pan MUST BE INSTALLED. Place the drain
pan on the mounting base, platform or angle iron support
frame. Be sure to allow enough room for the drain line
and connection (refer to Table 3). The assembled unit
should be placed over the secondary drain pan supported
by rails with rubber pads for isolation to raise the unit
above the 1.5-inch (38mm) sides of the secondary drain
pan.
Table 2 shows the secondary drain pans to be used for
horizontally mounted modules. For vertical up-flow ar-
rangements that use the cooling module, the 2-module
drain pans can be used where space permits and the return
air is entering from the side. These pans would be over-
sized compared to the footprint of the cooling module. If
a smaller drain pan is necessary it should be fabricated to
be at least ½-inch (12.7 mm) larger on each side of the
bottom module.
For vertical down flow (counter flow) arrangements it is
difficult to provide a secondary drain pan because of the
blower discharge at the bottom. The secondary drain pan
must be fabricated with an opening for the blower dis-
charge and plenum adapter and still provide a sealed drain
pan.














Like the modules, all the secondary drain pans except
UPC-24C, D will fit through the return air opening. For
these drain pans it will be necessary to fold the pans in
order to pass through the return opening. If you are unable
to use the UPC-24Dbecause of space limitations, use the
UPC-24B under the cooling and heating modules. In this
case the blower module will extend beyond the secondary
drain pan and should be supported with blocks or an angle
iron frame.
The modules come factory-ready for horizontal airflow
applications and may be modified for vertical airflow ar-
rangements (see Fig. 1) with the addition of the vertical
heat module (with or without the heating coil) and the ver-
tical spacer module.
Mount the unit hori-
zontally when vertical height is limited such as in an attic
or crawl space. It is easiest to mount the unit on a platform
but care must be taken to assure proper drain line pitch.
* See Table 3
The platform height must allow for proper pitch of the
condensate drain lines —at least ¼ inch drop per lineal
IL00332.CNV

Bulletin 30-20 —Page 8
© Copyright 2014, Unico, Inc.
foot (20 mm per meter). The platform can be built from a
sheet of ½ inch (13 mm) plywood and stud frame. Table
3 lists the maximum horizontal drain line run for various
framing materials and still provide adequate drainage.




The platform size must allow for the number of modules
being used. For dimensions for minimum platform size
see Fig. 13.
Place secondary drain pan on platform and unit on top of
isolation pads inside of secondary drain pan. Be sure that
the unit is raised above the height of the drain pan side to
allow duct connections.
The modules can
also be suspended from the ceiling or rafters. A typical
suspension method is shown in Fig. 14. Screw four (4) “J”
hooks into rafters. Suspend four (4) chains from “J” hooks
and attach eyebolts to chains. Secure angle iron to eye-
bolts and place secondary drain pan on top. Put isolation
pads in drain pan, making sure unit sits above sides of
drain pan.
As an alternative, rest the unit on the angle iron supports
and hang the secondary drain pan from the same supports.
As above, install “J” hooks, chains, and angle iron. Secure
angle iron to eyebolts and put isolation padding on angle
iron.
Adjust the length of the eyebolts and chains so there is
slight pitch towards the drain end.
Figure 14. Typical Suspended Mounting
Vertical Mounting. Because the units are top heavy, it
is not recommended to suspend a vertical unit. It should
be mounted on either a platform or a floor. Unico makes
a module specifically for vertical installations (refer to
previous section). If only a blower and heating module are
being installed, fabricate a return plenum for the unit to
sit upon.
Although the modules may be assembled without a spacer
module, this can severely restrict the airflow; especially if
the blower needs to achieve its maximum airflow. There-
fore, always use the spacer module for any vertical con-
figuration.
The main duct (or ple-
num) can be round, square or rectangular, provided it
meets the pressure drop requirements of the application.
Adapters are available for the standard sizes for both
round and square ducts.
Figure 15. Round Supply Plenum Adapter Dimensions
Figure 16. Square Supply Plenum Adapters
To attach the plenum adapter, first install the restrictor
plate, if required. Then install the adapter with eight (8)
sheet metal screws as shown in Fig. 17. Sheet metal
screws for installing both are provided with the blower.
Figure 17. Supply Plenum Adapter Installation
B
A
D
L
1 (25)
crimped
AIRFLOW
Model, UPC-61-
1218 2430
10 (254)
3642 4860
7.16 (182) 10.13 (257)
18 (457)
9 (229)
A
B
Dimension,
inch (mm)
6.5 (165) 6 (152)
3.25 (83) 6.38 (162)
D
L
7 (178)
12 (305)
3036
7.16 (182)
9 (229)
A2.0 (51)
Part No. A, inch (mm)
UPC-62-2430
UPC-62-3036
8.50 (216)
10.50 (267)
A
UPC-62-4860
11.50 (292)
UPC-62-3642
10.50 (267)
Blower
Module
Restrictor
Plate
Plenum Adapter
Plenum
Insulation Wrap IL00308.CVX

Bulletin 30-20 —Page 9
© Copyright 2014, Unico, Inc.
Restrictor Plate (single-speed motors only). The
single speed (non-ECM) blower include a restrictor plate
to fine-tune the airflow. The purpose of the restrictor plate
is to eliminate objectionable outlet noise because the
blower is delivering more air than required. In most cases
where the maximum airflow is required, the restrictor may
be omitted.
The restrictor plate is used to set the system airflow (see
Fig. 18). The full open position corresponds to the highest
airflow the installed duct system will allow. Set the re-
strictor plate to the full open position and measure the sys-
tem airflow. The required system airflow is 200-250 CFM
per nominal ton (27-34 L/s per nominal kW). Measure the
motor amperage and use this to ensure the 200-250 CFM
per nominal ton (27-34 L/s per nominal kW) has been
achieved. If elevated sound levels are noticed at the out-
lets with more than 250 CFM per nominal ton (34 L/s per
nominal kW), the airflow may be reduced with the restric-
tor plate. Always measure the system airflow by the motor
amperage (see Table 4). Refer to the airflow-amperage
charts provided with the blower.
Figure 18. Restrictor Setting
Note: Do not use restrictor plate to adjust
plenum static pressure. Adjust the restrictor
to the proper amperage. This will assure
proper airflow.
Table 4. Approximate Amperages at Given Airflows
Unit Size
Airflow,
CFM (L/s)
MBxxxxL
Amps
@230V †*
MBxxxxL+CB
Amps
@230V †
4860
1250 (590)
4.1
4.1
1000 (470)
3.5
3.3
800 (380)
3.1
2.8
3036
3642
1000 (470)
3.9
3.7
900 (420)
3.6
3.4
800 (380)
3.2
3.2
700 (330)
3.0
2.9
600 (280)
2.8
2.7
2430
600 (280)
2.2
1.9
500 (240)
2.0
1.6
400 (190)
1.8
1.4
* multiply by 1.1 if 208V
†for more exact airflow use the chart included with the blower
Attach main duct. Attach the plenum to the adapter by
inserting it over the supply adapter. If using sheet metal
duct, use three (3) or four (4) equally spaced sheet metal
screws or nails to secure the duct to the supply adapter.
Then tape around the seam with UL 181A aluminum tape.
Then wrap the outside of the plenum adapter with the sup-
plied blanket insulation and secure the insulation seams
with UL 181A tape.
Return Air Duct. Unico supplies a return duct system
but any return duct system is acceptable provided the
pressure loss does not exceed 0.15 inches of water (37 Pa),
including filters. The return duct should have at least one
90° bend between the unit and filter box to reduce sound
transmission directly from the unit.
The Unico Return Duct system has a single return that in-
cludes the return air box with filter, the return duct, and
the return air adapter (refer to Fig. 3). Multiple returns or
extra-long returns are possible so long as the maximum
pressure loss is not exceeded. For vertical installations or
tight spaces it may be necessary to fabricate a return duct
system from duct board or lined metal.
The typical return duct is 10-foot (3 m) in length so it may
have to be cut to avoid bunching if the distance to the unit
is significantly less than 100-inches. The minimum length
should be 7-feet (2 m). When given a choice, the shorter
distances should be avoided as this may increase sound
transmission from the unit.
Cut an opening for the return box as specified in Table 1.
For the 2430, 3036 and 3642 if the joists or studs are on
16-inch (410mm) centers, there is no need to build a frame
to hold the return air box. Otherwise, it will be necessary
to construct a frame around the opening. For the 4860 re-
turn, it will almost always be necessary to cut and header
at least one joist.
Center the return air box so the filter frame flange covers
all the gaps and make sure the flange is flush against the
wall or ceiling. Install the return air box against the frame
using nails or screws.
Screw holes are provided in the return air box. Use the
holes nearest the corners. The other holes are for mount-
ing the filter grille. See Fig. 19.
Figure 19. Return Air Box and Filter

Bulletin 30-20 —Page 10
© Copyright 2014, Unico, Inc.
Install filter frame into the return air box using four nails
or screws. Use the holes furthest from the corners. Insert
filter and hold in place by rotating metal clips. Close grille
and secure with clips.
Refer to Table 5 for correct Return Duct Adapter selec-
tion. Attach the proper return duct adapter to either the
Heating or Cooling Module. Then attach the return duct
to the adapter and to the return air box using the Q-bands
and Q-clips.
The return air adapter ships with an insulation blanket that
must be wrapped around the adapter. Tape the seams with
UL 181A aluminum tape.
Table 5. Return Duct Adapter
Unit Size
Blower Module +
Cooling Module
Heating Module
+ Cooling Module
4860
UPC-59-4860
UPC-104-4860
3642
UPC-59-3642
UPC-104-3642
3036
UPC-59-3036
UPC-104-3036
2430
UPC-59-2430
UPC-104-2430
Multiple Returns. If more than one return is desired,
Unico has designed a return plenum (MR) module. The
MR module is available in two sizes: 2430 and 3660, and
it includes a central filter. The MR module is easily fitted
to the air handling unit and multiple return openings may
be cut in the top back or sides of the box. Refer to Bulletin
20-20.6, Return Plenum Module, for additional infor-
mation.
PIPING
All piping must be in accordance with all local codes and
ordinances.
Condensate Lines. The primary drain pan condensate
connection is a ¾-inch (19mm) female pipe thread fitting
and the secondary drain pan connection is a ¾-inch
(19mm) PVC socket fitting.
Elevate the unit so the condensate lines are pitched at
least ¼-inch per lineal foot (20 mm per meter).
Trap the condensate line near the unit using U-trap
A00924-G05 as shown in Figure 20.
In some cases it may be necessary to wrap the conden-
sate line near the unit with insulation to prevent water
condensation on the outside of the pipe.
In some climates or locations it may be necessary to
protect trap from freezing in the winter.
Do not trap the secondary drain line and do not termi-
nate line into the primary drain line.
Figure 20. Typical Condensate Trap
The standard trap that ships with the cooling coil includes
a float switch to shut off the system if the drain is plugged
up. Run secondary drain line so that any drainage will be
immediately known without causing damage to property.
A typical location is to terminate the secondary drain line
above a windowsill so that the drainage splashes on the
window. This will serve as an indicator that there is a
problem with the primary drain. In cases where a second-
ary drain line cannot be run, add a float switch or a micro
switch with a paper fuse.
Refrigerant Connections. All refrigerant coils have
two refrigerant lines: a liquid (small tube) and a vapor
(large tube). The connections are either sweat or flare as
listed in table 6, depending on what type of outdoor unit
the cooling module is matched to.
Table 6. Refrigerant Line and Connection Size
Outdoor unit
Liquid line
Vapor line
1 or 2-stage
3/8 (9.5 mm)
ODF sweat
7/8 (22 mm)
ODF sweat
“iSeries”
Variable-stage
1/4 Flare (2430)
3/8 Flare (3036)
1/2 Flare (2430)
5/8 Flare (3036)
The refrigerant coils are equipped with a Schrader valve
port to relieve the pressure and for factory testing pur-
poses. It can also be used to check for leaks prior to in-
stallation. Unscrew the Schrader cap and press the de-
pressor.
If pressure is present, then go
ahead and relieve the pressure in the coil be continuing to
press on the depressor. When all the pressure is removed
cut the ends of the connections off if brazing the lines.
Otherwise, just remove the flare caps.
Note
All refrigerant coils are shipped from our
factory pressurized with nitrogen. They
do not contain any refrigerant.
WARNING
To prevent injury to eyes, face away from
the Schrader valve when releasing nitro-
gen gas.
5 3/8
(137 mm)
2 1/4
(57 mm)
Pitch ¼ inch per foot
(2 cm per m)
U-TRAP (A00924-G05)
(shipped with cooling module)

Bulletin 30-20 —Page 11
© Copyright 2014, Unico, Inc.
Figure 21. Cut end of connection as shown.
WARNING
To prevent injury, remove all pressure
from coil before removing connection
end caps.
CAUTION
When brazing, purge with nitrogen gas to
prevent the formation of oxides.
Refer to the condensing unit manufacturer’s instruction
for proper line sizing information based on distance from
condenser.
For 1 and 2-stage outdoor units (non iSeries), install a liq-
uid line filter drier as close to the coil module as possible
to protect the evaporator from foreign object debris. For
attic installations or when using long line sets, an optional
moisture indicating sight glass should also be installed be-
tween the filter-drier and expansion valve, near the indoor
unit.
Expansion Valve Installation. All refrigerant coils re-
quire a thermostatic expansion valve. Except for the
iSeries cooling coil, an R-410A valve is shipped loose
with the cooling module and should be installed inside the
cabinet prior to charging. The iSeries expansion valve is
in the outdoor unit already installed.
CAUTION
The iSeries expansion valve is located in
the outdoor unit. To prevent equipment
damage, DO NOT install an expansion
valve inside the indoor unit.
Always use new Teflon seals (part no. A00809-001) when
replacing the TXV.
Table 7. Expansion Valve model numbers
Model
Nominal
Condenser
Size
Valve Part Number
Nom.
Valve
Size
R-22
R-410a
Air-Conditioning or Heat Pump*
2430-B
2 to 2.5-ton
(7 to 9 kW)
A00805-002
A00805-012
2
3036-B
2.5 to 3-ton
(9 to 10 kW)
A00805-004
A00805-014
3
3642-B
3 to 3.5 ton
(10 to 12 kW)
A00805-004
A00805-014
3
4860-B
4 to 5 ton
(14 to 17 kW)
A00805-005
A00805-015
4
Heat Pump
2430-E
2 to 2.5-ton
(7 to 9 kW)
A00808-002
A00808-012
2
3036-E
2.5 to 3 ton
(9 to 10 kW)
A00808-004
A00808-014
3
3642-E
3 to 3.5 ton
(10 to 12 kW)
A00808-004
A00808-014
3
4860-E
4 to 5 ton
(14 to 17 kW)
A00808-005
A00808-015
4
* Refer to AHRI directory to heat pump coil compatibility.
The step-by-step valve installation instructions are as
follows:
Figure 22. (Step 1) remove nut as shown.
Figure 23. (Step 2) Remove side panels as shown.

Bulletin 30-20 —Page 12
© Copyright 2014, Unico, Inc.
Figure 24. (Step 3) Install the white Teflon o-ring in both connec-
tions. Attach and tighten lower connecting nut as shown.
Figure 25. (Step 4) Attach and tighten upper connecting nut as
shown.
Figure 26. (Step 5) Route both the pressure and temperature
tubes as shown.
Figure 27. (Step 6) Tighten the pressure tube nut as shown.
Figure 28. (Step 7) The thermal measuring bulb is placed as
shown. It needs to be in contact with copper tube.
Figure 29. (Step 8) Secure bulb with cork tape as shown.
Water Coil Connections. If you are installing the hot
water coil, remove the side coil access panel and cut away
the insulation. Slide the coil into the cabinet and secure
with brackets supplied with the hot water coil. Install the
access panel after the coil is in place.
All water connections are 7/8-inch (22mm) sweat connec-
tions. Sweat the water connections, then fill the system.
Bleed the air from the coil by backing off the screw inside
the bleed valve for venting (Fig. 30).
If unit is in an unconditioned space below freezing, care
must be taken not to freeze the water in the coil. The best
method is to use a glycol-water antifreeze solution with a
freezing point below the coldest temperature expected.
After venting the chilled water coil, replace the access
panel and seal around the connections with the rubber gas-
ket provided.
Coil Cleaning. The coil should be sprayed with liquid
detergent, or any commercially available evaporator
cleaner solution, thoroughly and rinsed thoroughly before
installation to assure proper drainage of condensate from
the coil. This will eliminate moisture carry-over and as-
sure maximum coil performance. As an alternate to clean-
ing, allow approximately 50 hours of break-in time to
achieve the same results.

Bulletin 30-20 —Page 13
© Copyright 2014, Unico, Inc.
WIRING
WARNING
Disconnect electrical supply before
wiring unit to prevent injury or death
from electrical shock.
All electrical wiring must comply with all local codes and
ordinances. Blower module controls and components are
bonded for grounding to meet safety standards UL Stand-
ard 1995 and CAN/CSA-C22.2 No. 236 and are listed by
ETL. All 50 Hz units are CE marked and conform to the
Low Voltage 73/23/EEC and EMC 89/336/EEC Direc-
tives.
Use a separate power supply with appropriate circuit pro-
tection and wire gauge per code. The circuit protection,
either fuse or circuit breaker, must be sized between the
MCA and MOP as shown in table 8.
There are three different control box and power supply
options. The external wiring is similar for each of these
options although the internal wiring is different. Refer to
table
Connect the power supply to terminals L1 and L2, some-
times marked L1 and N. The equipment ground must also
be connected to terminal GND.
Table 8. Blower power supply specifications
Model
M2430B*1-
M(3036/3642/4860)B*1-
EC1(1 , 60 Hz, 115 V)
FLA
5.6
10.2
MCA
7.0
12.8
MOP
15
20
EC2, EC3, EA2, EA3 (1 , 50/60 Hz, 208-230 V)
FLA
3.2
6.1
MCA
4.0
7.7
MOP
15
15
ST2 (, 60 Hz, 208-230 V)
FLA
3.0
6.2
MCA
3.8
7.8
MOP
15
15
FLA = Motor Full Load Amperage, amps
MCA = Minimum Circuit Ampacity, amps
MOP = Maximum Overcurrent Protection, amps
Model
FLA
MCA
MOP
(1 , 60 Hz, 115 V)
M2430B*1-EC1
5.6
7.0
15
M(3036/3642/4860)B*1-EC1
10.2
12.8
20
(1 , 50/60 Hz, 208-230 V)
M2430B*1-(EA/EC)2
3.2
4.0
15
M(3036/3642/4860)B*1-(EA/EC)2
6.1
7.7
15
(, 60 Hz, 208-230 V)
M2430B*1-ST2
3.0
3.8
15
M(3036/3642/4860)B*1-ST2
6.2
7.8
15
FLA = Motor Full Load Amperage, amps
MCA = Minimum Circuit Ampacity, amps
MOP = Maximum Overcurrent Protection, amps
For all control box options, the control box must be
mounted externally on the blower (figure 12). There are
several possible locations: the top, the front, or the bottom
of the blower module cabinet. The control box attaches
with four sheet metal screws at each corner of the control
box base. Remove the knockouts on the cabinet for the
motor cable and the frost switch wires to pass through.
Then align the control box with the knockouts and attach
the box to the cabinet with four sheet metal screws (in-
cluded in the carton).
All refrigerant coils have sensors that need to connected
to the control box.
For the ST and EC control options, route the anti-frost
switch lead wires (located on the refrigerant coil)
through the interior of the modules to the control box.
-For control option ST2, connect the leads to terminals
#3 and #6 of the Low Voltage Terminal Block. ALL
DX COILS NEED THE FROST SWITCH.
-For control option EC1 or EC2, connect the leads to
the terminals marked AFS.
The iSeries control box option (EA2 and EA3) does not
have an anti-frost control. Instead it has two tempera-
ture sensors: one on the return bend of the coil, “the in-
door coil temperature sensor” (ICT) and one on the face
of the coil fins, “the return air temperature sensor”
(RAT). These must be plugged into the ICT and RAT
plugs on the board.
(a) Hot Water Coil
(b) Chilled Water Coil
Figure 30. Water Coil Connections

Bulletin 30-20 —Page 14
© Copyright 2014, Unico, Inc.
ST2 control box (P/N: A00175-G02). The ST2 con-
trol box option uses a single speed blower motor. At one
time, before the EC motor solution was developed, the
ST2 was our ‘standard’ control box offering. The ST2
control box includes a variable speed controller to adjust
the airflow for constant ventilation where required by
code or desired by the resident. The “ventilation” speed is
adjustable down to half airflow.
The control box includes a 24-volt transformer, the nec-
essary blower relays, and terminal blocks. Space is pro-
vided for a heat pump heating mode bypass relay (shipped
with heat pump cooling module). Space is also provided
for an additional double pole double throw (DPDT) relay
for wiring a boiler, pump, or valve if heating with hot wa-
ter.
1. Next, connect the control wiring per figures 31
through 33. For units with electric duct heaters, refer
to Bulletin 30-34. Match thermostat anticipator set-
tings for combined amperage load of all components,
including electric heater contactors, to prevent dam-
age to thermostat.
2. Connect power supply to terminals L1 and L2 on the
high voltage terminal block. Connect a ground wire
to equipment grounding on the side of the control box
near the incoming power opening.
WARNING
Be sure to insulate the unused trans-
former lead to prevent injury or death
from electrical shock.
The low voltage transformer is factory set for a pri-
mary voltage of 230V. If power supply is 208V, re-
move ORANGE lead from L2 terminal and connect
RED lead to L2. Insulate the connector on the unused
wire lead.
Figure 31. Cooling-only control wiring
The controller is set at the factory to provide constant ven-
tilation anytime the speed switch is turned in the ON po-
sition. To turn on or off this feature at the thermostat refer
to the supplementary wiring diagrams for instructions (lo-
cated near the end of this document).
EC1/EC2 control Box. The EC control box includes
the S.M.A.R.T. control board (SCB) for precise setting of
airflow. The wiring instructions are included in a separate
manual.
Figure 32. Heat pump control wiring (without electric heat)
Figure 33. Cooling with Typical Hot Water Heating control
wiring (with optional aquastat)
iSERIES EA2 control Box. The iSERIES EA control
box is designed to match with the iSERIES outdoor heat
pump. The wiring instructions are included with the out-
door unit installation manual. The most important differ-
ence in wiring is that the iSERIES Unico air handlers must
have a separate electrical supply. It cannot be powered
from the outdoor unit in the same way as the high wall
units.
Ventilation Speed Mode
The ST2 control box is factory configured to energize the
fan at full speed whenever there is a call for heat or cool,
or when the fan switch is set to ON. The unit can be set
for constant ventilation at the air handler whenever the fan
switch is in the AUTO position and there is no call for
heat or cool. There is a variable speed switch on control
box which can be adjusted for the desired speed. The var-
iable speed control is set to the OFF setting at the factory.
To enable this feature, we recommend setting it to the
lowest speed (fully clockwise).
In this configuration, the ventilation speed can only be ad-
justed or turned off or on using this switch. This can be
inconvenient if the unit is not easily accessible. To allow
the user to turn the ventilation speed mode on or off at the
thermostat using the FAN switch, the factory wiring can
be modified as shown in figures 22 to 25, depending on
the configuration. To accomplish this, two wires inside
the control box must be moved as described on the wiring
schematics.
W
Y
R
O
X
2
3
4
5
6
7
1
L
G
Y
B
R
O
W3
X
W2
E
TYPICAL HEAT PUMP
THERMOSTAT
POWER
COMMON
COMMON
REV. VALVE (COOLING)
COMPRESSOR
POWER
FAN
UNICO SYSTEM
AIR HANDLER OUTDOOR CONDENSING
UNIT
1
EMER. HEAT
REV. VALVE (HEATING)
AUX. HEAT
AUX. HEAT
DEFROST HEAT
REV. VALVE
COMPRESSOR
1
WIRING DIAGRAM AS SHOWN IS FOR A REVERSING VALVE THAT IS
ENERGIZED IN COOLING MODE. WHEN VALVE IS ENERGIZED IN
HEATING MODE, USE THE "B' TERMINAL ON THE THERMOSTAT,
INSTEAD OF THE "O" TERMINAL.
Il00062a.CVN
T
T
AQUASTAT
Honeywell R8222D1014 or Steveco90-340
Relay plusEnclosure(or equal)
DPDT RELAY
G
X
R
Y
W
Y
C
2
3
4
5
6
7
1
T
T
BOILEROR
PUMP
Honeywell T87F Thermostat with Q539A
subbase(or equal)
POWER
COMMON
COMMON
HEAT
COMPRESSOR
POWER
FAN
UNICOSYSTEM
AIRHANDLER
OUTDOOR
CONDENSINGUNIT
IL00130c.CVN
14
3
26 5
THERMOSTAT

Bulletin 30-20 —Page 15
© Copyright 2014, Unico, Inc.
Figure 34. M Series ST2 Electrical Wiring Diagram (with Motor Controller installed) for A00175-G02 Control Box

Bulletin 30-20 —Page 16
© Copyright 2014, Unico, Inc.
Figure 35. ST2 Control box. Wiring Schematic for Cooling-Only or Heat-Pump without Supplemental Heat
(Modified to control ventilation speed mode at thermostat)
TYPICAL
OUTDOOR
SECTION
TYPICAL
THERMOSTAT
230V
208V24V
COM
T
1
2
3
4
5
6
34567
12
1
2
3
4
5
6
1
2
3
4
5
6
CR-UN
CR-LO
L1
L2
CR-HI
BLU
*CommonX
PowerR
*ReversingValve
(Heating)B
*ReversingValve
(Cooling)O
CompressorY
Heating
(2ndstage)W
FanG
Common
C
Compressor
Y
Power
R
ReversingValve*
O
DefrostHeat*
W
(SEENOTE4)
EQUIPMENTGROUND
(SEENOTE3)
2
1
4
3
WARNING!
BESURETOINSULATETHEUNUSEDTRANS- FORMERLEADTOPREVENTINJURYOR DEATHFROMELECTRICALSHOCK.
NOTES
1.IFREVERSINGVALVEISENERGIZEDONHEATING,CONNECTTERMINALNO.4TOB
INSTEADOFO.
2.IFMEASUREDSUPPLYVOLTAGEIS208VORLESSREMOVEORANGETRANSFORMER
LEADATTHETERMINALANDINSULATEWITHTAPE.REMOVETAPEFROMRED (UNCONNECTED)TRANSFORMERLEADANDSECURETOTERMINAL.INSULATETHELEAD ONTHEORANGEWIRE.
3.ANTI-FROSTBYPASSCONTROLRELAYISSHIPPEDWITHHEATPUMPCOOLINGMODULE
(MODELMC2430H,MC3642H,ANDMC4860H).FIELDINSTALLRELAYASSHOWNWHEN USEDWITHTHESEMODULES.
4.ANTI-FROSTCONTROLISUSEDONLYWITHREFRIGERANTCOOLINGMODULES(MODELS
MC2430C,H,MC3642C,HANDMC4860C,H).FIELDATTACHLEADSTOTERMINALSAS SHOWN.
BLU
ForRefrigerantCooling-OnlyorHeatPumpsystems. ModifiedtoControlVentilationmodewiththermostatFANswitch. RefertoEL00041ifsystemhashotwaterheatorEL00046ifsystemhas electricheat.
EL00040
BKR
BR
BR
RC
FM
GND.
G/Y
COMPONENTCODE
AFSANTI-FROSTCONTROLSWITCH CR-BPAFSBYPASSCONTROLRELAY CR-HIHIGHSPEEDCONTROLRELAY CR-LOLOWSPEEDCONTROLRELAY CR-UNUNLATCHINGCONTROLRELAY FMFANMOTOR RCRUNCAPACITOR SCSPEEDCONTROL TTRANSFORMER
FACTORYLINEVOLTAGE FACTORYLOWVOLTAGE FIELD(NEC)CLASS1 FIELD(NEC)CLASS2
WIRINGLEGEND
R
BK
R
RBK
R
SC
R
BK
BR
CR-BP
*Emergency
HeatE
AFS
BLU
BLU
Y
BLU
BLU
BR
BR
BR
BR
BR
DWG
OUTSIDE ELECTRICAL BOX
INSIDE ELECTRICAL BOX
TOFUSED208/230V DISCONNECT NOTOVER15AMP FUSE
Y
Y
Y
OR
2
12
Thiswireisconnectedtoterminal1oflowvoltageterminal boxatthefactory.Removeandconnecttoterminal3as shown.
Thiswireisconnectedtoterminal5oflowvoltageterminal boxatthefactory.Removeandconnecttoterminal1as shown.
(SEENOTE1)
(SEENOTE2)
Y
1
Forcooling-onlysystems,omititems marked*.
®
SERIESM

Bulletin 30-20 —Page 17
© Copyright 2014, Unico, Inc.
Figure 36. ST2 Control Box. Wiring schematic Refrigerant Cooling with Hot Water Heat
(Modified to control ventilation speed at thermostat)
TYPICAL
OUTDOOR
SECTION
TYPICAL
THERMOSTAT*Optional
230V
208V24V
COM
T
1
2
3
4
5
6
34567
12
1
2
3
4
5
6
1
2
3
4
5
6
CR-UN
CR-LO
L1
L2
CR-HI
BLU
*CommonX
PowerR
CompressorY
*HeatingW
FanGCommon
C
Compressor
Y
(SEENOTE2)
EQUIPMENTGROUND
WARNING!
BESURETOINSULATETHEUNUSEDTRANS- FORMERLEADTOPREVENTINJURYOR DEATHFROMELECTRICALSHOCK.
NOTES
1.IFMEASUREDSUPPLYVOLTAGEIS208VORLESSREMOVEORANGETRANSFORMER
LEADATTHETERMINALANDINSULATEWITHTAPE.REMOVETAPEFROMRED (UNCONNECTED)TRANSFORMERLEADANDSECURETOTERMINAL.INSULATETHELEAD ONTHEORANGEWIRE.
2.ANTI-FROSTCONTROLISUSEDONLYWITHREFRIGERANTCOOLINGMODULES(MODELS
MC2430C,H,MC3642C,HANDMC4860C,H).FIELDATTACHLEADSTOTERMINALSAS SHOWN.
3.EMERGENCYHEATCONTROLRELAYISNOTSUPPLIEDBYUNICO.RECOMMENDEDMODEL
ISHONEYWELLMODELR8222D1014OREQUIVALENTDOUBLE-POLE,DOUBLE-THROW RELAYWITH24VCOILANDCONTACTSRATEDFORLINEVOLTAGE.
4AQUASTATISOPTIONAL.
BLU
ForCooling-Onlysystemswithhotwaterheat. ModifiedtoControlVentilationmodewiththermostatFANswitch.
EL00041
BKR
BR
BR
RC
FM
GND.
G/Y
COMPONENTCODE
AFSANTI-FROSTCONTROLSWITCH AQAQUA-STAT CR-HTREMERGENCYHEATCONTROLRELAY CR-HIHIGHSPEEDCONTROLRELAY CR-LOLOWSPEEDCONTROLRELAY CR-UNUNLATCHINGCONTROLRELAY FMFANMOTOR RCRUNCAPACITOR SCSPEEDCONTROL TTRANSFORMER
FACTORYLINEVOLTAGE FACTORYLOWVOLTAGE FIELD(NEC)CLASS1 FIELD(NEC)CLASS2
WIRINGLEGEND
R
BK
R
RBK
R
SC
R
BK
BR
1
CR-HTR
COIL
3
2
46
5
BLU
BLU
Y
BLU
BLU
BR
DWG
OUTSIDE ELECTRICAL BOX
INSIDE ELECTRICAL BOX
TOFUSED208/230V DISCONNECT NOTOVER15AMP FUSE
Y
Y
Y
OR
12
12
Thiswireisconnectedtoterminal1oflowvoltageterminal boxatthefactory.RemoveandconnecttoEmergency HeatRelayasshown.
Thiswireisconnectedtoterminal5oflowvoltageterminal boxatthefactory.Removeandconnecttoterminal1as shown.
(SEENOTE3)
(SEENOTE1)
Y
(SEENOTE4)
AQ
TOBOILER ORPUMP
AFS
®
SERIESM

Bulletin 30-20 —Page 18
© Copyright 2014, Unico, Inc.
Figure 37. ST2 Control Box. Wiring schematic Heat-Pump with Supplemental Electric Duct Heater (second stage)
(Modified to control ventilation speed at thermostat)

Bulletin 30-20 —Page 19
© Copyright 2014, Unico, Inc.
Figure 38. ST2 Control Box. Wiring schematic Heat-Pump with Supplemental Hot Water Heat (second stage)
(Modified to control ventilation speed at thermostat)
TYPICAL
OUTDOOR
SECTION
TYPICAL
THERMOSTAT*optional
230V
208V24V
COM
T
1
2
3
4
5
6
34567
12
1
2
3
4
5
6
1
2
3
4
5
6
CR-UN
CR-LO
L1
L2
CR-HI
BLU
*CommonX
PowerR
ReversingValve
(Heating)B
ReversingValve
(Cooling)O
CompressorY
Heating
(2ndstage)W
FanG
Common
C
Compressor
Y
Power
R
ReversingValve
O
DefrostHeat
W
(SEENOTE4)
EQUIPMENTGROUND
(SEENOTE3)
2
1
4
3
WARNING!
BESURETOINSULATETHEUNUSEDTRANS- FORMERLEADTOPREVENTINJURYOR DEATHFROMELECTRICALSHOCK.
NOTES1.IFREVERSINGVALVEISENERGIZEDONHEATING,CONNECTTERMINALNO.4TOB
INSTEADOFO.
2.IFMEASUREDSUPPLYVOLTAGEIS208VORLESSREMOVEORANGETRANSFORMER
LEADATTHETERMINALANDINSULATEWITHTAPE.REMOVETAPEFROMRED (UNCONNECTED)TRANSFORMERLEADANDSECURETOTERMINAL.INSULATETHELEAD ONTHEORANGEWIRE.
3.ANTI-FROSTBYPASSCONTROLRELAYISSHIPPEDWITHHEATPUMPCOOLINGMODULE
(MODELMC2430H,MC3642H,ANDMC4860H).FIELDINSTALLRELAYASSHOWNWHEN USEDWITHTHESEMODULES.
4.ANTI-FROSTCONTROLISUSEDONLYWITHREFRIGERANTCOOLINGMODULES(MODELS
MC2430C,H,MC3642C,HANDMC4860C,H).FIELDATTACHLEADSTOTERMINALSAS SHOWN.
5.EMERGENCYHEATCONTROLRELAYISNOTSUPPLIEDBYUNICO.RECOMMENDEDMODEL
ISHONEYWELLMODELR8222D1014OREQUIVALENTDOUBLE-POLE,DOUBLE-THROW RELAYWITH24VCOILANDCONTACTSRATEDFORLINEVOLTAGE.
6.AQUASTATISOPTIONAL.
BLU
ForHeatPumpsystemswithemergencyhotwaterheat. ModifiedtoControlVentilationmodewiththermostatFANswitch.
EL00047
BKR
BR
BR
RC
FM
GND.
G/Y
COMPONENTCODE
AFSANTI-FROSTCONTROLSWITCH CR-BPAFSBYPASSCONTROLRELAY CR-EMEMERGENCYHEATCONTROLRELAY CR-HIHIGHSPEEDCONTROLRELAY CR-LOLOWSPEEDCONTROLRELAY CR-UNUNLATCHINGCONTROLRELAY FMFANMOTOR HTRELECTRICDUCTHEATER RCRUNCAPACITOR SCSPEEDCONTROL TTRANSFORMER
FACTORYLINEVOLTAGE FACTORYLOWVOLTAGE FIELD(NEC)CLASS1 FIELD(NEC)CLASS2
WIRINGLEGEND
R
BK
R
RBK
R
SC
R
BK
BR
CR-BP
Emergency
HeatE
AFS
1
CR-EM
COIL
3
2
46
5
BLU
BLU
Y
BLU
BLU
BR
BR
BR
BR
BR
DWG
OUTSIDE ELECTRICAL BOX
INSIDE ELECTRICAL BOX
TOFUSED208/230V DISCONNECT NOTOVER15AMP FUSE
Y
Y
Y
OR
12
12
Thiswireisconnectedtoterminal1oflowvoltageterminal boxatthefactory.RemoveandconnecttoEmergency HeatRelayasshown.
Thiswireisconnectedtoterminal5oflowvoltageterminal boxatthefactory.Removeandconnecttoterminal1as shown.
(SEENOTE5)
(SEENOTE1)
(SEENOTE2)
Y
(SEENOTE6)
AQ
TOBOILER ORPUMP
®
SERIESM

Bulletin 30-20 —Page 20
© Copyright 2014, Unico, Inc.
STARTUP
! IMPORTANT !
The most important step when installing
the Unico System is making sure it has the
correct airflow. Be sure to record the am-
perage and voltage of every system in or-
der to verify the airflow through the unit.
Also, measure the airflow at each outlet to
verify the airflow in each room. Both meth-
ods are described later in this section.
Sequence of Operation
The sequence of operation depends greatly on the options
installed and type of control thermostat used. Most ther-
mostats have a fan AUTO-ON switch. When the fan
switch is set to ON, the “G” circuit is closed and the
blower relay is energized. The indoor blower starts after
about a 20 second delay. The following paragraphs de-
scribe the sequence of operation when the fan is set to
AUTO. If the fan switch is set to ON, the sequence is the
same except the “G” circuit is always closed and the in-
door fan is always operating.
Cooling Cycle (A/C or Heat Pump). When the ther-
mostat calls for cooling, the “Y” and the “G” circuits are
closed, and a 24 V signal is sent to the compressor con-
tactor in the outdoor unit and fan relay in the indoor unit.
After about 20 seconds, the indoor blower starts. At the
same time, the compressor and outdoor fan also start. De-
pending on the control circuitry in the outdoor unit, there
may be a time delay before the outdoor unit starts. If the
system was just turned off, the time delay could be as
much as five minutes. The cooling system is now operat-
ing.
For heat pump thermostats setting the switch to ‘cooling’
immediately closes the “O” circuit, which is used to ener-
gize the reversing valve solenoid if required by the heat
pump. Otherwise, the “B” circuit, which closes when
switched in heating, is used to energize the reversing
valve solenoid. (Refer to the heat pump manufacturer’s
instructions to see which mode the solenoid needs to be
energized –whether in heating or cooling.)
When the thermostat is satisfied, the 24 V signals are
opened and the outdoor unit stops. The indoor blower
continues to operate for about 40 seconds, then stops. The
system is now off.
Heating Cycle (Heat Pump). Setting the thermostat to
HEATING will automatically switch the reversing valve
solenoid. This setting closes the “B” circuit which sends
a 24V signal to energize the solenoid if required by the
heat pump. Otherwise the “B” circuit is not used and the
solenoid is not energized during heating.
When the thermostat calls for heating, the “Y” and “G”
circuits are closed, sending a 24 V signal to the compres-
sor contactor in the outdoor unit and the fan relay in the
indoor unit. This starts the indoor blower and the outdoor
compressor. There is a time delay of about 20 seconds for
the indoor unit. The heating system is now operating in
stage one.
If the first stage does not satisfy the thermostat, the second
stage thermostat calls for more heat. This closes the “W2”
contacts and energizes the sequencer for electric heat (if
installed). When the second stage thermostat is satisfied,
the “W2” circuit is broken and the sequencer is de-ener-
gized. The electric heating system is now off.
When the first stage thermostat is satisfied, the 24 V sig-
nals are opened and the outdoor unit stops. The indoor
blower continues to operate for about 40 seconds, then
stops. The system is now off.
Heating Cycle (Electric Heat-Only). When the ther-
mostat calls for heating, the “W” and “G” circuits are
closed. The W circuit completes the 24V signal to the se-
quencer in the electric duct heater, which cycles on the
electric heating elements. The G circuit completes the
24V signal to the fan relay in the indoor unit, which starts
the indoor blower after a time delay of about 20 seconds.
The heating system is now operating.
When the thermostat is satisfied, the 24 V signals are
opened and the indoor blower stops after about 40 sec-
onds. At the same time the sequencer cuts the power to
the electric elements. The system is now off.
Note: Use a thermostat designed for electric
heat. A normal heating-cooling thermostat will
not close the “G” circuit on heating.
Ventilation Cycle. When the thermostat is satisfied and
the fan switch is set to “AUTO”, the “G” circuit is open
so that power to the motor goes through the variable speed
controller and the motor runs at reduced speed. The speed
controller is set by the installer to a specific speed. (The
factory default setting for the speed control is “OFF”.)
Using the typical wiring schematic, the fan will operate
continuously if the variable speed control is switched on.
It will either operate at normal speed (full speed) or at a
reduced speed. Use the alternate wiring diagram to allow
the user to turn the ventilation mode off at the thermostat.
To turn it off simply move the fan switch to the AUTO
position.
Checking Air Flow
CAUTION
Do not operate blower with free dis-
charge or low static pressures (below 1-
inch w.c. (250 Pa)) to prevent motor from
overloading.
After the system is installed and before charging system,
check for proper airflow. Record the position of the re-
strictor plate, the plenum static pressure, and the motor
amperage. With this information, the amount of airflow
can be determined.