Airmax MaxAir 30 LV User manual

Brochure I0607B –Rev. 04-03-19
209 Citation Drive, Units 5 & 6
Concord, ON, Canada, L4K 2Y8
Telephone [phone]
Fax [phone]
E-mail: [e-mail]
Web Site: www.airmaxtechnologies.com
MaxAir30(e), 50(e), 70(e), 100(e) Low
Velocity (LV) Fan Coil Systems
Combination Heating/Cooling Equipment
Design, Installation and Maintenance
Instructions
AirMax Technologies Mini Ducted
MaxAir(e)fan coil systems
Important: Read and save these instructions.
Install in accordance with CEC and NEC; All wiring shall conform to CEC, NEC, and
local building and electrical codes.
CERTIFIED
FAN COIL UNITS

Table of Contents
INTRODUCTION ................................... 5
BENEFITS............................................................................................................................. 5
APPLICATIONS ...................................................................................................................... 5
PRODUCT DESCRIPTION ................................... 6
CABINET .............................................................................................................................. 6
HEATING COILS..................................................................................................................... 6
COOLING COILS .................................................................................................................... 6
FAN..................................................................................................................................... 6
OFF SEASON CIRCULATION..................................................................................................... 6
WATER HEATER .................................................................................................................... 6
BOILER ................................................................................................................................ 6
ACCESSORIES . .................................. 7
CHECK VALVE....................................................................................................................... 7
CIRCULATION PUMP............................................................................................................... 7
FLOW CONTROL VALVE.......................................................................................................... 7
EQUIPMENT SELECTION AND SIZING ................................... 7
SELECTING THE FAN COIL....................................................................................................... 9
SUPPLY DUCT DESIGN NOTES ................................................................................................. 9
RETURN DUCT DESIGN NOTES................................................................................................. 9
INDOOR AIR QUALITY ........................................................................................................... 10
COMBINATION MAXAIR FAN COILS AND HYDRONIC HEATING....................................................... 10
LOW WATER TEMPERATURE SYSTEMS................................................................................... 10
INSTALLATION . ................................ 11
AIR HANDLER MOUNTING...................................................................................................... 11
DOMESTIC WATER PIPING..................................................................................................... 11
ANTI-SCALD VALVE.............................................................................................................. 12
COOLING COIL &TX VALVE................................................................................................... 12
WATER HEATER/BOILER....................................................................................................... 12
DUCTWORK........................................................................................................................ 12
FAN COIL PLACEMENT.......................................................................................................... 13
TRUCK DUCT ...................................................................................................................... 13
BRANCH DUCTWORK ........................................................................................................... 13
AIRFLOW............................................................................................................................ 13
CONDENSATION.................................................................................................................. 13
DX REFRIGERANT COOLING .................................................................................................. 13
CONDENSING UNIT .............................................................................................................. 14
FREEZESTAT AND TX VALVE.................................................................................................. 14
EVAPORATOR COIL ASSEMBLY.............................................................................................. 14
REFRIGERATION PIPING ....................................................................................................... 15
CONDENSING UNIT WIRING ................................................................................................... 15
EVACUATING AND CHARGING................................................................................................ 15
ELECTRICAL (STANDARD UNITS) ................................ 15

THERMOSTAT ..................................................................................................................... 16
ELECTRICAL INFORMATION................................................................................................... 16
CONNECTION LOCATIONS..................................................................................................... 16
CHANGING MOTOR SPEED SETTINGS ..................................................................................... 16
FIGURE 1-CONNECTION LOCATIONS..................................................................................... 16
ELECTRICAL (MAXe UNITS) . ................................. 18
DCC7235 LAYOUT AND CONNECTIONS................................................................................... 18
POWER INPUT..................................................................................................................... 18
CONTROL SYSTEM INPUTS.................................................................................................... 18
OUTPUTS........................................................................................................................... 19
OUTPUTS WITH DIP SWITCH.................................................................................................. 21
TYPICAL HOOK UP ............................................................................................................... 26
DIMENSIONS AND MOUNTING ................................................................................................ 26
START-UP PROCEDURES ................................. 27
SEQUENCE OF OPERATION ................................. 28
SERVICE AND MAINTENANCE ................................. 29
FILTER............................................................................................................................... 29
DUCT CLEANING.................................................................................................................. 29
COILS................................................................................................................................ 29
AIR CONDITIONING COIL ....................................................................................................... 29
FAN AND MOTOR................................................................................................................. 29
EXTERNAL PUMP................................................................................................................. 30
TROUBLESHOOTING ................................ 30
EXTERNAL PUMP DOES NOT RUN........................................................................................... 30
EXTERNAL PUMP IS NOISY AT START-UP................................................................................. 30
WATER HEATER T&P IS WEEPING.......................................................................................... 30
INSUFFICIENT OR NO HEAT ................................................................................................... 30
COLD WATER AT HOT FAUCET............................................................................................... 30
FAN RUNS FOR COOLING BUT NOT HEATING............................................................................ 30
HEATING DURING OFF CYCLE................................................................................................ 31
WIRING DIAGRAM (STANDARD UNITS) . ......................... 31
WIRING DIAGRAM (MAXe UNITS) . ......................... 32
FAN COIL DIMENSIONS AND RETURN AIR SIZE AND LOCATION …………………..33
HORIZONTAL AIR FLOW SPACE CONSTRAINED
EVAPORATOR COIL SIZES ........................... 37
50/70/100 COOLING COIL FILTER FRAME CABINET .......................... 38
VERTICAL AIR FLOW EVAPORATOR COILS ……………………39
1, 1.5, 2 TON EVAPORATOR COIL SIZES ……………………40

2, 2.5 TON EVAPORATOR COIL SIZES ……………………41
SAMPLE PIPING SCHEMATICS .......................... 42
TERMS AND CONDITIONS OF SALE . ......................... 46
WARRANTY REGISTRATION ......................... 47
WARRANTY PARTS REQUEST ......................... 48

Page 5
INTRODUCTION .
The MaxAir(e)™line of combo air handlers
is specifically designed for use in residential
and commercial combination space and
water heating systems (Combo Systems).
Combo heating systems use the home’s
water heater or boiler to provide both space
heating and domestic hot water, eliminating
the need for a furnace.
Combo heating systems are ideally suited for
single family homes, townhouses and
apartments where the use of a furnace may
not be feasible or where space requirements
are limited. They can also be used for
additions, renovations, and finished
basements as a replacement for, or in
addition to the existing heating system. Our
air handlers are the smallest units available
in their capacity range.
We provide you with the quietest operating
air handler available. By using large capacity,
high output heating coils, our product
delivers more heating per volume of air than
any of our competitors, which means warmer
delivered air temperatures. Our blower fans
are also the widest available in their size
range, which translates into slower fan
speeds to deliver the same amount of air. All
these features add up to warmer, more
comfortable air, quiet operation, and a
satisfied customer.
Water heaters, boilers and air handlers can
be purchased from a wholesale supplier,
rented from your Gas Utility, or purchased
from Airmax Technologies as part of a
complete heating package.
Benefits of the MaxAir(e)™Low Velocity
systems are:
Very little maintenance required.
Can be installed in existing structures with
minimal structural changes.
Provides a quiet, draft free environment.
MaxAir(e)™Low Velocity systems
applications:
Retrofit construction to add heating,
cooling, humidification, or filtration to a
building.
New construction to deliver air throughout
the entire building envelope.

Page 6
PRODUCT DESCRIPTION .
cabinet
All cabinet panels are insulated and have a
tough, durable low maintenance galvanized
finish inside and out for extra long life.
The air handler can be suspended with 4
resilient hanging straps. Hanging straps can
be secured at all corners, using existing
screw locations without fear of damaging
internal components.
Cabinet dimensions are designed to provide
maximum installation flexibility. Refer to
installation requirements for more details.
heating coils
All heating coils are potable water grade
copper suitable for use in plumbing systems.
No lead solder is used in any component
construction. All coils and internal piping
conform to ASTM B68 or ASTM B88
standards.
High density aluminum fins provide maximum
heat transfer for small coil surface. Lower air
flow and higher fin density equals warmer,
more comfortable air with much less fan
noise than other air handlers.
cooling coils
All Airmax accessory slab cooling coils are
shipped with the liquid and suction lines
piped to the exterior of the unit casing. A TX
valve where included, is shipped installed.
High density aluminum fins provide maximum
heat transfer for minimal coil surface. Coils
are sized for low face velocities to prevent
carry over and the galvanized unit drain pans
are below the entire coil including the return
bends and suction header.
fan (standard unit)
All fans are wide body dynamically balanced
for extra quiet operation.
Three speed motors allow for separate
speeds for heating, cooling, and continuous
run, providing the installer or home owner
maximum choice of options.
Multi-directional sleeve bearing motors allow
mounting in any direction for maximum
installation flexibility.
fan (e unit)
Variable speed motors allow for discrete and
selectable speeds for heating, cooling, and
continuous fan, providing the installer or
home owner maximum choice of options.
off-season circulation
An off-season circulation cycle is included on
the air handler to provide periodic circulation
of water through the space heating loop
during periods of infrequent use.
water heater
Any properly sized gas, propane, or oil fired
water heater will work in a combo heating
system. Make sure the water heater being
used is approved for combo applications.
(Most manufacturers’ heaters are approved.)
Warranties are typically not affected by using
a water heater in combo applications.
boiler
All Airmax Technologies combo air
handlers are compatible for use with boilers
or instantaneous water heaters. Contact your
Airmax Technologies representative for
specific installation details.

Page 7
ACCESSORIES .
check valve
Check valves serve two purposes:
protect against back-flow of water to
avoid short circuiting around the water
heater during domestic water use.
protect against thermal siphoning.
Thermal siphoning is flow of water through
the space heating circuit while the circulating
pump is not operating due to hot water rising
by natural convection. This phenomenon is
of little consequence during winter months,
but during the summer this will cause
overheating, interfere with air conditioning,
and waste energy.
The check valve is supplied an integral part
of the circulating pump.
circulating pump
Air handlers come with external, field
installed pumps, for flexibility and service.
The circulating pump is matched for
maximum performance for combo use
utilizing a storage type water heater. Contact
your Airmax representative for applications
other than storage tanks.
flow control valve
An adjustable flow control valve is
recommended to optimize system
performance and ensure that the output from
the water heater is stable. Any throttling type
valve may be used, but for convenience,
AirMax can include a valve, at additional
cost, with each air handler for field
installation.
Combo heating systems function poorly if the
temperature drop through the air handler’s
coil is not maintained between 20-30°F (11-
17°C). The only way to adjust the water
temperature drop through the coil to match
the rated output conditions of the coil is to
adjust the flow of water.
The performance relationship between the air
handler and the water heater is ignored by
most manufacturers. The MaxAir(e)™
combo fan coil system has been specifically
designed to optimize the output of the water
heater to which the air handler is attached.
If the temperature drop is less than 20°F
(11°C), the system has an excessive flow
rate. This will cause turbulent mixing
within the water heater storage tank,
reducing the domestic water capacity,
and creating large fluctuations in
delivered water temperature.
If the temperature drop across the heating
circuit is greater than 30-40°F (17-22°C)
there is inadequate flow. This will cause
poor heating performance of the air
handler and can cause stacking of the
water heater leading to unsafe water
delivery temperatures for domestic use.
EQUIPMENT SELECTION AND SIZING .
This section of the manual is to assist the
designer of the MaxAir™ Low Velocity fan
Coil System in the size and location of the
fan coil. To size an MaxAir™ system for a
residence, it is necessary to have an
accurate heat loss/gain done for the structure
in order to eliminate improper sizing.
After completing the room by room load

Page 8
calculations, select the MaxAir™ model unit
that will properly meet the load requirements. .
Table 1 Unit Performance Ratings
Model
MaxAir 30 LV
MaxAir 30e LV
Btuh Heating @180F E.W.T.
48,393
46,236
Btuh Heating @170F E.W.T.
43,938
41,983
Btuh Heating @160F E.W.T.
39,488
37,735
Btuh Heating @150F E.W.T.
35,045
33,492
Btuh Heating @140F E.W.T.
30,610
29,257
Btuh Heating @130F E.W.T.
26,186
25,031
DX Cooling (Tons) (1)
1
1
C.F.M. @ 0.5" E.S.P.
450
425
HP-RPM
¼-1,075
1/3-1,250
FL Amps @ 120/1/60
5.4
5.3
G.P.M. Flow rating
5
5
Fan Coil Size (L/W/H)
24"x14"x18 1/2"
24"x14"x18 1/2"
Supply Air Size
11" x 15 ½”
11" x 15 ½”
Return Air Size Required
12" x 14" min.
12" x 14" min.
Model
MaxAir 50 LV
MaxAir 70 LV
MaxAir 100 LV
Btuh Heating @180F E.W.T.
60,047
79,316
122,103
Btuh Heating @170F E.W.T.
54,496
71,780
110,753
Btuh Heating @160F E.W.T.
48,953
64,428
99,427
Btuh Heating @150F E.W.T.
43,422
57,098
88,132
Btuh Heating @140F E.W.T.
37,904
49,795
76,875
Btuh Heating @130F E.W.T.
32,404
42,523
65,664
DX Cooling (Tons) (1)
1 to 1.5
2
3
C.F.M. @ 0.5" E.S.P.
600
850
1300
HP-RPM
1/4-1,075
1/3-1,075
1-1,075
FL Amps @ 120/1/60
5.1
7.0
12.0
G.P.M. Flow rating
5
7
8
Fan Coil Size (L/W/H)
24"x14"x18 1/2"
30"x19 1/2"x18"
30"x25 1/2"x18"
Supply Air Size
11" x 15 ½”
15" x 16 ½
15" x 22 ½
Return Air Size Required
12" x 14" min.
16" x 15" min.
16" x 16" min.

Page 9
Model
MaxAir 50e LV
MaxAir 70e LV
MaxAir 70e LV
HO
Btuh Heating @180F E.W.T.
72,850
95,496
103,541
Btuh Heating @170F E.W.T.
66,085
86,566
93,833
Btuh Heating @160F E.W.T.
59,334
77,662
84,156
Btuh Heating @150F E.W.T.
52,601
68,790
74,518
Btuh Heating @140F E.W.T.
45,888
59,957
64,924
Btuh Heating @130F E.W.T.
39,202
51,169
55,386
DX Cooling (Tons) (1)
1.5 to 2
2 to 2.5
2.5 to 3
C.F.M. @ 0.5" E.S.P.
830
1,050
1,200
HP-RPM
1/2-1,750
1/2-1,750
3/4-1,750
FL Amps @ 120/1/60
7.7
7.7
9.9
G.P.M. Flow rating
5
7
7
Fan Coil Size (L/W/H)
24"x14"x18 1/2"
30"x19 1/2"x18"
30"x19 1/2"x18"
Supply Air Size
11" x 15 ½”
15" x 16 ½
15" x 16 ½
Return Air Size Required
12" x 14" min.
16" x 15" min.
16" x 15" min.
Model
MaxAir 100e LV
MaxAir 100e LV HO
Btuh Heating @180F E.W.T.
136,268
153,390
Btuh Heating @170F E.W.T.
123,548
139,150
Btuh Heating @160F E.W.T.
110,862
124,941
Btuh Heating @150F E.W.T.
98,216
110,768
Btuh Heating @140F E.W.T.
85,621
99,791
Btuh Heating @130F E.W.T.
73,087
82,565
DX Cooling (Tons) (1)
4
4
C.F.M. @ 0.5" E.S.P.
1,700
1,600
HP-RPM
1-1,800
1-1,800
FL Amps @ 120/1/60
11.6
11.6
G.P.M. Flow rating
8
8
Fan Coil Size (L/W/H)
30"x25 1/2"x18"
30"x25 1/2"x18"
Supply Air Size
15" x 22 ½
15" x 22 ½
Return Air Size Required
16" x 16" min.
16" x 16" min.
(1) Smaller condensers maybe matched to fan coil when required ( match TXV to condenser size)
Selecting the fan coil
Once the heat load and the corrected
number of outlets required is known for the
job you can then finalize the model of the
MaxAir™fan coil(s) you need.
supply air duct design notes
The supply air is to be sized based on the
available static pressure, and as per local
building codes and good practices.

Page 10
return air duct design notes
The return air is to be sized as per local
building codes and good practices. It is good
design practice to line the first five feet of the
return air duct with a sound acoustic
insulation. This will reduce sound transfer
through the duct and operating sound levels.
It is recommended to install a grill which is
10-20% larger than the return duct area to
ensure adequate free area and no velocity
noise at the grill. Where allowed by local
codes, a single return air grill may be used.
When using flexible duct for return air, use
one size larger duct due to the higher friction
loss.
For areas that require fresh air make-up
(either direct or through an ERV or HRV), an
intake may be installed in the system. Size
and insulate the fresh air supply as per local
code. Remember, should you install a duct
that is too large, the excess fresh air will
increase the system operating cost and
effect overall equipment capabilities. It is
recommended to install a well fitted damper
into the return air plenum. The damper can
then be adjusted to supply the exact amount
of fresh air needed to meet local building
codes.
indoor air quality
The main factors of indoor air quality are air
filtration, humidity control, and fresh make-up
air. All of these factors can best be achieved
with a continuous run fan system. It is
important to have a good quality air filter for
your MaxAir™fan coil system. Maintaining a
clean air filter will increase the unit life span,
allow the unit to operate efficiently and
effectively, and will provide clean air for the
occupants.
Humidity control is also an important factor to
indoor air quality. It is acceptable to install a
humidifier following the manufacturers
installation requirements.
combination MaxAir™ and hydronic
heating
One of the benefits of using a hydronic
system is the versatility that you have when
designing the heating system. Radiant
underfloor heating is an excellent system, but
it does have limitations. You cannot have
cooling, air filtration, and humidification with a
radiant heating system.
It is in rooms such as this that a hybrid
system of both radiant heating and a
MaxAir™fan coil would be the optimum
system to provide comfort conditioning. This
will provide the homeowner with good indoor
air quality, and warm floor comfort.
One of the most common approaches to
heating with a hybrid system is using the
MaxAir™fan coil to provide the comfort
conditioning for the main floor (and second
floor if applicable) and radiant tubing in the
basement and tile areas. A few outlets
located in the basement is recommended in
order to provide good air circulation and
supplementary heating if required.
low water temperature systems (combo
systems with conventional hot water
tanks + geothermal sytems)
Operating MaxAir™fan coils in a low
temperature system, care must be taken
when designing and installing the system.
Due to the lower air temperatures, when
installing ductwork in an unconditioned
space, extra insulation is recommended in
order to maintain a consistent air
temperature at the outlets. The main supply
plenum must be insulated and wrapped with
a vapor barrier in order to meet local codes.
All duct work should then be covered with
another layer of insulation. Due to the fact
that with lower water temperatures you get a
lower supply air temperature, it is imperative
that the water temperature is known at the
design stage. If possible, a higher tank
setting should be used, and an anti-scald
valve be installed for the domestic use. The

Page 11
higher water temperature will increase
system capacity, and the anti-scald valve will
reduce the risk of scalding. Since some
areas have specific regulations regarding
combo systems, check your local building
code for details on water tank temperatures,
tempering valves, and pump timers.
cooling coil capacities
Possible cooling coil capacities are given in
the Table 1.
INSTALLATION .
The installer must adhere strictly to all local
and national code requirements pertaining to
the installation of this equipment.
Detailed instructions are shipped with all
accessory items and should also be followed
in detail.
air handler mounting
The MaxAir(e)™combo air handler can be
installed in most configurations. Some
precautions must be observed for some of
the possible mounting positions.
For installations where the access door faces
up or down ensure the external circulating
pump is not mounted with its shaft in the
vertical position. The pump shaft must be
mounted horizontally to avoid damage during
operation.
The air handler can be mounted by securing
straps through any of the existing screw
holes in the cabinet. Should the existing
screw be too short for securing a mounting
strap, a longer screw can be used provided
care is taken not to damage any internal
components.
When fastening straps using screws, special
care should be taken in the vicinity of the coil
to avoid tube puncture.
The cabinet is designed so that the return air
can be located on either side of the cabinet,
through the bottom of the cabinet, or from the
back. Position the filter rack so that the filter
is readily accessible.
Install the air handler with the door firmly
screwed in place to make certain the cabinet
is mounted without racking. Provide at least
24 inches of service access clearance in
front of the access panel of the air handler.
zero clearance is acceptable on all other
faces.
domestic water piping
Install a ½”(12mm) sediment faucet for use
as a drain/purge valve. The drain valve must
be located downstream of the pump and
check valve, and upstream of the isolation
valve (if isolation valve is present). This
arrangement will allow any air trapped in the
system to be easily flushed out. Follow the
instructions in the Start-up & Troubleshooting
sections.
Isolation valves are recommended, but not
required. Installing isolation valves facilitates
easy servicing and ensures positive purging
of the system during start-up.
The isolation valves, if installed in the system
should not be used as a throttling valve.
All joints in copper pipe must be lead free
solder. All piping must be suitable for potable
water use. All pipe & pipe connections shall
comply with local building codes.
When soldering, special care should be
taken to not overheat the water connections
on the unit. Use a wet rag or heat absorption
compound to prevent excessive heat buildup.
Maximum pipe lengths for all MaxAir(e)™
combo air handlers can be calculated using
the information in the Design Manual.
When both top and side connections are
provided on the water heater,

Page 12
recommendations of the manufacturer or
supplier should be followed regarding
connection.
When the space heating loop connections
are made to the domestic water connections:
the heating loop connections should be
positioned horizontally in a vertical
section of the domestic water line for both
inlet and outlet. Refer to the suggested
piping schematic for details.
connect the heating loop to the domestic
water connections as close to the water
heater as possible.
Avoid sections of pipe in the heating loop
that can trap air where possible.
It is usually impossible to install a system
without having at least one part of the system
or heating coil able to trap air. This will not be
a problem if the connection to the domestic
water lines is made properly, and the system
is properly purged on set-up:
The circulating pump is capable of
removing small amounts of entrained air
from the heating loop.
Following the flushing procedures in the
Start-up section will ensure that there is
no air in the system after initial set-up.
Proper connections between the
domestic water lines and the heating loop
will ensure that any air that collects in the
water tank, does not make its way into the
heating loop.
Inclusion of air bleed valves at high points of
the heating system can be included but are
to be specified by the plumbing designer.
cooling coil & TX valve
The Airmax accessory slab cooling coil is
shipped loose. A factory installed TX valve
where applicable, is shipped with the cooling
coil. The TX valve is installed onto the
distributor and an external equalizing line is
piped into the suction line. Detailed
instructions on the TX valve and the location
of the external equalizing line and sensing
bulb are available from your MaxAir™
dealer.
When brazing care should be taken to not
overheat the connections on the coil. Use a
wet rag or heat absorption compound to
prevent excessive heat buildup.
Once the brazed connections cool down,
apply a bead of silicone sealant to the copper
pipes where they pass through the rubber
grommet. This will prevent air leaks and air
noise.
The MaxAir(e)™fan coils with the accessory
external cooling coil option are a draw
through design. The drain pans have to be
trapped to avoid air losses. The proper
height of the trap is 2 times the internal static
in the unit casing. For most applications a
trap height of 3" is acceptable. This is the
minimum distance between the trap outlet
and the bottom of the trap. The trap inlet
should be higher than the outlet to allow for
proper drainage.
Important:Fill trap with water before running
the unit.
It is acceptable to vent the trap in situations
with insufficient height and clearance.
In applications where a fan or motor body
block the cooling coil face a space should be
left between the cooling coil discharge face
and the fan coil to avoid excessive and
uneven coil velocity.
water heater/boiler
Follow the water heater manufacturer’s
instructions for installation and start-up of the
water heater. Make sure the water heater is
turned off during air handler installation and
service. Ensure the water heater has been
refilled, and all air is purged from the system
before turning on the water heater.
duct work
To minimize fan noise in the living space, it is
recommended that the first five feet of return
air duct be lined with acoustic insulation,

Page 13
when the duct directly communicates with the
living space.
Return and supply air duct work should be
the same size as the air handler openings up
to the first branch, fitting or transition.
Warning! Special care should be taken in
the vicinity of the coil to avoid tube puncture.
Screw into opening flange instead of top of
cabinet when fastening the supply air duct.
Engineered duct design guidelines are based
on a nominal external static pressure of 0.5”
wc.
fan coil placement
The MaxAir(e)™fan coil unit is to be placed
according to the layout supplied by the
designer. If a change in location is required,
the person responsible for the design is to be
consulted. The fan coil unit can be located in
a horizontal or vertical position.
The location of the fan coil is not as critical
as it is with conventional low velocity
systems. Location of the fan coil unit will
depend on:
Minimizing all duct runs.
Maximizing usable floor space.
Reducing structural changes.
Serviceability and access to the unit.
Location of heat/cool source to fan coil.
Available space in mechanical room.
When suspending the unit from the ceiling, it
is recommended to use spring vibration
isolators at each corner of the fan coil unit.
This will provide a secure means of hanging
the unit, and will also reduce any transfer of
vibration into the building structure. Rubber
belting is also acceptable. Another common
means of suspending the fan coil is with
angle iron, sheet metal channel, or uni-strut
placed underneath the unit, and supported by
threaded rod. If this method is used, isolators
(rubber or equivalent) must be placed
between the fan coil unit, and the support.
Ensure that the hanging method does not
hinder any piping, electrical runs, filter
access, or blower access.
trunk duct
Inspect the location for the trunk duct as per
the duct layout for the home or building. An
important consideration in placement of the
main supply plenum is that the fan coil unit
must be connected to the main supply
plenum. Therefore, it is necessary to have a
clear path from the fan coil unit to the main
supply plenum.
branch ductwork
After securing the take-off to the trunk duct,
be sure to eliminate any air leaks.
airflow
Once all the ducts are installed, the airflow
from the vents should be checked. If you
have vents that are not blowing strongly,
there are a few things to check. Make sure
that the branch duct is not blocked. Check for
air leaks in the ducts, and seal all leaks with
tape or duct sealant, as per local codes.
condensation
On units supplied with an Airmax Accessory
slab external cooling coil, a drain connection
is provided on the cooling coil. A drain line,
with a trap must be installed (the size of the
trap is discussed in the previous section). For
cooling installations where the fan coil unit is
installed in hot, humid areas, condensate
may form on the outer cabinet of the unit.
When this potential exists, a secondary drain
pan should be installed under the entire unit.
This pan should also extend under the piping
connections and TX valve. This is especially
critical in attic installations where condensate
can cause damage to the ceiling
DX refrigerant cooling
When installing the fan coil, either in the
horizontal or vertical position, make certain

Page 14
that the unit is installed level in order to
handle condensate drainage. The
condensate drain should be trapped, and the
drain line sloped toward the drain at a 1/4"
per foot slope. Ensure that no screws
puncture the drain pan.
The Airmax Accessory slab coil must be
installed in a vertical position (horizontal
airflow through the coil) or condensate
drainage problems will result. It is acceptable
use a field supplied “A” type evaporative coil .
Some building codes call for a secondary
drain pan under the entire unit. Check local
codes for more information. Any installation
that has the potential of property damage
due to condensate should have a secondary
drain pan installed. If the unit is installed in a
high heat and/or humidity location, extra
insulation around the unit casing may be
required to prevent excessive condensate
from forming on the outer surface of the
casing. Install the unit so that there is
adequate clearance on all sides for service
and for piping runs.
When connecting the refrigerant lines to the
cooling coil, installations instructions with the
coil should be followed. It is also
recommended, but not mandatory that you
install a site glass and filter/drier at the
condensing unit, as well as both high and low
side access ports. This is useful for both the
system setup, and for future trouble shooting.
Care must be taken when mounting the
Airmax Accessory slab coil directly to the
side of a Airmax vertical airflow fan coil. This
is acceptable only on the side of the fan coil
opposite the fan motor end. If mounting the
coil on the side where the end of the fan
motor is located use a short spacer fitting to
move the coil face away from the back of the
motor housing. Failure to do so will cause
excessive or non-uniform velocity across the
coil surface and may cause condensate carry
over into the fan coil cabinet.
condensing unit
Locate the outdoor unit in a suitable location,
as close as possible to the fan coil. Maintain
the clearances recommended by the
condensing unit manufacturer’s installation
manual to ensure proper airflow. The outdoor
unit must be installed in a level, properly
supported location. A sight glass and liquid
line filter/drier is recommended but not
mandatory.
freezestat and TX valve
MaxAir™accessory DX evaporator coils
come with an anti-ice control frost thermostat
(see appropriate wiring diagram) installed on
the suction line. Ensure that the TXV bulb
and the frost thermostat control are fastened
securely and are well insulated. DO
NOT use a self-tightening clamp on the frost
thermostat as excessive tightening may
damage the thermostat.
The remote sensing bulb for the TX valve
should be located on a clean, horizontal
section of the suction line. It should be
mounted on the top half of the pipe in the 2
o’clock or 10 o’clock position.

Page 15
evaporator coil assembly
1) Liquid line
2) Site glass (not Supplied)
3) High side access port
4) Adjustment stem cap (not applicable)
5) Superheat adjustment stem (not
applicable)
6) Thermal expansion valve(TXV)
7) Refrigerant distributor
8) Distributor tubes
9) External equalizer line
10) Suction line
11) Anti-ice control (Frost thermostat)
12) Low side access port
13) TX capillary tube
14) TX sensing bulb
refrigeration piping
Use only refrigerant grade pipe and fittings.
Plumbing fittings may contain wax or other
contaminants which are detrimental to the
proper operation of the system. Insulate the
suction line as per condenser manufacturer’s
instructions
Install the refrigeration lines as per local
codes and good piping practices, supporting
the pipe every 5 feet. Run the pipes in the
most direct route possible, taking into
account structural integrity and building
finishing details. If the evaporator is located
above the condenser, slope any horizontal
runs toward the condenser and provide a
trap at the evaporator to prevent liquid
migration during the off cycle. If the
condenser is located above the evaporator, a
trap must be installed in the suction line at
the bottom of the vertical riser. For long
vertical risers, additional traps must be
installed for every twenty feet. For lines
running over 50', a suction line accumulator
must be installed. Lines running over 100'
are not recommended.
Flow nitrogen at a low pressure through the
piping when welding to prevent oxidation.
condensing unit wiring
Make all connections to the outdoor unit with
liquid tight conduit and fittings. Most building
codes require a rain tight disconnect switch
at the outdoor unit as well. Run the proper
size wire to the unit, and connect as per the
manufacturer’s recommendations. Ensure
that the unit is setup for a TX valve system. If
not, a hard start kit may be required.
evacuating and charging
After the piping is installed, and all
components connected, pressurize the
system and check for leaks. The use of an
electronic leak detector is recommended, as
it is more sensitive to small leaks under the
low pressures commonly used for initial leak
detection.
Fill the system with nitrogen to 100 psig and
test for leaks. Using a good, quality vacuum
pump, evacuate the system from both the
low and high side of the system to 500

Page 16
microns and ensure that the system holds at
the vacuum pressure. If not, check for leaks
and evacuate again. If the vacuum is
maintained, add refrigerant to raise the
pressure to 2 psig, and either open the
service valves (suction first) on pre-charged
condensing units, or add refrigerant to the
system until the proper operating charge is
obtained.
ELECTRICAL (STANDARD UNITS) .
Warning! - All air handlers operate on
115v/1ph/60hz line voltage. All control
circuits are 24 volt. Make certain the
MaxAir™unit is properly grounded.
Locate air handler on a separate electric
circuit as per local electrical
codes.thermostat
The MaxAir™series air handlers are
compatible with any standard heat/cool, heat
pump, “electric heat”, “gas heat”, set-back or
electronic thermostat.
Thermostat Heat
Anticipator Setting
0.04 amps
Thermostats without cooling: do not connect
the yellow wire at the air handler.
Thermostats without continuous run switch
(fan ON): do not connect the green wire at
the air handler.
electrical information
The MaxAir™air handler wiring diagrams are
located inside of the main access panel on
the control panel for easy reference during
installation.
Nameplate data is located on the exterior
face of the blower door.
For other electrical details and schematics,
please contact your MaxAir™representative.
NOTE: Total accessory amp draw must not
exceed 1.0 Amp per CSA 236, C.l. 36.12.
connection locations
A terminal strip located inside the control
panel is provided for the following electrical
connections:
Main power connection
Circulation pump
Thermostat
Condensing unit
Heating accessory
Cooling accessory
changing motor speed settings
MaxAir™air handlers are equipped with
three speed motors.
Factory settings are:
Cooling speed = high
Heating speed = high
Continuous run = low
Motor speeds for cooling, heating or
continuous run are all field selectable, in any
combination.
Changes to motor speeds are made at the
unit control panel.
Warning! All connections are clearly marked.
It is acceptable to put two or more fan relay
connections under one terminal lug. (The unit
comes factory set with both the continuous
run and heating speed relay connections
under the motor low speed terminal lug.) Do
not use jumpers between terminal lugs.
Connecting two or more motor taps together
will result in immediate motor failure and
possible fire hazard.

Page 17
PSC MOTOR CONTROL BOARD
Figure 1 - Connection Locations
ELECTRICAL (MAXe UNITS) .
The DCC7235 is a microcontroller-based electronic volume controller for brushless dc motor-driven fan coils,
furnaces or other systems. It commands discrete or variable blower speeds, torques or airflow in heating,
cooling and ventilation modes from inputs provided from a discrete or proportional thermostat or controller
whose switched 24VAC signal outputs activate a blower's air volume. Discrete output blower command values
are selected and scaled from tables, individually selected by dip-switches. One controller can be used with
several different products of different capacities. An on-board dip-switch optionally selects a 0-10V input for
variable/proportional volumecontrol.TheDCC7235canbeusedwithproportional,1-stage HEAT/COOL, 1or2-
Stage COOL, and 1 or 2-Stage HEAT thermostats.
Five relay contact outputs are available for activating accessories. Two are high voltage, dry contacts. Three
others switch the 24VAC (“R”) powering the controller. One of those three can be isolated from “R” by removing
a shunt and providing 24VAC dry contacts.

Page 18
DCC7235 LAYOUT
FIG 1
FIG 1
1. POWER:
24VAC (nominal) supplied by a Class II transformer between terminals "R" (“24VAC LINE”) and "C"
(“24VAC RET”). The RED “POWER” LED illuminates when the control is powered.
Transformer rating: 20VA minimum
Voltage: 22.5Vac Minimum, 30Vac Maximum
Current: <100ma (All outputs and relays active)
NOTE: SUPPLY 24VAC POWER FROM THE SECONDARY OF AN NEC CLASS-2
TRANSFORMER ONLY.
2. CONTROL SYSTEM INPUTS
a.) 0-10vdc Command —When SW3-1 “TEST” is ON, a 0-10 VDC input to J2 between Vin+ and
Vin–produces a variable PWM output of 0% through 100%. The polarity of the input signal
must be observed. See Figs 1 & 2:
Differential Input Voltage: 0 V to 10 VDC represents 0 to 100% PWM
Maximum Input V dc: +10.2 Vdc
Common Mode Voltage: - 0.2 V max negative, +5 V max positive
Signal (differential) Input impedance: >150K Ohm (Vin+ to Vin-)
Common mode impedance: > 150K Ohm to COM

Page 19
ON/OFF: ON = input VDC > 0.5VDC +/- 0.1V
OFF = input VDC <0.4VDC +/- 0.1V
FIG 2
b.) Switched 24VAC INPUTS (SW3-1 IN "DISCRETE POSITION": (see para. 5.)
G –Fan Only MODE
Y2 &O &G –HIGH COOL MODE
Y1 &O &G –LOW COOL MODE
W1 –1st STAGE HEAT MODE
W2 –2nd STAGE HEAT MODE
Y1 &G & NOT O–Low Stage Heating (with Heat Pump)
Y2 &G & NOT O–High Stage Heating (with Heat Pump)
D –Accessory Control (Dehumidifier, Aquastat, etc). D is connected to ”R”
when shunt H5 is in place. Remove H5 to control the D terminal by an
external switch.
b.1.) INPUTS SPECIFICATIONS
Input Impedance:
Y1 and Y2
~1K Ohm between: each terminal to C(24VAC Return).
Minimum acceptable cooling anticipatorresistance: 3.3KOhmsbetween24Vac(R)to Y1
or Y2
All other inputs:
>10K Ohm between each terminal and C(24VAC return).
Load Current FORM FACTOR —All Inputs: PositiveHalf-Wave(withrespecttoC(24VAC
RTN)
MIN AND MAX INPUT VOLTAGE –All 24VAC Inputs:
Signals ACTIVE: 20VAC minimum. 30VAC Maximum; Current: <15ma @30VAC.
Signals INACTIVE: <4VAC (Current from any signal source, switch, and/or external
snubbers must hold inputs to <4VAC or DC)
NOTE: DO NOT CONNECT THE SWITCHED 24VAC INPUTS FROM A 2nd, SEPARATE
TRANSFOMER THAN THE 24VAC SOURCE SUPPLYING POWER TO THIS CONTROL
UNLESS THE TRANSFORMER SUPPLYING THIS CONTROL AND THE 2ND
TRANSFORMER ARE PHASED PROPERLY WITH THEIR COMMONS CONNECTED.
3. OUTPUTS
A. CONNECTIONS TO EC MOTOR (ECM): J3 PIN-OUTS

Page 20
(SEE FIG 3):
J5–pin-1: START/STOP: When the Blower motor is commanded to operate this signal
enables motor operation. (Use is optional. Use if the system requires a separate
enable.)
0VDC = not enabled, 22VDC (nom) = enabled
10ma maximum sourced current.
J5–pin-2: COMMON –J5 Outputs Common (to isolated common input(s) on motor/drive).
DO NOT CONNECT COMMON TO 24VAC RET
J5–pin-3: PWM Motor Command: 0% to 100% duty-cycle.
OFF: 0VDC (min). ON: 22VDC (peak). 10ma max sourced current.
When measured on a DC voltmeter, the signal level varies from 0VDC to ~22VDC
max as the percent PWM duty cycle increases from 0 to 100%.
The Green LED “BLWR CMND” illuminates when the PWM command is active.
Brightness increases with PWM duty cycle.
J5–pin-4: NO CONNECTION
B. HIGH VOLTAGE RELAY OUTPUTS:
a. A1, A2, A3 (PUMP) Relay (Formerly “WV RELAY”)
Contacts A1 (NO), A2 (NC) to A3 (Pole): A3 is “Dry” and can be connected to an external
voltage source for switching to A1, A2.
The WV Relay is energized under the following conditions:
1) SWITCH “PUMP TMR ON” POSITION, AND
2) Upon detecting a call for W1 or W2 (no delay) OR
3) If W1 or W2 was not active for 6 (or 24) consecutive powered hours.
The green “W_TIMER” LED illuminates when the PUMP relay is activated.
b. ACCESSORY Relay (ACC, ACCp):
Contact ACC (NO) connectsto pole ACCp. These are DRYContacts and can be connected
to an external voltage source.
The Accessory relay is energized with "G". i.e. Any call from the thermostat that includes
an active "G" signal energizes this relay.
c. MAXIMUM CONTACT RATINGS:
8A @120 VAC (resistive)
8A @ 240 VAC (resistive)
C. LOW VOLTAGES RELAY OUTPUTS:
All Three low voltage relaycontacts are rated 1AMP maximum @ 30VAC maximum.
a. "X1" LOW STAGE "Y" RELAY (Contact X1):
i. The LOW Stage Y relay activates upon detecting a call for “Y1” (with or without
“O” active).
ii. Upon activation, the X1 terminal connects to "R" (the 24VAC powering the
DCC7235). This relay is NOT DRY; i.e. its pole is permanently connected to
“R”.
b. "X2" High Stage "Y" RELAY" (Contact X2):
i. The HIGH Stage Y relay activates on a call for Y2 (with or without “O” active.
ii. On activation, the X2 terminal connects to "R" (the 24VAC powering the
DCC7235). This relay is NOT DRY; i.e. its pole is permanently connected to
“R”.
c. “Z” RELAY" (Contacts Z1, Z1p):
i. The Z1terminal switches to Zp on any