Airmark GEW Series Manual

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©2017 AirMark
GEW SERIES
INSTALLATION & OPERATING INSTRUCTIONS
HIGH EFFICIENCY X13
VERTICAL WALL MOUNT AIR HANDLER
(ELECTRIC HEAT)
MODEL
(INCLUDING HEATER MODEL #) ________________________________
SERIAL #____________________________________________________
INSTALLER __________________________________________________
INSTALLATION DATE _________________________________________
These instructions should be retained and kept adjacent to the unit for future use
373 Atascocita Rd.
Humble, TX 77396
Phone [phone]
Fax [phone]
www.airmark-ac.com

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Safety Instruction
Potential safety hazards are alerted using symbol. The symbol is used in conjunction with terms that
indicate the intensity of the hazard.
 WARNING This symbol indicates a potentially
hazardous situation which if not avoided, could
result in serious injury, property damage, product
damage or death.
 CAUTION This symbol indicates a potentially
hazardous situation which if not avoided, may
result in moderate injury or property damage.
 WARNING Certified technicians or those
individuals meeting the requirements specified
by NATE may use this information. Property
and product damage or personal injury hazard
may occur without such background.
 WARNING All power sources should be
disconnected prior to servicing. Failure to do so
may cause personal injury or property damage.
 WARNING Product designed and
manufactured to permit installation in accordance
with local and national building codes. It is the
installer’s responsibility to ensure that product is
installed in strict compliance with national and
local codes. Manufacturer takes no responsibility
for damage (personal, product or property) caused
due to installations violating regulations. In
absence of local/state codes, refer to National
Electric Code: NFPA 90A & 90B Uniform
Mechanical Code.
 WARNING When this unit is installed in an
enclosed area, such as a garage or utility room
with any Carbon Monoxide producing devices (i.e.
automobile, space heater, water heater etc.)
ensure that the enclosed area is properly
ventilated.
 CAUTION Only factory authorized kits and
accessories should be used when installing or
modifying this unit unless it is so noted in these
instructions. Some localities may require a
licensed installer/service personnel.
 WARNING Unit is not approved for outdoor
installations.
 WARNING The unit is designed for operation
with 208/240 V, single phase, 60 Hz power supply.
Airmark will not be responsible for damages
caused due to modification of the unit to operate
with alternative power sources.
Inspection
On receiving the product, visually inspect it for any
major shipping related damages. Shipping
damages are the carrier’s responsibility. Inspect
the product labels to verify that the model number
and options are in accordance with your order.
Manufacturer will not accept damage claims for
incorrectly shipped product.
Installation Preparation
Read all the instructions in this guideline carefully
while paying special attention to the WARNING
and CAUTION alerts. If any of the instructions are
unclear; clarify with certified technicians. Gather all
the tools needed for successful installation of the
unit prior to beginning the installation.
This unit is designed for zero clearance installation
on three sides and adequate clearance to provide
access for service in the front. A min of 2.5 –3.5
feet clearance is recommended on the front end.
These units are designed to be installed on top of
a water heater or recessed into a wall. The unit
should be installed in Vertical Upflow position
ONLY. While installing the unit into a recessed
wall, attach unit to
"4"2 
framing stud along the
front flange. These air handlers are provided with
an offset hanging bracket at the rear for certain
wall mount applications.
The drain lines must be installed with ¼” per foot
pitch to provide free drainage. A condensate trap
MUST be installed on the primary drain line to
ensure proper drainage of the condensate. The
trap must be installed in the drain line below the
bottom of the drain pan. Fig.1 illustrates the typical
drain trap installation.
These units are equipped with a bottom primary
and secondary drain and a single side primary OR
secondary. When utilizing the unit, disable switch
on the secondary line. It must be located on the
side connection to avoid a false shutdown created
by condensate droplets falling into the bottom
secondary connection. The switch should be
adjusted to permit normal operation of the unit and
disable the unit in the event of a clogged primary

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before the condensate spills over the pan. In lieu
of this a hood may be field fabricated to slide over
the secondary to keep droplets out but allow
trapped condensate into secondary fittings.
 CAUTION Since coil is upstream of the
blower; all drains MUST be trapped or sealed.
Failure to do so will result in condensate overflow
from the drain pan. Airmark will NOT be
responsible for any damages resulting from failure
to follow these instructions.
2" MINIMUM
3" MINIMUM
FLEXIBLE
TUBING-HOSE
OR PIPE
A POSITIVE
LIQUID SEAL IS
REQUIRED
DRAIN
CONNECTION
Fig.1. Typical drain line trap set up
Ductwork
Duct systems should be installed in accordance
with standards for air-conditioning systems,
National Fire Protection Association Pamphlet No.
90A or 90B. They should be sized in accordance
with National Environmental System Contractors
Association Manual K, or whichever is applicable.
On any job, non-flammable flexible collars should
be used for the return air and discharge
connections to prevent transmission of vibration.
Although these units have been specially designed
for quiet vibration-free operation, air ducts can act
as soundboards can, if poorly installed, amplify the
slightest vibration to the annoyance level.
All main supply and return air drops should be
properly sized as determined by the designer of
the duct system and should not necessarily be the
size of the duct flange openings of the unit.
These models have a bottom or front return.
Discard the drain access panel in the bottom of
the unit if this is a bottom return application. In
case of a front return application, the front access
panel should be removed and discarded. If an
accessory grill as shown in Fig 2. is being used;
the front access panel should be removed and
discarded.
A filter rack is provided for
1"´20"´20"
nominal
size filter. Inspect and clean or replace fliter every
month. A blocked filter can reduce air flow to the
coil and hinder the performance of the system.
It is recommended that wherever supply and
return air sheet metal ducts pass through
unconditioned areas, they be insulated to prevent
excessive heat loss during heating operation.
When applied in conjunction with summer air
conditioning, sheet metal duct routed through
unconditioned areas should be insulated and have
an outside vapor barrier to prevent formation of
condensation.
Fig.2. GEW air handler grill and drain connections
Installation
 CAUTION Ensure that the unit is adequately
sized. The tonnage of the outdoor unit should
never exceed the tonnage of this unit.
 WARNING The coil was manufactured with a
dry nitrogen pre-charge. Release the pressure
through the Schrader valve test port prior to

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installation. If holding pressure is not present,
return coil to distributor for exchange.
Clean coil fins with degreasing agent or mild
detergent and rinse fins clean prior to installation.
All connection joints should be burr-free and clean.
Not removing the burr and cleaning may increase
the chance of a leak. It is recommended to use a
pipe cutter to remove the spun closed end of the
suction line.
To avoid damage to grommets (where present),
remove these prior to brazing by sliding over the
lines. Use a quenching cloth or allow the lines to
cool before reinstalling the grommets.
 CAUTION Some Airmark coils may include a
Schrader valve on the suction manifold. Ensure
that the Schrader valve and valve core (where
present) are protected from heat during brazing
and installation to prevent leakage.
Metering Device
Airmark coils are available with two kinds of
metering devices a) flowrator or b) TXV.
Instructions below are separated in sections
according to the metering device. Ensure that the
applicable section is thoroughly read and
understood.
Flowrator Coils:
PISTON
DISTRIBUTOR
TAILPIECE
13/16" NUT
TEFLON O-RING
Fig.3. Flowrator assy components
 CAUTION Use Piston sizes recommended by
the outdoor unit manufacturer whenever possible.
The piston should be sized according to the
capacity of the outdoor unit.
 WARNING Failure to install the proper piston
can lead to poor system performance and possible
compressor damage.
During some installations a piston change may be
required. If so the installer MUST change the
piston. As stated earlier, use piston sizes
recommended by the outdoor unit manufacturer. If
a sizing chart is not available, use Table 1 below
to size the required piston. The size of the piston
is stamped on the piston body.
Table.1. Piston Size Chart
Instruction for piston change
1) Turn the 13/16 nut once to release any
residual pressure in the coil.
2) After ensuring that the coil is free of any
residual pressure, disassemble the
flowrator body completely using two
wrenches. Distortion of the feeder tubes
should be avoided.
3) The wrench used to clasp the nut should
be turned in a counter-clockwise direction
to unscrew the nut.
4) Slide the 13/16 nut over the line set and
separate the two halves of the flowrator.
 CAUTION Pay close attention to the Teflon O-
ring. Be sure to replace the O-ring to attain a
proper seal. (The Teflon O-ring is located between
the two halves of the flowrator)
5) Pull the piston out using a small wire or
pick. Verify the piston size (size is typically
stamped on the body of the piston). If a
different piston size is required by the
Outdoor
Capacity
Orifice
Size–R22
Orifice
Size-R410A
12,000
0.041
N/A
18,000
0.055
0.049
24,000
0.059
0.055
30,000
0.068
0.059
36,000
0.074
0.068
42,000
0.080
0.074
48,000
0.084
0.080
60,000
0.092
0.089

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outdoor unit manufacturer replace the
piston using the small wire provided with
the piston kit.
 CAUTION Pay close attention to the piston
orientation. The pointed end of the piston
MUST go into the distributor body/towards the
coil. Failure to ensure this orientation will
cause the piston to be bypassed during
operation which might damage the outdoor
unit.
6) Assemble the two halves correctly and
ensure that the white Teflon O-ring is
present between the two halves.
7) Slide the 13/16 nut onto the distributor
body.
8) Tighten the nut to a torque of
approximately 10-30 ft-lbs. Do NOT over
tighten the nut. This will hamper the piston
movement during operation.
9) Slide the grommet back to position to
prevent air leakage.
TXV Coils:
 WARNING The sensing bulb and TXV body
MUST be protected from overheating during
brazing. The sensing bulb and TXV body must be
covered using a quench cloth or wet cloth when
brazing. Pointing the brazing flame away from the
valve and sensing bulb provide partial protection
only.
 CAUTION Ensure that the TXV selected is
compatible with the refrigerant used in the outdoor
system (R22 or R410A). TXV caps are painted
green for R22 or pink for R410A. In absence of
color, the caps will be marked with the compatible
refrigerant.
 CAUTION The valves should be sized
according to the capacity of the outdoor unit.
Failure to install the right valve can lead to poor
performance and possible compressor damage.
TXV Bulb Mounting
The orientation and location of the TXV bulb has a
major influence on the system performance.
 CAUTION Ensure that the TXV bulb is in
direct contact with the suction/vapor line. Gap
between the bulb and tube should be avoided.
Failure to do so will impair the proper functioning
of the TXV valve.
It is recommended that the TXV bulb be installed
parallel to the ground (in a horizontal plane). The
bulb position should be above and between 4
o’clock and 8 o’clock. Fig. 4 shows the
recommended position for the TXV bulb
installation in the horizontal plane.
The TXV sensing bulb SHOULD be mounted
using the metal clamp provided. In order to obtain
a good temperature reading and correct superheat
control, the TXV sensing bulb must conform to
ALL of the following criteria:
1) The sensing bulb MUST be in direct and
continuous contact with the suction line
2) The sensing bulb should be mounted
horizontally on the suction line.
3) The sensing bulb must be mounted above
and between the 4 and 8 o’clock position
on the circumference of the suction line.
4) The sensing bulb MUST be insulated from
outside air.
TXVBULBPOSITION
4O'CLOCKOR
8O'CLOCK
METALSTRAP
SUCTION/VAPORLINE
Fig.4. Recommended location of the TXV bulb in a
horizontal orientation
The mounting location and insulation guards the
sensing bulb from false reading due to hot outside
air or liquid refrigerant formed inside the
suction/vapor line.
As recommended earlier, the TXV sensing bulb
should be mounted in a horizontal plane in relation

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to the suction/vapor line. However, in case such a
mounting is not feasible and the sensing bulb has
to be mounted vertically; then place the bulb as
shown in Fig.5.
Fig.5. Figure showing the sensing bulb mounted in
a vertical orientation
 CAUTION If the TXV sensing bulb is mounted
vertically; the capillary MUST be directed upwards.
The bulb must be mounted on the wall opposite to
that being directly hit by the refrigerant and oil
leaving the distributor tubes.
Field –Installed Expansion Valve Coils
Remove the valve identification sticker from the
valve and place it adjacent to the Airmark model
number on unit name plate.
When installing an expansion valve, it is not
necessary to remove all the access panels and
slide the coil out of the housing.
1) Disassemble the flowrator body using two
wrenches. Unscrew the body with a
counter-clockwise motion.
2) Replace the white Teflon seal in place
(located between the halves).
3) Remove the existing flowrator piston using
a small wire or pick.
4) Inspect the TXV box to confirm that the
valve is compatible with the refrigerant in
the system.
5) Remove the valve from the box and note
the location of the inlet side (threaded
male port) and the outlet side (female
swivel nut port).
6) After ensuring that the white Teflon seal is
still in place inside the flowrator body,
screw the female swivel nut onto the
flowrator body.
7) Place the attachment nut on the liquid line.
8) Braze the stub-out portion to the liquid line
and let cool.
 WARNING Do not attempt to touch the braze
joint while hot. Touching it may cause sever burns.
9) Remove the additional white Teflon seal
ring from the box and place on the
shoulder just inside the inlet port. Screw
the nut attached to the stub-out portion of
the flowrator body onto the inlet port of the
TXV.
10) Tighten all connections taking care to use
proper back up.
Some Airmark coils come with a Schrader valve
on the suction line. If a Schrader port is present
11) Remove valve stem from the Schrader
port mounted on the suction line
12) Screw flare nut on TXV equalization tube
in to the Schrader valve stem
Coils without Schrader Ports
13) Locate a convenient spot on the suction
line and punch a ¼” hole with a pick or
other suitable tool.
 CAUTION Do NOT drill a hole as chips will
enter suction manifold.
14) Insert TXV equalizer tube approximately
3/8” into the hole and apply solder to seal.

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Fig. 6. shows the components of a typical TXV
assembly
TXV BULB
TAIL PIECE
DISTRIBUTOR
TEFLON O-RINGS
Fig.6. Components of a typical TXV assembly
 CAUTION Using a non-bleed expansion valve
may require the use of a hard-start kit. Follow the
outdoor unit manufacturer’s guidelines.
Electrical Installation
These units are designed for single or three phase
208/240 volts, 60 Hz power supply. Wire selection
and wiring must be in accordance with the
National Electric Code and/or local codes. Unit
terminals are designed to accommodate copper
and aluminum wirings. If aluminum wiring is used;
please observe special precautions relative to
sizing, wire connections and corrosion protection.
All models with 5, 8 or 10 kW electric heat are
arranged for single circuit connections. Models
larger than 10 kW are arranged for multi-circuit
protection. Fig. 7 shows the typical electrical
connections required for the air handler unit.
Fig.7. Typical electrical connections required
System Charging
 CAUTION An improperly charged system may
cause degradation in system performance and
damage the compressor.
After installation of the coil, refer to the outdoor
unit manufacturer for charging techniques and
amount of charge. If outdoor unit manufacturers
charging instructions are unavailable; then refer to
instructions below to charge the system.
1) Bring airflow up to the maximum CFM
possible according to Table 4 below.
2) Flowrator coils –Add refrigerant until the
superheat measured at the outdoor unit
suction/vapor line matches the superheat
listed in Table 2.
3) Expansion valve coils –Add refrigerant
until the subcooling measured at the
outdoor unit liquid line matches the
subcooling recommendation of the
outdoor manufacturer (typically 7º –10º
F). If chart is unavailable, charge unit to
a subcooling value of 8ºF +/- 1ºF.

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Outdoor Temp
°F D.B.
Superheat °F
Min
Nom
Max
65
35
40
45
70
31
35
39
75
26
30
34
80
22
25
28
85
17
20
23
90
13
15
17
95
8
10
12
100
4
5
6
Table.2. Superheat chart
Start up
After all connections are made, start-up and
check-up must be performed before proper
evaluation of the entire system can be made.
Make sure that heat anticipator is properly set as
noted on thermostat instructions.
Load requirements can vary in each residence and
it may be necessary for the installer or homeowner
to make slight adjustments to the heat anticipator
setting for longer or shorter cycles. It is
recommended to change the setting no more than
plus or minus 0.05 amps at a time. Greater
changes can cause the unit to rapid cycle or
remain on excessively. To properly check the
unit's operation, the installer should have an
electrical current measuring device (0-10 amp
Amprobe, Fluke), air pressure measuring device
(0-1.0 in slope gauge), and a temperature-
measuring device (0-200ºF thermometer).
Install the Amprobe to measure blower current, the
slope gauge to measure static air pressure at the
units and the temperature device to measure unit
supply and return air temperature. Before taking
measurements, be sure that all registers, grilles
and dampers are open or set to their proper
positions. Be sure that clean filters are in place.
Temperature measuring device must be installed
to obtain average temperature at both inlet and
outlet. For outlet, measure temperature of each
main trunk at a location far enough away to avoid
heater radiation and read the average
temperatures. Table 3 below shows the CFM that
should be achieved at various external static
pressures
Table 3. CFM delivered at various external statics
Electrical Heat Controls:
•Turn on power supply. Set thermostat fan
switch to on. Set the cooling indicator to
maximum, heating to minimum. System
switch may be on heat or cool. Check
slope gauge measurement against
appropriate air flow chart. Make damper,
register and motor speed adjustments to
obtain required airflow.
•Set thermostat fan switch to auto, system
to heat and thermostat heating indicator to
maximum heat. Blower should start and all
heat be energized.
•Check air flow using temperature rise
method.
 
RISETEMP
BTUHOUTPUT
CFM  08.1
NOTE: BTUH output should be computed by
VOLT x AMPS x 3.4 = BTUH OUTPUT. Since line
volt can vary, do not use nameplate rating to
determine output.
0.10
0.20
0.30
0.40
0.50
Tap 5
909
864
840
800
782
Tap 4
723
690
652
631
600
Tap 3
600
565
539
502
480
Tap 2
909
864
840
800
782
Tap 1
723
690
652
631
600
Tap 5
1365
1332
1303
1271
1240
Tap 4
1174
1132
1106
1078
1047
Tap 3
898
873
853
827
800
Tap 2
745
698
668
630
600
Tap 1
1365
1332
1303
1271
1240
GEW18-24
GEW30-36
SPEED
TAP
MODELS
230 Volt
CFM V. EXTERNAL STATIC

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OPERATION AND MAINTENANCE
Below are brief descriptions of the key
components of the unit and installation. This
manual only provides a general idea of the
components and recommended practices. The
installer should use best judgment to ensure safe
installation and operation of the unit.
1) Room Thermostat- This is the device that
controls that operation of your heating and/or
cooling unit. It senses the indoor temperature
and signals the equipment to start or stop
maintaining the temperature you have
selected for your comfort. The room
thermostat should be in a central, draft free
inside wall location for best operation. Do not
place any heat producing apparatus such as
lights, radio, etc., near the thermostat as this
will cause erratic operation of the comfort
system. The thermostat can accumulate dust
or lint which can affect its accuracy. It should
be cleaned annually.
2) Air Filter(s) - All central air moving comfort
systems must include air filter(s). These filters
will be located either in the equipment or in the
return air duct system upstream of the
equipment. The filter(s) removes dust and
debris from the air thus helping to keep your
air-conditioned space clean. More important,
the filter keeps dust and debris from collecting
on the heat transfer surfaces thus maintaining
optimum equipment efficiency and
performance. Inspect and clean or replace
filters every month. This routine maintenance
procedure will pay big dividends in reduced
operating cost and reduced service expense.
Never operate comfort equipment without
filter(s).
3) Fuses and/or Circuit Breakers- This comfort
equipment should be connected to the building
electric service in accordance with local and
National Electric codes. This electrical
connection will include over-current protection
in the form of circuit breakers. Have your
contractor identify the circuits and the location
of over-current protection so that you will be in
a position to make inspections or
replacements in the event the equipment fails
to operate.
4)  WARNING
a) Do not store combustible materials or use
gasoline or other flammable liquids or
vapors in the vicinity of this appliance.
b) Do not operate the comfort equipment with
panels removed.
c) Have your contractor point out and identify
the various cut-off devices, switches, etc.,
that serve your comfort equipment. There
is a main switch that will cut off energy to
your heating system. Know where they are
so that you may cut off the flow of energy
in the event of overheating.
5) Periodic Checkup and Service- This product is
designed to provide many years of
dependable, trouble-free comfort when
properly maintained. Proper maintenance will
consist of annual check-ups and cleaning of
the internal electrical and heat transfer
components by a qualified service technician.
Failure to provide periodic checkup and
cleaning can result in excessive operating cost
and/or equipment malfunction.
6) Lubrication- Direct drive blower motors are
equipped with permanently lubricated bearings
and do not require further lubrication.
7) Air filter replacement: An air filter can restrict
the airflow to the fan coil if it is not cleaned or
replaced periodically. When replacing the air
filter, always replace with the same type and
size as originally furnished with the unit.

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WARNING
HIGH VOLTAGE disconnect all power sources prior to servicing. Failure might lead to safety hazard
Wiring diagram for GEW models