This Whirlpool Job Aid, “Packaged Terminal Air Conditioners” (Part No. 8178315), provides the
technician with information on the installation, operation, and service of the Packaged Terminal Air
Conditioners . It is to be used as a training Job Aid and Service Manual. For specific information
on the model being serviced, refer to the “Use and Care Guide,” or “Tech Sheet” provided with the
air conditioner.
The Wiring Diagrams and Strip Circuits used in this Job Aid are typical and should be used for
training purposes only. Always use the Wiring Diagram supplied with the product when servicing
the unit.
GOALS AND OBJECTIVES
The goal of this Job Aid is to provide detailed information that will enable the service technician to
properly diagnose malfunctions and repair the Packaged Terminal Air Conditioners.
The objectives of this Job Aid are to:
•Understand and follow proper safety precautions.
•Successfully troubleshoot and diagnose malfunctions.
•Successfully perform necessary repairs.
•Successfully return the air conditioner to its proper operational status.
WHIRLPOOL CORPORATION assumes no responsibility for any repairs made
on our products by anyone other than Authorized Service Technicians.
CFM = Cubic Feet per Minute
COP = Coefficient Of Performance (applies to PTHP only)
1-3
WHIRLPOOL PACKAGED TERMINAL
AIR CONDITIONER (PTAC) AND PACKAGED
TERMINAL HEAT PUMP (PTHP) WARRANTY
LENGTH OF WARRANTY:
ONE YEAR FULL WARRANTY
FIVE YEAR FULL WARRANTY
SECOND THROUGH FIFTH YEAR
LIMITED WARRANTY
WHIRLPOOL WILL PAY FOR:
For one year from the date of installation, if this PTAC/PTHP fails
when operated and maintained according to instructions attached
to or furnished with the product, Whirlpool Corporation will pay for
replacement parts and repair labor to correct defects in materials
or workmanship. Service must be provided by a Whirlpool designated service company.
For five years from the date of purchase, if this PTAC/PTHP fails
when operated and maintained according to instructions attached
to or furnished with the product, Whirlpool Corporation will pay for
replacement parts and repair labor to correct defects in materials
or workmanship in the sealed refrigeration system, including the
compressor, evaporator, condenser, reversing valve and connecting tubing. Service must be provided by a Whirlpool designated
service company.
For the second through fifth year from the date of purchase, if this
PTAC/PTHP fails when operated and maintained according to instructions attached to or furnished with the product, Whirlpool Corporation will pay for replacement parts to correct defects in materials or workmanship in the electrical or air flow systems including
the fan motor, capacitor, fan, blower wheel, switches, thermostat,
relays, frost controls, heat control, heater, heater protectors, compressor overload, solenoids, auxiliary controls, and transformer.
This is a limited parts-only warranty and does not include labor or
transportation to and from the service shop. Service must be provided by a Whirlpool designated service company.
WHIRLPOOL WILL NOT PAY FOR:
1. Service calls to correct the installation of the PTAC/PTHP, instruct you how to use the PTAC/PTHP, to replace
fuses, correct wiring, reset circuit breakers, or to clean or replace owner accessible air filters.
2. Damage resulting from accident, alteration, misuse, abuse, fire, floods, acts of God, improper installation not
in accordance with local electrical and plumbing codes, or use of products not approved by Whirlpool
Corporation, or Whirlpool Canada, Inc.
3. Replacement parts or repair labor costs for units operated outside the United States or Canada.
4. Pickup and delivery, or any transportation and reinstallation charges that may be required.
5. The removal and reinstallation of the PTAC/PTHP.
6. Repairs to parts or systems resulting from unauthorized modifications made to the PTAC/PTHP.
WHIRLPOOL CORPORATION AND WHIRLPOOL CANADA, INC. SHALL NOT BE LIABLE FOR INCIDENTAL
OR CONSEQUENTIAL DAMAGES.
Some states and provinces do not allow the exclusion or limitation of incidental or consequential damages, so this
exclusion or limitation may not apply to you. This warranty gives you specific legal rights and you may also have other
rights which vary from state to state or province to province.
Outside the United States and Canada, a different warranty may apply. For details, please contact your
Whirlpool authorized dealer.
If you need service, first see "Troubleshooting" section of the Installation/Operation Manual. After checking
“Troubleshooting,” additional help can be found by checking the “Assistance or Service” section, or by calling the
Whirlpool Corporation Customer Interaction Center at 1-800-253-1301 (toll-free), from anywhere in the United
States. In Canada, please call 1-800-807-6777.
1-4
INSTALLATION INFORMATION
ELECTRICAL REQUIREMENTS
Electrical Shock Hazard
Plug into a grounded 3 prong outlet.
Do not remove ground prong.
Do not use an adapter.
Do not use an extension cord.
Failure to follow these instructions can
result in death, fire, or electrical shock.
IMPORTANT: Connect PTAC/PTHP to a
single-outlet circuit only.
230/208 VOLT PTAC/PTHP
All 230/208 volt PTAC/PTHPs are equipped
with power cords.
230/208 volt250 volt Receptacles and
PTAC/PTHPOvercurrent Protection
AMPS15 20 30
RECEPTACLE
Electrical Shock Hazard
Electrically ground PTAC/PTHP.
Connect ground wire to green pigtail lead.
Use copper wire for supply connection.
Correct wire gauge is shown in the chart
below.
Failure to follow these instructions can
result in death or electrical shock.
Rating Plate Ampacity AWG
Less than 15 14
16 - 20 12
21 - 30 10
265 VOLT PTAC/PTHP
All 265 volt PTAC/PTHPs are equipped with
pigtail leads for field wiring.
IMPORTANT:
NEMA Type 6-15R 6-20R 6-30R
The field-supplied outlet must match plug on
service cord and be within reach of service
cord.
• Use copper conductors only.
• Wire sizes are per NEC.
• Use on individual branch circuit only.
• Use overcurrent protection indicated on
PTAC/PTHP’s rating plate.
• PTAC/PTHP must be grounded to branch
circuit.
• Check local codes.
2-1
DRAIN KIT INSTALLATION
LOCATION REQUIREMENTS
• Unpack and dispose of packaging materials.
• The drain kit accessory contains 10 complete drain kits.
• Locate the drain kit in the primary area for
best drainage. Maintain at least 1/2″ (1.27
cm) distance from the embossed area. If the
primary area cannot be used, locate the
drain kit in the secondary area and cut away
the foam insulation to allow access to the
drain. Do not locate the drain kit within 3″ (7.6
cm) of the indoor side of the sleeve.
1
2
3
1. Secondary area
2. Primary area - no foam insulation
3. If the drain must be located in the secondary area,
the foam insulation must be cut away and removed
to allow access to the drain.
4. Embossed area
4
3"
(7.6 cm)
NOTES:
Determine whether the drain will be located
on the exterior of the wall, internally in the wall
cavity or internally in the room.
Internal Drain
• Drain kit located inside the room will allow
condensate to drain to a field drain located
inside the room.
• Drain kit located inside the wall cavity will
allow condensate to drain to a field drain
located inside the wall cavity.
External Drain
• Drain kit located outside will allow condensate to drain to a field drain located outside
or to drain away from the wall sleeve.
• When using an external drain system, select
the drain hole on the back of the wall sleeve
which best meets your drainage situation.
• The cover plate and external drain tube
assembly may be placed on either side of the
wall sleeve.
2-2
INTERNAL DRAIN INSTALLATION
(Located Inside The Wall Cavity Or
In The Interior Of The Room)
NOTE: If installing an internal drain, install drain
kit on the wall sleeve before the wall sleeve is
installed.
1.Using the mounting plate from the drain kit
as a template, mark and drill two 3/16″
mounting holes and a 1/2″ drain hole at the
location chosen above.
2.Remove the backing from the gasket and
mount it on the flat side of the mounting
plate. Insert the drain tube through the
hole in the gasket and mounting plate so
the tube flange will be against the wall
sleeve.
1
2
3
4
5
6
3.Position the assembly beneath the drilled
holes and secure it with #10 - 24 x 1/2″
machine screws and locknuts (provided).
Seal the tops of the screws with silicone
sealant.
4.Connect the drain tube to the drain system
in the building.
IMPORTANT: Follow all local building
codes when making this connection.
5.Attach the 2 cover plates and gaskets over
the drain holes at the rear of the wall
sleeve with #10 sheet metal screws (provided).
NOTE: Check that the 4 overflow slots at
the rear of the wall sleeve are not blocked.
1
3
4
5
1. Screw
2. Wall sleeve
3. Gasket
4. Mounting p late
5. Nut
6. Drain tube
7. Optional 4 in. (10.2 cm)
straight drain tube
1
2
1. Drain holes
2. Overflow slots
3. Gasket
4. Cover plate
5. #10 sheet metal screws
2-3
EXTERNAL DRAIN INSTALLATION
(Located On The Exterior
Of The Wall)
1.Peel the backing tape from the gaskets
and mount them on the curved side of one
cover plate and one mounting plate.
2.Place the drain tube through the gasket
and the mounting plate with the flange
toward the wall sleeve.
3.Using 2 - #10 x 1/2″ sheet metal screws
(provided), attach the drain tube assembly
to one of the 2 drain holes at the rear of the
wall sleeve.
Position the large flange at the bottom of
the sleeve facing toward the sleeve, and
partially tighten the screws. Rotate the
drain tube to a horizontal position to allow
for the wall sleeve to be installed into the
wall. Once the wall sleeve is installed,
position the drain tube to the desired angle.
Before tightening the screws, check to be
sure the tube’s position will allow the wall
sleeve to fit through the wall. Tighten screws.
1
3
8
1
2
3
4
1. Drain holes
2. Overflow slots
3. Foam gasket
4. Mounting plate
5. #10 x 1/2 in. sheet metal screws
6. 1/2 in. O.D. tube
7.
Optional 4 in. (10.2 cm) straight drain tube
Cover plate (no center hole)
8.
7
6
5
4.Using 2 - #10 x 1/2″ sheet metal screws
(provided), attach the cover plate to the
remaining drain hole. Check that the large
flange on the plate is positioned at the
bottom of the sleeve.
NOTE: Check that the 4 overflow slots at
the rear of the wall
5.Discard any unused kit parts.
2-4
CHASSIS INSTALLATION
Excessive Weight Hazard
Use two or more people to move and
install PTAC/PTHP.
Failure to do so can result in back or other
injury.
1.Remove banding and carton.
2.Remove the 2 chassis shipping brackets
from the ends of the shipping pallet.
1
2
NOTES:
• Check to be sure wall sleeve, wall sleeve
extension (if used), wall sleeve adapter (if
used), rear grille, and drain kit are properly
installed before chassis installation.
• Locate PTAC/PTHP near the location it will
be installed.
IMPORTANT: Copper refrigerant tubes are not
handles. Product damage will occur if tubes
are used to lift or move the chassis.
3
1. Compressor
2. Chassis shipping bracket
3. Shipping pallet
3.Remove the front cover, which is contained in a protective plastic bag, from
chassis.
4.Dispose of all shipping and packaging material.
2-5
INSTALL THE CHASSIS
3.Locate the 4 - #10 x 1″ chassis mounting
screws (provided). Tighten the screws into
the wall sleeve screw clips.
Electrical Shock Hazard
Disconnect power before servicing.
Replace all parts and panels before
operating.
Failure to do so can result in death or
electrical shock.
1.Disconnect power.
2.Center the chassis in the installed sleeve
and carefully push the chassis until the
chassis flange and gasket contact the
sleeve flange.
2
1
3
1. Chassis mounting screw
2. Screw clips
3. Chassis flange
4.Install the front cover by placing the top of
the front cover onto the metal flange at the
top of the chassis. Rotate the front cover
into place. Insert the thumbscrews (provided) into the slots located at the bottom
back corners of the front cover. Tighten to
secure the cover.
NOTE: If the unit has been placed in such
a way that there is no room to insert the
thumbscrews from the bottom, a side
mounting kit may be used.
1
MAKE ELECTRICAL CONNECTIONS
1. Wall sleeve
2. Chassis flange and gasket
2
IMPORTANT: The installation of field wiring
must conform to the requirements of the National Electrical Code, ANSI/NFPA NO. 70 (latest edition) in the United States, and any state
laws and local ordinances (including plumbing
or wastewater codes). In Canada, field wiring
must conform to the Canadian electrical code
PART I, CSA STANDARD C22.1-1993 or current edition. Local authorities having jurisdiction should be consulted before installation is
made. Such applicable regulations or requirements take precedence over the general instructions in this Job Aid.
2-6
Cord Connected Models
Electrical Shock Hazard
Plug into a grounded 3 prong outlet.
Do not remove ground prong.
FIELD WIRING CONNECTIONS
1.Disconnect power.
2.Remove the PTAC/PTHP front cover using the thumbscrews.
3.Route the incoming power supply through
suitable conduit to the PTAC/PTHP control box.
4.Remove the 4 screws holding the control
box.
Do not use an adapter.
Do not use an extension cord.
Failure to follow these instructions can
result in death, fire, or electrical shock.
1.Plug into a grounded 3 prong outlet.
2.Reconnect power.
Direct Wired Models
Electrical Shock Hazard
Disconnect power before servicing.
Replace all parts and panels before
operating.
Failure to do so can result in death or
electrical shock.
1
2
1. Remove these screws.
2. Do not remove these screws.
3. Bushing
1
2
3
5.Pivot the control box down, pull the chassis pigtail wires into the control box, and
remove the bushing from the hole. The
field-supplied wires will be routed through
this hole.
1
2
Field wiring connections for direct-wired models can be done in one of 2 ways:
• Using field-supplied conduit and wires.
• Using the Conduit with Junction Box Kit
accessory.
1. Bushing
2. Control box
2-7
6.Install field-supplied conduit into the same
)
hole as the original bushing for the chassis
pigtail wires on the control box.
1
2
1. Field-supplied co nduit
2. Control box
7.Connect the chassis pigtail wires to the
incoming power supply wires using the UL
listed wire nuts (provided). Connect the
black wire to the incoming L1 (black) wire.
Connect the white wire to the incoming
neutral (white) wire. Connect the green
wire to the incoming ground (green or
bare) wire.
123
1. Black wire
2. Incoming L1 wire (black wire)
3. Green wire
4
4. Ground wire (green or bare wire
5. White wire
6. Neutral wire (white wire)
56
8.Reattach the PTAC/PTHP control panel
using the 4 screws removed earlier.
9.Reattach the PTAC/PTHP front cover using the thumbscrews removed earlier.
10. Reconnect power.
2-8
REMOTE WALL THERMOSTAT INSTALLATION
INSTALLATION REQUIREMENTS
• Unpack and dispose of packaging materials.
• This thermostat is a wall mounted, low-voltage thermostat that maintains room temperature by controlling the operation of the
PTAC/PTHP. Batteries are not required—
temperature and mode settings are preserved with the power off.
• This is not a 2-stage heat pump thermostat
with emergency heat selection. The PTAC/
PTHP turns on the electric heat automatically based on the outdoor coil temperature,
which is influenced by the outdoor temperature and humidity conditions.
• Chassis must be installed before installing
remote thermostat.
IMPORTANT: Improper wiring or installation
may cause the thermostat not to function. Wiring must conform to local and national electrical codes.
LOCATION REQUIREMENTS
For best performance, thermostat should be
mounted:
• Approximately 5 ft (152.4 cm) from floor.
• Close to or in the room with the PTAC/PTHP,
preferably on an inside partitioning wall.
• On a section of wall without pipes or duct
work.
For best performance, do not mount thermostat:
• Close to a window, on an outside wall, or
next to a door leading to the outside.
• Exposed to direct light and heat from a lamp,
the sun, a fireplace, or other heat source.
This may cause a false reading.
• Close to or in direct airflow from the PTAC/
PTHP.
• In areas with poor air circulation (behind a
door or in an alcove).
Wall Thermostat Terminal Designation
Terminal LetterOperationContact Made
YCoolingDuring call for
cooling.
WHeatingDuring call for heat-
ing.
GFanContinuous if the
slider is in the “Fan”
position; otherwise,
on call for cooling or
heating.
C (common)CommonConstant
Terminal
R24 V to theConstant (directly
thermostatfrom the transformer)
B (Heat PumpReversingMade continuously
units Only)Valvewhen the mode
switch is in heating.
INSTALL THE REMOTE WALL
THERMOSTAT
Replacing Existing Thermostat
1.Disconnect power to avoid product dam-
age during removal of existing thermostat.
2.Disconnect wires from existing thermo-
stat, one at a time. Do not allow wires to fall
back into the wall.
3.As each wire is disconnected, record wire
color and terminal marking.
4.Remove existing thermostat from wall.
5.See “Installing The New Thermostat.”
IMPORTANT: Mercury is a hazardous waste
and must be disposed of properly. Contact the
Thermostat Recycling Corporation at
www.nema.org/trc for further information, or
contact your local waste management authorities.
2-9
Installing The New Thermostat
1.587
2.375
2.625
3.275
1.Disconnect power to avoid product damage during installation of new thermostat.
2.Remove the PTAC/PTHP front cover.
3.Locate the terminal strip on the front of the
control box.
Remote Control UnitRemote Control Unit
5.Route the 24 volt thermostat wire alongside the conduit or service cord to the
location chosen for the thermostat.
6.Separate the front housing and back plate
of the thermostat.
1
OFF
ON
CWY RG B
4.Connect the field supplied 5 or 6 conductor, NEC Class 2, 24 volt thermostat wire
to the terminals in accordance with the
wiring diagram.
1
2
2
1. Back plate
2. Front housing
7.Route thermostat wires through hole in
back plate. Level back plate against wall
(for aesthetic value only—thermostat need
not be leveled for proper operation) and
mark wall through any 2 of the 6 available
mounting holes.
8.Drill two 3/18″ mounting holes in wall where
marked.
Optional Mounting Method: Mounting holes
on thermostat are designed to fit on a
horizontally-mounted junction box.
1. Typical PTAC/PTHP unit
2. Used for PTHP only
3. Wall thermostat
3
2-10
9.Secure back plate to wall with 2 anchors
and screws (provided) making sure all
wires extend through hole in back plate.
10. Connect wires to proper terminals of the
thermostat connector block.
1
2
14. Reconnect power.
NOTE: On power up, the LCD readout will display “oP” momentarily, and then the room temperature.
1
2
3
4
5
6
(20.3 mm)
0.8"
3.30"
(83.8 mm)
3
1. Typical PTAC/PTHP unit
2. Used for PTHP only
3. Wall thermostat
11. Push any excess wire back into wall. Excess wire inside the thermostat housing
can interfere with proper airflow across
the temperature sensor. Seal hole in wall
to prevent air leaks. Air leaks can affect
operation.
After a power outage, the Whirlpool digital thermostat will wait between 3 and 5 minutes before allowing the unit to restart. This is to keep
multiple units from restarting at the same time
when power is restored, thus preventing a circuit overload.
2-11
— NOTES —
2-12
PRODUCT OPERATION
THEORY OF OPERATION
Refrigeration Operation
The refrigeration system uses the following
four basic principles in its operation:
1.Heat always flows from a warmer body to
a cooler body.
2.Heat must be added to or removed from a
substance before a change in state can
occur.
3.Flow is always from a higher pressure
area to a lower pressure area.
4.The temperature at which a liquid or gas
changes state is dependent upon the pressure.
The refrigeration cycle begins at the compressor. Starting the compressor creates a low
pressure in the suction line which draws refrigerant gas (vapor) into the compressor. The
compressor then “compresses” this refrigerant, raising its pressure, and its temperature.
The refrigerant leaves the compressor through
the discharge line as a hot, high pressure gas.
The refrigerant enters the condenser coil where
it gives up some of its heat. The condenser fan
moves air across the finned surface of the
condenser coil, and facilitates the transfer of
heat from the refrigerant to the relatively cooler
outdoor air.
When a sufficient quantity of heat has been
removed from the refrigerant gas, the refrigerant will “condense” (change to a liquid). Once
the refrigerant has been condensed to a liquid,
it is further cooled by the air flowing across the
condenser coil.
The Packaged Terminal Air Conditioner (PTAC)
design determines at exactly what point (in the
condenser) the change of state (gas to liquid)
takes place. In all cases, however, the refrigerant must be totally evaporated (changed to a
gas) before leaving the evaporator coil.
Suction Line
Evaporator Coil
Capillary Tube
(Metering)
Refrigerant
Strainer
Discharge Line
Condenser Coil
Compressor
Liquid Line
Filter/Drier
3-1
The refrigerant leaves the condenser coil as a
warm high pressure liquid. It then passes
through the filter/drier (if so equipped). It is the
function of the filter/drier to trap any moisture,
contaminants, and large particulate matter
present in the sealed system.
The liquid refrigerant next enters a metering
device called a “capillary tube” whose purpose
is to “meter” (control or measure) the quantity
of refrigerant entering the evaporator coil.
Since the blower is moving indoor air across
the finned surface of the evaporator coil, the
expanding refrigerant absorbs some of the
heat. This results in a lowering of the indoor air
temperature, hence the “cooling” effect.
The expansion and absorption of heat causes
the liquid refrigerant to evaporate, and change
back to a gas. Once the refrigerant has been
evaporated, it is further heated by the air that
continues to flow across the evaporator coil.
In the capillary tube, this is accomplished
through its size and length, and the pressure
difference present across the device.
Since the evaporator coil is under a lower
pressure than the liquid line, (due to the suction
created by the compressor), the liquid refrigerant leaves the capillary tube, and enters the
evaporator coil.
As the liquid enters the evaporator coil, the
larger area and lower pressure allows the
refrigerant to expand, and lower its temperature. This expansion is often referred to as
“boiling.”
Suction Line
The particular system design determines at
exactly what point the change of state, from a
liquid to a gas, takes place in the evaporator. In
all cases, however, the refrigerant must be
totally evaporated (changed to a gas) before
leaving the evaporator coil.
The low pressure (suction) created by the
compressor causes the refrigerant to leave the
evaporator through the suction line as a cool,
low pressure vapor. The refrigerant then returns to the compressor, where the cycle is
repeated.
Discharge Line
Evaporator Coil
Capillary Tube
(Metering)
Refrigerant
Strainer
Compressor
Condenser Coil
Liquid Line
Filter/Drier
3-2
COOLING
Heat Pump Operation
All air conditioners are basically heat pumps.
They move, or “pump,” heat from inside a room
to the outdoors. A heat pump air conditioner
adds a component called a “reversing valve.” It
REVERSING
INSIDE COIL
VALV E
DISCHARGE
LINE
COMPRESSOR
allows heat to be transferred from the outdoors
into the room. When the reversing valve is not
energized, the system operates in the cooling
mode.
SUCTION LINE
OUTSIDE COIL
ACCUMULATOR
HEATING
When the reversing valve is energized, the
normal direction of refrigerant flow is diverted
at the valve. The outdoor coil now becomes the
low-pressure side of the system, and the inside
REVERSING
INSIDE COIL
VALV E
DISCHARGE
LINE
COMPRESSOR
coil becomes the high-pressure side. The flow
of all refrigerant past the reversing valve
changes direction, and now brings heat into the
room from the outdoors.
SUCTION LINE
OUTSIDE COIL
ACCUMULATOR
3-3
Reversing Valve Operation
PILOT VALVE SOLENOID
DE-ENERGIZED (COOLING)
The operation of the reversing valve is governed by the pilot solenoid coil. There are two
small lines going to the pilot valve, and two
lines going from the pilot valve to the main
valve body. With the solenoid de-energized,
the direction of flow is as shown, and the valve
is in the cooling mode.
TO EVAPORATOR
PILOT VALVE
(SOLENOID DE-ENERGIZED)
SUCTION LINE
TO CONDENSER
PILOT VALVE SOLENOID
ENERGIZED (HEATING)
When the solenoid is energized, refrigerant
flow from the suction and discharge lines is
redirected (reversed) through the pilot valve to
opposite ends of the main valve body. This
reverse in flow (pressure) causes the main
slide in the valve body to shift to the opposite
end, and reverses the flow of the entire system.
This reversed direction of refrigerant flow is
maintained as long as the pilot solenoid is
energized.
TO EVAPORATOR
DISCHARGE LINE
PILOT VALVE
(SOLENOID ENERGIZED)
SUCTION LINE
TO CONDENSER
DISCHARGE LINE
3-4
Remote Thermostat Operation
ROOM THERMOSTATS
Room thermostats are controlled by the use of
a remote thermostat that will cycle the air
conditioner to maintain the desired room temperature.
The fan speed switch controls the high and low
fan speed operation. The switch is located on
the control panel, and is independent of the
thermostat.
Room thermostats range from the simple bimetallic type, to the more complex electronic
setback type. No matter how simple or complex, they are simply a switch (or series of
switches) designed to turn equipment on or off
under the desired conditions.
An improperly operating, or poorly located room
thermostat, can be the source of perceived
equipment problems. A careful check of the
thermostat and wiring must be made then to
insure that it is not the source of problems.
THERMOSTAT LOCATION
Thermostats should not be mounted where
they may be affected by drafts, discharge air
from registers, (hot or cold), or heat radiated
from the sun or appliances.
HEAT ANTICIPATORS
Heat anticipators are small resistance heaters
that are built into most electromechanical thermostats (wired in series with the control “W”
circuit). Their purpose is to prevent wide swings
in room temperature during system operation
in the “heating” mode. Since anticipators are
wired in series, the “W” section of the circuit will
open if one burns out, preventing the “heat”
operation.
The heat anticipator provides a small amount
of heat to the thermostat causing it to turn off
the heat source just prior to reaching the setpoint of the thermostat. This prevents exceeding the set point.
To accomplish this, the heat output from the
anticipator must be the same regardless of the
current flowing through it. Consequently, some
thermostats have an adjustment to compensate for varying current draw in the thermostat
circuits.
Electronic thermostats do not use a resistance-type anticipator. These thermostats use
a microprocessor that determines a cycle rate
based on a program loaded into it at the factory.
The thermostat should be located about 5′
above the floor, in an area of average temperature, with good air circulation. Close proximity
to the return air grille is the best choice.
Mercury bulb type thermostats must be level to
control temperature accurately to the desired
set-point.
3-5
CALCULATING THE
APPROXIMATE CFM
The approximate CFM actually being delivered
can be calculated by using the following formula:
Kilowatts x 3413
Temperature Rise x 1.08
Do not use the kilowatt rating of the heater, as
this will result in an incorrect airflow calculation.
Kilowatts can be calculated by multiplying the
measured voltage to the unit, times the measured current draw of all the heaters that are in
operation to obtain the wattage (watts). Kilowatts are then obtained by dividing the watts by
1000.
EXAMPLE: The measured voltage to the unit is
230 volts. The measured current draw of the
heaters is 11.0 amps.
230 x 11.0 = 2530
2530 ÷ 1000 = 2.53 Kilowatts
2.53 x 3413 = 8635
Supply Air 95°F
Return Air 75°F
Temperature Rise 20°F
20 X 1.08 = 21.6
= CFM
8635
= 400 CFM
21.6
3-6
Heat Pump Function
THE HOT START SENSOR
Under cold room conditions, (50°F, or below),
the Hot Start Sensor turns on the heater strips
with a call for heat to distribute warm air at the
beginning of the “Heat” cycle. Once the return
air has warmed sufficiently, (above 65°F), the
heat pump mode will begin.
THE HEAT PUMP
The heat pump uses backup electric resistance heating coils. At extremely low outdoor
ambient temperatures, the heat pump is automatically disabled, and the unit operates solely
on electric resistance heat.
The heating control (defrost thermostat) is located behind the decorative front cover, and is
found on the right side panel of the chassis. Its
function is to allow the temperature range in
which the heat pump operates to be manually
adjusted.
Emergency Heat Operation Only: In the event
of a compressor malfunction in the “heat pump”
mode, turn the adjustment screw to the extreme counterclockwise “emergency heat” position. The heater will then cycle using electric
resistance heat only. Note that in the emergency heat position, the compressor is locked
out, disabling both the heat pump, and the
cooling operations. IMPORTANT: Do not forget to return the control to its original position
after repairs have been made. Otherwise, the
compressor will remain locked out, and will not
turn on during the “cooling” mode.
The heating control switches the unit’s heat
operation between the heat pump, and electric
resistance heat, based on the outdoor ambient
temperature. These change-over temperatures
are based on the settings of the control. The
factory set-point is at the one o’clock position.
If you wish to change the factory set-point,
insert a flat-bladed screwdriver into the slot and
turn counterclockwise to increase the changeover set-point, or clockwise to decrease it.
NOTE: Use the factory set-point for optimum
performance.
Adjustment
Screw
3-7
OPERATING THE CONTROLS
TEMPERATURE CONTROL
The temperature control is a full range thermostat that maintains room temperature at the
desired setting for both heating and cooling.
Turn the knob counterclockwise for a warmer
temperature, and clockwise for a cooler temperature.
NOTE: Always rotate the temperature control
in small increments in the warmer or cooler
direction. Moving the control more than 1/4″ at
a time may overcompensate, and result in an
extreme hot or cold condition.
MODE (SYSTEM) SWITCH
Low and High Cool
This setting operates the unit in the “cooling”
mode. Cooling will not begin if the room temperature is below 60°F (15.5°C).
Low and High Heat
This setting operates the unit in the “heating”
mode.
Fan Only
This setting operates the fan continuously at
high fan speed to circulate air within the room.
No heating or cooling functions are active in
this mode.
TEMPERATURE LIMITING
THERMOSTAT
The temperature limiting thermostat allows the
temperature range of the thermostat to be
varied.
To adjust the temperature range:
1.Turn the thermostat (temperature) control
to the center position.
2.Pull the two control knobs off the control
shafts and remove them.
3.Remove the four screws from the control
panel and rotate the panel up.
4.Note the location of the two temperature
limiting screws and remove the screws
from their present location. NOTE: The
screws are factory installed for a temperature range of between 60 and 90°F (15.5
to 32.2°C).
5.To adjust the temperature range, reinstall
the two screws at the desired hole locations. NOTE: Each hole represents an
approximate change of 4°. To set a maximum temperature range of approximately
64 to 86°F (17.7 to 30.0°C), install the two
screws at the hole locations shown in the
round illustration below.
6.Lower the control panel and install the two
screws, then reinstall the two control knobs.
3-8
Loading...
+ 64 hidden pages
You need points to download manuals.
1 point = 1 manual.
You can buy points or you can get point for every manual you upload.