Friedrich Room Model Number Code .........................................................................................................4
Application and Sizing ..............................................................................................................................5
Instructions For Using Cooling Load Estimate Form .................................................................................6
Cooling Load Estimate Form .....................................................................................................................7
Heat Load Form ........................................................................................................................................8
Heating Load Form Friedrich Unit Heat Pumps ..........................................................................................9
Fan Motor ................................................................................................................................................ 17
Capacitor, Run .........................................................................................................................................18
System Control Switch (Heat Pump & Electric Heat Models) ................................................................... 18
Heat Element ...........................................................................................................................................21
Drain Pan Valve........................................................................................................................................ 22
"YS" - "YM" - "YL" Series Parts List ........................................................................................................ 39
"ES" - "EM" Series Parts List .................................................................................................................. 46
"EL" Series Parts List .............................................................................................................................. 51
"EK" Series Parts List ............................................................................................................................. 56
Page 3
FRIEDRICH ROOM MODEL NUMBER CODE
1st DIGIT - FUNCTION
S = Straight Cool, Value Series
C = Straight Cool, Budget Series
Y = Heat Pump
E = Electric Strip
K = Straight Cool, Challenger Series
W = Thru-The-Wall, WallMaster Series
2nd DIGIT - TYPE
C = Casement
P = PowerMiser “Portable”
Q = QStar
S = Small Chassis
M = Medium Chassis
L = Large Chassis
W = Built-In
H = Hazardgard
3rd & 4th DIGITS - APPROXIMATE BTU/HR (Cooling)
Heating BTU/HR capacity listed in Specifications/Performance Data Section
In the application and sizing of room air conditioners for cooling, it is most important to give full consideration to all
factors which may contribute to the heat loss or gain of the space to be conditioned. It is therefore necessary to make
a survey of the space to be conditioned and calculate the load requirements before a selection of the size of the
equipment needed can be made.
The load requirement may be determined very easily by simply using the standard "AHAM" Load Calculating Form, on
Page 7. This form is very easy to use and is self explanatory throughout. It is necessary only to insert the proper
measurements on the lines provided and multiply by the given factors, then add the result for the total load requirements.
Cooling load requirements are generally based on the cooling load for comfortable air conditioning which does not
require specific conditions of inside temperature and humidity. The load calculation form is based on outside design
temperature of 95° FDB and 75° FWB. It can be used for areas in the Continental United States having other outside
design temperatures by applying a correction factor for the particular locality as determined from the map shown on
Page 7.
When sizing a TwinTemp unit for cooling and heating, we must remember that the heating capacity of any given unit
varies directly with the outdoor ambient temperature. Also, we must keep in mind the average low temperatures which
might be experienced in the locality where the unit is to be installed. Therefore, when sizing a TwinTemp unit, both
cooling and heating requirements must be calculated. Do not oversize, or undersize, one phase of the unit’s capacity
at the expense of the other. In those cases where the unit will provide satisfactory cooling at all times but will be
inadequate for those few times that the outdoor temperature is below the maximum low for the unit, additional auxiliary
heating facilities must be provided to insure that adequate heat is available at all times.
Page 5
INSTRUCTIONS FOR USING COOLING LOAD ESTIMATE
FORM FOR ROOM AIR CONDITIONERS
(AHAM PUB. NO. RAC-1)
A.This cooling load estimate form is suitable for estimating the cooling load for comfort air conditioning installations
which do not require specific conditions of inside temperature and humidity.
B.The form is based on an outside design temperature of 95°F dry bulb and 75°F wet bulb. It can be used for areas
in the continental United States having other outside design temperatures by applying a correction factor for the
particular locality as determined from the map.
C.The form includes "day" factors for calculating cooling loads in rooms where daytime comfort is desired (such as
living rooms, offices, etc.)
D.The numbers of the following paragraphs refer to the corresponding numbered item on the form:
1.Multiply the square feet of window area for each exposure by the applicable factor. The window area is the
area of the wall opening in which the window is installed. For windows shaded by inside shades or venetian
blinds, use the factor for "Inside Shades." For windows shaded by outside awnings or by both outside
awnings and inside shades (or venetian blinds), use the factor for "Outside Awnings." "Single Glass" includes
all types of single thickness windows, and "Double Glass" includes sealed airspace types, storm windows,
and glass block. Only one number should be entered in the right hand column for Item 1, and this number
should represent only the exposure with the largest load.
2.Multiply the total square feet of all windows in the room by the applicable factor.
3a.Multiply the total length (linear feet) of all walls exposed to the outside by the applicable factor. Doors should
be considered as being part of the wall. Outside walls facing due north should be calculated separately from
outside walls facing other directions. Walls which are permanently shaded by adjacent structures should be
considered "North Exposure." Do not consider trees and shrubbery as providing permanent shading. An uninsulated frame wall or a masonry wall 8 inches or less in thickness is considered "Light Construction." An
insulated wall or masonry wall over 8 inches in thickness is considered "Heavy Construction."
3b.Multiply the total length (linear feet) of all inside walls between the space to be conditioned and any
unconditioned spaces by the given factor. Do not include inside walls which separate other air conditioned
rooms.
4.Multiply the total square feet of roof or ceiling area by the factor given for the type of construction most
nearly describing the particular application (use one line only.)
5.Multiply the total square feet of floor area by the factor given. Disregard this item if the floor is directly on the
ground or over a basement.
6.Multiply the number of people who normally occupy the space to be air conditioned by the factor given. Use
a minimum of 2 people.
7.Determine the total number of watts for light and electrical equipment, except the air conditioner itself, that
will be in use when the room air conditioning is operating. Multiply the total wattage by the factor given.
8.Multiply the total width (linear feet) of any doors or arches which are continually open to an unconditioned
space by the applicable factor.
NOTE: Where the width of the doors or arches is more than 5 feet, the actual load may exceed the
calculated value. In such cases, both adjoining rooms should be considered as a single large room, and the
room air conditioner unit or units should be selected according to a calculation made on this new basis.
9.Total the loads estimated for the foregoing 8 items.
10.Multiply the subtotal obtained in item 9 by the proper correction factor, selected from the map, for the
particular locality. The result is the total estimated design cooling load in BTU per hour.
E.For best results, a room air conditioner unit or units having a cooling capacity rating (determined in accordance
with the NEMA Standards Publication for Room Air Conditioners, CN 1-1960) as close as possible to the estimated
load should be selected. In general, a greatly oversized unit which would operate intermittently will be much less
satisfactory than one which is slightly undersized and which would operate more nearly continuously.
F.Intermittent loads such as kitchen and laundry equipment are not included in this form.
Page 6
COOLING LOAD ESTIMATE FORM
HEAT GAIN FROM
1.WINDOWS: Heat gain from the sun.
Northeast
East
Southeast
South
Southwest
West
Northwest
North
2.WINDOWS: Heat by conduction
(Total of all windows.)
Single glass
Double glass or glass block
3.WALLS: (Based on linear feet of wall)
a. Outside walls
North Exposure
Other than North exposure
b. Inside Walls (between conditioned and
unconditioned spaces only.)
4.ROOF OR CEILING: (Use one only)
a. Roof, Un-insulated
b. Roof, 1 inch or more insulation
c. Ceiling, occupied space above
d. Ceiling, insulated, with attic space above
e. Ceiling, Un-insulated, with attic space above
* These factors are for single glass
only. For glass block, multiply the
above factors by 0.5; for double
glass or storm windows, multiply
the above factors by 0.8.
QUANTITY
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
____ ft.
____ ft.
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
____sq. ft.
5.Floor: (Disregard if floor is directly on ground or over
a basement.
6.NUMBER OF PEOPLE
7.LIGHTS AND ELECTRICAL EQUIPMENT IN USE
8.DOORS AND ARCHES CONTINUOUSLY OPENED TO
UNCONDITIONED SPACE: (TOTAL LINEAR FEET OF
WIDTH.)
9.SUBTOTAL
10. TOTAL COOLING LOAD (BTU per hour to be used for
selection of room air conditioner(s).)
____ Total in Item 9 X ____(Factor from Map) =_______
____sq. ft.
____
____watts
____ft.
*****
3
600
3
300
*****
_____
_____
_____
_____
_____
Page 7
HEAT LOAD FORM
The heat load form, Page 9, may be used by servicing
personnel to determine the heat loss of a conditioned
space and the ambient winter design temperatures in
which the unit will heat the calculated space.
The upper half of the form is for computing the heat loss
of the space to be conditioned. It is necessary only to
insert the proper measurements on the lines provided
and multiply by the given factors, then add this result for
the total heat loss in BTU/Hr./°F.
The BTU/Hr. per °F temperature difference is the 70°F
inside winter designed temperature minus the lowest
outdoor ambient winter temperature of the area where
the unit is installed. This temperature difference is used
as the multiplier when calculating the heat loss.
The graph shows the following:
Left Hand ScaleUnit capacity BTU/Hr. or heat loss
BTU/Hr.
Bottom ScaleOutdoor ambient temperature,
base point.
Heat Pump ModelBTU/Hr. capacity heat pump will
deliver at outdoor temperatures.
Balance PointMaximum BTU/Hr. heat pump will
deliver at indicated ambient temperature.
Below is an example using the heat load form:
A space to be conditioned is part of a house geographically located in an area where the lowest outdoor ambient winter temperature is 40°F. The calculated heat loss
is 184 BTU/Hr./°F.
Subtract 40°F (lowest outdoor ambient temperature for
the geographical location) from 70°F (inside design temperature of the unit) for a difference of 30°F. Multiply 184
by 30 for a 5500 BTU/Hr. total heat loss for the calculated space.
On the graph, plot the base point (70°) and a point on the
40°F line where it intersects with the 5500 BTU/Hr. line
on the left scale. Draw a straight line from the base
point 70 through the point plotted at 40°F. This is the
total heat loss line.
Knowing that we have a 5500 BTU/Hr. heat loss, and we
expect that our heat pump will maintain a 70°F inside
temperature at 40°F outdoor ambient, we plot the selected unit capacity BTU/Hr. of the unit between 35° and
60° on the graph and draw a straight line between these
points. Where the total heat loss line and the unit capacity line intersect, read down to the outdoor ambient temperature scale and find that this unit will deliver the required BTU/Hr. capacity to approximately 30°F.
Page 8
HEATING LOAD FORM
FRIEDRICH ROOM UNIT HEAT PUMPS
BTU/HR PER
WALLS: (Linear Feet°F. TEMP. DIFFERENCE
2" InsulationLin. Ft. x 1.6
AverageLin. Ft. x 2.6
WINDOWS & DOORS (Area, sq. ft.
Single Glass:Sq. Ft. x 1.13
Double Glass:Sq. Ft. x 0.61
INFILTRATION - WINDOWS & DOORS: AVG.Lin. Ft. x 1.0
LooseL i n. Ft . x 2 . 0
CEILING: (Area, Sq. Ft.)
Insulated (6")Sq. Ft. x 0.07
Insulated (2")Sq. Ft. x 0.10
Built-up Roof (2" insulatedSq. Ft. x 0.10
Built-up Roof (1/2" insulated)Sq. Ft. x 0.20
No InsulationSq. Ft. x 0.33
FLOOR: (Area, Sq. Ft.)
Above Vented Crawl space
Insulated (1:)Sq. Ft. x 0.20
Un-insulatedSq. Ft. x 0.50
* Slab on GroundLin. Ft. x 1.70
1" Perimeter insulationLin. Ft. x 1.00
* Based on Linear Feet of outside wallTOTAL HEAT LOSS PER °F BTU/HR/°F
Multiply total BTU/HR/°F X 30 and plot on the graph below at 40°F. Draw a straight line from the
70 base point thru the point plotted at 40°F. The intersection of this heat loss line with the unit
capacity line represents the winter design heating load.
In the cooling cycle, both capillary tubes feed the evaporator coil
Heating Cycle (Refer to Chart Below)
In the heating cycle, the one-way check is closed and the refrigerant flows through one capillary only to the
condenser
Page 14
INSTALLATION INSTRUCTIONS
FOR DC-2 DRAIN KIT
STEP 1Before sliding chassis into outer shell, turn chassis on its side and add drain hole by drilling ½"
diameter hole as shown in Figure 1.
STEP 2DC-2 mounts to the bottom of the outer shell as shown in Figure 2 on the right side as you face
the unit. Use two (2) 10 - 24 x 3/8" long machine screws and 10 - 24 hex nuts provided.
STEP 3SQ, KQ, YQ Models - Drill two ¼" holes in outer shell as shown in Figure 3. Also drill a 3/8"
diameter hole in the base pan 3½" from the back and 3½" from right side.
STEP 4Small and Medium Chassis Models - Mount in second and third holes from the rear of shell; See
Figure 4.
STEP 5Large Chassis Models - Mount in third and fourth holes from the rear of shell; see Figure 5.
STEP 6Connect a suitable length of garden hose or other tubing to end of the drain tube to drain the
condensate away.
FIGURE 1FIGURE 2
RIGHT SIDE
APPROXIMATE
LOCATION OF
EMBOSSMENT.
DRILL 1/2" DIA.
HOLE
BACK OF BASE PAN
FIGURE 3
FIGURE 4FIGURE 5
2ND & 3RD HOLES
FROM REAR OF
SHELL
10-24X 3/8" LONG
SCREWS
DRAIN PLATE
10X24 NUTS
3RD & 4TH HOLES
FROM REAR OF
SHELL
SQ, KQ, YQ MODELS
BOTTOM VIEW
SMALL & MEDIUM
CHASSIS MODELS
BOTTOM VIEW
LARGE
CHASSIS MODELS
BOTTOM VIEW
Page 15
COMPONENT OPERATION & TESTING
WARNING
DISCONNECT ELECTRICAL POWER TO
UNIT BEFORE SERVICING OR TESTING
COMPRESSORS
GROUND TEST
Use an ohmmeter set on its highest scale. Touch one
lead to the compressor body (clean point of contact as
a good connection is a must) and the other probe in turn
to each compressor terminal (see Figure 2.) If a reading
is obtained, the compressor is grounded and must be
replaced.
Compressors are single phase, 115 or 230/208 volt,
depending on the model unit. All compressor motors are
permanent split capacitor type using only a running
capacitor across the start and run terminal.
All compressors are internally spring mounted and
externally mounted on rubber isolators.
COMPRESSOR WINDING TEST (See Figure 1)
Remove compressor terminal box cover and disconnect
wires from terminals. Using an ohmmeter, check
continuity across the following:
1. Terminal "C" and "S" - no continuity - open winding
- replace compressor.
2. Terminal "C" and "R" - no continuity - open winding
- replace compressor.
3. Terminal "R" and "S" - no continuity - open winding - replace compressor.
Figure 2: Typical Ground Test
CHECKING COMPRESSOR EFFICIENCY
The reason for compressor inefficiency is normally due
to broken or damaged suction and/or discharge valves,
reducing the ability of the compressor to pump refrigerant
gas.
This condition can be checked as follows:
1. Install a piercing valve on the suction and
discharge or liquid process tube.
2. Attach gauges to the high and low sides of the
system.
Figure 1:Compressor Winding Test
Page 16
3. Start the system and run a “cooling or heating
performance test.”
If test shows:
A. Below normal high side pressure.
B. Above normal low side pressure.
C. Low temperature difference across coil.
The compressor valves are faulty - replace the
compressor.
THERMAL OVERLOAD (External)
Some compressors are equipped with an external
overload which is located in the compressor terminal
box adjacent to the compressor body (see Figure 3.)
The overload is wired in series with the common motor
terminal. The overload senses both major amperage and
compressor temperature. High motor temperature or
amperage heats the disc causing it to open and break
the circuit to the common motor terminal.
Figure 3: External Overload
Should the internal temperature and/or current draw become excessive, the contacts in the overload will open,
turning off the compressor. The overload will automatically reset, but may require several hours before the heat
is dissipated.
CHECKING THE INTERNAL OVERLOAD
(see Figure 4.)
Figure 4INTERNAL OVERLOAD
Heat generated within the compressor shell is usually
due to:
1. High amperage.
2. Low refrigerant charge.
3. Frequent recycling.
4. Dirty condenser.
TERMINAL OVERLOAD - TEST
(Compressor - External Type)
1. Remove overload.
2. Allow time for overload to reset before attempting
to test.
3. Apply ohmmeter probes to terminals on overload
wires. There should be continuity through the overload.
TERMINAL OVERLOAD (Internal)
1.With no power to unit, remove the leads from the
compressor terminals.
2.Using an ohmmeter, test continuity between terminals C-S and C-R. If not continuous, the compressor overload is open and the compressor must be
replaced.
FAN MOTOR
A single phase permanent split capacitor motor is
used to drive the evaporator blower and condenser
fan. A self-resetting overload is located inside the
motor to protect against high temperature and high
amperage conditions.
FAN MOTOR - TEST
1.Determine that capacitor is serviceable.
Some model compressors are equipped with an internal
overload. The overload is embedded in the motor windings to sense the winding temperature and/or current
draw. The overload is connected in series with the common motor terminal.
2.Disconnect fan motor wires from fan speed switch
or system switch.
3.Apply "live" test cord probes on black wire and common terminal of capacitor. Motor should run at high
speed.
Page 17
Figure 5: Fan Motor
4. Apply "live" test cord probes on red wire and
common terminal of capacitor. Motor should run
at low speed.
5. Apply "live" test cord probes on each of the
remaining wires from the speed switch or system
switch to test intermediate speeds.
CAPACITOR, RUN
A run capacitor is wired across the auxiliary and main
winding of a single phase permanent split capacitor motor
such as the compressor and fan motor. A single capacitor
can be used for each motor or a dual rated capacitor can
be used for both.
The capacitor's primary function is to reduce the line
current while greatly improving the torque characteristics
of a motor. The capacitor also reduces the line current to
the motor by improving the power factor of the load. The
line side of the capacitor is marked with a red dot and is
wired to the line side of the circuit (see Figure 6.)
CAPACITOR - TEST
1. Remove capacitor from unit.
2. Check for visual damage such as bulges, cracks, or
leaks.
3. For dual rated, apply an ohmmeter lead to common
(C) terminal and the other probe to the compressor
(HERM) terminal. A satisfactory capacitor will cause
a deflection on the pointer, then gradually move back
to infinity.
4. Reverse the leads of the probe and momentarily
touch the capacitor terminals. The deflection of the
pointer should be two times that of the first check if
the capacitor is good.
5. Repeat steps 3 and 4 to check fan motor capacitor.
NOTE: A shorted capacitor will indicate a low resistance
and the pointer will move to the "0" end of the
scale and remain there as long as the probes
are connected.
An open capacitor will show no movement of
the pointer when placed across the terminals of
the capacitor.
SYSTEM CONTROL SWITCH
(Heat Pump & Electric Heat Models)
An eight position control switch is used to regulate the
operation of the fan motor and compressor. The
compressor can be operated with the fan operating at
low, medium or high speed in the cooling or heating mode.
The fan motor can also be operated independently on
medium speed. See switch section as indicated on
decorative control panel (see Figure 7.)
Figure 6: RUN CAPACITOR HOOK-UP
Page 18
1. "Off" Position - everything is off.
2. "Lo Cool" Position - fan operates on low speed,
compressor is on.
3. "Med Cool" Position - fan operates on medium speed,
compressor is on.
4. "Hi Cool" Position - fan operates on high speed,
compressor is on.
5. "Hi Heat" Position - fan operates on high speed,
compressor or electric heater is on.
6. "Med Heat" Position - fan operates on medium speed,
compressor or electric heater is on.
Figure 7: SYSTEM CONTROL PANEL
(Heat Pump & Electric Heat Models)
SYSTEM CONTROL SWITCH - TEST
Disconnect leads from control switch. Turn control to
position being tested (see Figure 8.) There must be
continuity as follows:
1. "Off" Position - no continuity between terminals.
2. "Lo Cool" Position - between terminals "C" and "3",
"C2" and "2", "LO" and "M/S", "AR" and "5".
3. "Med Cool" Position - between terminals "C" and
"3", "C2" and "2", "M" and "M/S", "AR" and "5".
4. "Hi Cool" Position - between terminals "C" and "3",
"C2" and "2", "H" and "M/S", "AR" and "5".
5. "Hi Heat" Position - between terminals "C" and "1",
"C2" and "4", "H" and "M/S", "AR" and "5".
6. "Med Heat" Position - between terminals "C" and
"1", "C2" and "4", "M" and "M/S", "AR" and "5".
7. "Lo Cool" Position - between terminals "C" and "1",
"C2" and "4", "LO" and "M/S", "AR" and "5".
7. "Lo Heat" Position - fan operates on low speed,
compressor or electric heater is on.
8. "Fan Only" Position - operates on medium speed.
NOTE: Heat pump models with electric heat - in the
heat position, heating element only will be
energized when outdoor temperature is below
the operating range of the heat pump.
Figure 8: SYSTEM CONTROL SWITCH
(Heat Pump & Electric Heat Models)
8. "Fan Only" Position - between terminals "L1" and
"M".
THERMOSTAT - (see Figure 9)
A cross ambient thermostat is used on all heat pump
and electric heat units. In addition to cycling the unit in a
heating or cooling operation, the thermostat will terminate
the cooling cycle in the event ice forms on the evaporator
coil, in this case the thermostat functions as a de-ice
control. A resistor (anticipator) is positioned
Figure 9: THERMOSTAT
Page 19
within a plastic block to supply a small amount of heat
to the bulb area to prevent long "off cycles" in the "CoolFan Auto" (MoneySaver) position (see Figure 10.) A
current feedback through the fan motor windings during
"off cycle" completes the circuit to the resistor.
In the heating cycle, the heat anticipator is energized to
supply a small amount of heat during the "on" cycle.
This will open the contacts in the thermostat prematurely
to maintain a closer differential between the "cut in" and
"cut out" temperature. The heat anticipator is energized
in the heating mode regardless of whether fan is placed
in the automatic (MoneySaver) or constant run position.
RANGE:Cooling Model Thermostat
(Part No. 618-224-00)
60°F (±2°) to 92°F (±4°),
TEST:
Cooling/Heating Models: Remove wires from
thermostat and check continuity between terminal "2"
(common) and "3" for cooling. Check between terminals
"2" (common) and "1" for heating. Also check that
contacts in thermostat open after placing in either
position. NOTE: Temperature must be within range listed
to check thermostat. Refer to the troubleshooting section
in this manual for additional information on thermostat
testing.
RESISTOR (Heat Anticipator)
Failure of the resistor will cause prolonged "off" and "on"
cycles of the unit. When replacing a resistor, be sure and
use the exact replacement. Resistor ratings are as
follows:
115 Volt - 5,000 ohms 3 watt
230 Volt - 20,000 ohms 3 watt
MONEYSAVER® SWITCH
(Rocker Switch) - See Figure 11
This rocker switch can be depressed to either YES or
NO. In the YES position you will get the most economical
operation. Both the fan and compressor will cycle on
and off together, maintaining the selected temperature
at a more constant level and reducing the humidity more
efficiently in the cooling mode. This control will only
operate when the unit is in a cooling or heating mode. In
the NO position, the fan will run constantly as long as
the unit is in the cooling or heating mode.
TEST:
Disconnect leads from switch. Depress switch to function
being tested.
1. When YES is depressed, there should be continuity
between terminals "1" and "2".
THERMOSTAT ADJUSTMENT
No attempt should be made to adjust thermostat. Due to
the sensitivity of the internal mechanism and the
sophisticated equipment required to check the calibration,
it is suggested that the thermostat be replaced rather
than calibrated. Thermostat bulb must be straight to
insure proper performance.
Figure 10: RESISTOR
2. When NO is depressed, there should be continuity
between terminals "2" and "3".
Figure 11: ROCKER SWITCH
Page 20
HEATING ELEMENT - See Figure 12
All heat pumps and electric heat models are equipped
with a heating element with the exception of the YS09J10.
The "YS", "ES" and "EK12" models are equipped with a
3.3 KW element. The "YM", "EM" and "EK18" models
are equipped with a 4.0 KW element. The "YL" and "EL"
models are equipped with a 5.2 KW element.
across the terminals after the connecting wires have been
removed. A cold resistance reading of approximately 14.5
ohms for the 3.3 KW heater, 11.9 ohms for the 4.0 KW
heater and 9.15 ohms for the 5.2 KW heater should be
registered.
DEFROST THERMOSTAT
(Heat Pump Models Only)
The heating element contains a fuse link and a heater
limit switch. The fuse link is in series with the power
supply and will open and interrupt the power when the
temperature reaches 161.6°F, or a short circuit occurs in
the heating element. Once the fuse link separates, a
new fuse link must be installed. NOTE: Always replace
with the exact replacement.
The heater element has a high limit control. This control
is a bimetal thermostat mounted in the top of the heating
element.
Figure 12: HEATING ELEMENT
This thermostat (Figure 13) is single pole - double throw
with contacts between terminals "2" and "3" closing on
temperature rise and contacts between terminals "2" and
"1" closing on temperature fall. When the contacts
between terminals "2" and "1" make, power is supplied
to the heater element.
This control is dual purpose control that acts as an
outdoor thermostat and defrost control.
When the sensing bulb, attached to the condenser coil,
senses enough icing on the outdoor coil, it will interrupt
power to the compressor and supply power to the heating
element until the coil temperature reaches above 43°,
then the heater will shut off and the unit will resume
operating in the reverse cycle mode.
When the outdoor coil temperature drops below 20°, the
unit will operate in electric heat mode continuously until
the outdoor coil temperature rises above 43°.
The fan motor will not turn off when defrost occurs, and
the 4-way valve will not reverse.
Should the fan motor fail or filter become clogged, the
high limit control will open and interrupt power to the
heater before reaching an unsafe temperature condition.
The control is designed to open at 110°F ±6°F. Test
continuity below 110°F and for open above 110°F.
The heating element for the "Y" model is energized by
an outdoor thermostat. The outdoor thermostat is adjusted
at a predetermined temperature to bring on the heating
element and turn off the compressor. The room thermostat
will then control the cycling of the element when the
selected indoor temperature is reached.
Testing of the elements can be made with an ohmmeter
Figure 13: DEFROST THERMOSTAT
(Heat Pump Models)
Page 21
DEFROST BULB LOCATION
(Heat Pump Models Only)
CHECK VALVE (Figure 15)
(Heat Pump Models Only)
The defrost control bulb must be mounted securely and
in the correct location to operate properly (see Figure
14.)
Figure 14: DEFROST THERMOSTAT BULB
LOCATION (All Heat Pump Models)
Retainer
Slide the bulb
end of the
thermostat
defrost under
the retainer as
shown
SOLENOID COIL
(Heat Pump Models Only)
A one-way check valve is installed in the capillary tube
circuit to allow the flow of refrigerant through both tubes
to the evaporator during the cooling mode.
In the heating mode, one capillary is closed by the check
valve to allow flow through one capillary only to the
condenser.
Figure 15:ONE-WAY CHECK VALVE
(Heat Pump Models)
NOTE: The slide (check) inside the valve is made of
teflon. Should it become necessary to replace
the check valve, place a wet cloth around the
valve to prevent overheating during the brazing
operation. The flow arrow on the valve must
point toward the evaporator.
VALVE, DRAIN PAN (see Figure 16)
The solenoid coil is an electromagnetic type coil mounted
on the reversing valve and is energized during the
operation of the compressor in the heating cycle.
Should the reversing valve fail to shift during the heating
cycle, test the solenoid coil. Also, refer to Touch Test
Chart on page 26.
TO TEST:
1. Disconnect power to unit.
2. Disconnect coil leads.
3. Attach probes of an ohmmeter to each coil lead and
check for continuity.
NOTE: Do not start unit with solenoid coil removed from
valve, or do not remove coil after unit is in
operation. This will cause the coil to burn out.
During the cooling mode of operation, condensate which
collects in the drain pan is picked up by the condenser
fan blade and sprayed onto the condenser coil. This
assists in cooling the refrigerant plus evaporating the
water.
During the heating mode of operation, it is necessary
that water be removed to prevent it from freezing during
cold outside temperatures. This could cause the
condenser fan blade to freeze in the accumulated water
and prevent it from turning.
To provide a means of draining this water, a bellows type
drain valve is installed over a drain opening in the base
pan.
Page 22
This valve is temperature sensitive and will open when
the outside temperature reaches 40°F. The valve will close
gradually as the temperature rises above 40°F to fully
close at 60°F.
Figure 16:DRAIN PAN VALVE
REVERSING VALVE
(Heat Pump Model Only)
Figure 17:REVERSING VALVE
The pilot valve is responsible for directing the refrigerant
flow to the indoor or outdoor coil. There are three small
tubes connected to the pilot valve body. The center pilot
tube is the common pilot tube and is connected to the
center suction line. The outside tubes are connected to
each end of the main valve body. The pilot valve consists
of a needle valve and spring. When the solenoid is deenergized, the spring tension closes one pilot port while
the others remain open. When the solenoid is energized,
the opposite end is closed. The piston in the main valve
is pressure operated and will always travel in the direction
of the open pilot tube port which provides a path to the
center tube. Pressure which will increase in the opposite
end of the valve will escape through a bleed port located
in each piston. When de-energized, the valve will be in
the cooling position.
TESTING REVERSING VALVE
Occasionally, the reversing valve may stick in the heating
or cooling position or in the mid-position.
A reversing valve is used to change the refrigerant flow
within the system to permit heating or cooling (see Figure
17.)
The reversing valve consists of a main valve body which
houses the slide and piston, plus a pivot valve which is
activated by a solenoid.
There are three tubes connected to one side of the main
valve body and one tube on the opposite side. The single
tube is connected to the compressor discharge line. The
center tube on the opposite side is the common suction
line to the compressor. The outside tubes are connected
to the indoor and outdoor coils.
Figure 17:REVERSING VALVE
When stuck in the mid-position, part of the discharge
gas from the compressor is directed back to the suction
side, resulting in excessively high suction pressure.
Check the operation of the valve by starting the system
and switching the operation from "cooling" to "heating"
and then back to "cooling". Do not hammer on the valve.
If valve fails to change its position, test the voltage to
the valve coil while the system is in the heating cycle. If
voltage to coil is satisfactory, replace reversing valve.
Should the valve fail to shift from cooling to heating,
block the air flow through the indoor coil and allow
discharge pressure to build in the system. Then switch
the system from cooling to heating.
If valve is stuck in the heating position, block the air
flow through the indoor coil and allow discharge pressure
to build in the system. Then switch the system from
heating to cooling.
Should the valve fail to shift in either position after
increasing the discharge pressure, replace the valve.
NOTE: When brazing a reverse valve into the system,
it is of extreme importance that the temperature
of the valve does not exceed 250°F at any time.
Wrap the reversing valve with a large rag
saturated with water. "Re-wet" the rag and
thoroughly cool the valve after brazing operation
of the four joints involved.
The wet rag around the reversing valve will
Page 23
eliminate conduction of heat to the valve body
when brazing the line connection.
IMPORTANT
introduced into the system.
5. Facilities for flowing nitrogen through refrigeration
tubing during all brazing processes.
ANY SEALED SYSTEM REPAIRS TO HEAT PUMP
MODELS REQUIRES THE INSTALLATION OF A
SUCTION LINE DRIER IN THE SUCTION LINE
BETWEEN THE COMPRESSOR AND THE
REVERSING VALVE. ELECTRIC HEAT MODELS
REQUIRE A LIQUID LINE DRIER (SEE PARTS
LIST FOR PART NUMBERS.)
SEALED REFRIGERATION SYSTEM REPAIRS
EQUIPMENT REQUIRED
1. Voltmeter
2. Ammeter
3. Ohmmeter
4. E.P.A. Approved Refrigerant Recovery System.
5. Vacuum Pump (capable of 200 microns or less
vacuum.)
6. Acetylene Welder
7. Electronic Halogen Leak Detector (G.E. Type H-6
or equivalent.)
HERMETIC COMPONENT REPLACEMENT
The following procedure applies when replacing components in the sealed refrigeration circuit or repairing refrigerant leaks. (Compressor, condenser, evaporator,
capillary tube, refrigerant leaks, etc.)
1.Recover the refrigerant from the system at the
process tube located on the high side of the system by installing a line tap on the process tube.
Apply gauge from process tube to EPA approved
gauges from process tube to EPA approved recovery system. Recover CFCs in system to at
least 5%.
2.Cut the process tube below pinch off on the suction side of the compressor.
3.Connect the line from the nitrogen tank to the suction process tube.
4.Drift dry nitrogen through the system and unsolder the more distant connection first. (Filter drier,
high side process tube, etc.)
5.Replace inoperative component, and always install a new filter drier. Drift dry nitrogen through the
system when making these connections.
8. Accurate refrigerant charge measuring device such
as:
a. Balance Scales - 1/2 oz. accuracy
b. Charging Board - 1/2 oz. accuracy
9. High Pressure Gauge - (0 - 400 lbs.)
10. Low Pressure Gauge - (30 - 150 lbs.)
11. Vacuum Gauge - (0 - 1000 microns)
EQUIPMENT MUST BE CAPABLE OF:
1. Recovery CFC's as low as 5%.
2. Evacuation from both the high side and low side of
the system simultaneously.
3. Introducing refrigerant charge into high side of the
system.
4. Accurately weighing the refrigerant charge actually
6.Pressurize system to 30 PSIG with proper refrigerant and boost refrigerant pressure to 150 PSIG
with dry nitrogen.
7.Leak test complete system with electric halogen
leak detector, correcting any leaks found.
8.Reduce the system to zero gauge pressure.
9.Connect vacuum pump to high side and low side
of system with deep vacuum hoses, or copper
tubing. (Do not use regular hoses.)
10.Evacuate system to maximum absolute holding
pressure of 200 microns or less. NOTE: This process can be speeded up by use of heat lamps, or
by breaking the vacuum with refrigerant or dry nitrogen at 5,000 microns. Pressure system to 5
PSIG and leave in system a minimum of 10 minutes. Recover refrigerant, and proceed with evacuation of a pressure of 200 microns or a minimum
of 10%.
11.Break vacuum by charging system from the high
Page 24
side with the correct amount of refrigerant specified.
This will prevent boiling the oil out of the crankcase.
NOTE: If the entire charge will not enter the high
side, allow the remainder to enter the low
side in small increments while operating the
unit.
ROTARY COMPRESSOR SPECIAL
TROUBLESHOOTING AND SERVICE
Basically, troubleshooting and servicing rotary
compressors is the same as on the reciprocating
compressor with only a few exceptions.
12.Restart unit several times after allowing pressures
to stabilize. Pinch off process tubes, cut and solder
the ends. Remove pinch off tool, and leak check
the process tube ends.
SPECIAL PROCEDURE IN THE CASE OF
COMPRESSOR MOTOR BURNOUT
1.Recover all refrigerant and oil from the system.
2.Remove compressor, capillary tube and filter drier
from the system.
3.Flush evaporator condenser and all connecting
tubing with dry nitrogen or equivalent, to remove
all contamination from system. Inspect suction and
discharge line for carbon deposits. Remove and
clean if necessary.
4.Reassemble the system, including new drier
strainer and capillary tube.
5.Proceed with processing as outlined under
hermetic component replacement.
1.Because of the spinning motion of the rotary, the
mounts are critical. If vibration is present, check
the mounts carefully.
2.The electrical terminals on the rotary are in a
different order than the reciprocating compressors.
The terminal markings are on the cover gasket.
Use your wiring diagram to insure correct
connections.
REFRIGERANT CHARGE
1. The refrigerant charge is extremely critical. Measure
charge carefully - as exact as possible to the
nameplate charge.
2. The correct method for charging the rotary is to
introduce liquid refrigerant into the high side of the
system with the unit off. Then start compressor and
enter the balance of the charge, gas only, into the
low side.
The introduction of liquid into the low side, without
the use of a capillary tube, will cause damage to the
discharge valve of the rotary compressor.
NOTE: All inoperative compressors returned to
Friedrich must have all lines properly plugged
with the plugs from the replacement
compressor.
Page 25
TROUBLESHOOTING TOUCH TEST CHART
TO SERVICE REVERSING VALVES
NORMAL FUNCTION OF VALVE
VALVE
OPERATING
CONDITION
DISCHARGE TUBE
from Compressor
SUCTION TUBE to
Compressor
Tube to INSIDE
COIL
Tube to OUTSIDE
COIL
LEFT Pilot
Capillary Tube
RIGHT Pilot
* TEMPERATURE OF VALVE BODY
** WARMER THAN VALVE BODY
Capillary Tube
NOTES:
123456POSSIBLE CAUSESCORRECTIONS
NormalHotCoolCoolHot*TVBTVB
Coolingas (2) as (1)
Normal HeatingHotCoolHot Cool *TVBTVB
as (1) as (2)
MALFUNCTION OF VALVE
No voltage to coil.
Defective coil.
Low charge
Pressure differential too high.
Pilot valve okay. Dirt in one
Hot
bleeder hole.
Piston cup leak
Clogged pilot tubes.
Hot
Hot
Hot
Hot
Hot
Both ports of pilot open. (Back seat
port did not close).
Defective Compressor
Not enough pressure differential at
start of stroke or not enough flow to
maintain pressure differential.
Body damage
Both ports of pilot open.
Body damage
Valve hung up at mid-stroke.
Pumping volume of compressor not
sufficient to maintain reversal.
Both ports of pilot open.
Piston needle on end of slide leaking.
Pilot needle and piston needle leaking
**
Pressure differential too high
.
Clogged pilot tube.
Dirt in bleeder hole.
Valve will not
shift from
cool to heat.
Valve will not
shift from
cool to heat.
Starts to
shift but
does not
complete
reversal.
Apparent
leap in
heating.
Will not shift
from heat to
Hot
Hot
Hot
Warm
Hot
Hot
Hot
Hot
Hot
Hot
Hot
Hot
Check Electrical circuit and coil
Check refrigeration charge
Cool
Cool
Cool
Cool
Warm
Warm
Hot
Hot
Cool
Cool
Cool
Cool
Cool,
as (2)
Cool,
as (2)
Cool,
as (2)
Cool,
as (2)
Warm
Warm
Hot
Hot,
Hot,
as (1)
Hot,
as (1)
Hot,
as (1)
Hot,
as (1)
Hot,
as (1)
Hot,
as (1)
Hot,
as (1)
Warm,
as (1)
Hot
Hot
Hot
Hot
Cool,
as (2)
Cool,
as (2)
Cool,
as (2)
Cool,
as (2)
*TVB
*TVB
Hot
*TVB
*TVB
Hot
*TVB
Hot
*TVB
**
WVB
*TVB
Hot
*TVB
Warm
*TVB
WVB
*TVB
*TVB
cool.
Hot
Cool
as (1)
Hot
Cool
Warm
Valve operated satisfactorily PRIOR to compressor motor burnout – caused by dirt and small greasy particles inside the valve. TO CORRECT: Remove valve,
thoroughly wash it out. Check on air before reinstalling, or replace valve. Add strainer and filter-drier to discharge tube between valve and compressor.
Cool
as (1)
Warm,
as (1)
Hot,
Hot,
Cool,
as (2)
Cool,
as (2)
Cool,
as (2)
Hot
Hot
Warm
*TVB
Hot
*TVB
Piston cup leak
Defective pilot.
Defective compressor.
Repair electrical circuit.
Replace coil.
Repair leak, recharge system.
Recheck system.
De-energize solenoid, raise head pressure,
reenergize solenoid to break dirt loose. If
unsuccessful, remove valve, wash out.
Check on air before installing. If no
movement, replace valve, add strainer to
discharge tube, mount valve horizontally.
Stop unit. After pressures equalize, restart
with solenoid energized. If valve shifts, reattempt with compressor running. If still no
shift, replace valve.
Raise head pressure, operate solenoid to free.
If still no shift, replace valve.
Raise head pressure, operate solenoid to free
partially clogged port. If still no shift, replace
valve.
Check unit for correct operating pressures
and charge. Raise head pressure. If no shift,
use valve with smaller port.
Replace valve
Raise head pressure, operate solenoid. If no
shift, replace valve.
Replace valve
Raise head pressure, operate solenoid. If no
shift, use valve with smaller ports.
Raise head pressure, operate solenoid. If no
shift, replace valve.
Operate valve several times, then recheck.
If excessive leak, replace valve.
Operate valve several times, then recheck.
If excessive leak, replace valve.
Stop unit. Will reverse during equalization
period. Recheck system
Raise head pressure, operate solenoid to free
dirt. If still no shift, replace valve.
Raise head pressure, operate solenoid.
Remove valve and wash out. Check on air
before reinstalling, if no movement, replace
valve. Add strainer to discharge tube. Mount
valve horizontally.
Stop unit. After pressures equalize, restart
with solenoid de-energized. If valve shifts,
re-attempt with compressor running. If it still
will not reverse while running, replace the
valve.
Replace valve.
Page 26
TROUBLESHOOTING COOLING
Compressor does not
run.
PROBLEM
Fan motor
does not run.
POSSIBLE CAUSEPROBLEM
Low voltage.
Thermostat not set cold enough or
inoperative.
Compressor hums but cuts off on
overload.
Open or shorted compressor
windings.
Open overload.
Open capacitor.
Inoperative system switch.
Broken, loose or incorrect wiring.
POSSIBLE CAUSE
Inoperative system switch.
Broken, loose or incorrect wiring.
Open capacitor.
Fan speed switch open.
Inoperative fan motor.
TO CORRECT
Check for voltage at compressor. 115 volt and 230 volt
units will operate at 10% voltage variance
Set thermostat to coldest position. Test thermostat
and replace if inoperative.
Hard start compressor. Direct test compressor. If
compressor starts, add starting components.
Check for continuity and resistance.
Test overload protector and replace if inoperative.
Test capacitor and replace if inoperative.
Test for continuity in all positions. Replace if
inoperative.
Refer to appropriate wiring diagram to check wiring.
TO CORRECT
Test switch and replace in inoperative.
Refer to applicable wiring diagram.
Test capacitor and replace if inoperative.
Test switch and replace if inoperative.
Test fan motor and replace if inoperative. (Be
sure internal overload has had time to reset.)
PROBLEM
Does not cool, or cools
only slightly.
POSSIBLE CAUSE
Undersized unit.
Thermostat open or inoperative.
Dirty filter.
Dirty or plugged condenser or
evaporator coil.
Poor air circulation in area being
cooled.
Fresh air or exhaust air door open
on applicable models.
Low capacity – undercharge.
Compressor not pumping properly.
TO CORRECT
Refer to Sizing Charts.
Set to coldest position. Test thermostat and
replace if necessary.
Clean as recommended in Owner’s Manual.
Use steam or detergents to clean.
Adjust discharge air louvers. Use high fan
speed.
Close doors. Instruct customer on use of
this feature.
Check for leak and make repair.
Check amperage draw against nameplate. If
not conclusive, make pressure test.
Page 27
PROBLEM
Unit does not run.
POSSIBLE CAUSE
Fuse blown or circuit tripped.
Power cord not plugged in.
System switch in "Off" position.
Inoperative system switch.
Loose or disconnected wiring at
switch or other components.
TO CORRECT
Replace fuse, reset breaker. If repeats,
check fuse or breaker size. Check for
shorts in unit wiring and components.
Set switch correctly.
Test for continuity in each switch position.
Check wiring and connections. Reconnect
per wiring diagram.
PROBLEM
Evaporator coil
freezes up.
PROBLEM
Compressor runs
continually.
Does not cycle off.
POSSIBLE CAUSE
Dirty filter.
Restricted air flow.
Inoperative thermostat.
Short of refrigerant.
Inoperative fan motor.
Partially restricted capillary.
POSSIBLE CAUSE
Excessive heat load.
Restriction in line.
Refrigerant leak.
Thermostat contacts stuck
Thermostat incorrectly wired.
TO CORRECT
Clean as recommended in Owner’s Manual.
Check for dirty or obstructed coil - clean as required.
Test for shorted thermostat or stuck contacts.
De-ice coil and check for leak.
Test fan motor and replace if inoperative.
De-ice coil. Check temperature differential across
coil. Touch test coil return bends for same temperature. Test for low running current.
TO CORRECT:
Unit undersized. Test cooling performance of unit.
Replace with larger unit.
Check for partially iced coil. Check temperature
split across coil.
Check for oil at silver soldered connections. Check
for partially iced coil. Check split across coil.
Check for low running amperage.
Check operation of thermostat. Replace if contacts
remain closed.
Refer to appropriate wiring diagram.
PROBLEM
Thermostat does not
turn unit off.
Page 28
POSSIBLE CAUSE
Thermostat contacts stuck.
Thermostat set at coldest point.
Incorrect wiring.
Unit undersized for area to be cooled.
TO CORRECT:
Replace thermostat.
Turn to higher temperature setting to see if the unit
cycles off.
Refer to appropriate wiring diagram.
Refer to Sizing Chart.
PROBLEM
Compressor attempts
to start, or runs for
short periods only.
Cycles on overload.
POSSIBLE CAUSETO CORRECT
Overload inoperative. Opens too soon.
Compressor attempts to start before
system pressures are equalized.
Low or fluctuating voltage.
Incorrect wiring.
Shorted or incorrect capacitor.
Restricted or low air flow through
condenser coil.
Compressor running abnormally hot.
Check operation of unit. Replace overload if
system operation is satisfactory.
Allow a minimum of two (2) minutes for pressures
to equalize before attempting to restart. Instruct
customer of waiting period.
Check voltage with unit operating. Check for other
appliances on circuit. Air conditioner should be on
separate circuit for proper voltage, and be fused
separately.
Refer to appropriate wiring diagram.
Check by substituting a known good capacitor of
correct rating.
Check for proper fan speed or blocked condenser.
Check for kinked discharge line or restricted
condenser. Check amperage.
PROBLEM
Thermostat does not
turn unit on.
PROBLEM
Noisy operation.
PROBLEM
Water leaks into room.
POSSIBLE CAUSE
Loss of charge in thermostat bulb.
Loose or broken parts in thermostat.
Incorrect wiring.
POSSIBLE CAUSE
Poorly installed unit.
Fan blade striking chassis.
Compressor vibrating.
Improperly mounted or loose cabinet
parts.
POSSIBLE CAUSE
Evaporator drain pan overflowing.
Condensation forming on base pan.
Poor installation resulting in rain
entering room.
Condensation on discharge grilles.
TO CORRECT
Place jumper across thermostat terminals to check
if unit operates. If unit operates, replace thermostat.
Check as above.
Refer to appropriate wiring diagram.
TO CORRECT
Refer to Installation Instructions for proper
installation.
Reposition - adjust motor mount.
Check that compressor grommets have not
deteriorated. Check that compressor mounting
parts are not missing.
Check assembly and parts for looseness, rubbing
and rattling.
TO CORRECT
Clean obstructed drain trough.
Evaporator drain pan broken or cracked. Reseal or
replace.
Check Installation Instructions. Reseal as required.
Dirty evaporator coil - clean. Very high humidity
level.
Page 29
PROBLEMPOSSIBLE CAUSETO CORRECT
Replace thermostat.
Check gasket. Reposition or replace.
Clean and advise customer of periodic cleaning of
filter.
Replace tubular insulation on bulb.
(Applicable models.)
Adjust bulb bracket.
(Applicable models.)
Thermostat short
cycles.
Thermostat differential too narrow.
Plenum gasket not sealing, allowing
discharge air to short cycle
thermostat.
Restricted coil or dirty filter.
Tubular insulation missing from top of
thermostat bulb.
Thermostat bulb touching thermostat
bulb support bracket.
PROBLEM
Prolonged off-cycles.
(automatic operation)
PROBLEM
Switches from
cooling to heating.
PROBLEM
Outside water leaks.
POSSIBLE CAUSE
Anticipator (resistor) wire
disconnected at thermostat or system
switch.
Anticipator (resister shorted or open).
(Applicable models.)
Partial loss of charge in thermostat
bulb causing a wide differential.
POSSIBLE CAUSE
Thermostat sticking.
Incorrect wiring.
Evaporator drain pan cracked or
obstructed.
Water in compressor area.
Obstructed condenser coil.
Fan blade and slinger ring improperly
positioned.
TO CORRECT
Refer to appropriate wiring diagram.
Disconnect plug from outlet. Remove resistor from
bracket. Insert plug and depress "Cool" and "Fan Auto (MoneySaver)" buttons. Place thermostat to
warmest setting. Feel resistor for temperature. If
no heat, replace resistor.
Replace thermostat.
TO CORRECT
Change room thermostat.
Refer to appropriate wiring diagram.
TO CORRECTPOSSIBLE CAUSE
Repair, clean or replace as required.
Detach shroud from pan and coil. Clean and
remove old sealer. Reseal, reinstall and check.
Steam clean.
Adjust fan blade to 1/2" clearance from condenser
coil.
Page 30
High indoor
humidity.
POSSIBLE CAUSEPROBLEM
Insufficient air circulation in air conditioned area.
Oversized unit.
Inadequate vapor barrier in building
structure, particularly floors.
Set thermostat to a warmer position.
Replace — do not attempt to adjust.
Check compressor wiring. Check for open internal
or external overload. Check wiring.
Test system switch
TO CORRECT
Clean as recommended in Owner’s Manual.
Check if outdoor thermostat is energizing the
heating element at its predetermined temperature
setting
Check control setting.
TO CORRECT
Check continuity of switch.
Check applicable wiring diagram.
TO CORRECT
Incorrect differential setting. Replace thermostat.
Check voltage to resistor. If voltage okay, remove
resistor from thermostat bulb block. With current
on, feel resistor for warmth. If no heat can be felt,
replace anticipator.
Wide differential — partial loss of
thermostat bulb charge.
Incorrect wiring.
POSSIBLE CAUSE
Incorrect wiring.
Defrost control timer motor not advancing.
Defrost control out of calibration.
Defrost control contacts stuck.
Defrost control bulb removed from coil,
or not making good coil contact.
TO CORRECT
Disconnect power to unit. Remove resistor from
thermostat bulb block. Plug in unit and allow to
operate. Feel resistor for heat. If no heat is felt,
replace resistor.
Replace thermostat and check.
Refer to appropriate wiring diagram. Resistor is
energized during the "on" cycle of compressor or
fan.
TO CORRECT
Refer to appropriate wiring diagram.
Check for voltage at "TM" and "TM1" on timer. If
voltage, replace control.
If outside coil temperature is 25° F or below, and
pre-selected time limit has elapsed, replace the
defrost control.
If the contacts remain closed between terminals "2"
and "3" of the defrost control after pre-selected time
interval has passed, replace control.
Reinstall and assure that good bulb to coil contact
is made.
Page 31
PROBLEM
Unit does not heat
adequately.
POSSIBLE CAUSE
Outdoor thermostat does not cut off
compressor at the pre-selected
temperature and bring on the heating
element.
Fresh air or exhaust door open.
Dirty filter.
Unit undersized.
TO CORRECT
Defective thermostat — replace.
Check if operating properly. Instruct customer on
proper use of control.
Clean as recommended in Owner’s Manual
Check heat rise across coil. Refer to performance
data sheet on heat rise at various outdoor ambients.
If heat rise is satisfactory, check if insulation can be
added to attic or walls.
Unit cools when heat
is called for.
PROBLEM
Cooling adequate —
heating insufficient.
Compressor will not turn
off and operate on
heating element only
during low outside
ambients.
POSSIBLE CAUSEPROBLEM
Incorrect wiring.
Defective solenoid coil.
Reversing valve fails to shift.
Reversing valve failing to shift completely — bypassing hot gas.
POSSIBLE CAUSEPROBLEM
Outdoor thermostat.
(Applicable models.)
TO CORRECT
Refer to applicable wiring diagram.
Check for continuity of coil.
Block condenser coil and switch unit to cooling.
Allow pressure to build up in the system, then switch
to heating. If valve fails to shift, replace valve.
Check for continuity of system switch.
TO CORRECT
Check for partially starved outer coil. Replace
heating capillary tube.
Switch unit several times from heating to cooling.
Check temperature rise across the coil. Refer to
specification sheet for correct temperature rise.
De-energize solenoid coil, raise head pressure,
energize solenoid to break loose. If valve fails to
make complete shift, replace valve.
TO CORRECT
Refer to the heating data on applicable models for
the pre-selected temperature the compressor shuts
off and the electric element is energized.
Compressor shuts off
on outdoor thermostat
but element does not
heat.
Page 32
POSSIBLE CAUSEPROBLEM
Fuse link.
Heating element shorted.
Incorrect wiring.
Heat relay or heater contactor coil open.
TO CORRECT
Check fuse link for continuity. If defective, replace.
Check amperage draw of element. If no amperage,
replace.
Check voltage to element. If voltage is okay, check
wiring.
Defective coil. Test coil for continuity.
Troubleshooting Heating
(Cooling/Electric Models)
Heater relay or contactor coil open.
Heater relay or contactor stuck open,
Fan Operates –
heating element does
not come on.
pitted or burned.
High limit control open.
Open thermal fuse.
Open or shorted element.
Loose connections.
TO CORRECTPOSSIBLE CAUSEPROBLEM
Check continuity of coil.
Inspect, test continuity with ohmmeter.
Check continuity – if open, replace.
Check continuity. Check reason for failure.
Check voltage across heater terminals. Check
amperage draw of heater.
Tighten all terminals.
PROBLEM
Heating inadequate.
PROBLEM
Fan operates in "Con-
stant" position, but not
in "Automatic" (Money-
Saver).
PROBLEM
Long "off" and "on"
cycles.
POSSIBLE CAUSE
Restricted filter.
Cycling high limit control.
Exhaust or fresh air door open.
POSSIBLE CAUSE
Fan relay contacts open.
Inoperative system switch.
Loose connection.
POSSIBLE CAUSE
Heat anticipator (resistor) shorted.
Defective thermostat.
TO CORRECT
Clean as recommended in Owner’s Manual.
Control is set to open at 155°F± 5°F and close at
130°F± 8°F. If cycling prematurely, replace control.
Check position of fresh air door control slide. Adjust
cable if door does not close properly.
TO CORRECT
Check continuity of fan relay. NOTE: Some
models have the fan relay energized during the
heating cycle while others do not.
Check continuity between terminals "L2" and "3" of
the system switch.
Check connections on system switch and fan relay.
TO CORRECT
Disconnect power to unit. Remove resistor from
thermostat bulb block. Plug in unit and allow to
operate. Feel resistor for heat. If no heat is felt,
replace resistor.
Replace thermostat and check operation.
Page 33
PROBLEM
Fan motor does not
operate in "Constant"
or "MoneySaver"
position.
POSSIBLE CAUSE
Defective motor.
Open or shorted capacitor.
Condenser fan frozen to base pan.
Loose connections.
TO CORRECT
Check and replace.
Replace capacitor and check.
Check if drain pan valve is open. If not, replace.
Check all connections. Check voltage to fan motor.
Reversing valve failing to shift
completely – bypassing hot gas.
POSSIBLE CAUSE
Outdoor thermostat.
(Applicable models.)
TO CORRECT
Check for partially starved outer coil. Replace
heating capillary tube.
Switch unit several times from heating to cooling.
Check temperature rise across coil. Refer to
specification sheet for correct temperature rise.
De-energize solenoid coil, raise head pressure,
energize solenoid to break loose. If valve fails to
make complete shift, replace valve.
TO CORRECT
Refer to the heating data on applicable models for
the pre-selected temperature the compressor shuts
off and the electric element is energized.
Compressor shuts off
on outdoor thermostat
but, element does not
heat.
Page 34
Fuse link.
Heating element shorted.
Incorrect wiring.
Heat relay or heater contactor coil open.
TO CORRECTPOSSIBLE CAUSEPROBLEM
Check fuse link for continuity. If defective, replace.
Check amperage draw of element. If no amperage,
replace.
Check voltage to element. If voltage is okay, check
wiring.
Defective coil. Test coil for continuity.
Troubleshooting Heating
(Cooling/Electric Models)
PROBLEMPOSSIBLE CAUSE
Heater relay or contactor coil open.
Heater relay or contactor stuck
Fan operates –heating
element does not
come on.
PROBLEM
Heating inadequate.
PROBLEM
Fan operates in the
"Constant" position,
but not in
"Automatic."
(MoneySaver).
open, pitted or burned.
High limit control open.
Open Thermal fuse.
Open or shorted element.
Loose connections.
POSSIBLE CAUSETO CORRECT
Restricted filter.
Cycling high limit control.
Exhaust or fresh air door open.
POSSIBLE CAUSE
Fan relay contacts open.
Inoperative system switch.
Loose connection.
TO CORRECT
Check continuity of coil.
Inspect, test continuity with ohmmeter.
Check continuity – if open, replace.
Check Continuity. Check reason for failure.
Check voltage across heater terminals. Check
amperage draw of heater.
Tighten all terminals.
Clean as recommended in Owner’s Manual.
Control is set to open at 155ºF±5ºF and close at
130ºF±8ºF. If cycling prematurely, replace control.
Check position of fresh air door control slide.
Adjust cable if door does not close properly.
TO CORRECT
Check continuity of fan relay. NOTE: Some
models have the fan relay energized during the
heating cycle while others do not.
Check continuity between terminals "L2" and "3"
of the system switch.
Check connections on system switch and fan
relay.
Long "off" and "on"
cycles.
Heat anticipator (resistor) shorted.
Defective thermostat.
TO CORRECTPOSSIBLE CAUSEPROBLEM
Disconnect power to the unit. Remove the
resistor from the thermostat bulb block. Plug in
the unit and allow to operate. Feel the resistor for
heat. If no heat is felt, replace the resistor.
Replace thermostat and check operation.
Page 35
WIRING DIAGRAM FOR MODEL YS09J10-1
Page 36
WIRING DIAGRAM FOR MODELS YS13J33, YM18J34A & YL24J35A
Page 37
WIRING DIAGRAM FOR MODELS ES12J33, ES15J33A, EM18J34A