Friedrich OES Series, Installation & Operation Manual

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920-138-02 (3-04) 920-138-02 (3-04)
III. START UP
SEQUENCE OF OPERATION
COOLING - Any call for cooling from the thermostat completes
the R-Y circuit which activates the compressor contactor,
starting both the compressor and outdoor fan motor. The G
circuit (indoor fan motor) is automatically completed on any call
for cooling operation. It can also be energized by the manual fan
switch on the thermostat to provide constant air circulation.
HEATING (OHS Models) - Positioning the thermostat system
switch for heat activates the 24-Volt solenoid on the reversing
valve. The solenoid terminal "B" is activated constantly from
thermostat contact "R" while the switch is in the heating
position. A thermostat call for 1st stage heat also completes
R-Y, the circuit activating the compressor contactor starting
the compressor and blower motor in the same manner that it
does in cooling.
DEFROST CYCLE
(OHS MODELS ONLY)
The heat pump control manages temperature and time to control
the defrost cycle.
Ambient temperatures below 40°F can result in coil temperatures
below freezing. At these temperatures the coil temperature
sensor will signal the heat pump control which starts the
defrost timer.
The heat pump control will place the system in defrost mode
after it has received coil temperature reports of 30°F or below
for 30, 60, or 90 minutes.
In Defrost Mode, the reversing valve switches the unit to normal
cooling mode, and the hot gasses melt the ice and frost off of the
outdoor coil. During this process, the outdoor fan motor stops,
and electric strip heaters are activated indoors to maintain the
temperature. Once the coil sensor detects 55°F, the heat pump
sensor returns the unit to the heating cycle.
Occasionally in high winds and extreme cold, temperatures may
create a situation where the sensor does not detect 55°F. In this
situation, the heat pump control will restart heat pump operation
in the heating mode after ten minutes.
The heat pump control provides three timer settings (30, 60, and
90 minutes). These settings control the time that the outdoor coil
remains below 32°F before the defrost cycle is started. Units are
shipped at the 60 minute setting for greatest operating economy.
If you need to change the setting, remove the wire connected to
the "60" terminal and reconnect it to the desired terminal.
FINAL INSTALLATION CHECKLIST
1. Make sure circuit breakers inside unit are ON.
2. Check to see if all duct work is sealed to unit for an
airtight fit.
3. Thermostat is level and properly installed. Heat
anticipator indicator is set to the correct setting.
4. Test run in Heating, Cooling, and Emergency Heat
(OHS only) mode as follows:
a. Set fan control to ON. If fan runs, return
control to AUTO setting. This verifies fan is
working properly.
b. Set system control from OFF to COOL. Lower
temperature selector to 50°F or lower. The
compressor should energize and cool air
should flow from room registers. Once cooling
test is complete, return system control to OFF
setting. Wait 5 minutes.
c. Set system control to HEAT and raise
temperature selector to 80°F or higher. On
OHS models, compressor should energize,
and warm air should flow from room registers.
On OES models, strip heater will turn on.
d. Set system control to EM HEAT (Emergency
Heat). Compressor should turn off and warm
air should continue to flow from registers.
NOTE: On heat pump units in EM HEAT operation, the
compressor is turned off and heat is provided by the electric
heating strips. Therefore, the temperature of the discharge
air may be warmer or cooler depending on the capacity of the
heat strips used during EM Heat operation.
5. Leave this Installation/Operation Manual with owner or
user of equipment.
6. After 72 hours of operation, the unit will achieve full
rated operating performance.
Make sure that ALL panels are properly installed and ALL screws
are returned to their original location and fastened securely.
IV. SERVICE / WARRANTY
SERVICE HINTS
Caution the end user to maintain clean air filters at all times,
and to not needlessly close off supply and return air registers.
This reduces air flow throughout the system which shortens
equipment service life and increases operating costs.
Alert the end user that switching to the heating cycle when the
ambient temperature is 75 ° F or higher may trip the automatic
reset high pressure switch. The switch will reset automatically
once the high pressure situation is eliminated. Check all power
fuses or circuit breakers to ensure they are of the correct rating.
Periodic cleaning of the outdoor coil is essential to permit full
and unrestricted air flow circulation.
PRESSURE SERVICE PORTS
High and low pressure service ports are standard on all units
so the system operating pressures can be measured.
A technical service data label is located on the actual unit.