Data Manual

21
HEAT PUMP OPERATION—ZONELINE AZ65 SERIES
Heat sources: Heat pump, heat pump with partial
electric resistance heat, or electric resistance heat.
Zoneline heat pumps employ a highly featured
microprocessor control system interfaced with thermistors
to accurately measure indoor air temperature, outdoor
air temperature, indoor coil temperature and outdoor coil
temperature. This system allows the microprocessor to
precisely and predictably react to changing conditions
in order to provide a very advanced packaged terminal
heat pump operating system.
Zoneline heat pumps are designed to help ensure a
comfortable room. When “HEAT” is selected, the unit
will determine if the room air is warm enough to satisfy
the thermostat setting. If the temperature at the unit
sensor is below the desired temperature, the electric
resistance heater will be utilized to warm the room to
the point where the thermostat is satisfied. Quick Heat
Recovery is designed to allow the temperature of a
room to be maintained at an energy-saving level without
inconveniencing the room occupant. Once the thermostat
has been satisfied, the resistance heater will turn off and
the heat pump will operate (as shown below in the Heat
Source Logic chart) when the thermostat calls for
heat again.
ROOM
TEMPERATURE
VS. THERMOSTAT
SET POINT
ABOVE
46°F*
BETWEEN 46°F
AND 25°F
BELOW
25°F
1.8 to 2.9°F Below Heat Pump Heat Pump*
Full Resistance
Heat
2.9°F to 4.0°F
Below
Heat Pump
Heat Pump +
Supplemental
Heater**
Full Resistance
Heat
More than 4.0°F
Below
Heat Pump
Full Resistance
Heat
Full Resistance
Heat
* At OD temperatures above 46°F, the electric heaters are locked out.
At OD temperatures above 85°F, heat pump operation is locked out.
** Simultaneous supplemental heater: 1.0 KW @ 230 V & 265V; 0.8 KW @ 208V
The Quick Heat Recovery feature is not affected by the
Heat Source Logic shown in the prior chart.
For more information about the Quick Heat Recovery
feature, see page 11.
The full heat output of the resistance heater is dependent
upon circuit amperage and the power connection kit used.
See pages 4, 43–45 and 53 for information on power
connection kits and available heater capacities.
An option is provided in the auxiliary controls (Mode 8) to
allow the unit to operate only in resistance heat. The use of
this option significantly increases the cost for heating.
ZONELINE HEAT PUMP HEAT SOURCE LOGIC
The chart below indicates the standard heating source
of the Zoneline AZ65 Series heat pump unit under
various indoor and outdoor conditions. The unit is
designed to provide heat pump savings without
sacrificing room comfort.
BOOST HEAT
The Zoneline AZ65 series offers a Boost Heat option
feature that utilizes partial supplemental resistance heat
at the same time as the heat pump operation. The boost
heat feature changes stage one heating (heat pump)
to be heat pump with partial resistance heat. Stage two
heating stays as full resistance heat. This applies to both
unit control and remote thermostat control.
NOTE: Heat Pump and full resistance heat shall never
be on at the same time.
HEAT PUMP DEFROST
Zoneline heat pumps utilize a reverse-cycle, demand-
defrost system to extend heat pump operation and
increase savings from extended operation.
The microprocessor determines the need for defrosting
from criteria based on continuous compressor run time,
outdoor air temperature and outdoor coil temperature.
When defrosting is required, the unit reverses the flow
of refrigerant to direct the hot gas into the outdoor
coil to melt the frost buildup.
Before and after the reverse-cycle defrost, the unit shuts
off the compressor to allow the refrigerant pressures
to equalize throughout the system. During these periods
of pressure equalization, the full resistance heat capacity
of the unit is activated to help ensure room comfort
conditions during the defrost cycle. The unit remains
in the defrost cycle for a minimum of three minutes
and up to a maximum of nine minutes. The defrost cycle
terminates when the outdoor coil reaches a temperature
of 68°F or the maximum time has been reached.
HEAT PUMP CONDENSATE
Zoneline AZ65 Series heat pumps may be ordered with
a factory-installed Internal Condensate Removal (ICR)
system to minimize the amount of condensate water
draining from the unit during heat pump operation.
The ICR system has proven to be an effective means
of minimizing the amount of heat pump condensate
dripping from the unit. However, if the requirements
of a particular installation will allow no dripping of
condensate water from the wall sleeve, the installation
of an internal or external drain system is recommended.
See pages 36–38 for more information on heat pump
condensate.
Units with an ICR system may not be installed in
seacoast or other corrosive environments.
HEAT PUMPS & ENERGY SAVINGS (CONTINUED)
ARCHITECTS & ENGINEERS DATA MANUAL AZ45/AZ65 SERIES