8
803161 Rev. 01
ESEC Heat/Cool Units
Electric Heat / Cool units can accommodate the
following thermostats in either manual or automatic
changeover:
Single Stage Heat/Cool, Single Speed Fan
Single Stage Heat/Cool, Two Speed Fan
Note: The thermostat selection must be verified to
ensure its control logic will always energize a Fan
output (G) on a call for heat – also known as an
Electric Heat Type Thermostat.
General:
All the above can have single speed or two speed fan
control.
The wiring diagrams affixed to the units will guide the
specific connection strategies for the particular
thermostats used.
THERMOSTAT LOCATION:
Proper functioning of the thermostat depends on
accurate room temperature sensing. Be conscious of
locating the thermostat where temperatures near the
thermostat are not representative of room temperature.
For example, do not install the thermostat where it is
subjected to direct sunlight, other sources of heat, or to
cold drafts, including air discharged from a supply air
register. A common error is forgetting to seal the hole
in the wall where the thermostat cable passes through,
directly behind the thermostat body. Air bleeding from
behind the wall can drastically affect the temperature
sensed by the thermostat.
REMOTE THERMOSTAT OPERATION
When the unit is first plugged in, or when recovering
from a power outage, there will be a random 5 to 15
second delay before the electronic control powers up.
The keypad will be totally disabled once the DIP
switch has been set for remote mode. The unit will
obey the commands from the thermostat only.
The thermostat will automatically maintain the
temperature in the room, based on the setting pre-set by
the user. If the thermostat has only single fan speed
capability, a decision will need to be made as to
whether the fan will always run in high speed or low
speed, and then the appropriate fan speed wiring
connection can be made at the unit.
All the internal control features of the electronic board
remain active, except for keyboard and display
interface functions and room temperature sampling.
Room temperature is detected at the location of the
wall thermostat, and is usually a much more accurate
representation of bulk room temperature. The
thermostat used may have advanced features beyond
the basic functions described below. Consult your
thermostat Installation and Operating Instructions for
further information.
In addition to controlling room temperature, the room
thermostat is also used to select whether the unit is to
be in heating mode, or cooling mode, or in automatic
changeover between the modes. It also determines
whether the system is to be ON or OFF, and whether
the fan is to run continuously, or to cycle with heating
or cooling demand.
Figure 2
Once a comfortable temperature setting is established,
no other adjustments are necessary, except for fan
speed, which may or may not be adjustable on your
particular thermostat.
CAUTION
: One side of the unit’s 24-volt control system
is grounded. When wiring the thermostat, care must be
taken not to ground the wires, or drive a nail through the
thermostat wire bundle, thereby potentially burning out
the transformer.
