Daikin DAR09 - Page 49

49
SYSTEM OPERATION
AFE18-60A Control Board
Descripon
The AFE18 control is designed for use in heat pump applicaons
where the indoor coil is located above/downstream of a gas or
fossil fuel furnace. It will operate with single and two stage heat
pumps and single and two stage furnaces. The AFE18 control
will turn the heat pump unit o when the furnace is turned on.
An an-short cycle feature is also incorporated which iniates
a 3 minute med o delay when the compressor goes o. On
inial power up or loss and restoraon of power, this 3 min-
ute med o delay will be iniated. The compressor won’t be
allowed to restart unl the 3 minute o delay has expired. Also
included is a 5 second de-bounce feature on the “Y, E, W1 and
O” thermostat inputs. These thermostat inputs must be present
for 5 seconds before the AFE18 control will respond to it.
An oponal outdoor thermostat, OT18-60A, can be used with
the AFE18 to switch from heat pump operaon to furnace
operaon below a specic ambient temperature seng, i.e.
break even temperature during heang. When used in this
manner, the “Y” heat demand is switched to the “W1” input to
the furnace by the outdoor thermostat and the furnace is used
to sasfy the rst
stage “Y” heat demand. On some controls, if the outdoor ther-
mostat fails closed in this posion during the heang season,
it will turn on the furnace during the cooling season on a “Y”
cooling demand. In this situaon, the furnace produces heat
and increases the indoor temperature thereby never sasfying
the cooling demand. The furnace will connue to operate and
can only be stopped by switching the thermostat to the o
posion or removing power to the unit and then replacing the
outdoor thermostat. When the AFE18 receives a “Y” and “O”
input from the indoor thermostat, it recognizes this as a cooling
demand in the cooling mode. If the outdoor thermostat is stuck
in the closed posion switching the “Y” demand to the “W1”
furnace input during the cooling mode as described above, the
AFE18 won’t allow the furnace to operate. The outdoor ther-
mostat will have to be replaced to restore the unit to normal
operaon.
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing. Multiple power sources
may be present. Failure to do so may
cause property damage, personal injury
or death.