Installation guide

O
_[_0
•slq]l] 0
_R[_ 0
©
0 0
0
O0
_T
ABeD
* SUPPLIED BY UTILITY PROVIDER
%
MODEL
PLUG
O
_l_Z1 0 0 0
0
o
oo
,#
MODEL
PLUG
_'r
©
i iquk{ i ine S,,lenok{
A06525
Fig. 6 - 2-Stage Control Board
GENERAL INFORMATION
Low Ambient Cooling
When this unit is operating below 55°F (12.78°C) outdoor
temperature, provisions must be made for low ambient operation.
Infinity Controlled low ambient cooling:
This unit is capable of low ambient cooling without a kit ONLY
when using Infinity control. A low ambient kit is not required, and
the outdoor fan motor does not need to be replaced for Infinity
controlled low ambient operation. The Infinity Control provides an
automatic evaporator coil freeze protection algorithm that
eliminates the need for an evaporator freeze thermostat. Low
ambient cooling must be enabled in the User Interface set up. Fan
may not begin to cycle until about 40°F (4.4°C) OAT. Fan will
cycle based on coil and outdoor air temperature.
Infinity controlled low ambient mode operates as follows:
• Fan is OFF when outdoor coil temp is < (outdoor air temperature
+ 3 °F / 1.7° C) or outdoor fan has been ON for 30 minutes. (Fan
is turned off to allow refrigerant system to stabilize.)
• Fan is ON when outdoor coil temp > (outdoor air temperature +
25°F / 13.9°C) or outdoor coil temp > 80°F/26.7°C or if
outdoor fan has been OFF for 30 minutes. (Fan is turned on to
allow refrigerant system to stabilize.)
• Low pressure switch is ignored for first 3 minutes during low
ambient start up. After 3 minutes, ifLPS trips, then outdoor fan
motor is turned offfor 10 minutes, with the compressor running.
IfLPS closes within 10 minutes then cooling continues with the
outdoor fan cycling per the coil temperature routine listed above
for the remainder of the cooling cycle. If the LPS does not close
within 10 minutes, then the normal LPS trip response (shut
down cooling operation and generate LPS trip error) will occur.
For 25HNA9 models, the PWM output for both high and low stage
equals the value for low stage operation below 55°F (12.8°C).
A06526
Defrost
This control offers 5 possible defrost interval times: 30, 60, 90, 120
nfinutes, or AUTO.
These are selected by dip switches on the unit control board or by
the Infinity Control User Interface. The Infinity Control selection
overrides the control board dip switch settings.
AUTO defrost adjusts the defrost interval time based on the last
defrost time as follows:
• When defrost time <3 minutes, the next defrost interval=120
minutes.
• When defrost time 3-5 minutes, the next defrost interval=90
minutes.
• When defrost time 5-7 minutes, the next defrost interval=60
minutes.
• When defrost time >7 minutes, the next defrost interval=30
minutes.
The control board accumulates compressor run time. As the
accumulated run time approaches the selected defrost interval time,
the control board monitors the coil temperature sensor for a defrost
demand. If a defrost demand exists, a defrost cycle will be initiated
at the end of the selected time interval. A defrost demand exists
when the coil temperature is at or below 32°F (0°C) for 4 nfinutes
during the interval.
The defrost cycle is ternfinated when the coil temperature reaches
65°F (18.33°C)or 10 nfinutes has passed.
On 25HNA6 models, defrost will occur in low- or high-stage as
demanded by the thermostat or User Interface regardless of OAT
On 25HNA9 models, when OAT is >25°F (-3.9°C), defrost will
occur in low- or high-stage as demanded by the thermostat or
User Interface.
On 25HNA9 models, if OAT is _<25°F (-3.9°C), defrost will
occur in high-stage only, regardless of thermostat or User Interface
demand, and will ternfinate at 50°F (10°C) coil temperature with a
minimum of 2.5 nfinutes in defrost.
If the coil temperature does not reach 32°F (0°C) within the
interval, the interval timer will be reset and start over.
• Upon initial power up the first defrost interval is defaulted to
30 minutes. Remaining intervals are at selected times.
• Defrost is only allowed to occur below 50 °F (10 ° C)outdoor
ambient temperature.