Lennox Core Unit Controller Setup Manual page 60

Control
Parameter Screen Name
No
ECN FRCL ENTH
163
OFFST
ECONOMIZER
164
PROFILE
FAH STAGE
165
DIFFER
FAH REHEAT
166
OAT SP
FAH REHEAT
167
DAMPER
168 FAH REHEAT SP
Table 12. CORE Control System Unit Parameters
Parameter Short
Description
Min.
Economizer Free
Cooling Enthalpy 1
Offset
Economizer
0
Profile
System 2 Parameters
Fresh Air Heating
0
Stage Differential
Fresh Air Heating
Control Reheat
Outdoor Air 20
Temperature Set
Point
Fresh Air Heating
Control Reheat 5
Damper Position
Fresh Air Heat
40
Control Set Point
Control Value
Default Max.
1 5
2 3
2 20
45 60
40 100
40 70
60
Units Description
mA Economizer Free Cooling Enthalpy Offset
These are the operating profile options
for the economizer damper during free
cooling when any compressor is on and
can be selected as follows:
• Option 0: Damper continues to
modulate while compressors are on,
but the effect of mechanical cooling
may force the damper closed to its
minimum position. After compressor
starts, the free cooling setpoint is
lowered to a fixed temperature of
45°F.
Option 1: Damper opens to its
•
max open position (Parameter 131 -
FREE CL MAX DAMPER) when any
compressors start.
NOTE: When using Option 1 and after
the compressor
the M3 will resume damper
modulation.
• Option 2: Damper continues to
modulate while compressors are on,
but the effect of mechanical cooling
may force the damper closed to its
Option
minimum position. This is the factory
default setting.
> Holds off compressor on
Y2 call until damper has
modulated to maximum
position (Parameter 131 -
FREE CL MAX DAMPER) for
three minutes.
> After three minutes,
compressor starts and the
free cooling setpoint is
lowered to 45°F. Damper is
not locked at maximum open
while compressor is on, but
modulates to maintain 45°F
discharge air temperature.
> When Y2 is satisfied,
compressor goes off and free
cooling setpoint is restored to
55°F (Parameter 159 - FREE
COOL SUPPLY SP).
• Option 3: Same as Option 2, but
with a 10 minute delay instead of a
three minute delay.
• Fresh Air Heating stage differential.
°F
• 0 value for first stage heating only
for Fresh Air Heating.
Outdoor air temperature set point that
enables fresh air heating for reheat
°F demand and opens damper to Parameter
167 when outdoor air is less than set
point.
Fresh air damper position during Fresh
%
Air Heating reheat operation.
°F Fresh Air Heating Reheat set point.
is stopped,