14
Fig. 30 — Differential Enthalpy Control Wiring (33CSENTHSW and 33CSENTSEN)
START-UP
Follow the procedure in Table 6 to check the EconoMi$er2 system
when the unit is started.
OPERATION
NOTE: For units using a third party control, operation of the
EconoMi$er2 system is based on the type of control and sensors
used. The following operation sections are for units with
PremierLink control only.
Cooling, Units with EconoMi$er 2, PremierLink
Control and a Thermostat
When free cooling is not available, the compressors will be
controlled by the PremierLink control in response to the Y1 and
Y2 inputs from the thermostat.
The PremierLink control will use the following information to
determine if free cooling is available:
• Indoor fan has been on for at least 30 seconds.
• The SPT, SAT, and OAT inputs must have valid readings.
• OAT must be less than 75°F.
• OAT must be less than SPT.
• Enthalpy must be LOW (may be jumpered if an enthalpy
sensor not available).
• Economizer position is NOT forced.
Pre-cooling occurs when there is no call from the thermostat
except G. Pre-cooling is defined as the economizer modulates to
provide 70°F supply air.
When free cooling is available, the PremierLink control will
control the compressors and economizer to provide a supply air
temperature determined to meet the Y1 and Y2 calls from the
thermostat using the following 3 routines. The 3 control routines
are based on OAT.
The 3 routines are based on OAT where:
• SASP = Supply Air Set Point
• XCTLO = Direct Expansion Cooling Lockout Set Point
• PID = Proportional Integral
ROUTINE 1 (OAT<DXCTLO)
• Y1 energized - economizer maintains a
SASP = ( 3)
• Y2 energized - economizer maintains a
SASP = ( 3)
LEGEND
N/C
- Normally Closed
N/O
- Normally Open
24 VAC
SECONDARY
24 vac output from n/c contact
when the outdoor enthalpy is
less than the indoor enthalpy
(Enable economizer)
24 vac output from n/c contact
when the Indoor enthalpy is
greater than the outdoor enthalpy
(Enable energy$recycler
)
ORN
BRN
RED
HI LOW GND 24
ENTHALPY VAC
4-20 24-36
mA
IN
VDC
OUT
33CSENTHSW
33CSENTSEN
mA
IN
VDC
OUT
4-20
24-36
JUMPER SETTINGS FOR 33CSENTHSW
JUMPER SETTINGS FOR 33CSENTSEN
0%
50%
100%
OFF
M1
M2
M3
0%
50%
100%
OFF
M1
M2
M3