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Manual 2100-571A
Page 12 of 31
2. 1-Stage Compressor Units with Newer
ECONWMT Economizers (See Note A)
1
st
stage cooling set point is the setting (SP) input into
the controller. Factory default is 77F (25C). On a call
for cooling the blower of the lead unit will come on
immediately (if not already on – See Blower Operation),
and the Stage 1 LED will blink for 10-seconds before
going solid, at which time the lead unit Y1 cooling
output turns on. If the outdoor temperature and
humidity conditions are below the set point of the
economizer control the lead unit economizer will
operate instead of the compressor. If outdoor conditions
are not acceptable for free cooling the compressor will
automatically operate instead of the economizer.
2
nd
cooling set point is 4F (default setting, user
selectable 2-6F) warmer than Stage 1. On a call for
2
nd
stage cooling the lead unit Y2 cooling output turns
on. If the outdoor temperature and humidity conditions
are below the set point of the economizer control the
lead unit economizer will continue to operate, and the
compressor will operate. If the compressor is already
operating on 1
st
stage cooling because outside free
cooling range no action occurs at 2
nd
cooling set point.
3
rd
cooling set point is 2F (default setting, user selectable
2-3F) warmer than Stage 2. On a call for 3
rd
Stage cooling
the blower of the lag unit will come on immediately (if
not already on – See Blower Operation), and the Stage
3 LED will blink for 10-seconds before going solid,
at which time the lag unit Y1 cooling output turns on.
The lag unit economizer will operate if the outdoor
temperature and humidity conditions are below the set
point of the economizer control. If outdoor conditions
are not acceptable for free cooling the compressor will
automatically operate instead of the economizer.
4
th
cooling set point is 2F (default setting, user
selectable 2-3F) warmer than Stage 3. On a call for
4
th
Stage cooling the lag unit Y2 cooling output turns
on activating the lag unit compressor. If the outdoor
temperature and humidity conditions are below the set
point of the economizer control the lag unit economizer
will continue to operate. If the compressor is already
operating on 3
rd
stage cooling because outside free
cooling range no action occurs at 4
th
cooling set point.
3. 2-Stage Compressor Units with Newer
ECONWMT Economizers (See Note A)
1
st
stage cooling set point is the setting (SP) input into
the controller. Factory default is 77F (25C). On a call
for cooling the blower of the lead unit will come on
immediately (if not already on – See Blower Operation),
and the Stage 1 LED will blink for 10-seconds before
going solid, at which time the lead unit Y1 cooling
output turns on. If the outdoor temperature and
humidity conditions are below the set point of the
economizer control the lead unit economizer will
operate instead of the compressor. If outdoor conditions
are not acceptable for free cooling the compressor will
automatically operate on compressor Stage 1 partial
capacity instead of the economizer.
2
nd
cooling set point is 4F (default setting, user
selectable 2-6F) warmer than Stage 1. On a call for
2
nd
stage cooling the lead unit Y2 cooling output turns
on. If the outdoor temperature and humidity conditions
are below the set point of the economizer control the
lead unit economizer will continue to operate, and the
compressor will operate on compressor Stage 1 partial
capacity. If the compressor is already operating on
Stage 1 partial capacity because outside free cooling
range the compressor will switch to compressor Stage 2
full capacity.
3
rd
cooling set point is 2F (default setting, user
selectable 2-3F) warmer than Stage 2. On a call for 3
rd
Stage cooling the blower of the lag unit will come on
immediately (if not already on – See Blower Operation),
and the Stage 3 LED will blink for 10-seconds before
going solid, at which time the lag unit Y1 cooling output
turns on. The lag unit economizer will operate if the
outdoor temperature and humidity conditions are below
the set point of the economizer control. If outdoor
conditions are not acceptable for free cooling the
compressor will automatically operate on compressor
Stage 1 partial capacity instead of the economizer.
4
th
cooling set point is 2F (default setting, user
selectable 2-3F) warmer than Stage 3. On a call for 4
th
Stage cooling the lag unit Y2 cooling output turns on
activating the compressor. If the outdoor temperature
and humidity conditions are below the set point of
the economizer control the lag unit economizer will
continue to operate, and the compressor will operate on
compressor Stage 2 full capacity. If the compressor is
already operating on Stage 1 partial capacity because
outside free cooling range the compressor will switch to
compressor Stage 2 full capacity.
Note A: Economizers in ECONWMT-Series are available
with either “T” temperature only outdoor sensor or “E”
enthalpy (temperature and humidity) outdoor sensor. The
“T” versions will have a xed (but selectable) outdoor
temperature decision whereas on the “E” versions
the outdoor temperature decision will oat based on
outdoor humidity and the selected Enthalpy curve in the
economizer control module.
HEATING SEQUENCE OF OPERATION
Note: All heating sequences for air conditioners with
electric heat or heat pumps will automatically operate
in Alternating Lead/Lag/Lead/Lag sequence even if
controller is set to Non-Alternating for cooling with or
without economizers.
1. Air Conditioners with Electric Heat
1
st
stage heating set point is the dead-band (db) below
the 1
st
stage cooling set point (the SP entered into the
program). The dead-band is adjustable from 2-40F, and
factory default is 27F.
2
nd
stage heating set point will operate at same inter
stage differential as set for cooling mode.