Manual 2100-410
Page 15
LOW VOLTAGE CONNECTIONS
FOR
DDC CONTROL
Fan Only
Energize G
Cooling Mode
Energize Y, G
Heat Pump Heating
Energize Y, G, B
2nd Stg Heating
Energize G, W2, Y, B
w/Heat Pump (if employed)
Ventilation
Energize G, O1
Emergency Heat
Energize B, W2, E, G
HEAT ANTICIPATION
All of the thermostats shown in Table 4 have a fixed
heat anticipator for stage 1 with no adjustment required.
Stage 2 has an adjustable anticipator of the W2
connection and fixed for the W3 connection. Both the
W2 and W3 circuits are controlled by the stage 2 bulb.
The only heat anticipator that needs to be checked is
stage 2 and it should be set to match the load carried by
the W2 circuit. The normal factory wiring provides for
only one electric heat contactor to be controlled by W2,
and the anticipator should be set at .40A. If special field
wiring is done, it is best to actually measure the load but
a good rule is .40A for each heat contactor controlled
by W2.
THERMOSTAT INDICATOR LAMPS
The red lamp marked “Em. Ht.” comes on and stays on
whenever the system switch is placed in the emergency
heat position. The green lamp marked “check” will
come on if there is any problem that prevents the
compressor from running when it is supposed to be.
EMERGENCY HEAT POSITION
The operator of the equipment must manually place the
system switch in this position. This is done when there
is a known problem with the unit, or when the green
“check” lamp comes on indicating a problem.
COMPRESSOR MALFUNCTION LIGHT
Actuation of the green “check” lamp is accomplished
by a relay output from the heat pump control board
which is factory installed. Any condition such as loss of
charge, high head pressure, etc., that will prevent
compressor from operating will cause the green lamp to
activate. This is a signal to the operator of the
equipment to place system in emergency heat position.
LOW VOLTAGE CONNECTIONS
These units use a grounded 24 volt AC low voltage
circuit.
The “R” terminal is the hot terminal and the “C”
terminal is grounded.
“G” terminal is the fan input.
“Y” terminal is the compressor input.
“B” terminal is the reversing valve input. The
reversing valve must be energized for heating mode.
“R” terminal is 24 VAC hot.
“C” terminal is 24 VAC grounded.
“L” terminal is compressor lockout
output. This
terminal is activated on a high or low pressure trip by
the electronic heat pump control. This is a 24 VAC
output.
“W2” terminal is second stage heat (if equipped).
“O1” terminal is the ventilation input. This terminal
energizes any factory installed ventilation option.
“E” terminal is the emergency heat input. This
terminal energizes the emergency heat relay.
NOTE: For total and proper control using DDC, a
total of 6 controlled outputs are required (5 if
no ventilation system is installed). For
proper system operation under Emergency
Heat conditions where the compressor needs
to be deactivated, the B-W2-E outputs need to
be energized. Removing the Y (compressor)
signal alone turns the compressor off, but
does not activate the additional circuitry
embedded in the heat pump for proper and
complete operation.
