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Sequence of Operation (continued)
Fan Purge Time Delay
After the Y1, Y2 and/or W1 terminals turn off, the G
terminal, if the ELEC/GAS switch is in the ELEC
position, will remain on for one (1) minute if the
PURGE/No Purge switch is set to Purge. The G
terminal will immediately turn off, if on, when the
switch set to No Purge.
Dual Fuel
Your control panel acts as a dual fuel system when
the HEAT PUMP/HEAT COOL switch is set to the
HEAT PUMP position and the ELECTRIC/GAS switch
is set to the GAS position. The dual fuel system is set
up so that when the auxiliary heat comes on, the
compressor outputs (Y1 and Y2) turn off before the
W1 output is turned on. The dual fuel mode effects
auxiliary heat operation only.
To lock out the heat pump at low ambient conditions
(below the system balance point) and service heat
calls with the furnace, use the SignatureStat or Elite
heat pump dual fuel compatible thermostats with
outdoor temperature sensors on all thermostats (see
thermostat selection guide on page 5). Each
thermostat must have its own outdoor temperature
sensor. To set the SignatureStat or Elite stat to use
the balance points for dual fuel control, in the
thermostats menu go to: menu, installer settings,
system setup, add on – comp = off. When the
thermostat is properly set up, it will send the
appropriate signals to the LZP-4. When the outdoor
temperature is between the low and high balance
points, first stage heating demands are serviced
through the heat pump and second stage heating
demands are serviced through the gas furnace.
Below the low balance point, all heat demands are
serviced though the gas furnace. Above the high
balance point, all heating demands are serviced with
the heat pump. If using a two-stage furnace with a
dual fuel application, set the furnace to stage on its
own (W2 timed); do not connect W2 from the LZP-4
to W2 on the furnace control board. If both W1 and
W2 are connected between the zone panel and the
furnace, only second stage furnace will be used
when servicing a gas heat call.
If you choose not to use the SignatureStat or Elite
thermostats dual fuel feature or wish to use a
standard heat pump thermostat to control the dual
fuel system, the furnace will turn on with an auxiliary
heat call after the condensing unit stops regardless of
the outdoor temperature. This auxiliary heat call will
be serviced with a W1 furnace call, and an
emergency call will be serviced with a W1+W2
furnace call. See Table 5 on page 8 for detailed
thermostat call and equipment output information.
EMERGENCY HEAT OPERATION –
HEAT PUMP SYSTEMS
There is no Emergency Heat operation when the HEAT
PUMP or HEAT/COOL switch is set for HEAT/COOL.
When set for HEAT PUMP operation, an Emergency
Heat call is recognized by a thermostat calling explicitly
for Emergency Heat or by a zone calling for heat with
the E-HEAT SELECTOR switch set to Emergency Heat.
A thermostat can explicitly call for Emergency Heat only
when the Zone 1 or Any Zone Selector switch is in the
Any Zone position and the Auxiliary Heat Timer DIP
switches are set to zero, which requires the use of heat
pump thermostats in all zones.
When a call for Emergency Heat is recognized, the
Y terminal will de-energize (if energized), after which
the B and W terminals (and G terminal if set to
ELECTRIC) will energize. Immediately, the W terminal
will de-energize when (1) all zones stop calling for
emergency heat, (2) the call has exceeded the
heat/cool changeover time limit while a cooling call
exists or (3) the call is interrupted by the high limit
setting. When the W terminal is de-energized, it has a
4 minute minimum off time if set to GAS or no minimum
off time if set to ELECTRIC.
Fan Purge Time Delay
After the W1 and W2 terminals turn off, the G
terminal, if the ELEC/GAS switch is in the ELEC
position, will remain on for one (1) minute if the
PURGE or No Purge Selector switch is set to Purge.
The G terminal will immediately turn off, if on, when
the switch set to No Purge.
With the ELEC/GAS switch in the GAS position, the
G terminal is not turned on during purge regardless
of the position of the PURGE/NO PURGE switch.
To aid in setting the system configuration DIP switches
correctly, use the system setup flowcharts on the
following pages.
Page 19
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