Fossil Fuel Applications:
Fossil fuel may be used as the auxiliary heat
source with the Z-300-HPS allowing for up to 2
stages of cooling and 3 stages of heating. For
systems having a 2 stage furnace, W1 and W2
are jumpered at the furnace. This method utilizes
the internal furnace upstage timer to bring on
second stage fossil fuel.
Sequence of Operation:
2 Heat / 1 Cool
When a zone thermostat calls for heating and the
outdoor temperature is above the balance point
as established by the Z-300-OTS, the heat pump
operates as first stage heat. If there is a call for
second
stage
heat (auxiliary),
or if any
thermostat is placed in the emergency heat
mode, the panel will automatically de-energize
the heat pump and bring on the furnace. When
the outdoor temperature falls below the balance
point, the heat pump will be locked out and the
furnace will become first stage.
3 Heat / 2 Cool
When a zone thermostat calls for heating and the
outdoor temperature is above the balance point
as established
by the
Z-300-OTS,
both
compressor stages of the heat pump will operate
as normal. If there is a call for third stage heat
(auxiliary), or if any thermostat is placed in the
emergency
heat
mode,
the
panel
will
automatically de-energize all heat pump stages
and bring on the furnace. When the outdoor
temperature falls below the balance point, the
heat pump will be locked out and the furnace will
become first stage.
Installing and wiring the Z-300-OTS
The Z-300-OTS is an adjustable electronic
sensor used for both selecting the outdoor
balance point and measuring the outdoor
temperature. This information determines when
the heat pump will be locked out and only the
furnace will be used for heating.
Before installing the Z-300-OTS, remove the
retaining cover and select the outdoor balance
point temperature using the slide switches.
Mount the Z-300-OTS on a vertical surface
inside the heat pump cabinet to avoid direct
sunlight, freezing rain or snow.
Z-300-OTS
HEAT PUMP
INTERIOR COMPARTMENT
SENSOR
PROBE
COVER
ADHESIVE
BACKING
COVER
RETAINER
SCREW
Z-300-HPS Installation and Operation Instructions
3 Heat / 2 Cool Heat Pump or Fossil Fuel
Auto Changeover - First Call Priority - Time Share
Z NE
N
E
E
R
G
E
H
T
Zone Control Made Simple
TM
TM
OPEN
1
2
3
4
SETPOINT
SWITCH SETTING
30° F
1 Closed - 2,3,4 Open
35° F (Default)
2 Closed - 1,3,4 Open
40° F
3 Closed - 1,2,4 Open
45° F
4 Closed - 1,2 3 Open
OPEN
1
2
3
4
PANEL
SENSOR
30° 35° 40° 45°
WIRE TO
SENSOR
WIRE TO
PANEL
ODT
TERMINALS
SLIDE
SWITCHES
