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Guardian 2.0 LP or Natural Gas Heater
Owner’s Manual • Guardian 2.0
13
FIG. 8
FIG. 9
Interconnection for
Variable Heat (Smart
Sense Model)
■ The Smart Sense™ variable rate heater incorporates a
signal conditioner board in the control box. This signal
conditioner takes the control signal supplied from the
building controller and provides the necessary power to
control the variable rate gas control valve.
■ When interconnecting the building controller to the
signal conditioner:
-- Use customer supplied 1/4 insulated female terminals.
-- Use 18 gauge 2 conductor stranded shielded cable
for supply of DC volts or milliamp signal from building
controller to signal conditioner.
1. Open the heater’s control box for access to the signal
conditioner and wiring connections.
2. Route the wiring from the building controller through
the furthest left liquid tight connector. Securely tighten
the connector after wiring has been connected to the
conditioner.
A. SIGNAL CONDITIONER SWITCH
SETTINGS
See Fig. 10
a. 0-10 mV DC signal,
- No setting is required.
b.4-20 mA or 0-20 mA signal,
- Set the selector switch accordingly.
Control signal wire connections are made at the screw
terminals. Observe polarity when making connections.
ATTENTION
In the event the building controller fails and providing the
heater has a backup thermostat, the signal conditioner
will boost the gas valve output to full heat. With the
heater operating in this condition the gas control valve
will not modulate.
FIG. 10
Building controller
control signal
connections (screw
terminal) mA or DCV
Output to
the gas
control
valve
24V
transformer
connection
Selector
Switch
GAS
MANIFOLD
THROTTLE
VALVE
GAS CONTROL
VALVE