L.B. White AW250(building controller) - Manual (Page 5)

This heater uses Smart Sense
™
technology for variable
rate heat control. When integrated to a building controller
and L.B.White Smart Box
™,
precise, automated control of
the environment is achieved by operating the heater over a
broad heat range from 65,000 btu to 250,000 btu. This
provides better, more even temperature distribution by
allowing the heater to operate where it needs to. This results
in consistent temperatures and reduced fuel consumption.
As shipped from the factory, the heater is wired to start
and operate at minimum heat. Connection to a building
environment controller capable of providing a 0-10 VDC
o r 4 - 2 0 m i l l i a m p s i g n a l f o r t h e h e a t e r ’ s Smart
Sense™gas control valve is required for further
operation.
See Fig.1 for a typical system diagram.
Sequence of Operation
a . Call for heat occurs from building controller.
b. Building controller closes heating contacts, and
sends either 1-15 VDC or 4-20 milliamps to signal
conditioner in the heater’s control box.
c. Signal conditioner sends the signal to the Smart
Sense
™ variable rate gas control valve.
-- Variable rate valve opens at specific firing rate
to meet temperature demands
d. Ignition of gas occurs.
-- Room warms to desired temperature.
e. Building controller recognizes desired temperature
has been achieved.
f. Building controller disconnects signal from heater.
h. Heater shuts down. Process begins again on a call for
heat.
5
FANS
ENVIRONMENT
CONTROLLER
CONTROL SIGNAL TO
GAS VALVE
115 VAC TO HEATER
EXISTING ROOM
SENSORS
GUARDIAN
HEATER(S) WITH
Smart Sense ™
FIG. 1
GUARDIAN WITH Smart Sense
™
Basic Operation