Steffes DLF40B - Manual (Page 8)

FURNACE START-UP
On start­up of the furnace, you may experience some odors relating to first time operation of the heating compo­
nents. There may also be an odor associated with dust accumulation in the system if the furnace is shut­down for
an extended period of time. Upon restart, allowing the furnace to charge to its maximum brick core charge level
will help expel these odors in a timely manner.
During operation, it is normal for the furnace, like any heating system, to produce expansion noises. These noises
are the result of the internal components reacting to the temperature changes they are exposed to.
ROOM TEMPERATURE CONTROL
Room temperature is adjusted at the wall thermostat. With a heat call to the thermostat, the core blower in the
furnace is energized to circulate hot brick core air through the furnace’s heat exchanger. The core blower
automatically adjusts its' speed (low or high) in relation to the brick core temperature. The blower operates in low
speed with a hot brick core and in high speed with lower brick core temperatures.
After the brick core air warms the heat exchanger, the supply air blower is energized. The supply air blower
circulates the room air through the heat exchanger to warm it; and, then, delivers it back into the living space
through the duct system.
The delay between the core blower operating and the supply air blower being energized ensures only warm,
comfortable, even heat is being delivered into the living area. Intermittent supply air blower operation may occur
with lower brick core temperatures in an effort to maintain a constant temperature and even distribution of heat
into the living area.
Some thermostats incorporate a room temperature set back feature which allows for room temperature to
automatically be set back a specific number of degrees at specified times. If using a thermostat with this feature
in a program where the power company has 8 or more consecutive hours of control, it is important to bring the
room temperature back to the desired occupied temperature a minimum of three (3) hours before the off­peak
(charge) period ends. This will ensure optimum heat storage for maintaining the desired room temperature
throughout the on­peak (control) period.
BRICK TEMPERATURE CONTROL (CORE CHARGING)
The amount of heat stored in the brick core of the furnace is regulated automatically in relation to outdoor tem­
perature and to its control panel settings. The outdoor temperature sensor that ships with the furnace as standard
equipment MUST be mounted outside. It provides temperature information to the furnace for proper brick core
charging.
In standard configuration from the factory, the outdoor sensor signals the furnace to maintain a level 1 (1/3) brick
core charge at a 55
o F outside temperature, a level 2 (2/3) core charge at 35 o F, and a level 3 (maximum) core
charge at 15 o F. At temperatures above 55 o F, the furnace will not maintain a core charge; however, if there is a
heat call from the thermostat during off­peak times, 1/3 of the elements will be energized to provide heat for the
duration of the heat call. (Refer to Table 1, Brick Core Charging Schedule, for more information on charging
levels in relation to outdoor temperature and the furnace control panel settings.)
If outdoor temperature charging set points other than the standard configuration are pre­
ferred, the sensor must be specially ordered from the factory.
Operating the Furnace 7
2
3
1
NOTE