Thomas & Betts LDAP 1200 - Manual (Page 18)

Form RZ-NA-I-LDAP, P/N 207733 (Rev 2), Page 18
Each heat section in this heater is equipped with a direct spark integrated control
module (circuit board). The module monitors the safety devices and controls the
operation of the fan and venter motors and the gas valve between heat cycles.
20. Ignition
System
FIGURE 13 – DSI
Integrated Control
Module (circuit
board) in Each
Heat Section
Spark
Transformer
Contr
ol
Plug
Fuse
Thermostat
Connections
Fan/Blower
Off
Delay
Status
Lights
x
LED
Lights
Dip
Switch
Supply
Voltage
Connections
19. Adjustable
Air Destrati-
fication Fan
Control
An adjustable fan control is located on top of the first heat section. It is adjacent to the
circulating air fan and motor and controls the fan motors in all heat sections. The
purpose of the fan control is to energize the fan motor(s) when the ambient air tem-
perature around the heater reaches the setting on the control. The fan motor(s) will be
de-energized when the fan control is satisfied. The fan(s) re-circulates the heated air
near the ceiling down to the floor level (destratification) and improves heat recovery.
A call for heat by the thermostat overrides the air destratification fan control.
Set the adjustable fan control for the desired temperature setting for energizing the
circulating air fan(s). The fan control setting should be set 5 to 10°F higher than the
wall-mounted thermostat setting. The heater is factory wired to energize the fan(s) at
medium speed when energized by the adjustable fan control. For lower mounting
heights it may be desirable to operate the fan(s) at low speed. Switching the blue
(medium speed) and red (low speed) fan motor wires on each heat section will change
the fan motor(s) speed. Refer to the wiring diagram for the wire locations.
To manually override the fan control, the heater may be tuned off at the circuit breaker
in the main electrical panel, or a field-installed electrical box with a SPST switch can
be located near the wall thermostat with the switch wired in series with the fan con-
trol.
The air destratification can also be a benefit in the summer time. Using the fan(s) in
the summer time can improve working conditions by alleviating stagnant air condi-
tions and creating a cooling effect for the occupants.
the Maintenance Section for information on probable causes . (For location, see FIG-
URE 22, page 33.)
DANGER: If a manual reset high limit control activates, identify
and correct the cause before resetting the switch. Never bypass the
high limit control; hazardous conditions could result. See Hazard
Intensity Levels, page 2.
18. High Limit
Control
(cont’d)