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LDAP-IOM (01-22) 207733-A
CONTROLS—CONTINUED
Combination Gas Valve
⚠ WARNING ⚠
The combination gas valve is the prime safety shutoff. All gas supply lines must be free of dirt or
scale before connecting the unit to ensure positive closure.
Each heat section in the heater has a combination gas valve (see
for location): unit size 400 has one,
unit size 800 has two, and unit size 1200 has three . The gas valve is powered by the 24V control circuit through the
thermostat and safety controls . The diaphragm-type valve is pre-set at the factory and provides regulated gas flow .
Fan Motor
Each heat section in the heater has a fan motor (see
for location): unit size 400 has one, unit size 800
has two, and unit size 1200 has three . The fan motor is equipped with automatic-reset thermal overload protection .
If the motor does not run, the cause may be due to improper current . Ensure that the correct voltage is available at
the motor .
Thermostat
⚠ CAUTION ⚠
IMPORTANT: all units MUST be operated by a 24V thermostat. Never use a line voltage disconnect
switch as a means of operating the heater. Operating by means other than a 24-volt thermostat may
result in the high limit control tripping and may cause damage to the heater from excessive heat.
For all availaible thermostat and thermostat accessory options, contact contact an authorized Factory Distributor .
Multiple Heater Control (Options CL31 and CL32)
•
If the heater was ordered with a relay kit (option CL31 or CL32) for multiple heater control option, one thermostat
can be used to control multiple heaters . For unit size 400, up to six heaters can be connected . For unit size 800,
three, and for unit size 1200, two . The relay kit is installed on the control heater and on up to five additional heaters .
•
The kit includes a 40VA transformer that replaces the standard transformer in the control heater and a relay
assembly that connects to the non-control heater . Option CL31 provides for control of two heaters . If control of
additional heaters is desired, option CL32—the relay assembly only—must be installed on each non-control heater .
•
The option kits are shipped separately and include complete instructions for installation and wiring .
Circuit Board (DSI Control Module)
Each heat section’s ignition system is controlled by a circuit board (Direct-Spark Integrated (DSI) control module,
see
) that monitors the safety devices and controls the operation of the fan and venter motors and the
gas valve between heat cycles . Troubleshooting the heater using the circuit board’s LEDs is described in the
Troubleshooting Using DSI Control Module
section .
Air Destratification 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 temperature 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) recirculates 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 .
