Reznor LDAP Unit Installation Manual - Manual (Page 31)

Form I-LDAP, P/N 207733R6, Page 31
Continuous Fan
Operation
Lockouts
Undesired Flame - If flame is sensed longer than 20 seconds while the gas
valve is de-energized, the control shall energize the heat section venter motor,
the main venter motor, and the fan motor on heat speed. When flame is no
longer sensed, the heat section venter motor and main venter motor will run
through postpurge, and the fan motor will run through the selected heat fan off
delay time. The control will do a soft lockout, but will still respond to open limit
and flame. The FLAME (yellow) LED shall flash rapidly when lockout is due to
undesired flame.
Gas Valve Relay Fault - If the control senses the gas valve as energized for
more than one second when the control is not attempting to energize the gas
valve, or the gas valve is sensed as not energized when it is supposed to be
energized, then the control will lockout with the green LED off. The control
assumes either the contacts of the relay driving the gas valve have welded
shut, or the sensing circuit has failed. The heat section venter motor is forced
off to open the heat section pressure switch to stop gas flow unless flame is
present.
If the gas valve was sensed as closed when it should be open, and has not
de-energized after the heat section venter motor and main venter motor was
shutoff for 15 seconds, then the heat section venter motor and main venter
motor are re-energized to vent the unburned gas.
Soft Lockout - The control shall not initiate a call for heat or call for continuous
fan while in lockout. The control will still respond to an open limit and unde-
sired flame. Lockout shall automatically reset after one hour. Lockout may be
manually reset by removing power from the control for more than one second
or removing the thermostat call for heat for more than one and less than 20
seconds.
Hard Lockout (Green LED - steady off) - If the control detects a fault on the
control board, the status LED will be de-energized, and the control will lockout
as long as the fault remains. A hard lockout will automatically reset if the hard-
ware fault clears.
Power Interruption - During a momentary power interruption or at voltage
levels below the minimum operating voltage (line voltage or low voltage), the
system will self-recover without lockout when voltage returns to the operating
range.
Power interruptions of less than 80mS shall not cause the control to change
operating states. Power interruptions greater than 80mS may cause the control
to interrupt the current operating cycle and re-start. Power interruption during
a heat cycle may trip the manual reset high limit switch.
Fault Modes
over, the fan motor is de-energized, and a heat cycle is begun if the call for
heat still exists.
When the thermostat calls for continuous fan (G) without a call for heat, the fan
motor is energized after a .25 second delay. NOTE: This brief on delay is to
allow the “G” terminal to energize slightly before “Y” and an external change-
over relay to switch from “G” to “W” without causing momentary glitches in the
fan motor output. The fan remains energized as long as the call for fan remains
without a call for heat.
If a call for heat (W) occurs during continuous fan, the fan will de-energize.
A call for fan is ignored while in lockout.