75
SERVICING
Open Thermal Protection Device (4 FLASH CODE)
If the primary limit switch opens, the gas valve is
immediately deenergized, the induced draft and air
circulating blowers are energized. The induced draft and
air circulator blowers remain energized until the limit
switch recloses. The diagnostic fault code for an open limit
is four (4) flashes.
A primary limit will open due to excessive supply air
temperatures. This can be caused by a dirty filter,
excessive duct static, insufficient air flow, or a faulty limit.
Check filters, total external duct static, blower motor,
blower motor speed tap (see wiring diagram), and limit.
Check for loose or missing wires on the limits. This limit
will automatically reset once the temperature falls below a
preset level.
Flame Detected with Gas Valve Closed (5 FLASH CODE)
If flame is detected with the gas valve deenergized, the
combustion and air circulator blowers are energized. The
diagnostic fault code is five (5) flashes for this condition.
The control can be reset by removing the power supply
to the unit or it will automatically reset after one hour.
Miswiring is the probable cause for this fault.
Abnormal Operation - Cooling Codes
Short Cycle Compressor Delay (6 FLASH CODE)
The automatic ignition control has a built-in feature that
prevents damage to the compressor in short cycling
situations. In the event of intermittent power losses or
intermittent thermostat operation, the ignition control
will delay output to the compressor contactor for three
minutes from the time power is restored. (Compressor is
off a total of three minutes). The diagnostic LED will flash
six (6) times to indicate the compressor contactor output is
being delayed.
NOTE: Some electronic thermostats also have a built-in
compressor short cycle timer that may be longer than
the three minute delay given above. If you are using an
electronic thermostat and the compressor has not started
after three minutes, wait an additional five minutes to
allow the thermostat to complete its short cycle delay
time.
S-314 Checking Flame Sensor
A flame sensing device is used in conjunction with
the ignition control module to prove combustion. If a
microamp signal is not present the control will de-energize
the gas valve and “retry” for ignition or lockout.
DSI Direct Spark Ignition Systems
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
1. Disconnect the flame sensor wire from terminal FS of
the ignition control module.
Flame Sensor
2. Connect a microamp meter in series with this wire
and terminal FS.
3. Be sure the negative side of the meter is to the wire
and the positive of the meter is to terminal FS.
4. Turn on Power.
WARNING
Line Voltage now present.
5. With Power ON, Place the unit into a heating cycle.
6. As soon as flame is established a microamp reading
should be evident once proof of flame (microamp
reading) is established, the direct spark ignitor will be
de-energized.
7. The microamp reading should be 4 - 6 microamps.
8. If the microamp current is less than 0.5 microamp the
control will lockout and flash a code of 1 flash after
attempting to reestablish flame sense.
Summary of Contents for DRG0361DL00001S
Page 20: ...20 SYSTEM OPERATION...
