Heating Sequence Of Operation; Ignition Control Led - Dyna-Glo GUH50NE/LE Operating Instructions And Owner's Manual

1. STOP! Make sure you have read and understand
all of the safety information regarding the operation
of this gas appliance. Any and all service should be
performed by a licensed installer
2. Set the thermostat to lowest setting.
3. Turn off all electrical power to appliance.
4. This appliance is equipped with an ignition device
which automatically lights burner. DO NOT attempt
to light the burners manually.
5. Wait five minutes to clear out any gas. If you then
smell gas, STOP! Immediately call your gas supplier
from a phone remote from the building. Follow the
gas supplier's instructions. If you do not smell gas go
to next step.
6. Turn on electrical power to unit.
7. Set the thermostat to desired setting.
8. The combustion air blower will start. The burners will
light within 30 seconds.
9. If unit does not light first time (gas line not fully
purged) it will attempt up to two more ignitions before
locking out.
10. If lockout occurs, repeat steps 1 through 9.
11. If appliance still will not operate, follow the
instructions "TO TURN OFF GAS TO UNIT" and call
your service technician or gas supplier.
TO TURN OFF GAS TO UNIT
1. Set thermostat to lowest level.
2. Turn off all electrical power to unit if service is to be
performed.

HEATING SEQUENCE OF OPERATION

1. When the thermostat calls for heat, the combustion
air blower starts immediately.
2. Combustion air pressure switch proves blower
operation before allowing power to the ignition
controller. This switch is factory set and no
adjustment is necessary.
3. After pre-purge of approximately 30 seconds, the
spark ignition is energized and the solenoid valve
opens in the gas valve.
4. The spark then ignites the gas, the ignition sensor
proves the flame and the combustion process
continues.
5. In the event that the flame is not detected after the
first 10-second trial for ignition, the controller will
repeat steps 3 and 4 an additional two times before
locking out the gas valve. Refer to ignition control
board table 3. Ignition control will then automatically
repeat steps 3, 4, and 5 after 60 minutes.
To interrupt the 60-minute lockout period, move
thermostat from "HEAT" to "OFF" then back to
"HEAT." Heating sequence then restarts at step 1.
6. The burners shall light without noticeable crossover
delay. There shall be no flame lifting from the burner
heads, flashback or burning within the burner. The
flames shall be predominantly blue in color and
shall be approximately centered in the tubes with no
apparent impingement taking place.
7. The ignition control will energize the fan
approximately 45 seconds after ignition is
established.
8. After the thermostat demand is satisfied the gas valve
is closed; 5 seconds after the demand is satisfied the
combustion air blower is shut off.
9. The control center shall shut off the system fan
approximately 150 seconds after the gas valve is
de-energized.

IGNITION CONTROL LED

The ignition control board contains a green LED which
indicates the following:
TABLE 3 - DIAGNOSTIC FAULT CODES
LED INDICATION FAULT MODE
Slow Flash Normal Operation - No call for heat.
Fast Flash Normal Operation - Call for heat
2 Flashes Ignition Lockout - No flame detected
3 Flashes Airflow Fault - Pressure switch open or closed
4 Flashes High limit or rollout switch open
5 Flashes Flame Sense Error - Gas valve not energized
Steady On Internal control failure
LIMIT CONTROL
The limit control switch is factory set and not field
adjustable.
LOUVER VANE ADJUSTMENTS
Rotate louver vanes to direct airflow upward, downward,
straight, or any combination of these directions.
COMBUSTION AIR PRESSURE SWITCH
This pressure switch checks for proper combustion air
blower operation before allowing an ignition trial. The
switch is factory set and no field adjustment is necessary.
If a 3 flash LED occurs Please make sure your venting is
not blocked. Next, remove the end of the pressure switch
tubing from the EXHAUST FAN hose barb. There might
be an obstruction in the hose barb opening clear out
the opening with a thin object that will fit inside the hose
barb. Push that through the length of the hose barb PLUS
at least another 1/2 inch, into the exhaust fan housing.
This will clear out anything stopping the vacuum from
engaging the pressure switch.
FLAME ROLLOUT SWITCH
The flame rollout switch is located on the burner box top,
behind the ignition control board. This normally closed
switch opens on a temperature rise. Check for adequate
combustion air before manually resetting switch.
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GAS UNIT HEATER