BASO BGH2UNCNTRLHT-01 - Manual (Page 11)

BGH2UNCTRLHT-01 Universal Hot Surface Ignition Control Installation Instructions 11
• 100% Shutoff (Flame Not Sensed) With 3
Ignition Trials (Bad Flame/No Flame):
If the control does not prove the presence of
igniter flame within the “Trial-For-Ignition” time,
then the relay gas valve is turned “OFF” (de-
energized) and the control initiates a time delay of
“Between-Trial-Purge” time, and then followed by
another ignition sequence. If flame is not sensed,
an ignition sequence is repeated until the total
number of Trials-for-Ignition are completed. If
flame is still not sensed then all relays are turned
“OFF” (de-energized) and the control goes into
lockout mode. See Troubleshooting Guide for
possible faults.
• Number of Ignition Trials: If 100% shutoff
occurs and the control was set up for 3 ignition
trials, the control will delay for the “Between-Trial-
Purge” time and begin another Trial-For-Ignition
sequence.
• Run (Operation): Once an igniter flame is proven
then the hot surface igniter is turned “OFF”
(de-energized) and the gas valve is turned “ON”
(energized). The gas valve remains “ON”
(energized) until the thermostat is satisfied (Call
for Heat).
• Flameout (Flame Lost): After a flame is
established, and a loss of proven flame occurs
during burner operation the gas valve is turned
“OFF” (de-energized) and the control will delay for
the Between-Trial-Purge time before it begins
another ignition sequence.
• Lockout: An internal or external fault has caused
the control to de-energize the hot surface igniter
circuit and valve relays. The thermostat contacts
must be opened for a minimum of 30 seconds and
then closed to begin another ignition sequence.
Sequence of Operation
The heating cycle begins when a call for heat from the
thermostat supplies 24VAC to the 24V (TH) terminal 8
on the Control which starts an ignition sequence. After
a 1 second maximum diagnostic period, the prepurge
cycle starts.
During the Pre-Purge cycle the gas valve relays and
HSI (Hot Surface Igniter) remain “OFF” (de-
energized). The controls “LED” will flash green “ON”
and “OFF” at 0.5 s rate. At the end of the Prepurge
time, the control begins the igniter warmup cycle.
Igniter Warmup (Timed Ignition) cycle turns “ON”
(energizes) both HSI relays and remains on for a set
time. The controls “LED” will flash green “ON” and
“OFF” at 0.5 s rate. At the end of the Igniter Warmup
time, the control begins the Trial-For-Ignition cycle.
Trial-For-Ignition cycle turns “ON” (energizes) the
gas valve relay and the hot surface igniter remains
“ON” (energized) to allow a flame to be established.
The control attempts to prove flame within the Trial-
For-Ignition time. The “LED” will flash green at 0.5 s
“ON” and 0.5 s “OFF”.
Once, a flame is detected a current path is connected
between the “Igniter” and “Main Burner” ground on
“Internal Flame Sense” Models, or between a “Flame
Sense Rod” and “Main Burner” ground on “Remote
Flame Sense” Models and the hot surface igniter is
turned “OFF” (de-energized) while the gas valve
remains “ON” (energized) as long as a flame is
present. The control will remain in this state until the
igniter flame is lost or the call for heat ends.
If igniter flame is not detected or flame lost, the gas
valve is turned “OFF” (de-energized) and the controls
go into 100% lockout for models having only 1 ignition
trial or will restart the Ignition Sequence for Models
having 3 ignition trials. The control will wait for the
“Between-Purge” time while blinking the “LED” at the
end of each 15 seconds during the Between-Purge
cycle. When the “Between-Purge” time cycle is
completed a new Ignition sequence will begin.
When the “Call for Heat” ends, the thermostat opens
and the control turns “OFF” (de-energizes) the gas
valve, there by extinguishing the flame.
Table 2: LED Indications during Normal Operation
Green Flash Code Flash Code Indication
Steady On
Flame detected,
Good flame,
Main burner on
0.5 Second On
0.5 Second Off
Pre-purge,
Between trial purge,
Igniter warmup
2 Continuous
Quick Flashes
Flame detected,
Weak flame,
Main burner on