64659-001 REV. A 07/06/18
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SEQUENCE OF OPERATION
On a call for heat, the ignition control’s diagnostic LED will flash rapidly while the ignition control begins
sparking. After successful ignition, the LED will light green and remain lit as long as a flame is detected. If
the burner fails to light, the control will wait for the interpurge time, then spark again. During this time,
the diagnostic LED will flash green at a rate of twice per second. If the burner does not light after three
trials for ignition, the ignition control will be locked out, and the diagnostic LED will flash red. If this
happens, remove power from the control, then try again. The number of LED flashes indicates the type
of failure that occurred (see table below). If the burner lights, but loses flame, the ignition control will
attempt to relight immediately without a purge.
iHEAT BOARD FEATURES
On/Off Feature
In order to maintain temperature at the low end of the range of temperature set points, the iHEAT
system incorporates an on/off feature. When the iHEAT system has modulated down to the minimum
heat input, but the set temperature is not maintained, the iHEAT system will turn the burner off. This
will be indicated by the Valve light, as it will flash during the burner off cycle. When the appliance
temperature reduces a few degrees below the temperature set point, the iHEAT will bring the burner
back on. The iHEAT system will continue to cycle the burner on and off to maintain the set temperature.
In some appliances, it may not be necessity for the iHEAT system to employ the on/off feature. This will
depend upon the heat loss of the appliance, the load to be heated, the desired operating temperature,
and the low firing rate of the iHEAT system in the particular application. The on/off feature is disabled
when the iHEAT board’s dip switches are set for a manual configuration (switch 1 or 2 on).
Trial for ignition
4 seconds
Interpurge time
30 seconds
Number of flashes
Problem
1
No flame during trial for ignition
2
Flame sense fail
3
Gas valve relay failure
4
Multiple flame loss
7
Input voltage error
Table 11 - Ignition Control Error Codes
