Page 61
Troubleshooting: Heating Sequence of Operation (continued)
CALL FOR HIGH FIRE WITH TWO-STAGE THERMOSTAT
1st Call
for High
Fire?
Wait for Call for Heat Satisfied
2 Stage
Thermostat
2nd Stage
Recognition Delay
(30 Seconds)
YES
High
Pressure Switch
Closes Within
10 Seconds?
NO
Error Code
Flashes
NO
YES
Wait 5
Minutes
3A
2
1
2
1
System will always light at 70% even if 2nd stage call for heat is in place
If the high pressure switch does not close within 5 attempts, the system
will operate at low fire for the remainder of the call for heat at request
Combustion Air Inducer ON
(100% Rate Speed)
Increase Combustion
Air Inducer Speed
if Not at 100%
Rate Speed
Adjust Indoor
Blower to
Appropiate speed
