Allied Air A97USMV Installation Instructions Manual page 68

Troubleshooting : Heating Sequence of Operation (continued)
Combustion Air Inducer ON
System will always light at 70% even if 2nd stage call for heat is in place
1
If the high pressure switch does not close within 5 attempts, the system
2
will operate at low fire for the remainder of the call for heat at request
Page 68 of 74
Call for High Fire With Two Stage Thermostat
2
1
2 Stage
Thermostat
1st Call
for High
Fire?
YES NO
2nd Stage
Recognition Delay
(30 Seconds)
(100% Rate Speed)
High
Pressure Switch
NO
Closes Within
10 Seconds?
YES
Adjust Indoor
Blower to
Appropiate speed
Wait for Call for Heat Satisfied
3A
Increase Combustion
Air Inducer Speed
if Not at 100%
Rate Speed
Issue 1622
Error Code Wait 5
Flashes Minutes
507028-03