Page 41
GAS HEAT SEQUENCE OF OPERATION LDT078H-150H
First Stage Heat:
1 - Heating demand initiates at W1 in the thermostat.
2 -
A3 Ignition Control. The Ignition control then routes
the 24VAC to the N.C. primary limit S10. The A3
Ignition control energizes the combustion air blower
B6.
3 - After the combustion air blower B6 has reached
full speed, the combustion air proving switch S18
contacts close. The A3 routes 24VAC through N.C.
contacts of combustion air proving switch S18 to
energize the ignition module A3.
4 - After a 30 second delay A3 energizes the ignitor
Second Stage Heat:
demand initiates W2 in the thermostat.
6 -
Unit Controller.
7 -
valve GV1.
End of Second Stage Heat:
8 -
is de-energized.
9 - Terminal HI of GV1 is de-energized by A3 control
module.
End of First Stage Heat:
10 -
is de-energized.
11 -
turn de-energizing terminal LO of GV1. Combustion
air blower relay K13 located in the A3 ignition control
is also de-energized.
Optional Low Ambient Kit:
12 -
F20 and N.C. low ambient kit thermostats S60 and
S61,to energize low ambient kit heater HR6.
To Next Page
Loading...
