Setpoints and related data
The setpoints and related data include the following items:
- Number of gas valves installed (#GasVlvs)
- Reset lockouts (ResetLO)
Inputs
The inputs include the following items:
- 24 VAC monitoring at the MV input on the UCB (MV, GV2, GV3)
- 24 VAC from terminal W1
Outputs
The output for the main valve is the output relay for fan.
Operation
Any time the UCB senses W1 and does not read voltage at the gas valve for a continuous 5-minute period, it flags an alarm and displays an alarm on the user interface. If GV reappears after the alarm, the alarm is reset and normal operation occurs. If W1 goes away, the UCB resets the alarm.
Any time the UCB senses GV voltage without W1 the UCB energizes the fan relay immediately. If the voltage remains for a continuous 5-minute period, the UCB flags an alarm, locks on the fan relay, and displays the alarm on the user interface. If the GV voltage goes away, the alarm is reset and the fan performs a delay off.