Sequence Of Operation - Lochinvar Armor AWH0400N Installation & Operation Manual

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Operating information

Sequence of operation

1.
Upon a call for heat, the control turns on the DHW pump.
2.
The control confirms that the low water cutoff / flow switch contacts are closed and energizes the louvers (optional).
The control confirms that the gas pressure switch, blocked drain switch, limits, louver proving switch (optional), and
3.
contacts close. The Pre-Purge cycle begins.
4.
The control confirms the blower comes up to the desired speed.
Once the Pre-Purge cycle is complete, the control lowers the blower speeds, initiates sparking of the ignition
5.
electrode, and opens the gas valve.
After a short wait, the control stops sparking and checks for the presence of flame current through the flame sense
6.
electrode.
If the fl ame is not detected aft er the sparking ends, the control will perform a postpurge, then start another prepurge
cycle and try to light the burner again. On the 500 and larger models, the control will lock out if this second attempt
7.
also fails. On the 400 model, the control will perform a total of 4 attempts before locking out. Once the control has
locked the unit out, the RESET button will need to be pressed on the touch screen LCD.
If the control detects flame current, the control will hold the blower speed constant for a few seconds to allow the
8.
flame to stabilize, then begin modulating the firing rate in order to maintain the controlling sensor to the desired set
point temperature.
Once the DHW call for heat is satisfied, the control will turn off the gas valve and begin the Post-Purge cycle. Any
9.
pumps that are running will begin their respective Pump Delay cycles.
10.
At the end of the Post-Purge cycle, the louver relay contacts will de-energize.
11.
At the end of the Pump Delay cycle(s), the pump(s) will be turned off.
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Installation & Operation Manual