Lochinvar SNA285-125 Manuale Utente

1.  When the tank temperature falls below the set point minus the 

differential, the control will start the burner.

2.  The control connects 120 VAC to the blower.  The blower does 

not run at this time.

 

•  The manual reset high limit must be closed before the control 
   powers up the blower.

 

•  The control starts the internal pump.

 

•  If there is an external limit connected to the heater, it must be 
   closed.

3.  The control then starts the prepurge cycle.  

4.  Once the prepurge cycle is complete, and the blocked drain  
 

switch and auto-reset high limit are closed, the control starts the                 

 

trial for ignition by sending spark voltage to the spark electrode 

      and opening the gas valve.

5.  If the control does not detect flame by the end of the trial for 
 

ignition, the control performs the postpurge, another prepurge 

     and tries to light the burner again.  If the burner does not light 
       after 4 trials, the control locks out for 1 hour and then tries another 
      set of 4 trials.

6.  If the control detects a flame before the trial for ignition ends, it 
 

begins to modulate the burner in order to maintain the set point.   

 

7.  Once the tank temperature goes 3 - 4°F above the set point, the 

control will turn off the burner.  The blower will remain on for the 
postpurge cycle.  The internal pump will continue to run for its 
pump delay time, then turn off.

8. Burner off.

       

Installation & Service Manual

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