Lochinvar SNA285-125 Manuale Utente

(will require a manual 

reset once the condition 

has been corrected.  

Press the RESET button 

on the display to reset.)

The flame detector circuit is seeing a flame 
signal while no flame is present.

 • Check supply voltage for proper polarity.

 • Check external wiring for voltage feedback.

 • Check the flame rod and make sure it is clean.

 • Check the internal wiring for bad connections.

 • Replace main control board.

(will require a manual 

reset once the condition 

has been corrected.  

Press the RESET button 

on the display to reset.)

The unit has failed to prove main burner 
ignition after four (4) attempts.

•  Ensure gas valve switch is ON (Models SNR150-100 
 and 

SNA285-125).

•  Check wiring harness connection at the gas valve and 
  at the main control board.

• Inspect spark electrode and associated wiring for 
  damage and connection.  Reference page 60 of this 
 manual for removal and cleaning procedures. 

 

  Replace if necessary.

•  Check for proper electrical grounding of the unit.

• Check incoming supply gas pressure.  Natural gas 
  pressures should be between 4 - 14 inches w.c. and 
 LP gas pressures should be between 8 - 14 

 

 

 

 

   

  inches w.c. Refer to Section 6 - Gas Connections for 
  detailed information concerning the gas supply.

• Verify that the plastic hose from the gas valve to the 
  air inlet is connected and is not damaged.

• Verify that the vent/air intake pipes are correctly 
  installed and that there are no obstructions.

• Check for 24 VAC to the gas valve at the 2-pin 
  connection on the side of the main control board 
  during the ignition attempt.  If no voltage is present, 
  replace the main control board.

•  If 24 VAC is present at the main control board, check 
  the wiring between the main control board and the 
  gas valve.  Replace the wiring if necessary.  

• If 24 VAC is present, check the outlet of the valve to 
  ensure the valve is flowing gas. With a manometer 
  connected to the outlet tap of the gas valve, when the 
  unit is in the prepurge period, there should be a 
 negative pressure present. When the valve is 
  energized a change in pressure should occur.  If the 
  pressure change does not occur, the gas valve is not 
  opening.  Replace the gas valve.

• 

Inspect flame sensor and associated wiring. 

 

  Reference page 60 of this manual for removal and 
  cleaning procedures.  Replace if necessary.

•  Inspect the burner.  Reference page 60 of this manual 
  for removal and cleaning procedures. Replace if 
 necessary.

•  Replace the main control board.

       

Installation & Service Manual

TM