by Ron Walker
Once the call for heat is completed, the EFT starts the timing cycle (field adjustable) to allow the air handler to complete the blower-on timing.
The above sequence applies to SV9X00 and the SV9X01. The SV9X02 includes a pre-purge timing (15 or 30 seconds) and the SV9X03 includes a lockout after one attempt to light-off.
TROUBLESHOOTING SMART VALVE SYSTEMS
The steps to correctly troubleshoot Smart Valves are as follows:
#1 -Shut off the flow of gas to the appliance in question with the ' A ' cock.
#2 -Make certain that the gas cock, located on top of the SV9X00 family of Smart Valves or later generations of Smart Valves SV9X01, SV9X02, SV9X03 which include an electrical slide switch (replaces the rotary gas cock) are placed in the Open or on position.
# 3 -Unplug the 2 x2 system harness plug located on top of the valve operating head.# 4 -Make certain there is 24 VAC available from the system’s control circuit transformer.
The transformer MUST be a minimum 40 VA (NEMA) rated. Such systems as SV96XX must have 50 VA NEMA-rated transformers at a minimum.
# 5 -Measure for output voltage at the 2 x 2 connector for 24 VAC between the 24 VAC common connector pin (Locate the proper pin locations in the Smart Valve instruction sheet) and the 24 VAC power source pin from the thermostat and/or air proving switch. There should also be 24 VAC between the 24 VAC common connector pin and the 24 VAC connector pin. (Note -there must be 2 pins powered for the system to operate. (One is constantly powered and one powered through the thermostat and/or air pressure switch).
# 6 -Plug the 2 x 2 wiring plug to the 2 x 2 wiring receptor. With 24 VAC present on the 2 receptacle pins the system will be energized. A 2-3 second delay will occur in the start up to allow the system to self check its electronics for a flame simulating component failure (If a component should have failed it will not continue to operate.)
After this delay the ignition sequence will begin in the SV9X01 and SV9X03 systems. The SV 9X02 has a pre-purge delay of either 15 or 30 seconds -OEM's choice.)
#7 -The silicon nitride 24 VAC igniter should begin to heat and in 1 to 2 seconds glow red. If the igniter fails to glow to incandescence and you have the proper voltage present (19.5 26 VAC) -replace the igniter if the nominal voltage is not present to the igniter -replace the Smart Valve.
# 8 -If the igniter, which is part of the pilot burner assembly (Q3450 or Q3480) glows red, turn the main gas supply gas cock back to the open position. The pilot gas should ignite. If not confirm that gas is present in the piping system, that all of the air has been purged from the pilot gas line (all the air must purge the pilot gas orifice.)Make certain a call for heat still exists -if the pilot gas does not ignite at this point replace the Smart Valve. Please note that all of the ignition module components are contained in the gas valve and the entire Smart Valve must be replaced... to be continued
Once the call for heat is completed, the EFT starts the timing cycle (field adjustable) to allow the air handler to complete the blower-on timing.
The above sequence applies to SV9X00 and the SV9X01. The SV9X02 includes a pre-purge timing (15 or 30 seconds) and the SV9X03 includes a lockout after one attempt to light-off.
TROUBLESHOOTING SMART VALVE SYSTEMS
The steps to correctly troubleshoot Smart Valves are as follows:
#1 -Shut off the flow of gas to the appliance in question with the ' A ' cock.
#2 -Make certain that the gas cock, located on top of the SV9X00 family of Smart Valves or later generations of Smart Valves SV9X01, SV9X02, SV9X03 which include an electrical slide switch (replaces the rotary gas cock) are placed in the Open or on position.
# 3 -Unplug the 2 x2 system harness plug located on top of the valve operating head.# 4 -Make certain there is 24 VAC available from the system’s control circuit transformer.
The transformer MUST be a minimum 40 VA (NEMA) rated. Such systems as SV96XX must have 50 VA NEMA-rated transformers at a minimum.
# 5 -Measure for output voltage at the 2 x 2 connector for 24 VAC between the 24 VAC common connector pin (Locate the proper pin locations in the Smart Valve instruction sheet) and the 24 VAC power source pin from the thermostat and/or air proving switch. There should also be 24 VAC between the 24 VAC common connector pin and the 24 VAC connector pin. (Note -there must be 2 pins powered for the system to operate. (One is constantly powered and one powered through the thermostat and/or air pressure switch).
# 6 -Plug the 2 x 2 wiring plug to the 2 x 2 wiring receptor. With 24 VAC present on the 2 receptacle pins the system will be energized. A 2-3 second delay will occur in the start up to allow the system to self check its electronics for a flame simulating component failure (If a component should have failed it will not continue to operate.)
After this delay the ignition sequence will begin in the SV9X01 and SV9X03 systems. The SV 9X02 has a pre-purge delay of either 15 or 30 seconds -OEM's choice.)
#7 -The silicon nitride 24 VAC igniter should begin to heat and in 1 to 2 seconds glow red. If the igniter fails to glow to incandescence and you have the proper voltage present (19.5 26 VAC) -replace the igniter if the nominal voltage is not present to the igniter -replace the Smart Valve.
# 8 -If the igniter, which is part of the pilot burner assembly (Q3450 or Q3480) glows red, turn the main gas supply gas cock back to the open position. The pilot gas should ignite. If not confirm that gas is present in the piping system, that all of the air has been purged from the pilot gas line (all the air must purge the pilot gas orifice.)Make certain a call for heat still exists -if the pilot gas does not ignite at this point replace the Smart Valve. Please note that all of the ignition module components are contained in the gas valve and the entire Smart Valve must be replaced... to be continued