Troubleshooting SmartValve® Systems

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 ‘ ****.

#2 – Make certain that the gas ****, 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 ****) 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 **** 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.

If gas flow is present to the igniter and ignition doesn’t occur measure for voltage between the 24 VAC common connector pin and the 24 VAC hot pin. If a nominal 24 VAC (19.5 to 26) is not present check the 24 VAC transformer output and replace the transformer with a properly sized, NEMA rated transformer (required for warranty purposes.) If you have the proper voltage to the igniter and it does not glow replace the igniter with a replacement igniter/flame rod assembly Q3400A1024. The igniter and flame rod must be replaced at the same time – they are combined into a one piece assembly and are packaged with a new stainless- steel spring mounting clip. This one unit fits both the Q3450 and Q3480 pilot burners.

# 9 – If the main burner does not light after the pilot has ignited and the igniter has been de-energized:
A. – Make certain that the pilot flame and the flame rod are making good contact.
B. – Check that the pilot burner bracket is not misaligned or bent from its original position
C. – Use a gas pressure reading instrument (i.e… Manometer etc… ) to check for proper inlet gas pressure. There is an outlet gas pressure tap on the outlet side of the gas valve for this measurement – there is also an inlet pressure tap as well. For natural gas systems, the pressure required is normally #.5 inches of water column however check the appliances Manufacturers rating plate to verify the pressure needed on this unit for correct firing
D. – Inspect the pilot orifice or clogging or apparent damage. If necessary, replace the orifice – DO NOT attempt to drill out the orifice.
E. – Check the electrical system for a good system ground through the pilot burner gas tubing ‘ You can use a jumper cable (with alligator clips). Connect one end of the cable to the pilot burner bracket and the other end to the gas valve – if the system then operates, you have isolated the problem to a bad or insufficient ground.
F. – If none of these checks surfaces the system problem then replace the ignition assembly (Q 3400 a 1024) At this point the system should operate properly – if not – replace the Smart Valve.

TROUBLE-SHOOTING TIPS.

To correctly diagnose system problems in Smart Valve products you should have a digital multi-meter or a analog meter – either of which should be able to measure one tenth of a micro amp ( .0000001 amps / dc. )The meter should also read ohms resistance down to one tenth of one Ohm (.01)

AA. – The resistance of a Norton silicon igniter used in the Q3450 or Q 3480 pilot assemblies, when new and cold, will be between 3 and 4 Ohms (average 3.7 Ohms) as the igniter ages the resistance will increase. When its resistance reaches 10 Ohms the igniter should be replaced

BB.-.A test harness for use in making micro amp readings while the system is working is available through your Honeywell distributor – the part number is 395466 .Smart Valves – Generation 1 will need a minimum reading of .0000003 micro amps (Three tenths of one micro amp) Generation 1 systems can be easily identified by the rotary gas **** knob on the top of the valve. It will also have part numbers SV 9500 or SV 9600 Generation 2 systems or later can be identified by an electrical slide switch on top of the gas valve. This slide switch electrically opens or closes the gas flow circuit in the valve and replaces the rotary gas ****. Generation 2 valves are the direct replacement for both generation 1 and 2 valves .This test harness also will allow you to easily convert micro amps to kilovolts. The minimum value you want for a microamp reading on generation 2 systems is 2 (.000002 A). Most importantly is the need that the microamp signal, on either system, be a steady signal. A wavering signal indicates that the pilot flame is not playing on the flame rod steadily – the flame recognition time is less than 2 seconds – and nuisance shutdowns will occur. Check for drafts across the pilot burner.