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How to Troubleshoot Honeywell Smart Valve?

Last Updated: 10 December 2020

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If you own a SmartValve, then you understand how tough Honeywell smart gas valve troubleshooting can be, mostly because of the technicalities involved. In this article, we are, however, going to simplify the whole troubleshooting and installation process for you to give you a layman’s perspective that is easier to digest. But first, there are important things you should keep at the top of your mind.

Important Info Before Troubleshooting

Important Info Before Troubleshooting
  • If you want to properly diagnose Honeywell Smart Valve problems, you should either have a digital multimeter or an analog meter. With the best multimeter, you should be able to measure one-tenth of a microamp (0.0000001 amps/dc) and read ohms resistance down to one-tenth of one Ohm (0.01).
  • We recommend a resistance of between 3 and 4 Ohms (and an average of 3.7) in the Norton silicon igniter used in the Q3450 or Q 3480 pilot assemblies. As the igniter ages, the resistance increases and will, therefore, need replacement once it reaches 10 Ohms.
  • You can obtain from your Honeywell Distributor a test harness to use when making micro amp readings while the system is working. The part number should be 395466, and Generation 1 Smart Valves will need a minimum 0.0000003 microamp reading. A Generation 1 system will have a rotary gas knob on top of the valve and part numbers of SV 9500 or SV 9600. Generation 2 and later systems have an electrical slide, which opens or closes the gas flow circuit electronically at the top of the valve.
Honeywell SV9501M8129 Gas Valve
  • This is a genuine OEM replacement part.
  • Brand name: Honeywell
  • Model number: SV9501M8129
  • Country of Origin: China

These valves are a Honeywell Smart Valve replacement of the older rotary gas knobs. This test harness also allows you to convert microamps to kilovolts. For a generation 2 system, you will need a minimum microamp reading of 2 (0.0000002 A), and a steady microamp signal as a wavering one is an indication of the pilot flame not playing right on its rod steadily. Also, the flame recognition time is less than 2 seconds, which will result in a nuisance showdown. If this happens, the pilot burner should be checked for drafts.

Step-by-step Guide for Troubleshooting Honeywell Smart Valve

Step-by-step Guide for Troubleshooting Honeywell Smart Valve

Honeywell SmartValve system controls have intermittent pilot gas ignition sequencing, which makes them able to sense the pilot flame and provide pilot and main gas control functions all in one unit. This makes them great for gas-fired heating in the home, such as in cooking or in commercial appliances like heaters. This system, however, makes Honeywell furnace gas valve troubleshooting a bit complicated, and without proper instruction, you might go as far as ruining it and ask for a Honeywell Smart Valve recall when it was not really necessary. Use the following steps for safe Honeywell SmartValve troubleshooting:

  • Step 1
    You have to make sure the gas supply is turned off. For this, check whether the SmartValve switch reads “ON.” Then disconnect the system control harness and change the thermostat setting to “Heat.”
  • Step 2
    If the element is good, disconnect it from the Honeywell smart gas valve and ensure its resistance at room temperature stays below 10 Ohms.
  • Step 3
    Turn the Honeywell SmartValve switch or knob on.
  • Step 4
    Ensure that the call to heat function on the appliance is compatible with the Honeywell Smart gas valve and stick to the voltage requirements indicated in the manual.
  • Step 5
    Check the wiring system: power line, transformer, switches, and thermostat and ensure the vent damper is open.
  • Step 6
    Check that the voltage at the control is properly set. Make sure it is 24V between the thermostat or pressure switch and 24V Common and 24V between the 24V Common and 24V Hot as well.
  • Step 7
    Next, plug the harness into the SmartValve and wait for a resurgence of the internal check delay. If everything is well set, the igniter warms up and glows red. If it does this, turn everything back on, but if it does not, measure the Smart Valve’s element output voltage to get 24V. If this is not the case, you have no alternative other than replacing the ignition assembly.
  • Step 8
    Light the gas on the pilot burner to check if it is flowing. If it does not light, replace the Smart Valve. If it lights, measure voltages between the 24V Hot and Common that lead to the SmartValve, which should be about 19.5VAC when the igniter is on. If it fulfills this, replace the igniter assembly, and if not, check the transformer and power line supply.
  • Step 9
    Check whether the pilot flame and burner flame rod make good constant and whether the electrical connection through the pilot tubing is good. This will be indicated by the main burner lighting when you have the main valve open. If you cycle the thermostat on and off and it still does not light, replace the SmartValve.

Final Word

best Honeywell Smart Valve troubleshooting

For the best Honeywell Smart Valve troubleshooting, you will need a good mastery of the instruction manual and a quick browse of a nice instruction review like this one. While a bit technical, it does not have to be that complicated and tough to solve Honeywell Smart Valve problems. Read the manual carefully and always have the proper screwdriver set to help with ascertaining that the ignition system is in perfect condition. And now, you can troubleshoot it easily and successfully if you follow the steps here.

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