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Flame Rod Testing

jim lockardjim lockard Member Posts: 1,059
the fancy tests on flame sensors but by and large have found I am better off just to change the flame rod and be gone. If I do not have that flame rod on the truck I clean the old one (I know you can't clean a mushroom nor do you need to test it) and put it back in most of the time it will work til I can get one. I also make sure the ground is bright and tight. J. Lockard


  • Craig BergmanCraig Bergman Member Posts: 7
    Testing flame rod's

    What is the proper way to test one? I have a "Fluke 16"
    and want to know if this tester will handle the job or will I need something else?

    Thanks for the help.

  • Mike BMike B Member Posts: 155
    any meter with

    any meter with a DC micro-amp setting should work. I use a fluke 87. Nice feature is the backlit display for dark basements and crawlspaces.(Altho those are usually brightly lit and clean...right!)

  • jim sokolovicjim sokolovic Member Posts: 439
    Flame current reading on a Flame Rectification type control...

    Yes - any meter with a microamp (uA) scale should work. I have a Radio Shack model that even does this. Honeywell offers a special one for this - the W136, which has a "banana" plug accessory for the few ignition controls that provide a flame signal jack to plug into. Otherwise, you have to pull the flame signal wire off of the flame sensing probe and put the meter in series with it (while burner is off). Then turn the burner on - 1 or 2 uA is normally the lowest reading that will keep the burner on. 5 to 10 uA is normally considered a strong reading. If you get no reading or a negative reading, try reversing the leads. Sometimes the reading needs time to build-up to full strength. If the reading is very low, some causes are low voltage, lean flame, bad ground, or faulty flame rod (oxidized, warped, deteriorated, cracked insulator). Hope this covers your inquiry.
  • DaleDale Member Posts: 1,317
    The 16

    The fluke 16 has a microamp scale. Clean the rod with a scotch brite pad and use the ohm setting to check the rod length to the other end, should be less than 1 ohm with no cracks or tracking to ceramic. Then with meter in series flame microamps should be 2 or more. If less than 2 usually flame size or ground although sometimes internal problem in control.
  • Many digital meters

    will have interference from the spark signal and will not give you a micro amp reading. The Honeywell W-136 is foolproff and is the meter I have been using for 43 years on everything from industrial burners to residential.

    If you are interested I have a sale on some manuals which cover the entire procedure for doing this. Look at Community Bulletin board.
  • Glenn HarrisonGlenn Harrison Member Posts: 845
    Most of my coworkers have a 16

    and it works fine. The only problem I would see with it is reading the very low signal on Johnson controls modules. Johnson recomends having a meter with 100th's of a microamp (.00) range on it, and I believe the 16 only goes to 10th's of a microamp (.0). I personally have an 89-IV (now the 189)which has plenty of features for many different pieces of equipment that I work on, but may be way to much for many tech's.
  • jim sokolovicjim sokolovic Member Posts: 439
    Hey Timmie, with combined spark and flame sense electrode...

    I have been using the Honeywell W136 meter on an ignition control that senses the flame signal through the spark electrode (15,000 volts for spark) - and unless I put a silicon rubber sheet under the meter and carefully run the leads so they don't contact any metal, I get shorting (sparking noises) at the meter. This is only during the first couple of seconds, when the spark is energized, but it sometimes compromises the strength of the spark. The control checks flame current after the spark is de-energized, but I have to connect the meter before the ignition sequence is initialized. Have you found anything like this? It seems like it would be a problem in the field, if equipment or the meter could be damaged, or someone could get a shock if they are touching it at the wrong time?
  • Jim I assume you are

    talking about single rod (local sense) type spark ignition systems which are proprietory to Honeywell. I connect my W136 in the burner ground circuit and that takes care of the problem you mention in your post.
  • Mike BMike B Member Posts: 155

    Get 1 that does 1/100. some of the Johnson controls only require .1uA (G951Db) same with W-R (50A50-241)
  • jim sokolovicjim sokolovic Member Posts: 439
    Timmie - control and meter details...

    The particular control that I am testing is a Honeywell Direct Spark modulating ignition control (the same model that the Ultra utilizes). I have a ceramic burner, therefore I have a spark electrode and a ground electrode. Both electrodes have an insulator barrel around them. The meter is in series with the spark electrode. The ground electrode has a short wire leading to the boiler chassis, which is earth grounded. I am not following you on how the meter can be within the ground circuit, at least not for this application. If I were to put the meter in the ground circuit, the control would use the ground electrode as the flame sensing rod (rather than the spark electrode). Can you elaborate on your last post? Were you referring to completely different control? As you may know, the Ultra instructions refer only to using a dc voltage signal for checking the flame, no mention of how to check microamps (although I find the two comparable on this control). Any thoughts from anyone are of extreme interest to me!
  • Mike BMike B Member Posts: 155

    Rectification systems reference earth ground. Thats why a proper ground reference is essential for flame rectification. On spark systems you can check it using the ground path.

  • jim sokolovicjim sokolovic Member Posts: 439
    Mike - I think this control is different...

    Noel took a stroll over to show me a more common Honeywell control (IID, I assume) that has two ground connections - one can be used for the flame signal, as you guys are familiar with. But the control that I am using for development has only one terminal for spark and sensing (combined), and the single ground terminal is to be wired directly to the chassis (no signal can be established through this). Believe me - from all the testing that I have done on ceramic burners, which have no grounding ability (due to their non-conductive nature), I know very well the importance of a ground reference (which we have to build into the burner surface with a metal bar or rod). Perhaps this particular control is more unique than I had realized, and no one in the U.S. is familiar with it's distinct operation points yet?
  • The Ultra if I am not

    mistaken is measuring a DC signal which is created a little differently than conventional module systems. So as not to confuse any novices out there every systems I have seen allows you to use burner ground to check microamps. If it is a dual rod (remote sense) it can use burner ground or the sense wire for microamps.

    When flame rectification systems first came out we did some testing using the spark wire for trying to measure microamps. I did find a way to do it but would rather not get into that here. Taking readings is confusing enough for some folks so I try to keep it simple if I can.

    I am going to take a look at the Ultra but I do not have one in my center as of this time. I did have a class on the unit and am waiting for Weil-McLain to get me one.
  • Glenn HarrisonGlenn Harrison Member Posts: 845
    Sorry, I should have clarified

    that my Fluke 89-IV (189) goes to 1/100th (.01)of a microamp.
  • Glenn HarrisonGlenn Harrison Member Posts: 845
    Jim, I don't know if this will help any,

    but I found at the Ultra manual, they reference checking the flame signal using a voltage check to ground, and it should be at least 4 volts dc from the electrode connection to ground (4 to 9 according to the wiring diagram manual).

    If you wnat to check the info I found, the flame signal instructions are at 310/5501012330903Manual.pdf

    and go to the top of page 32, and you can check out the wiring diagram at 310/5501012410903Control.pdf
  • KevinKevin Member Posts: 31
    The Burner

    The flame grounds to the burner and its important to clean the face of the burner off. I use a small brass wire brush to clean the ones I look at. I work mainly residential and light commercial. Also there is voltage there. Try touching a Pulse furnaces flame wire. Its about 90 volts.
  • Glenn HarrisonGlenn Harrison Member Posts: 845
    Jim, if you cannot

    break the ground connection to put the microamp meter in series, then the only way the flame signal could be checked is by a voltage check. I know that Honeywell references a minimum 100 volts DC at the flame probe connection on the smart valves, and I looked in the Ultra manual since you said the control is similar to the Ultra's, and they reference checking for a 4 to 9 volt DC signal to ground. So I am going to assume the control you are playing with must be checked the same way, the question is what is the voltage range. I hop[e it is a high voltage circuit because I have seen a lot of problems with low voltage flame sensing circuits (Carrier comes to mind).

    Hope This helps somehow.

  • Jim & Glenn

    It is a good idea Jim to change the rod, but you should still check the microamps as you could have an electronic problem from the module or integrated control. There is more to this than meets the eye I assure you. In my manual "Troubleshooting Electric Ignition Systems" I break down all the potential problems these circuits present and how to diagnos and solve them.

    Glenn I believe the minimum signal from the flame proving circuit on Honeywell Smart Valve is 80 Volts AC which is then rectified thru the flame for a DC microamp signal. If there is something new I did not get the info. I got my information from the latest Honeywell "Source" class I attended. The old Generation I Smart Valve used 24 volts AC which was somewhat of a problem. This voltage is low amperage and is generated out of the Smart Valve Electronics.
  • Glenn HarrisonGlenn Harrison Member Posts: 845
    Tim, I went and looked in my Smart Valve books,

    and found that 100 volt number. It's in the SV9560/SV9570 water heater control book. In the troubleshooting chart (page 9 of my book) it references that if control shows code 6 and ignition lockout, one cause could be less than 100 volts between flame rod and burner pan with 120 volts to control. Now of course my book is a few years old now, and since you recently went to a class and they said 80 volts, I'll go with that for the future, but I thought you might like to know where I got that number from. I was also just thinking, would that voltage be the same on a 9500/9600 and/or 9501/9601 series smart valve that only has 24 volt input? is the voltage increased in the valve for better flame rectification, or is it kept at 24 volts and that would be the voltage between the flame rod and ground. I have always done the microamp test on these valves with the Honeywell/Heil test cord, so I have never bothered to check the voltage. Now I'm thinking and wondering, (and hoping I have one to check tomorrow).

    Thanks Tim,

  • The Smart Valve

    water heater control is different than the heating controls. The water heater control is 120 volts all the way.

    The heating controls Generation I (SV9500, SV9600) used 24 volts generated from within the control. This caused some problems with a very low microamp signal about .3 was the minimum. The Generation II(SV9501,2 & SV9601,2) ramped the voltage up to 80+ volts for a stronger signal and a minimum 1.3 microamps.

    That voltage can be tested with the pilot plugged in and going from back side of the plug on the black microamp wire (a paper clip works good to get into the wire) to ground (gas valve is a good ground). On Gen I less than 24 volts change Smart Valve on Gen II less than 80 volts change Smart Valve.

    This is all contained in my 102 page manual on Smart Valves Generation I, II, and III.

    The Honeywell Smart Valve Flame Measuring Kit Part # 395466 works great for checking microamps. There is also a Voltage Test Harness Part # 396085.
  • Glenn HarrisonGlenn Harrison Member Posts: 845
    O.K. that clears that up.

    what about a 9510/9520/9610/9620 or 9440/9540/9640? Do those have the 80 volt rule, or would they be under the 100 volt rule due to their high voltage (120vac) power connections?
  • Mike BMike B Member Posts: 155
    Do you

    Have the make and model of the control?
  • jim sokolovicjim sokolovic Member Posts: 439
    Direct Spark ignition control model...

    The control that I am testing with is called a Honeywell MCBA, from Europe, but made for the U.S. with a 120 volt, 60 Hz supply. It is the same basic model as the Ultra utilizes. I am doing development with it, and some of the discussion in this post seemed pertinent to how I am trying to read microamps for the flame signal. Although it is possible, it does not look appropriate to have you guys in the field attempt this - it looks like the dc voltage reading is as reliable a reference, and much easier to obtain, without causing interruption of the spark or damaging something.
  • Those are Gen III

    Smart Valve. The 9510, 9520, 9610, 9620 are 120 volt igniter systems one using the silicon carbide system the other the silicon nitride.

    The 9440, 9540 and 9640 are all the 24 volt igniter systems which would follow the minimum 80+ deal.

    All of these are fed 120 volts externally so they can power the combustion air blower off the Smart Valve.

    The voltage we are talking about is generated from with in the electronic network of the Smart Valve.
  • Glenn HarrisonGlenn Harrison Member Posts: 845
    Just when I thought I understood these darn SmartValves...

    Now I get the whole picture. The only thing that confuses me(I've got to stop thinking) is that if the water heater control, which is a 24 volt ignitor, but 120 volt powered, why does it go by the 100 volt minimum, and the 9440/9540/9640, which also uses the 24 volt ignitor is only 80 volts. Common sense tells me they should both be the same, but that's probably my problem, trying to apply common sense ;)

    Thanks again for the update, Tim.
  • Water Heater is a 120 volt

    igniter not 24.

    The important thing to remember is those superimposed voltages are generated from within the Smart Valve electronics not from without so it really does not matter what the applied voltages into the control are.
  • Glenn HarrisonGlenn Harrison Member Posts: 845
    Sorry, I thought the one I worked on was 24 volt ignitor.

    My appologizes. I think I've got it. thanks for all the info. And Merry Christmas. HO HO HO
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