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Fenwal flame strength

Plumdog_2Plumdog_2 Member Posts: 873
What's the correct method of determining flame signal strength with a RCLY type hot surface ignition control? I think it has pins marked F(C) and F(+). Burner drops out 1/2 second after lighting. Newer but generic ignitor. Working OK for awhile, then a bolt of lightning took out phones and computers in this particular mansion. Thanks for your help in advance!



  • Tim McElwainTim McElwain Member Posts: 4,358
    Put your meter on microamp scale

    and leave the wires connected to the F+ / FC connections, then just place the two leads from your meter right on F+ FC.

    I am not sure I am familiar with RCLY type hot surface ignition control. Do you have a picture? Be careful with Generic igniters as they may not match up electrically with some boards.
  • Mark EathertonMark Eatherton Member Posts: 5,843

    If I am not mistaken, an amperage reading has to be taken in series with the circuit, no?

    What I have done in the past, is to connect the positive lead of the DMM to the F+, and the other lead to the terminal on the board for F+, then touch the two together, and allow the systems to start. Once started, put the circuit into a series, by un-touching the two leads, and you should be able to see the flame signal current.

    Granted, it has been a while since I've had to do this, but if memory serves me correctly, this was the methodology spelled out in Honeywell's Troubleshooting manual for their universal ignition control module that uses the flame sensing circuit.
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Tim McElwainTim McElwain Member Posts: 4,358
    Fenwal is different than

    everyone else in that they provide two direct terminals for taking microamps with out disconnecting the leads on their modules.

    If you are talking about Industrial Flame Safeguard Honeywell Controls (R4795 or the old RA890E) that is a different animal than Honeywell say S8600 modules. On those you simply brake into burner ground wires and put the meter on microamps and and place it in series with the wire coming off the sensor and burner ground. If it is a dual rod pilot system you can use burner ground or the sense wire both give the same reading.

    The method Honeywell gave you for the Universal Module was there way of doing it. When I went on board with them doing the Source training in 1994 I showed them that my way was easier than the method they were teaching. They never did however take it out of their manual.

    It work for me and it is up to date as I just did readings in class on both a Fenwal Module today and a S8610U-3009 the new Universal module from Honeywell.
  • Mark EathertonMark Eatherton Member Posts: 5,843
    edited May 2011
    I learned something today...

    Thanks Tim!

    My reasoning for the probe contact/un contact is that when the ignition module is sparking, some of that voltage bleeds back through the sensing circuit and scrambles the brains of the DMM.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Rick165Rick165 Member Posts: 1
    Drop-out current for Fenwal ignition module

    According to Fenwal, the 35-65 ignition control module should "see" a minimum of 0.7 microamps with a good flame.  I am working on a two burner Nortec humidifier that is experiencing intermittent flame failures on the #2 burner.  With both burners operating, I am only reading 0.1 to 0.2 microamps at the F+ and F- flame sensor terminals of both controls but the burners continue running.  At some point, naturally when no one's around to witness it, the #2 control locks out.  I've tried calling Fenwal's tech support but they don't answer their phone or reply to my voicemails.  I've swapped the modules but the problem remains with the #2 burner.  The flame rods and hot surface ignitors have been replaced numerous times by another contractor.  Any advice?

    Thanks,  Rick
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