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  • Blodgett DFG1xl/AA not relighting.

    Blodgett DFG1xl/AA not relighting. 1 albumen updated 2 years, 3 months ago 1 Member · 25 Posts
  • Blodgett DFG1xl/AA not relighting. 2

    guest

    Member
    October 1, 2017 at 12:00 am

    My Blodgett DFG1xl/AA lights for a period of time and relights but every once in awhile, it fails to relight.  The red light is on, the fan is running but no heat.  Open and shut the door…relights but sometimes not.  Try again…no issue.  Runs fine.  Temp checks shows it hits on the nose 350.  Shut down and then relights.  After use..1 hr…will not relight unless you open and close door.  

     

    Model: DFG1XL/AA

    Serial: 030904 RI 010 A

     

    What I have done:  Door limit switch replaced 18 months ago.  Tightened door closer to ensure it was not tripping.  Checked for clearance in burners and on flame sensor…clean.  Checked the inlet/ outlet gas pressure on valve: 10.28/ 1.79 inches water column (hum?).  Valve says low 2.0 high 3.5″.  I observed the two middle burners illustrating yellow tips which is different from past observation 4 months ago.  relight seems to “drag” meaning it sparks a second before relit which is different from my other oven.  I am considering this is a bad gas valve.  What else can I check to ensure this diagnosis is correct?

     

    Thank you.  

  • Blodgett DFG1xl/AA not relighting. 2

    fixbear

    Member
    October 1, 2017 at 2:44 pm

    If you have ignition (spark) from the module and gas flow but it fails to proof, The flame sensing is failing.  Check the flame sense current with a milliamp meter in series with the burner ground terminal for a current flow.   It is common for the burner ground to have high resistance and not get enough current to tell the controller you have flame.  Especially when heat saturated.  If you have adequate current, change the gas controller. It’s locking out from flame sense.

     

    As for the yellow flame, place a manometer on the manifold tap. check pressures.  are you on Propane?  If not 10 inches is way to high.  Verify that the nozzles and carburetors are clean.  Spiders like them as well as airborne dust/grease..

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 1, 2017 at 3:20 pm

    Went down to check, as I turned it on..it did not light.  Opened the door and tried again..it lit.  I then turned the temp knob down so I could watch it kick on/off.  Once it reached temp, it shut down as it should.  I turned it up slowly..it never lit(no spark or gas).  The red light came on but it never sparked nor actuated the gas valve.  Fans running heat light on…no flame/spark.  I took the reading off the spark box flame sensor wire and used the ground from the box.  It read 1.98 volts.  Not sure if that is adequate voltage as I could not find what it should be.   Could it be the spark box is not communicating to the valve to open?  It is a blue box. 

  • Blodgett DFG1xl/AA not relighting. 5

    ectofix

    Member
    October 1, 2017 at 5:20 pm

    albumen.  A couple of things…

    • Don’t try reading VOLTAGE across the flame sensor and ground.  It would be an AC signal, but hardly any ignition control manufacturers tell you what the voltage is.  Testing the flame sensing should only be done using a micro-ammeter.  In doing so, you’re looking at the DC current flow that’s caused through a process called “flame rectification”.
    • You said the box is BLUE?  Well then, that oven has an old Johnson Controls module.  Its flame current is so low that NO meter can read in that range because the DC amp value they create is too low. 
      • By the way, the symbol for “micro” is “µ” – in case that’s what you see displayed on your meter.  Anyway, there’s a special tranducer to test those modules, but those modules are defunct now – so don’t worry about buying that tranducer.

    What I’d be checking for is whether you’re getting 24vac to the module each and every time there’s a call for heat.  I don’t know what control panel you have there, so that’s a factor to consider in its importance for troubleshooting this problem.

     

    Can you post a picture of the front of your oven?

  • Blodgett DFG1xl/AA not relighting. 5

    ectofix

    Member
    October 1, 2017 at 6:16 pm

    I reread what you’ve written to see that gas pressure out of your valve had tested low.  That’s also a concern.  I take it this is one of the ovens converted to LP that we’d discussed awhile back in a different thread?

    If so, then the manifold pressure (to the burners) should ne 10″WC.

     

    I’d still take a closer look at the voltage going to the module.  If it’s not sparking when it should EACH and EVERYTIME you close the door – and the heat light indicates that it INDEED calling for heat, then there might be a problem with the output of your temperature control.

     

    If that’s resolved and you’re getting 24vac TO the module each and everytime you should, then you should see 24vac to the valve AND you should see spark for ignition.

     

    You might have two different issues going on there.

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 1, 2017 at 7:59 pm

    If I open and shut the door, I do get a spark and ignition.  It is when I up the temp (250 to 300) after it has reached temp, I get a click in the blue box but then nothing.  The red light indicates but no spark or valve change.  Fans run etc.  Open and shut the door, it sparks and lites and goes to 300.  It is the brother of the one that had the conversion issue which is troubling to me.  I will grab a pic of the front and maybe a video of it doing it.

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 1, 2017 at 10:16 pm

    Oven pic.

    It seems that on occasion the red light is on…but the module does not make the call…seconds go by then it tries again and success sometimes it never makes the call…just sits there…check voltage in am.

     

    Sent from my Samsung Smart Phone

  • Blodgett DFG1xl/AA not relighting. 2

    guest

    Member
    October 2, 2017 at 12:15 pm

    It almost sounds like you have an intermittent door switch, or borderline switch adjustment… 

  • Blodgett DFG1xl/AA not relighting. 2

    fixbear

    Member
    October 2, 2017 at 2:55 pm

    OK, the thermostat controls the power to the gas control module  Check for 24 volt AC to the module upon call for heat. If you don’t have power you will not have spark or gas flow. Don’t stop there if no power. now check the 24 volt tranformer for 120 volt input.  Again thee thermostat controls this. Beyond this we would need to know what control system your oven has.  Solid state or mechanical thermostat is a starting point.  Cook and hold?   Single or two speed oven fan?.  Time temp control?  Fan delay with pulse plus?  Humidair?  Intelliplus with chain event?  Intellitouch or intellitouch II?   Each has a different wiring diagram and routes power control different.

     

    This is a dfg service manual http://www.blodgett.com/wp-content/uploads/DFG100-200-serv.pdf

  • Blodgett DFG1xl/AA not relighting. 5

    ectofix

    Member
    October 2, 2017 at 5:13 pm

    Guest wrote:

     

    It almost sounds like you have an intermittent door switch, or borderline switch adjustment… 

    If it’s a door switch problem, then the blower wouldn’t be running.  He said the blower was running and the heat light was on when the problem occurs.

     

    We really need a picture of the oven to know what control the oven uses.  Here’s why:

    • In ovens using a standard solid-state temperature control with potentiometer, the HEAT (“Light Off-Oven Ready) light is a separate component and is connected in parallel with the main valve.  So if the light is on, then the main valve should be getting power too.
      • In that arrangement, one can roughly surmise that if the light is on, the ignition module is working, the the main valve is on – so there’s flame at the burner.
      • If the light is off, then the burner is off too.  If that happens be while the ignition module still has 24vac being sent to it from the temperature board, then the module must be locked out – probably from failure to prove a flame.
    • Ovens using a solid-state DIGITAL TIME & TEMPERATURE control incorporates the HEAT light into that control module.
      • In that arrangement, the light (an integral LED) might work, but the ignition module or the main valve are NOT.
      • The possible scenario THERE is the possible failure of relay contacts within the temperature control which may not be sending 24vac to the ignition module.

     

    Based on everything I’ve read, I’m thinking the LATTER of the two.  He has a DIGITAL TEMPERATURE control.  Therefore, it sounds like it’s not proving flame.  Some of his observations hinting of an intermittent operation of spark for ignition may indicate the spark module is on its way out.  That low gas pressure in his original post leads me to think the gas valve is having issues too.

     

    As fixbear and I are both alluding to, our help in troubleshooting this problem is contingent upon our knowing which temperature control this oven has. 

    It’s just tough (to nearly impossible) to troubleshoot this without actually being there.

  • Blodgett DFG1xl/AA not relighting. 2

    fixbear

    Member
    October 5, 2017 at 7:25 am

    Is the axial cooling fan for the controller running, up to speed, and clean?  Electronics need to be cool to work.  How about the vents in the control area?

     

    Just a off the wall thought because it only does it with heat.

  • Blodgett DFG1xl/AA not relighting. 2

    fixbear

    Member
    October 5, 2017 at 12:20 pm

    DFG1xlaa

    Albumen, Is this your oven?  If so note that it has a 5 minuet delay to refire. built in.  And, unfortunately I do not have a wiring diagram for this one.  So it’s up to you to use the one on the machine for the little things that can happen.  At the bottom of the diagram there is a diagram number. I may be able to get a copy if I have that.

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 5, 2017 at 3:13 pm

    Oven pic

    I got it to upload.

  • Blodgett DFG1xl/AA not relighting. 2

    fixbear

    Member
    October 5, 2017 at 3:41 pm

    That’s the one I have pictured, just a different year/color. Part of the excell series that Blogett doesn’t release wiring diagrams.

  • Blodgett DFG1xl/AA not relighting. 2

    ryantruck9

    Member
    October 5, 2017 at 4:17 pm

    when you say click from the blue box I assume Ignition module?

    do you have a steady 24VAC at this module (between THS and Chassis) when you get  a click then nothing?

     

    As ectofix mentioned Blodgett phased out the Blue Johnson Controls Ign. module’s some time ago

    often when they are failing you will get intermittent issues, very short trials for ignition, or no trail for ignition

     

    the ignition module may also have no retry for ignition. after module lockout it needs a break in power to the module to reset.(opening door or thermostat turned below actual temp them back up above actual oven temp)

     

    if these have been converted to LP you have some serious gas pressure troubles if you are only reading 1.78 inWC at the manifold in low flame

  • Blodgett DFG1xl/AA not relighting. 5

    ectofix

    Member
    October 5, 2017 at 4:41 pm

    Thanks for the picture.  That’s a new one to me.  Two rates of fire?  Interesting.

     

    I had tried to correlate your oven’s model number to a standard DFG-100 – which I think I can fix with my eyes closed.  All that while I kept returning to Blodgett’s website looking for documentation on your DFG1XL/AA.  I I kept coming up empty-handed.

     

    SO, for my own curiosity:

    • Does your DFG1XL/AA use a pilot to light the main burners flame?

    – OR –

    • Does your oven lack a pilot burner altogether and simply use direct spark ignition to light the main burner?

     

    I ask because I’ve never seen a Blodgett designed for direct spark ignition.

     

    There ARE other oven makes out there that do use that.  For instance, Southbend (another Middleby company) makes convection ovens (at least the ones I’ve worked on) which use direct spark ignition.  In such an arrangement, an ignitor lights the main burners directly and the MAIN burner flame impinges upon a flame sensor rod to prove flame.

     

    Otherwise, every Blodgett I’ve ever worked on used intermittent pilot ignition.  So, a PILOT lights first.  Then, as the pilot’s flame impinges upon the flame sensor rod and a flame is proven, the main valve opens to supply the main burners.

     

    Sorry to confuse you by bringing that up.  I’m just curious about that oven.

  • Blodgett DFG1xl/AA not relighting. 2

    fixbear

    Member
    October 5, 2017 at 5:08 pm

    Ectofix, your not alone on this. What really thru me was that it had a built in 5 min delay caution on the bottom of the the page that I found the pic on. Must be interesting wiring diagram with the double firing rate.  Hopefully someone can post a schematic. 

  • Blodgett DFG1xl/AA not relighting. 5

    ectofix

    Member
    October 5, 2017 at 8:59 pm

    From my question to him, I was merely speculating and wanting to clarify exactly what possible burner design that his oven has.  It doesn’t sound like the one commonly used in a DFG-100…unless it’s a HSI.

     

    Anyway…

     

    In all of what albumen wrote, he never mentioned a PILOT flame.  He DID say that OCCASIONALLY only the right-hand burner would light – and then go out.  WELL – in a low gas pressure condition, the right-hand burner WOULD be the first to get gas.

    YET – in an intermittent pilot ignition system, the main burner would never get any gas AT ALL until a pilot flame is proven. 

     

    So from his description, it sounds like a direct spark ignition system. Therefore, no separate PILOT valve.

     

    Worth noting is that the pilot’s gas pressure isn’t regulated by the gas valve.  It’s raw pressure from the oven’s gas supply.  1/2 PSI or less.  SO…not subject to a failure of the gas valve’s internal regulator.

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 5, 2017 at 10:08 pm

    There is no pilot light on this one.  It is a direct spark to the two right hand burners.  I think it is a gas pressure issue due to a faulty conversion just like my other one we worked on a few months ago.  I did buy these as a set so the same folks “converted” them so it is likely.   

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 5, 2017 at 10:16 pm

    Yes Axial fans running no issue and clean.

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 5, 2017 at 10:17 pm

    I will check the THS tomorrow and let you know.

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 8, 2017 at 8:31 am

    Sorry I have not replied back.  Had to work the past two days and got overrun.  My oven pic did not load>?>  Anyway…it is a solid state controller.  NO digital No steam.No cook/hold.  Just an oven with a manual temp knob, timer and hi/low fan + 60 – 80k btu switch.  Here is what I found out.  During my work time, I have the kick plate off so I can watch it.  I have ran this oven hard over the last two days….12 hrs + with different scenarios .  When it fails, this is what I see. The burner closest to the spark (right hand side if you are facing the oven…closest to valve) is lighting (weak flame) but the others are not.  No Proof…shuts down.  correct @ectofix…fans are running.  Open door or wait on controller.  Tries to light…sometimes it works…sometimes not.  It will cycle for awhile trying to light then quit.  I adjusted the spark thinking that would help,,..did not.  Same result.  I think the gas pressure is the issue.  I did check the burner nozzles and they are propane and clear of junk.  Records show new spark ignitor, flame sensor and door switch 18 months ago.   I think I should order a new valve and perhaps upgrade the controller…sound like the best plan?  Get the right gas pressure…ensure a good spark/control…then check the temp module.  What do you think>

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 8, 2017 at 8:38 am

    Ok…had a chance to look into the gas problem.  I believe it is a White-Rodgers 36607 dual gas valve which only correlates to a Lennox/Carrier furnace from what I am finding online.  Have any of you ever seen one of these on an oven before?  Did Blodgett use these for awhile and now transitioned to Honeywell?  

  • Blodgett DFG1xl/AA not relighting. 2

    fixbear

    Member
    October 8, 2017 at 10:14 am

    albumen,  With a two stage gas valve on propane you should have a manifold pressure of 10″ high and 5.5″ low. This would reflect on flame rectification for the control. I’ve worked on several in furnaces, but none in cooking. I have also seen proportional control gas from 17,000 BTU fire rate to 168.000 BTU.  With a 98% efficiency less yet. Japanese design. But touchy and requires a temp sensing fuse link for overheat safety if the heat ex-changer gets dirty/mineralised. All in a unit only 8″ X 5″ X12″ excluding manifolds, draft inducers and gas valve.

     

    I expect the next generation of techs are going to see this technology in food equipment.  But it will require outside air supply to keep going. Air borne grease will wipe one out. due to fuel air shaper mixer. No nozzles.

  • Blodgett DFG1xl/AA not relighting. 2

    albumen

    Member
    October 11, 2017 at 7:54 pm

    Got the new gas valve installed today, cleaned and added new spade connector on spark, gaped it at 2.5 mm.  Gas pressures at manifold are 5.45″ and 9.95″ (may trim these a little but happy it is working).    Ignition is consistent with all 4 burners at once.  Hi/LO sequences ignite consistently and show very little yellow tips if any at all.  Contacted Blodgett and they confirmed this unit is part of the XCEL series.  This one is closed.  THANK YOU all.

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