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  • Blodgett DFG-200  Low Fan Oven Mode Not Working

    Posted by guest on September 17, 2017 at 12:00 am

    Hi Folks,

     

    I’m going to be working on a #Blodgett #DFG #DFG-200 convection oven today.  It has the Digital Solid State controller (controller is 1 yr old).  It had an issue where the “Oven On – High Fan” mode was working intermittently.  When I replaced the mode selector switch (got part # from parts manual) the switch was not same-for-same…  but similar and with prongs on the back marked L1, N, and then 1,2,3,4 (as the old one did).  Problem was… when I put it back together, the modes were not in the right order.  

    Old Modes (as labeled on the oven):  Top=Off, Right=On-Low, Bottom=On-High, Left=Cool Down

    New Modes:  Top = Off, Left = On-High, Right = Cool Down, Bottom = Off

     

    Bakers are complaining now that they need low fan mode to work…   I’ll have a chance to get to the oven soon…  got the Sequence of Operations and the electrical drawing but I’m wondering if there’s anything else to check?  My instinct tells me that someone used the incorrect mode switch last time and just re-wired it to work right…  and I’ll have to do the same with the new switch.  Of course I lost track of the old switch so I can’t just use a multi-meter to figure out if it was apples to apples  <facepalm>  

     

    Any advice greatly appreciated!!  

    fixbear replied 6 years, 6 months ago 1 Member · 30 Replies
  • 30 Replies
  • ectofix

    Member
    September 17, 2017 at 5:30 pm

    Sorting out Blodgett’s evolving array of control panels is about as clear as mud.

     

    So before I delve into this too far, let’s be sure of the control panel you’re talking about.  You said “Solid State” and Digital”.  Does this look like the control panel you have?

     

  • wired1000

    Member
    September 17, 2017 at 6:05 pm

    Yes that’s the one.  So…   I’ve made some additional “progress”:

     

    1)  Noticed that I had ordered a 3-position switch instead of a 4-position.  This is why the positions seemed off and why one wasn’t working (Why the 3 position switch STILL has FOUR positions and FOUR connectors on the back is a big mystery!!!)   

    2)  Decided based on wiring diagram that I could get the desired “Low Fan – Cook” setting to work if I changed some connectors around… so I removed the high-fan connectors from 4 and 2 and connected the low fan wire to position 4 on back of the switch.  

    3)  Plugged it back in…  tried it:   No dice.  I checked the relay…  it is engaging after a few seconds of the power being applied (and the controller powers on) but the fan is not coming on.  

    4)  Powered everything off again, cleaned the contacts on the relay…  tried again.  Still nothing.  

     

    That’s where I’m at at this point…  appreciate any help!!

     

    PS:  I misremembered the positions of the “Old Modes” switch in my first comment…  switched Cook High and Cook Low….   but at this point it’s not important since it’s the wrong switch… that problem is solved!!

     

    PPS:  Would be interested to know if there is a way to specifically check the low speed of the fan.  Is there a place I can just apply 110V to that would get it spinning or tell me if it’s shot?

  • ectofix

    Member
    September 17, 2017 at 7:22 pm

    If the relay is changing state, then the motor should go to low speed.  Certainly check that relay’s output with a meter.

     

    Just so you know, the side panel can be removed to expose a terminal board to which the motor wires to.  All of the wire colors are there per the schematic.  Looking at the schematic on page 2-11 of the service manual and assuming the relay depicted is in a de-energized state:

    High speed = neutral to the motor’s black wire and line to the motor’s blue wire. Low speed = neutral to the motor’s white wire and line is to the motor’s yellow wire.

     

    Worth noting is that a motor capacitor only exists on two-speed motors.  Single speed motors don’t use a capacitor.  So be sure to check the capacitor.  It’s located behind the control panel.

     

    FWIW:  I’m questioning that schematic because it isn’t making sense.  I’m not seeing line going to the motor during low speed.  Their illustration of the 4-position rotary switch leaves some questions.

  • wired1000

    Member
    September 17, 2017 at 7:30 pm

    Where would I check relay output?  I was kind of unclear on that…  

     

    How would you suggest checking the capacitor?  Actually I may have a spare of the capacitor…  but if it was failing wouldn’t both speeds be not functioning?

  • fixbear

    Member
    September 17, 2017 at 7:34 pm

    Wired1000,  They use 15 different controls on this oven depending on year and serial number.   A small bit of clarity here would help.  I only found 2 with 4 position selector switch.  What does your label on the switch say.

  • fixbear

    Member
    September 17, 2017 at 7:54 pm

    If it is the one ecto shows,  Violet 4 goes to L1,  violet 3 to 4, 

    Black7 to 1,  Violet 4 to 2,  Black1 to N,   and blue 1 or 4 (year) to 3

     

    L1/1 has to be closed to energize the low power fan relay.

  • wired1000

    Member
    September 17, 2017 at 7:57 pm

    Apologies.  The oven was built in 1991.  

  • wired1000

    Member
    September 17, 2017 at 8:00 pm

    We determined I purchased the incorrect (3 position switch).  So that wiring configuration doesn’t really help with the wrong switch.  I did figure out a workaround to get power to the low fan cook circuit but something else is wrong…  see above

  • wired1000

    Member
    September 17, 2017 at 8:02 pm

    Well I knew I had that capacitor spare so I dug around…  found I also have a spare for the relay.  I hate to just throw parts at things but they were right there!!  

     

    No joy…  no change from earlier configuration with the old relay / capacitor.  :-/  

     

    Also, checked out the side panel.  In the case of this oven the side panels have been welded in place.  Thanks Previous Owner!!

  • wired1000

    Member
    September 17, 2017 at 8:22 pm

    Serial#:  030194EA014B

     

    Not sure if it matters for this issue but the oven was converted from original Propane to Natural Gas at some point prior to me owning it.  

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