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      ***READ THIS PRIOR TO STARTING A NEW TOPIC***   05/02/2016

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Thermador RDFS30Q Oven Issues (S/N 96100089)

11 posts in this topic

Wife reported that when setting oven to bake, broil came on and crisped up her cake to charcoal.  I cannot get oven to duplicate this, thinking she inadvertantly hit some buttons (which are on the front) while cooking.  Will monitor.


However, I have noticed the oven heats up slowly.  If set to 350 F, it will get to 300 F, then take it's time approaching, but never getting to 350 F (I admit my thermometer is junk, but it read reliably in the past).  Same scenario to other temperatures.  Anyway, if set to bake, element heats up (red), temp comes up to 300 F and element clicks off, then element will come on again for the crawl to near 350 F.  Does this make sense? 


I checked the oven sensor resistance.  Service manula says it should be 1075 - 1110 ohms, I get 1100 ohms on the money, checked several times today. 


The oven controller has long since faded in terms of reading temperature, so I'm due to replace.  Not sure how this thing works, does it control temperature ramp up?


Finally, I think this bad boy has a high temperature cut out switch, manual does not address how to check, any thoughts on this?


Any help, from the guru's, as always, is appreciated.



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... I checked the oven sensor resistance.

Oven Sensor may be "flaky" at higher temperatures


there may be math involved:

Thermador Oven Sensor


GE Oven Sensor



would need to use ceramic wire nuts and splice behind Oven Wall

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Good point, the thing could be whacko at higher temps, right now, trying to get oven to heat up, but it's sure takin' its time.


OK, I don't like the Thermador part price, who would, as it's 10X the cost of the GE part, are you suggesting this part will work just as well, simply splice wire with ceramic nuts behind rear wall of oven?  These things don't go out that often, but 12 vs 150, I got kids in college.....

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... could be whacko at higher temps,

...  this part will work just as well,

1) yes, may have a "bad spot" ,,, how well does the Oven heat if set for .. say ... 450 ?

2) yes


I'm searching for some ceramic wire nut part numbers

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Thanks for the help.  Further reading in the manual, indicates the high temp cut out switch probably has not failed.  If it faIled the thing wouldn't even turn on if I understand manual.  So, I'm figuring it's probably the sensor.

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...  If it faIled the thing wouldn't even turn on if I understand manual. 

... So, I'm figuring it's probably the sensor.

1) correct, and it seems to have a manual reset button

2) cheap enough to try

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Thanks for the help, I'll try the sensor.  I have a local appliance parts place just down the road that should have this, and the ceramic wire nuts.  Probably into the weekend minimum on this job, will report back.  Also, found a refurb'd oven controller if it comes to that (need it anyway) for a good price. 


Thanks again.

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Thermador ovens are notorious for slow preheat.  Some oven thermometers are slow at reading current oven temperatures.  May even have to allow an additional 5-10 minutes after control indicates preheat is complete.  There is a calibration method to adjust oven sensor for hotter or cooler temps + or - 35 degrees.  To enter calibration mode, press bake.  Then press + until display reads 500.  Then press and hold bake key 3-4 seconds until "0" shows.  Press + or - to increase or decrease temperature in 5 degree increments.  Press cancel to store.  Sometimes to best way to check for proper oven temperatures is to buy a tube of biscuits and bake.  Let me know when they're done.

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Thanks for the tip, will check into calibration.  Oven is heating slower than you describe, sits like 50 F below set temperature.  Last night, barely got to 400 F, when set at 425 F.  Something don't seem right.  I have tiles in it for pizza baking, will remove and see how she does to say 450 F.  Will report back on what I find/replace.  Thanks.

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Here is Dacor's Oven Temperature Testing Procedure.  The same methodology applies to all oven.  Note especially the warning about relying on a $6 thermometer for testing.




Temperature Testing Procedures

** Note that all testing data is based upon controllers (ERC) that are incapable of receiving multiple adjustments. Be aware that some new controls allow you to individually adjust each bake mode. In this case, averages are unnecessary.

The Do’s and Don’ts


The Don’ts

  •   Prior to testing, don’t expect an oven with more than one bake mode to behave the same on all modes

  •   Don’t open the door during testing

  •   Don’t assume the homeowners $6.00 thermometer is more accurate than your own

    $200.00 digital meter

  •   Don’t assume that the homeowner always chooses the proper cycle; in fact, don’t assume

    the homeowner understands anything about proper cycle selection. There may not be a mechanical problem at all. 


  •   Don’t assume that your oven has stabilized at the preheat tone and start testing. Always wait twenty minutes for an accurate reading.

  •   If time allows don’t make an adjustment to the ERC without first determining how it will effect all three bake modes

  •   Don’t rush



  • The Do’s

  •   Take your time and get it right. It is better to stay a little longer than to come back.

  •   If your time is short, test the most accurate cycle (Pure Convection) and make an

    adjustment based on that result.

  •   Always use a meter with at least two leads

  •   Always educate on the benefits of convection

  •   Wait at least twenty minutes prior to recording any cut in/cut out temperatures. High or low,

    it will take the oven two or three complete cycles before it stabilizes

  •   Test as long as possible. Testing less than forty minutes will not give you a chance to record

    enough rises. 

  1. Recommended Temperature Meter

    Dacor recommends the relatively inexpensive Fluke 52 digital thermometer. This meter allows the use of two thermocouples for better accuracy,. We recommend that large alligator clips be attached to the ends of the thermocouple leads for accurate placement within the oven cell.

    Why Two Thermocouple Leads?

    A single lead attached to the center of the oven cell does not give you a good understanding of what is happening in other parts of the oven. A customer will often claim that the oven is hotter on one side than the other. Using two leads allows you to measure both sides of the oven cell at the same time. Measuring multiple locations also allows you to ovoid opening your oven door once testing has begun. Once you have begun testing, you can move freely from cycle to cycle but never open the oven door. If you do, add an extra ten minutes to your testing.


    The Long And Short Of It

    The longer the test, the more accurate the results will be.
    Regardless of the cycle selected, forty minutes is a
    minimum test period.
    You cannot do a thorough test sequence in a shorter time. If time allows, testing all three bake modes will give you the best averages. If time allows (1 1/4 hrs) the ideal test sequence should look like this.

Carefully discuss the customer’s problems to determine the problem Check ERC offset and record
Install dual probes with alligator clips as specified
Select Standard Bake and adjust to 350F.

Record start and preheat tone time 


  •   Record first cut out temp

  •   Record first cut in temp

  •   Continue to record until you have at least four to five complete rises. This will

    take approx thirty five to forty minutes.

  •   When you have recorded 4-5 rises, cancel cycle and select Convection Bake,

    adjust to 350F

  •   Continue testing Convection Bake for ten minutes. (Note that your testing

    times can drop because your oven is already thoroughly heated) Expect total

    performance change

  •   Record 3 rises and without opening the door, cancel the cycle and select Pure


  •   Repeat test sequence for 3 rises and record

  •   Terminate test. 

  1. Following temperature evaluation, you will be able to draw an average based upon all three cycles.

    If time is short we recommend that you perform your quick test as follows

    •   Be prepared to record your cut in and cut out temperatures. See sample graph at right.

    •   Determine if the ERC has already been recalibrated. Record the adjustment but do not readjust at this time.

    •   Chose Pure Convection and set the oven control for 350F.

    •   Allow the preheat tone to sound and wait ten minutes before recording temperature rises.

    •   Test and record for 30 minutes. Any less time and the oven may not have balanced.

    •   Following the test, compare the average cut in and cut out temperatures and from those figures determine the midpoint average.

    •   The average temperature will tell you whether an adjustment to the ERC is necessary. The ERC can be recalibrated plus or minus 35 degrees.

      ERC Calibration Method / All Models

    •   Select the Bake mode and using the temperature slew button raise display temperature above 500F.

    •   Quickly return and again press and hold the Bake keypad until the display changes. (Approx four seconds)

    •   Two red offset numbers will appear on the right side of the display. When illuminated, release the Bake keypad and using the temperature slew buttons adjust the ERC offset in five-degree increments up to 35 degrees plus or minus.

    •   When complete press cancel / secure.

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Well Samarai Appliance Repair Man,


Excellent tips, and yeah, i'm using the cheap thermometer (figuring a plus/minus 25 F on it).  Still fiddling with this unit and thinking I'll leave it be and watch it for a while.  I removed the tiles from the shelf last night and set it to 450 F, in 18 - 20 minutes, it was at 450 F on the cheap thermometer.  Tonight, I set it at 350 and in 20 mins was at 350 F, bumping it to 400 F takes me there in 5 - 10 mins.  Thinking, tiles suck up heat leading to even longer ramp time to set point.  Will watch it for a while as taking it apart this weekend isn't high on my list, not that it's that hard. 


Thanks for all the help.  Mike

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