Thermador PRD484EEG Shuts Off at Start Up (Sometimes)

[jeff@beckettandhensley.com]

My Thermador PRD484EEG double ovens will (sometimes) begin to start up and then shut back off.  After several restarts, the oven will stay on and operate normally.  It only happens about 75% of the time.  It is on propane.  Any suggestions as to the problem?

[jeff@beckettandhensley.com]

They are electric ovens.  Anyone have a suggestion?

[nolazach]

Sounds like either a bad/sticking relay on the main board (the relays are what switches the power on to the element after you turn oven on) or possibly a thermal fuse.  But it working again makes me think relay.   

   You have a multimeter?

  When it shuts off, is it the element or the entire oven?

[jeff@beckettandhensley.com]

Sorry for the late reply, but working on my furnace.  When it rains, it pours.  Don't have a multimeter.  I turn on either over (or both at the same time) and they start to heat, fan starts running, and then the whole thing shuts off.  I have to restart with the knobs off and back on again and after several tries it stays on.

[JP_Austin]

Nice Oven. My Thermador recently was shutting off inadvertently as well. Are all the indicator lights on that are supposed to be on when you flip the oven ON? If no or they are DIM than it could be the control panel up front. Before we go there, report how the controls are behaving and if the display's are giving you the correct lights and such.

[JP_Austin]

As a thing to look for... disconnect AC power to the oven (flip the breaker is easy) and pull the front control panel off. Look on the control board and see if the capacitors are bulging or a black goop has escaped from them. This is a known issue with some Thermador ovens as the capacitors dry out and go bad. That reduces the voltage on the board and the control signal to the relay board is never interpreted to turn on correctly. Will be a marginal situation and likely worse when hot. If the control board relays are really bad then they tend to intermittent as well. Will need a multi-meter and some skills to debug if the case. No matter we can help you through the fix.

[jeff@beckettandhensley.com]

My husband is at a volleyball tournament and will be back with you asap - thank you for your time and assistance!

[Chief Petty Officer Crowe]

Good tips, @JP_Austin.

Would also be worth checking the connections at the power cord terminal block. If they’re loose, they will heat up while the oven is in use and can drop enough voltage to shut the range down. May even see wire charring if this had been going on for a while. 

[jeff@beckettandhensley.com]

There is a big electric oven and an electric warming oven on this unit.  I have replaced the heating element in the warming oven several years ago and it has been working fine.  Now, if I turn one of them (ovens) on (or both at the same time) all blue lights light up on the control panel and the fan starts running and the oven(s) start to heat up.  After about 30 seconds the oven(s) will shut off and all blue indicator lights will blink and then go off as well.  I have to turn oven knobs all the way off and then back on again and after about three (sometimes more) of these procedures the oven(s) will stay on and work properly.  I am going to turn off the breaker and reboot first.  If that doesn't work, I will pull the oven out (heavy) and inspect all aspects of oven, switches, etc.  Your help is greatly appreciated fellas.  Shouldn't be that hard of a fix.

[jeff@beckettandhensley.com]

BTW, I do have a multi-meter. 

[jeff@beckettandhensley.com]

Okay, I was all set to check the control board as JP suggested, but not sure how to remove that cover.  I only found two screws underneath.  Don't want to force anything.  Do I have to remove all of the control knobs to get the cover off, or am I missing something?  (This is why I am just a lowly grasshopper).

[AccApp]

Screws are hidden behind the control knobs, good luck.

[jeff@beckettandhensley.com]

I was afraid of that, but wanted confirmation before I took it all apart.  Thanks.

[jeff@beckettandhensley.com]

Well, I took two screws off each end, took off all knobs and screws underneath them and the darn thing is still locked on solid.  Looks like there are two screws on each side WWAAAYYY up inside that are almost impossible to reach (or see).  Should be easier to get to the control board.  Smarter than me I guess.  On the bright side, since I flipped the breaker off and then turned it back on the ovens seem to fire up without shutting off.  Maybe temporary, but I have my fingers crossed.

[jeff@beckettandhensley.com]

I have a Thermador PD48.  It has a large oven (PRD484EEG205) and a small oven (PRD484EEG/05).  The large oven works fine.  When the small oven is turned on, it kicks back off and begins a light sequence code of:

Left blue light flashes twice, then right blue light flashes once.  I understand that to be light sequence code 21, but I am not sure exactly what the error code is or what it is telling me.  I thought it was a potentionmeter failure, but if so, not sure which one (it has 4 I believe).

I really just need to know what the code is telling me so I can order a part and fix it.  I have replaced all sorts of things on this unit with parts ordered through the Samurai Repair Man, including heating elements, cooling fans, etc.  If I know what part to order, I can fix it.

Thank you.   

[MrApplianceMatt]

This might help. This service manual covers a bunch of their ranges. If I had to narrow it down it would be either the small oven function switch or the small oven temperature selector. I'm leaning towards the latter as I don't know that the function selector would be considered a potentiometer. https://www.manualslib.com/products/Thermador-Pro-Grand-Prd484eeg-2083628.html