I have a Thermador oven that will not hold the correct temperature when set. Is there a fix for this? I was told by a repairman that the thermostat needs replacing but that it has been discontinued. Has anyone else run across this problem and if so were they able to fix it? How? Thanks!
Hello,
The Thermostat was not available for a little while, but Thermador found another thermostat that can takes it’s place. Unfortunately, Thermador states that self clean is no longer supported with this thermostat.
Also, if you feel that the temperature just needs to be adjusted, you can try to calibrate your oven using the attached document
KC
Thermostat_Calibration.pdf (106.6 KB)
Thanks for your help. Do you know what the new Thermador part number would be for this replacement thermostat?
Sorry - I meant to include it. The part number is 622568.
Thanks! Now, does anyone know where I can find instructions on how to remove and replace this part? Thank you!
[QUOTE=babalu3;400878]Thanks! Now, does anyone know where I can find instructions on how to remove and replace this part? Thank you![/QUOTE]
New at this, but after finding the original part (486945) was obsolete (and it’s replacement was $379+), I followed another persons idea of taking back off of the thermostat and cleaning the contact. I used a small piece of 320 grit sand paper. The heating was erratic before as well as a good 50 degrees high.
I was glad to find the PDF on how to calibrate the thermostat here on this forum!
Anyway, to get to the thermostat (on my Thermador PRDS304) I removed the grates and center piece from top of stove to access/remove (4) screws that hold the bracket that the t’stat is mounted to. Then from the front, I removed all the knobs then the front panel and removed panel. Careful to ‘slide’ (4) indicator lights off their little red lenses- mark these too (they break easily). I drew a picture with wire locations so I could put them back correctly. A metal piece slides off back of t’stat to access the interior where slide switch is. It was tricky to sand between the contacts, but it can be done.
Hopefully my newly calibrated t’stat will continue (past my test period) to maintain temperatures without wide variances like before.
Good luck
Hi - So I am not an appliance repair person but I do have a background in fixing things that others break along with an electrical background. My Thermador PRDS364GL was doing a similar heat then cool trick. What I found through observation was it would heat to nearly any temperature just fine. Cooked pizzas at 500 even during this condition. Once the t-stat opened the heat circuit it would not reheat further. Eventually temp would drop to 250 or so even though the heat indicator light was illuminated. Studying the schematic I came to the conclusion that you really couldn’t have both the heat indicator light on and no power to the bake element without something funny happening elsewhere past the t-stat. I pulled the t-stat to take a closer look and it was like new inside still. I then pulled the hot wire relay and there was significant carbonization on the bake element contact. I sanded both the bake and broil contacts nice and clean and then reinstalled. I have since ran the oven at 500 degrees and it maintained that for over an hour with regular cycling on and off. I would suggest this to anyone experiencing this problem. It is a fast fix without disassembling the entire top end.
Good luck!
[QUOTE=breaker;754779]Hi - I then pulled the hot wire relay and there was significant carbonization on the bake element contact. I sanded both the bake and broil contacts nice and clean and then reinstalled. … It is a fast fix without disassembling the entire top end. [/QUOTE]
Breaker,
Can you describe where the “hot wire relay” is located as well as it’s approximate size & description? My model 304 is built in, so I am hesitant to pull it out of the counter on each side to access the back, in case that is too involved. But I would like to check these/ this connection if easy to get to. My heating element bolts to the back wall of the oven (2 screws thru a flange).
Since my 12/6/11 report of cleaning the contact inside the thermostat (which was pitted), the oven seems to stay at the set temperature within the normal +/- range. I think I recall the OEM acceptable temp range was +/- 25 degrees F. That seems pretty wide to me, but I am not an appliance tech, so maybe that is standard.
[QUOTE=davekro;755041]Breaker,
Can you describe where the “hot wire relay” is located as well as it’s approximate size & description? My model 304 is built in, so I am hesitant to pull it out of the counter on each side to access the back, in case that is too involved. But I would like to check these/ this connection if easy to get to. My heating element bolts to the back wall of the oven (2 screws thru a flange).
Since my 12/6/11 report of cleaning the contact inside the thermostat (which was pitted), the oven seems to stay at the set temperature within the normal +/- range. I think I recall the OEM acceptable temp range was +/- 25 degrees F. That seems pretty wide to me, but I am not an appliance tech, so maybe that is standard.[/QUOTE]
I have no idea where it is on your model. On mine, a dual fuel freestanding range, it is in the kickpanel.
Breaker,
I see three relays in a line in the middle of the kick panel area. Can you think of a way to describe by orientation or wire color or size the “bake element contact” that needed cleaning on your model? Our models may be different, or not with regard to the relay layout.
I guess I could turn off the house breaker to that area and just start pulling and checking connectors one by one, but thought I’d ask first. :o)
Thanks
[QUOTE=davekro;755149]Breaker,
I see three relays in a line in the middle of the kick panel area. Can you think of a way to describe by orientation or wire color or size the “bake element contact” that needed cleaning on your model? Our models may be different, or not with regard to the relay layout.
I guess I could turn off the house breaker to that area and just start pulling and checking connectors one by one, but thought I’d ask first. :o)
Thanks[/QUOTE]
The hot wire relay looks like this. The high current contacts are at one end of the unit. You can remove the plastic cover to gain good access to them once the relay is removed from the appliance chassis.
I hope that helps.
[quote=davekro;755041]Breaker,
Can you describe where the “hot wire relay” is located as well as it’s approximate size & description? My model 304 is built in, so I am hesitant to pull it out of the counter on each side to access the back, in case that is too involved. But I would like to check these/ this connection if easy to get to. My heating element bolts to the back wall of the oven (2 screws thru a flange).
Since my 12/6/11 report of cleaning the contact inside the thermostat (which was pitted), the oven seems to stay at the set temperature within the normal +/- range. I think I recall the OEM acceptable temp range was +/- 25 degrees F. That seems pretty wide to me, but I am not an appliance tech, so maybe that is standard.[/quote]
I am also looking for the hot wire relay. Did you locate it on your model 304 and if so where? I am having issues like what breaker is mentioning. Were you any of your measures taken to fix hot wire relay successful?
Do you know where the Hot Wire Relay is located on my model Thermador PRD304? I have the diagrams but between the exploding diagrams and the matching parts list. None of the descriptions are similiar.
The model number given (PRD304) does not use a hot wire relay, but the units that did (GCR304, PRSE304 and PRDS304), had the HWR located on the bottom, behind the kick panel. Before working on it, make sure to turn the circuit breaker off.
Perhaps you have some other suggestion. I have fluctuating oven temperature. It seems as though the oven tries to reach set temp and then eventually 20-30 minutes reverts back to approximately 250 degrees, regardless of whether you have the oven set to 500 degrees or 350 degrees. We have done the follow. Replaced the oven thermostate sensor. Oven still not reaching temp. Upper Element will glow red hot for broiling so it is functioning. The lower element we disassembled and checked for continuity and it was fine. Did the 1 minute heat and felt the element with hand and it is warming. So it appears both elements are working and new thermostat sensor. Any suggestion on where to go next to isolate or eliminate issue? If the next item to look at is the control board. What measurement would I use to isolate or elimate if it needs to be replaced. Ohm reading? Or?
If the heat light is on while it’s not heating, it’s most likely the hot wire relay. The only other components in the circuit are the elements and selector switch, which are unlikely to work intermittently.
One test you can do (while the breaker is turned off) is switch the wire from the H1 terminal, which is specific to bake, to the H2 terminal, which is specific to broil. If it is the H1 side of the HWR that’s bad, the bake element should continue to heat and the broiler should start to drop out. Though the baking may heat better, it won’t be perfect, because the broil element is also used during bake, but only at 50%, and it will now start to drop out. Also, if you keep H1 and H2 switched, you will most likely lose broil, because the broil element will now turn off like the bake element did.
[quote=Servicer;871650]If the heat light is on while it’s not heating, it’s most likely the hot wire relay. The only other components in the circuit are the elements and selector switch, which are unlikely to work intermittently.
One test you can do (while the breaker is turned off) is switch the wire from the H1 terminal, which is specific to bake, to the H2 terminal, which is specific to broil. If it is the H1 side of the HWR that’s bad, the bake element should continue to heat and the broiler should start to drop out. Though the baking may heat better, it won’t be perfect, because the broil element is also used during bake, but only at 50%, and it will now start to drop out. Also, if you keep H1 and H2 switched, you will most likely lose broil, because the broil element will now turn off like the bake element did.[/quote]
I had read another post indicating that sounded very similiar to my issue. It said hot wire relay, too. However when I posted to forum to ask where my hot wire relay might be they indicated my model Thermador PRD304 doesn’t have a hot wire relay. Do you know if this correct? I have the exploding diagram specific to my unit and the corresponding parts list and none of the descriptions seem to me to be close enough in description. Also the blue heating light does come on during preheating and then when it reaches temperature goes off and then periodically continues to cycle on & off for short bursts (like normal) when trying to maintain temp.
[QUOTE=woocrotto;871653]I had read another post indicating that sounded very similiar to my issue. It said hot wire relay, too. However when I posted to forum to ask where my hot wire relay might be they indicated my model Thermador PRD304 doesn’t have a hot wire relay. Do you know if this correct? I have the exploding diagram specific to my unit and the corresponding parts list and none of the descriptions seem to me to be close enough in description. Also the blue heating light does come on during preheating and then when it reaches temperature goes off and then periodically continues to cycle on & off for short bursts (like normal) when trying to maintain temp.[/QUOTE]
You’re referring to another one of my posts. Like I mentioned in my previous post, if your model number starts with PRD304, it doesn’t have a HWR, and that the only ranges Thermador made with HWR’s started with GCR, PRSE and PRDS. Do you have the full model number, e.g. PRD304EG/02?
The full model # is PRD304EG/05