# Wolf Oven Preheat Cycle



## DanS26 (Oct 25, 2012)

Have a Wolf older A series 36" oven that has a strange preheat cycle. If I set the cold oven for 350 deg the oven will initially heat to 450 deg then settle back slowly to 370 deg and stay there. Just wondering if this is normal behavior or do I need to replace the thermostat mechanism?


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## jmon (Nov 5, 2012)

Doesn't sound like that's normal to me. You didn't mentioned if it was gas or electric. It could be a bad or loose heating element, bad wiring connection or thermostat. Have to investigate a little further. Just a suggestion.

Others will be along with more advice/suggestion.


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## nap (Dec 4, 2007)

a preheat setting is a high power setting so the oven will heat up more quickly.

It is normal to overrun the temp setting, some amount. I would think 100º would be a bit excessive. (but in reality it is only 80º. check out the calibration described below)


the other issue is the temp drops to only 370. 

the temp in an oven varies. It heats up to above the set temp and then shuts down the heat source and it cools to a predetermined point below the set point. The average should equal the set temp.


how far above and below varies with a high quality appliance have a smaller variation and cheaper appliances sometimes having a considerable range.

To start with, you might check to see if the knob/dial on the oven is adjustable. If so, start with calibrating the setting on the dial with a given temp in the oven. In other words, such as in your example you had a temp of 370 so you need to set the knob to match that. Of course that doesn't change the amount of the overrun temp. So, as it is, the setting should be 370 so while it overruns that on preheat, it is not quite as much as it appears to be but I suspect it might still be excessive.


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## DanS26 (Oct 25, 2012)

Thanks guys for the responses. I've done a little more experimenting with this stove. It is a natural gas range, older Wolf model with six burners on top and a fairly large oven. Very heavily built.

So here is what it does.....it overheats on the initial warmup or whenever the desired temperature is raised. So today I set the temp to 250....burner ran to 275 and flame shutdown but because of the thermal mass in the burner assembly the actual temp of the oven ran up to 350. Oven slowly returned to 275 and the temp stabilized at 275 and stayed there within +or- 5 deg. Now while the oven was at 275, I increased the desired temp to 350. Burner flame on till 375 then flame off but the thermal mass increased the ambient temp to 450 then the same long settlement back to 375.

My conclusions are that the thermostat is 25 deg high. And the the thermal overrun is caused by the flame shutting down too late. Maybe just the nature of this heavy beast.


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## Protocol. (May 31, 2012)

Nap, preheat has absolutely nothing to do with this. Burners will never vary voltage or heat output. With electric elements when you halve voltage you will not halve power output. With gas if you change pressure the burner characteristics change and you run a real risk of creating improper combustion (co gas)

Since your unit is gas it is going to overshoot a bit until the metal reaches heat saturation. If your using a digital thermometer or laser probe to check it will be higher. Air directly heated by gas will be much hotter until this heat saturation takes place. If your unit has an electrical thermocouple then this may be a bit high, but as long as it stabilizes back to temp nothing to worry about. If this is a liquid filled capillary tube with knob then this can certainly be normal. 

How long does it take to reach saturation and after it gets to its hot point how quickly does it cool off? What are you using to Check temps? Pics of the oven probe and thermostat would help.


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## DanS26 (Oct 25, 2012)

Protocol. said:


> Nap, preheat has absolutely nothing to do with this. Burners will never vary voltage or heat output. With electric elements when you halve voltage you will not halve power output. With gas if you change pressure the burner characteristics change and you run a real risk of creating improper combustion (co gas) Since your unit is gas it is going to overshoot a bit until the metal reaches heat saturation. If your using a digital thermometer or laser probe to check it will be higher. Air directly heated by gas will be much hotter until this heat saturation takes place. If your unit has an electrical thermocouple then this may be a bit high, but as long as it stabilizes back to temp nothing to worry about. If this is a liquid filled capillary tube with knob then this can certainly be normal. How long does it take to reach saturation and after it gets to its hot point how quickly does it cool off? What are you using to Check temps? Pics of the oven probe and thermostat would help.


What you describe as heat saturation appears to be the issue. When I measure the temp with a infrared laser right on the thermostat tube it registers the correct temp but the ambient air as measured by a hanging oven thermometer the temp is 80 to 100 deg higher. Then after I wait for stabilization the air temp and the tube temp will merge.

Trouble is that it takes 15 to 20 minutes for this stabilization to occur. This range was built for professional application. In a commercial kitchen probably no problem since the stove is expected to run all day.

I'm slowly coming to the conclusion that this stove is not really built for a residential application. I think Wolf probably wanted to penetrate this market but instead of designing a residential product, just took their professional product and sold it in the residential market. They stopped making the A series in 2000. Now I understand why.

Waiting 20 minutes for heat saturation in this metal monster is going to be a PITA. Will probably replace ASAP.


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## DanS26 (Oct 25, 2012)

DanS26 said:


> What you describe as heat saturation appears to be the issue. When I measure the temp with a infrared laser right on the thermostat tube it registers the correct temp but the ambient air as measured by a hanging oven thermometer the temp is 80 to 100 deg higher. Then after I wait for stabilization the air temp and the tube temp will merge. Trouble is that it takes 15 to 20 minutes for this stabilization to occur. This range was built for professional application. In a commercial kitchen probably no problem since the stove is expected to run all day. I'm slowly coming to the conclusion that this stove is not really built for a residential application. I think Wolf probably wanted to penetrate this market but instead of designing a residential product, just took their professional product and sold it in the residential market. They stopped making the A series in 2000. Now I understand why. Waiting 20 minutes for heat saturation in this metal monster is going to be a PITA. Will probably replace ASAP.


Perfect example of why a commercial product in a residential application is not always a good idea.


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## nap (Dec 4, 2007)

Protocol. said:


> Nap, preheat has absolutely nothing to do with this. Burners will never vary voltage or heat output. With electric elements when you halve voltage you will not halve power output. With gas if you change pressure the burner characteristics change and you run a real risk of creating improper combustion (co gas)
> .


\First, I never said the pre-heat was his problem. I said the oven operates on a high heat during a pre-heat cycle.



Then, I never said anything about altering the output of a burner or element. 

but where you come up with: if you halve voltage you will not halve power output of an electric element? Who cares? If you want to halve the power output you adjust the voltage or current accordingly. If you want to quarter it, you adjust the voltage or current accordingly. Ohm's law will get you there. 
btw: if you halve the voltage you reduce the power to 25%. 

but anyway, if you don't want to believe me, you might want to refer to Wolf's own literature. The specifically state the oven is not suitable for cooking during a pre-heat cycle. Wonder why? They also say that if you are going to increase the temp you need to cycle the setting to off first and then reset it to the new temp or it will take considerably longer to reach the new temp setting (because it does not go into preheat mode). Wonder why?

I'll tell you why.


Many ovens, and apparently Wolf among them, run the broiler burner or element as well as the oven burner or element during an oven pre-heat cycle so as to reach the set temp more quickly.

So, before chastising me about something, maybe you should refer to the manufacturers operations manual or repair manual and learn the correct information. 

from a Wolf owner's manual



> O V E N P R E H E AT
> During preheat the oven is heated in a manner
> unsuitable for cooking. Preheat should be used
> for all cooking modes except Broil and
> ...


It isn't suitable for baking because that darned broiler element is right above whatever you are wanting to bake all hot and ready to charbroil your baked Alaska.




Have a great day.


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## hardwareman (Oct 9, 2010)

if your trying to measure the true oven temp you have to use a thermocouple probe. Manufacturers tell us to let it cycle at least 2 times before you can get an accurate reading.


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