Possibly the ceramic igniter next to the bottom gas burner is not functioning properly. Not very expensive to buy a new one to replace. Not a very difficult repair.

However, I am under the impression that you are not a very handy person. If that's the case, don't try to take on that project and blow up your house.

dcarch.

Looks very easy to do:

https://www.youtube.com/watch?v=k9igDKzDg6E

You describe what may or may not be two problems. First you say that it takes a long time to preheat. That points to some kind of burner problem. Then you say it won’t go above a certain temperature, that could be a thermostat problem (e.g., not calibrated). Let’s say you have it set for 350° and turn it up to 400°, does the oven heating light go on but doesn’t heat or takes a long time to heat? If so, then I’d think it’s a burner issue. If the light doesn’t go on, then it’s may be a thermostat issue.

In any case, I’d get a qualified tech to look at it.

Thanks for the input all. I think I should call a tech - along with a tech for my speed queen, and the many other things that seem to be going wrong in my house all at once!

I recently realized that my l countertop Cuisinart oven as well as my main stove don't heat up accurately. My muffins weren't baking properly and I put the oven thermometer in, and it's off by 100°. Same as my Cuisinart, it beeps and it's well below temp, at least 100 as well. So I just let them heat up a long time before I need them.

Jasdip - I would suggest that you make sure your measuring device is accurate as you indicate 2 appliances are off by the same amount.

That is definitely something to check and there can be additional considerations to account for, as well.

As has also been pointed out here over the years, oven preheat signals are mostly very misleading. They just measure air temperature and are for brands' bragging rights.

Much of the relatively even baking and roasting heat in ovens actually comes from fully heating the walls of the oven cavity. It takes time for them to absorb enough heat to be able to evenly and steadily radiate heat at your desired temperature. It takes three or four times longer to achieve that as opposed to just raising the air temperature, even in small countertop ovens. When we open an oven door right after the preheat signal goes off, and place an oven thermometer, the air temperature will have dropped dramatically as soon as the oven door was opened. The oven has to repeat the preheating process. The drops are much less dramatic and recovery much quicker once the oven cavity walls are evenly heated.

The frequent advice here over the years has been to preheat for twenty to thirty minutes beyond the preheat signal. Of course, bigger ovens will take longer than smaller ones.

Another complicating consideration is that ovens' on board temperature sensors are often placed at the top of the oven towards one of the back corners. Probes in those locations will find air that that is much hotter much sooner than the oven thermometer placed in the middle of an oven. The oven may be telling you that it is heated to, say, 400°F while your oven thermometer may be seeing only 300°F (or less) at its location on a rack in the middle and/or front of the oven.

Mike C that's a valid point, especially when my Cuisinart countertop is only 1.5 years old. I use a little oven thermometer that sits or hangs on the rack. Ideally one of those laser reader things that reads the temps of surfaces would work, wouldn't it?

"ci_lantro

Looks very easy to do:

https://www.youtube.com/watch?v=k9igDKzDg6E"

There is a big difference between "Calibration" and "adjustment". What the video is showing is simple adjustment. Calibration involves instrumentation to verify changes to be made to return defect back to manufacturer's specification.

Looks like the video shows adjustment to the needle valve thru the knob shaft to vary the pinhole gas jet. This may vary the burning temperature, but is not a fix to the real problem, and should not be done.

dcarch

I was assuming this is a gas oven but I see that Blue Star makes electric ovens as well. So, we need to know if this is a gas or electric unit.

Also, how long is 'eons' in minutes? :-)

Also, how long have you had the oven? Did you recently switch to a gas oven from having an electric one before? (Gas ovens take longer to heat up.) When I had an electric oven, I would turn on the oven to preheat right before I started making cookie dough, etc. When the dough was ready, so was the oven. When I switched to an all gas oven, I learned that the oven had to be turned on to preheat while I was just thinking about making cookies! As in a good long 30-45 minutes before I wanted to bake.

So, if this a new to you oven, new to you gas oven, do a timed preheat. Let it heat for 30 minutes, check the oven temp vs set temp and repeat at the 45 minute mark. If it hasn't reached set temps after 45 minutes, then call for service.

How long have you had your BlueStar? Is it a range or wall oven?

dcarch7 ... :

The adjustment set screw in the shaft of the gas oven temperature control knob sets the thermostat trip point. It is not a gas needle valve.

Kendrah:

If the oven cannot get up to 450 degrees in less than a half hour, it is likely that the burner is not operating properly. One possibility is that its air shutter was not properly set during installation. You can do yourself (I did on mine) but, if you are not comfortable doing it, a Bluestar capable tech should be called.

Our Bluestar electric wall oven can take quite a while to preheat the baking stone to 500F. I've never actually timed it, but it's at least thirty minutes. It can easily hold 18 9 1/4" x 5 1/4" x 2 3/4" baking pans, or several full sized baking sheets.

Pear, eggplant, and goat cheese pizza

"---Bluestar ovens are famous for their huge oven cavities. ----"

The bigger the cavity, the thinner the insulation.

dcarch

There are different kinds of insulation, some being more effective than others. Heat has never been an issue with our Bluestar wall oven, and we live in a hot climate.

I put a 36" Bluestar range in my home in 2005. I've since moved (twice!) and I miss that range, but what I don't miss was the time it took to preheat. Easily 30 minutes to reach 350 degrees. It was a gas oven, btw..

My Blue Star is a gas oven. I have only ever had gas ranges so am not new to them. This is my first Blue Star, bought a year and a half ago. I've gotten used to it taking a bit longer to pre-heat than other ovens I have owned, but have in the last month noticed a dramatic difference. It is now taking so much longer, is shutting on and off a lot more than it used to to maintain temp, and is having a hard time even achieving a high temp. It is so disappointing to spend so much money on what is supposed to be a quality made in USA appliance and have it need repair so soon.

Check your ignitor.

I was having the same problem. Ignitor is normally on at all times. If it is cracked, it would open up randomly as it heats up. If the ignitor isn't drawing any current the gas valve is closed. That's why it struggles. It acts like a really bad thermostat but it is in the wrong place.

Easy replacement.