Need help from an expert on commercial gas ranges

I live in a student housing cooperative and we have a Montague Grizzly commercial gas range that the co-op picked up from a used restaurant supply store. It is a really nice stove, but the oven likes to go out all the time.

I’d like some advice on this. We’ve had a guy come and look at it and he tried to fix it but it still doesn’t work. He replaced the valve that controls the flow of gas to the pilot and the gas ring. We replaced the thermocouple, it still doesn’t work. I’ve tried adjusting the flame level and it doesn’t seem to fix the problem.

What I would like is help on this. I’ve educated myself a bit on the workings of the oven, mostly by watching it and reading a little bit on how gas stoves tend to work. From what I’ve observed I see that the oven turns off because the valve letting the gas in closes. It only seems to happen when the pilot light isn’t touching the thermocouple. Sometimes the flame coming from the pilot light shrinks, ussually when the gas ring has been lit for a while. So I can see that this is what causes the gas to shut off, but I can’t figure out why the pilot flame slackens. Does anyone have an idea?

There seems to be a thermostat that regulates the level of the flames in the gas ring, Is this the thermocouple that also regulates the pilot light? If the flames in the gas ring are are reduced will the pilot be reduced as well?

I see from my questions that I could probably do with so more information on the structure of this oven. If someone could explain or provide me a way to find schematics on Commercial ranges that would probably help.

Thank you

Oh, also it has no hood, which may make a difference.

I am not a range specialist but have done some safety testing on gas fired appliances such as water boilers and gas fired high pressure steam washers.

If the pilot is flame is not consistant, and the main safety valve has aleady been replaced, then perhaps you have an incompatibility problem with the city gas people. The gas range should be marked with the required gas pressure range. Ask the gas guy to come in and check the building regulator. Maybe it is failing or is just set to low. Turning up the pressure may help.

A quick fix may be to move the thermopile closer the pilot so it stay warm when the pilot gets dim.

Have you tried contacting the grizzly people yet ?
For phone,email see:

A few years ago I bought a Wolf stove. It was set up for propane so the pilot wouldn’t put out enough heat using methane. I ordered a replacement orifice for a few bucks, but for a quick fix I reemed out the old one. It’s been working fine with the quick fix.

Thank you for your replies. They may be useful. I’d still like to know more about how gas ranges work