pilot light going out

5 burner steam table, usually the lights on either end will go out, maybe once or twice a day. Tech has come out, and re-placed thermocouples, modules and such. Told kitchen staff same thing I have tried to tell...draft problem, but they insist it's the table itself. So just to prove our point, I said to re-place the parts, to a $1000 + bill. Pilots still going out. There are a couple of fans around, so I take them down (excuse to clean them) and monitor the situation. The ladies on night shift say they have no problems with them going out, just the day shift.
Question, how much of a draft does it take to blow out a pilot light? Any other solutions or things to try? Remember, working with women who "know it all"

This may or may not apply to your situation.

I have a Direct vent propane fireplace insert. The installers said they used to put in an intake all the way up to the top of the chimney, but that caused the pilot to go out. Draft was too strong. Now they put it about 1/3 to 1/2 of the way up and no problems.
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Have you tried watching the pilots as you turn each burner on? If the pilots shrink as more burners come on and the flames are reduced on the t'couples this will give you a starting point. Typically undersized line, line valve partially closed, line valve has grease in the core, flex (if equipped) undersized. I'm kind of shooting from the hip, but I have seen this many times. I have seen problems such as this when restaurants add lines without respect to proper sizing of lines and meter capacity.

I have seen this problem several times on gas steam tables. Usually the flame is hunting for oxygen and snuffs out the pilot. This is probably related to a negative air balance in the building. I hope this helps.

your reply of problem only occurring during dayshift leads me to believe gas supply pressure issue. higher gas usage causes pressure to drop. you don't spec nat or propane or 1/2lb or 2lb system.

mike3 makes alot of sense, that would be a very good starting point. Maybe audit all the appliances on the line and compare to sizing charts. Gas is like water, it wil follow the easiest path, low pressure will allow it to flow through the main burner and bypass the pilot.

what you may be experiencing might not be a lack of oxygen or a draft at all, if this unit uses barber pole burners, look above the burner, there should be a metal plate that the burner heats, i've had instances where that metal plate is warped or cracked, maybe debris is falling down into the pilot or burner. if the pilot and burner flame lift completely off before going out, it would sound exactly like a few calls of mine. i had sworn several times that it was gas volume or make up air problems, but this has been the case for me several times. aslo as apposed to focusing on gas pressure, take a look at the gas volume as well. although as little of an amount of gas is used in a steam table of this kind, i would assume they would be having trouble with the bigger appliances on the line before they would have trouble with the steam table. hope that this has given you some sort of help.

Is this a new concern with this piece of equipment?? Has there been any thing changed on the line?? The reason the pilots stay on at night is because the exhaust fans and make up air(if any) is off and all doors are closed. Is this equipment beside an outside door?? Does the building have MUA??

Does this unit have a regulator on it?? If so check the vent cap. 9 out of 10 times the cap gets plugged from grease and causes lack of air.Remove cap and watch pilot flame. It will be stable when main burner is on. Are other pilots on the line going out as well??

Would check if any work has been done on the exhaust hood and the fresh air make-up. Three pilots out of five do stay on and the two end pilots are going out. Makes me think towards grease falling into pilots, especially if they are the burners doing the most heating. Also check your fresh air vents that they are clean, only way to do that is to take them down and look. Two person job and no fun. Have cleaned a plenty that the help promised were cleaned recently, cleaning what you see does'nt quite do the job. If this does'nt solve the pilot problem then I would start looking into new gas valves.

If the two end ones are going out then i would think it is a walk by draft issue and then you may have to install a shield to stop the drafting.

Had one like that. Replaced pilot assemblies. Went out again. On my third trip out there, busboy propped open back door to take out trash. This door is a good 20 feet away. When he closed the door, pilot popped out. Built a draft sheild for it.

I have also bend t'couple assembly a little to get better flame on t'couple. NEVER try to bend pilot hood. It breaks before it bends even a nanometer.

Good luck, those can be a pain. Hopefully the owner has a little patience and confidence in you.

Ihave seen burners cycling on heat control when they relighted they would light hard knocking out the pilot lights on the end