Fireye Lingering Flame Failure Timing Question

I have one of the older fireye units (with the MP230H Programmer Module, with Selectable Timing Operations, and the MAUV1). Using the UV1A scanner (shutterless scanner)...
What is happening is that when the burner shuts off (ops control goes dead) the flame light stays on for 8-12seconds. I've verified that the flame is lingering (dissipating)...
What's happening is that the majority of the time I'm receiving an alarm (due to the lingering flame).
I spoke to a burner tech who said that the fireyes have a 10 second timer after they lose ops control, and that after that 10 seconds any flame seen results in an alarm.
But today I spoke with a Fireye tech who said that the timer is actually 60 seconds.. that either my chassis, timing module, or amp card is bad. I've swapped the amp card, and it's fine...
But... I'm stumped about this timing issue. The burner tech was adament that it was only 10 seconds, yet the fireye tech was certain it was 60.
Does anyone here have any experience with this and can you verify which time is correct?



Thanks,
Russ

just sending a nudge....any help anyone?

Russ

Do you have this manual?

http://www.fireye.net/pdf/C-4000.pdf

I've only used a burner control once so I don't have any experience but what is your purge time set at? Are you set up for recycle?

Maybe the control is re-cycling and seeing the lingering flame when it is trying to pre-purge????

In my experience as long as there is flame, the fire eye will see it. I have used them to watch a pilot light with good success in the past. If the flame is still actually lingering, then you might have too much line between the valve and the burner, your valve is before your regulator, or there is too much line pressure present. It might also be that the line pressure is too great for the valve and the valve is taking it's own sweet time closing. Double block and bleed valves can help with this problem.

On a side note they will also see the sun quite well. I had one customer that wanted to use a fire eye on a single mast flare that didn't have any mounting method except for pointing vertically. We spent quite a bit of time designing a shroud that would block the UV from the sun to allow it to work properly.

I can't profess to know much about the internal workings of the FireEye, but in my book 10s is about right for a lingering flame and 60s is probably pretty darn dangerous. I agree with icky on this; you've got a mechanical problem of some sort; if this system used to work ok then I'd be looking for trash on a valve seal or a pin-hole in a valve seal.

Purge timer.. it's set to 0.. because we use another hard wire timer, as well as a software backup for purge (6 minutes). There's no recycling done on the burner..
This unit has been in service for over 10 years. I've been familiar with it since 2000. Only just recently has there been the lingering flame alarm.
There are 2 maxon valves in the train, as well as a vent valve (also a maxon).. the pilot line has a red hat solenoid... and I've closed the manual valve on the pilot line (check for leaks) and still had the lingering flame.
It doesn't last for long, again... merely 8-12 seconds. I've adjusted the logic to open the burners up to 100% just before they shut off (to help the gas that's remaining in the pipe between the 2nd valve and the burner discharge quicker), and I've drained the y-strainers (found murky liquid in there, as well as small pieces of leaves).
One thought was possibly uneven static pressures at the two burners resulting in the gas 'loading' on one side, which at shutdown would take longer to dissipate.
According to our burner expert (a contractor that helps setup/troubleshoot our burners, and has been working in this field for years) The Honeywells have a 60 second timer before it gives an alarm for a lingering flame, and according to a Fireye tech... the fireye's should also have this same setup, yet the burner tech is fairly adamant that it's only a 10 second timer. Hmmmpphhh.. so.. I don't know...
Right now my guess (if the fireyes do have a 60 second timer) is that the timing circuitry (more than likely a resistor/capacitor combo) is corrupt (it's over 10 years old)... in fact.. I'm guessing this might be a common problem with these devices. As the cap/resistor fails the 60 seconds becomes 50, then 40, etc ... yet it doesn't shorten the time to a point that is obvious to the techs (because the flame lingers for only short periods of time, and even if the timing were 30 seconds, or even 20 seconds... nobody would be the wiser).
But.... hindsight is always 20/20... and I'd like to get some feedback/confirmation on this. It's quite interesting, and I'm fascinated by this problem (it's been a bugger, and that's what makes it memorable).. lol..
btw the sheets that came with the modules is woefully lacking in information. I'm looking forward to reading that pdf.

Given what you've said it could be a failing FireEye, but I'd still start by taking apart and looking at your gas valves. If you found liquid and leaves in the strainers there's no telling what you may find in the actual valve seats and o-rings. I've had several occasions where a very small piece of trash made it through the strainer and lodged itself on a rubber valve seat causing a vale to either leak or be slow to close (slow to close is anything greater than 1-2 seconds).

marksji said:

Given what you've said it could be a failing FireEye, but I'd still start by taking apart and looking at your gas valves. If you found liquid and leaves in the strainers there's no telling what you may find in the actual valve seats and o-rings. I've had several occasions where a very small piece of trash made it through the strainer and lodged itself on a rubber valve seat causing a vale to either leak or be slow to close (slow to close is anything greater than 1-2 seconds).

Click to expand...

That's a very good point! I changed the sensor, and swapped amp cards. Yesterday I replaced the timing module and chassis.
If the Fireye tech is right and the timing should be 60 seconds then the problem should be corrected.
But... lol... I think he might be wrong. Cleaning the valve seats is definitely a good idea. I'm suprised that the Maxon's haven't given me an alarm (though... I think the timing for an alarm is 3 seconds)... it might be a good idea to set up traps on the valves and see if there are any disrepencies between the closing times on burner #1 vs burner #2. A one or two second difference can make all the difference in the world..
Thanks for the heads up.

Since you stated the system is as old as it is, I'd suspect the grease that they lube the Maxon's with has possibly hardened and they just aren't closing as fast as they used to. This was a common problem for the plant that I worked at.

Personally I would send the valves in to Maxon to be checked out. I think this may be just the beginning of a more serious problem. 10 years is a great life for this type of valve, but they do require periodic servicing and tune up.

Russ,

There are many types of "fire eyes". I don't know of any that have built-in timers. Instead, the time functions are built into the burner controller, also called a "flame relay" by Honeywell. The Honeywell flame relay has two basic types: The so-called "continuous" type, which is made for old burners that have constant-on pilot lights and are lit by hand with a match. This type only "looks" at the fireeye about 1/2 second after it opens pilot valve. The "intermittant" type looks for a flame at ALL TIMES. If it sees a flame during the "purge" cycle, or before the pilot valve is energized, or after the stop signal is given and the valves close, then it goes into LOCK mode and shuts off.

Suggestions: Look for holes in the burner that is letting in outside light. If none found, replace the flame detectors.

Just another thought (not knowing anything about the burner itself) is there any chance of carbon deposits in the burner, due possibly to running gas rich?

I came across this problem once where the carbon continued to burn long after the gas was shut off leading to post shutdown lockouts.

Lancie1 said:

There are many types of "fire eyes". I don't know of any that have built-in timers. Instead, the time functions are built into the burner controller, also called a "flame relay" by Honeywell.

Click to expand...

Lancie,

"fireye" is a brand of burner controller.

http://www.fireye.com/default.jsp

The name is a little confusing and leads people to think of only the UV flame scanner.

Thanks for the feedback guys.. a few quick points..
carbon rich gas does sound intriguing and I agree that there could be carbon build-up on the burner itself. In fact I had planned on doing an inspection this past weekend. Unfortunately the plant's production schedule changed, and there wasn't anything I could do about that.
the burners are inside a burner box, and there are no visible holes in the burner itself. I've replaced the uv scanner already, and the problem has persisted.

The flame is lingering for only between 8-12 seconds, which I've heard is fairly normal. I'm interested in seeing if this problem resolves itself during the upcoming shutdown (in a few days).


Thanks again everyone!

geniusintraining said:

also you should have a release solenoid valve, when the other 2 valves close then this one should open venting to atmosphere...

Click to expand...

I think Russ has this valve; he refers to it as a vent valve.

Russ said:

the pilot line has a red hat solenoid... and I've closed the manual valve on the pilot line (check for leaks) and still had the lingering flame.

Click to expand...

Russ
Have you got a manual valve between the last Maxon valve and the burner that you can shut to prove that the main gas isn't lingering (i.e. the Maxons aren't passing when closed)?
If you have, I would try closing this valve as well as the manual pilot valve when the burner is running and time how long it takes for the "flame-on" light to go out on the Fireye.

I'm inclined to agree, 8-12 seconds can be normal depending on the type of burner, air flow characteristics, distance from the last shutoff valve to the burner, etc.

I've scoured all the Fireye data sheets - can't find any reference to post burnout times. Only thing I can find is a reference to a 15 second postpurge - might be that your 8-12 seconds occasionally drags on to 15 seconds.

As previously mentioned, check for carbon build up. Also you might want to check for partial blockage of the gas feed causing a slower release of the remaining gas in the pipe after a shutdown.