constant ignition required

sparkie

Hello all!  My question of the day is this.  Can someone tell me what the few units are that REQUIRE a constant ignition?   As usual, thank you much!

chapchap70

For what purpose?

I can't think of any new units that would require constant ignition or why I would want to set one up that way.

sparkie

just for my own info

Not just any new units, but any burners.  Have heard there were a few models that required constant. Was curious as to what those units were

icesailor

Burners requiring Constant Ignition:

Where I work, where the wind can be blowing the rectal orifice out of a bovine animal one day and dead calm the next day, if you set up a certain very popular burner that is a fixed head burner that everyone says to check the "Z" dimension (I've never found it off unless the end cone fell off), and you set it up on a mild day, when said wind is trying to injure said bovine animal, the flame can  be sucked away from the end cone, "Z" dimension be damned, and rumble like a thunderstorm in the distance if it has interuppted ignition. Changing it to constant ignition makes the thunderstorm go away. Usually.

Works for me.

Mac_R

Interrupted ignition

Interrupted ignition is a good thing.  Icesailor, sounds like you could use another draft regulator.  That might fix the problem you are having.  With intermittent ignition you run the risk of keeping a dirty flame running.  Just because you have flame does not mean the system is running correctly. 

icesailor

Backdrafting:

The wind causes the draft to go both ways. Draft dampers only swing one way with oil and RC's. Model "M"'s, that swing both ways aren't usually used on oil.

The problem is that the positive pressure into the chamber will blow the flame back into the retention ring. If there isn't a spark to help keep the flame, you get a flame out.

Trust me. You haven't seen draft like you do where I work. You can be standing next to a flue and all is quiet, the burner isn't running. You can hear the wind in the chimney. Suddenly, a blast of air hits you on the side of your face. Like FM.

Remember, flowing air has a lower pressure than static air. That's what makes draft. The higher the wind speed, the worse the draft. Every wood or coal stove I ever had smoked like a druggie when the wind was blowing hard. It would just "Puff" right back down.

lchmb

last I knew

There are two warm air furnaces on the market (sorry dont remember the brands) that state in their manual to stay constant ignition. I'll try and find the info this weekend ...

sparkie

Thanks Ich

That  info would be great.                    Ice, i  liked the bucolic analogy about the wind and  the bovine. I get the same thing here. The old wind blows right off the water. One day last summer, a gust out of nowhere launched my patio umbrella into the stratosphere.

icesailor

Gusts:

Sounds like that gust could have blown the feathers off a crow bar.

Mac_R

Good Point

I did not think of down drafts.  Wouldn't a good chimney cap take care of down drafts?  Or possibly making the chimney higher?  Down drafts are not a good thing.  

icesailor

Downing the draft:

Not always.

Remember, "Draft" is made by differential air pressures. Flowing air has a lower pressure that static air. The higher the wind speed, the lower the pressure. The air flowing around the building is much lower than the air in the building. The higher air pressure inside wants to equalize with the outside. The chimney allows this. As the draft/air is flowing up the chimney. It develops momentum and velocity. The higher the wind speed, the higher the velocity. If the wind slows down, the velocity can catch up with the draft. If the air pressure drops in the house while the wind speed is high, and the outside wind speed drops significantly to where the outside low pressure is greater than the inside, you get a real back-draft.

Wind is weird. When I go ice sailing at Lake Sunapee in New Hampshire, I sail at the State Beach. On the other side of the road from Newbury, is Mt. Sunapee Ski Area. As I (we) sail on the ice on the lake, I look up at the top of the mountain and see these moving dots and think that those skiers are nuts. One day, they shut down the mountain because of the wind and the skiers. We were sailing happily away at 40 or 50+ MPH. But there is an area where the wind comes off the mountain and the velocity of the falling cold wind will really give you a slammer. And a thrilling ride. This area is quite large and gusts of wind all over itself. Back toward the main body of the lake away from the mountain, the wind is much slower. But toward the mountain, look out. Lots of fun and excitement.

Mac_R

Back draft

If you run outside air to the burner you will get rid of that pressure differential you were talking about.  Not only will the system run cleaner and more efficiently, it will also reduce the amount of infiltration in the home.  Win win.  

Jim Davis_3

Constant ignition

When it comes to oil I can't understand why some have switched to intermittent or interrupted ignition.  Many times even on equipment that fired at 6gph to 7gph I have had to recommend switching to constant ignition to keep the equipment from bouncing across the floor.

When I first started watching oil burners using a digital carbon monoxide analyzer I noticed a distinct change in the CO readings when the ignition terminated.  Unfortunately than can be pulsations in oil burners caused by microscopic air bubbles in the oil.  This can cause momentary micro-seconds of no oil from the nozzle.  This creates pulsations, incomplete combustion, impingement etc.  This is difficult to see unless one pays really close attention the the CO readings every second of operation.  I have found these variations to be minimized by constant spark.  Because CO diagnostics of this kind are not normally taught by the oil industry and rarely monitored by anyone they are not recognized by most. 

I just don't believe in saving the transformer and messing up the furnace as a better alternative.

In a perfect world, with perfect oil, perfect piping, perfect filtering, perfect air removal and perfect combustion, constant ignition would not be necessary.  I don't think I am going to hold my breath.

icesailor

Pulsation: Really good point.

Good point.

I have an account with three W/McL WGO7's. I was working there the other day on a plumbing issue and the #3 boiler was pulsating like crazy for no reason. Well, the UST was replaced last Spring. When it was a UST, it ran with -2' of suction pressure through the filters from the lift pumps. Now, with an above ground tank, with a 5' head over the pumps, it is drawing 15" of suction/vacuum pressure because the clowns who did the install (low bidder) kinked the lines in the ground. The filters have become vacuum chambers and suck the air out of the oil. I have complained to the owners about it and the installers are trying to run out the warranty. Meanwhile, two Garber Model M filters don't work properly. The bottom one has 2" of product in it and the top one is 95% air. The air is getting to the #3 burner.

Good point about the CO analyzer :seeing" the pulsations. If I can get paid for it, I'll have to go back and prove a point. Meanwhile, I put them on notice that not to call me at 2:00 AM on a weekend if they have no heat or hot water. They need to fix the lines.