Flame rollout switch - keeps going out

foresthillsjd

So, I have just burned through my third flame rollout switch this week, and I'm stumped. Here's the story:

(and forgive my lack of proper terminology, I'm self-taught)
It's a Weil-McLain series 4 gas boiler, one-pipe steam. It has not been used since March of 2018. That same month, the chimney was relined with metal. We gut-renovated the house, and moved back, and it finally got cold enough to need this thing. After a week of working fine, it wouldn't start up.

Monday: Pilot is out. Won't light. Bad thermocouple, replaced that.

Wednesday: Won't start up. Bad flame rollout switch AND the thermocouple. Those were replaced, and the inside of the boiler was brushed and vacuumed. Took three hours.

Friday: CO detector goes off, we shut the boiler down. Also, bad flame rollout switch again.

Saturday: Replace the flame rollout switch (no plans to run the boiler full-time for heat, just testing), and run the boiler for 45 minutes. It's fine. I turn it off. But a couple hours later, when I went to test it, the switch was toast. I also had the chimney guy come to do an inspection, and the chimney is completely clear. He did mention that the draft hood has a lot of carbon in it, but it doesn't seem enough to restrict the airflow.

Also, for what it's worth, I clocked my gas meter and the boiler seems to be using 160,000 Btu/Hr (rating says input of 175,000/hr) Is that diagnostic of anything? Or is the quality of the flame most important?

At this point, I'm going to leave it in the hands of the professionals on Monday, but I want to know what they should be looking for. Time for combustion analysis? The whole thing is shut down, and I'm not going to mess with it, but I am trying to prepare myself for Monday.

Here's a link to the flame: https://drive.google.com/file/d/1kawR7QmwZcVhPC0qSgIoR-dO6mJyUqdY/view?usp=sharing

Thanks in advance,
~Jackie

Ironman

You're not getting proper draft. It could be the chimney, a dirty HX, dirty burners...

JohnNY

Your flame roll out switch has nothing to do with your chimney. Your boiler is carbonized and has scorch marks that are a dead giveaway of that condition. Get rid of that boiler. It's time and it's no longer safe.

Ironman

The boiler could also be over-firing.

You need to get a COMPETENT pro with good instruments to look at it.

Ironman

I just saw the video and I agree with Johnny.

foresthillsjd

@JohnNY What does carbonized mean? Is it one of those things that could potentially be cleaned off to extend the life of the boiler? Or is it like an aneurysm where you just don't know when it is going to suddenly turn dangerous?

Jamie Hall

It simply is dangerous. The flame rollout switch is one of the fundamental safeties on a gas boiler, and if it trips off the boiler -- or even more, gets fried -- do not replace it and try again until you find out why.

It's telling you that hot combustion gas is coming back into the structure, not up the chimney. There's a very limited future in that.

EdTheHeaterMan

There is a blockage, usually carbon that is keeping the byproducts of combustion (the fumes from the flame) from going out the vent. I agree with John to a point, A professional (usually a person that works on oil heat that is also familiar with gas heat) should disassemble the covering from the heater and remove the soot/carbon from the heat exchanger.

You still need to find out why the carbon build-up happened in the first place. A new heater will not solve the problem if there is insufficient combustion air in the boiler room. Replacing the heater is a very expensive way to find that out.

This is what you may find inside the heater after all the covers are removed. You need a Soot Vac and some brushes to clean it. Oil heat guys have all the stuff


This is what it should look like after they clean it. notice the brush strokes on the cast iron where there is a little residue left over. But most of it is gone.


This is from the underside. Top pic is from the top of the Heat Exch.

foresthillsjd

Is it possible that it’s just drywall dust from all the construction that settled on the boiler and carbonized?  I didn’t think to wrap or protect the boiler during the two years they were rebuilding the house.  Regretting overlooking that detail now...

The plumber gave the whole thing a good brushing/vacuuming on Wednesday.  Removed the cover and got in there with brushes.  I didn’t take any pictures, but it looks like the after picture above.  Are you supposed to use any cleaning products or is it just mechanical brushing and vacuum?  

JUGHNE

So your guy opened the top of the boiler and brushed the exchanger down and you still had rollout switch trip?

foresthillsjd

@JUGHNE, yes.  He spent a couple hours down there, and I would pop in periodically to check on progress. It looked clean to me when he was done.  The only thing he didn’t clean was the draft box (above), but he is going to do that Monday.  But from what you are saying, the problem is inside the boiler, not outside it.  

The boiler is probably 10ish years old (came with the house, and I can't look up the age on the W-M website.  It's a EG/PEG-50).  I would be willing to invest time and money and elbow grease to make it serviceable, but not at the risk of safety.  

Also, If you know any guys who do work in Queens, I am happy to call them!  

HVACNUT

At the 12 second mark, the flame drops out and re lights. Did you do something or that just "happened"?
That flame is waaay Orange. 
Gas pressure must be checked. I believe it should be 3.5" manifold for natural gas but check the valve label. 
If the boiler and chimney are clear as you say (no flue damper, right?) then gas valve, gas train, orifices, and burners need inspection/cleaning. 
If flame dropped out on it's own at 12 seconds, then wiring, controls, and other safeties must be checked as well. It could be the gas valve itself. 

EdTheHeaterMan

During the 2 years of construction, was the boiler room enclosed to make a finished basement? It sounds like there is a combustion air issue. The heater needs to breathe. Oxygen is needed for the fire triangle to work efficiently. If the room where the heater is, used to be an "unconfined space," as stated in the code for heating appliances, and you enclosed the heater without providing the means for the necessary amount of oxygen to reach the burner, then you have a "confined space". You will need to address that to stop the roll-out problem.

If not that, then...

Another issue may be an exhaust fan causing negative pressure in the boiler room. This will draw needed air from the vent pipe (down the chimney) to make up the low pressure in the home

If you have an exhaust blower at the cooking station, the clothes dryer and bathroom fans are all removing the air from your home. If the home is really tight and there's no other way for the air to get in to replace the air that leaves the home, your chimney or B-vent exhaust pipe will become an intake for your home.

Have a chimney professional or HVAC pro who has the correct combustion instruments inspect the vent system to see if you have a downdraft condition when the roll-out is happening.

foresthillsjd

@HVACNUT Nice eye! The only reason the flame died down a bit was because my husband was jumping the wires for the rollout switch so I could take a recording (we only did it for diagnostic purposes, maybe 15 seconds tops), and he wasn't holding the jumper steady.

We have a flue damper, but it opens first, then the flame.

@EdTheHeaterMan Also very astute observation, yes, the boiler got its own bedroom as a result of the renovation, and it has an open window in that room. I was worried about the negative pressure situation, so I also started propping the door open and opened another window in the basement. (Also, as a matter of habit, when I turn on the kitchen exhaust fan, I crack a window, because we have a tight home and a strong exhaust fan, and I didn't want to pay up for a make up air system.) That's why I was surprised that the rollout switch tripped this afternoon. I had an open door and open windows downstairs.

How do I find a company that has this equipment? Is this something that is customary for people in the business? My experience with all the local plumbers (even the ones that people say are excellent) is that they don't know that much about steam heat. They have tried to talk me out of venting my mains, they have tried to increase the pressure to get heat to far off rooms... It was easier finding a man to marry than a person I would trust with my boiler. I've never seen any of these professionals with combustion equipment.

neilc

https://heatinghelp.com/find-a-contractor/

HomerJSmith

Is that MOV that I looked at for your heater?

The ignition is improper and the flame exits the fire box on ignition and the flame doesn't appear correct, blue cones.

There doesn't appear lift-off is occurring so I suspect that the manifold pressure is at about 3.5" Water Column, but should be checked.

What is happening from the video is that there is a build up of gas and then ignition which shoot the flame out of the fire box destroying the chemical fuse.

I would pull out all the burner tubes one at a time and wire brush them and make sure they are clean. Pay particular attention to the cross-over slots on the tubes, making sure they are open and not carboned up. Clean the pilot tube and what appears to be a thermopile?. Set the burner tube shutters for the proper flame.

foresthillsjd

@HomerJSmith the movie is the flame at the bottom of my steam boiler.

EBEBRATT-Ed

@foresthillsjd

You need to make sure the chimney was lined. Did they put the correct size liner in?

When you pour water in a funnel and it overflows you stop pouring.

Same thing with the boiler. The combustion gasses are not going up the chimney as fast as the boiler is making them. That"s why the flames "back up" another word for roll out.

The chimney needs to be check that it's clean and the correct size liner

Boiler and draft hood and burners cleaned.

Gas pressure and combustion air supply checked and combustion analysis done

hot_rod

A draft gauge would be one tool to try.

HomerJSmith

YA-HOO! Wow! My 1,000th post. Who would have thought that I'd live that long.

Look at the movie, one frame at a time. It doesn't appear to me that the flame roll out is because of a blocked chimney. One can see the flame leave the firebox on ignition. The pilot flame is incorrect, too. I would want to know that everything down there is clean. I know that a blocked flue can kill a roll out fuse, but can other things kill it, too? I hear hoof beats and I think horses not zebras. But I would like to know what the solution is and hope she reports back.

foresthillsjd

@EBEBRATT-Ed I had the chimney relined two years ago. It's 7" smoke pipes that get reduced to 35' of 6" stainless steel liner.
Should be sufficient, right?

EdTheHeaterMan

"It was easier finding a man to marry than a person I would trust with my boiler."

What a lucky man!

Regarding the combustion air issue. You mentioned that the boiler has its own bedroom.
1. Is that room on the basement level?
2. The window is always open... is that window large enough for the amount of combustion air needed? it should also not be able to be closed. A permanent opening with a screen or louver with sufficient free area for the size of the burner (it's a square inch per BTU thing)
3. You leave the door to the room open. If the window is large enough you should leave the door closed. this way the exhaust fans throughout the home will have less of an effect on the boiler room.


You could use a draft gauge to test the direction of airflow (exhaust or downdraft) at the chimney vent.

Happy you are not using the Elves for your project this year. Husbands are a good alternative sometimes.

foresthillsjd

@EdTheHeaterMan

Yes, once the boiler needed more privacy to do the things that boilers do when they reach a certain age, we gave him his own bedroom. It's in the basement, because boilers are smelly and noisy. The window has a permanent screen and louver. 9" x 10". Is that big enough?

And my husband is 5'4", so half-elf I would guess.

Thanks for you help so far! This has been a very interesting discussion.

Jackie

Jamie Hall

Take a look at the discussion here: https://forum.heatinghelp.com/discussion/182197/how-do-you-to-calculate-combustion-air#latest

foresthillsjd

@Jamie Hall the room itself is about 420 cubic feet, but the flame video I took was with the door and a couple windows open.  The basement is 7000 cubic feet.  So, in addition to whatever is causing my issue, I probably need to make a plan for providing makeup air if I want to keep the door in that room closed.  

The house is pretty tight.  It has EIFS
and mostly new windows.  

HVACNUT

For combustion air, look into Fan In A Can by Fields Controls. Or high and low transfer grills can be ducted from outside. 
To me, once flame is established, its drafting fine. It's just a really bad flame, and will soot the boiler quickly. I would think a properly working spill switch would've tripped before killing a rollout due to draft. Even with a nasty downdraft, the hood is open underneath and shouldn't travel backwards through the block.
Again, the whole system must be checked but I would start down below. I'm interested in lockup and manifold gas pressures. 
BTW, is the gas meter and piping sized correctly for all the appliances? You mentioned a new draft hood. Is there also a new 48" Wolf range below it?

foresthillsjd

@HVACNUT, does the "can" part of the fan in a can sit inside the house envelope or outside it? That would definitely help my intake problem.

And I did check the spill switch, that thing is working fine. Is it possible that the flame needs more gas? I clocked the meter, and it's burning 160,000 Btu/hr vs the input rating of 175,000 Btu/hr.

The only three gas appliances are a dryer, the hot water heater, and the boiler. I got rid of the gas range and switched to an induction cooktop (with a 900 cfm exhaust). It's an Actaris 400A, installed in 2018. I had a full plan review with the NYC DOB, and they were really persnickety about all the gas stuff.

The lockup and gas pressure thing is something that I want looked at, just trying to find someone local who has the time to come out. They all got busy with the cold snap!

HVACNUT

The fan in the can had green eggs and ham and it sits on the floor near the boiler. It gets wired as a safety, that if the fan doesn't close its pressure switch, it doesn't allow the burner to fire.

JUGHNE

7000 cubic feet in the basement.....a 900 CFM kitchen hood will remove that air in 7.7 minutes. Then the clothes dryer will remove more.

The Fan in a can has a drum with a fan inside that pulls air from an outside hood to pressurize the room. It has to prove that pressure before allowing the boiler or water heater to fire.
They are a little loud.
The Tjernlund fan is a little quieter IMO, I have one hanging from the ceiling in a church basement and no problems.

Not sure if either can also be adapted to all water heaters.

But with either you would not have an open window to the weather.

foresthillsjd

@JUGHNE I very rarely turn the exhaust fan up that high, but I always, always open windows when I run the fan to avoid a negative pressure situation. I'm not as good about doing it when I run the dryer, but, we are all works in progress..

HomerJSmith

If it is window screen, it's too small a screen material. Where I come from 1/4" screen is the minimum size. The louvers lowers the combustion air even more.

There's nothing wrong in being 5' 4". The stature of a man is based on more than his height.

bburd

1/4 inch mesh will not keep out insects.

HomerJSmith

No, but it keeps out elephants!
bburd, my sentiments exactly. I just follow orders.
My wife trained me, well.

foresthillsjd

JUGHNE said:

So your guy opened the top of the boiler and brushed the exchanger down and you still had rollout switch trip?

I return, a little abashed. It turns out when he said, "I cleaned everything except the box at the top," I thought he meant draft box, but her really meant the top of the boiler. We opened it up today (what a mess) and brushed it out, and then took another pass at the burner tubes. I'm not really sure why he didn't open the whole thing to start with, but, in any case, the flame is much, much happier now. I'll take a video later tonight to post.

I remember when I would visit the dentist as a child, he had posters on the wall (as a cautionary tale) of children's teeth that were riddled with cavities. I feel like they should have a picture of dirty boiler that you have to stick on the boiler jacket with a note that those things need to be regularly checked too. I had no idea it could get that bad inside.

Thank you, thank you for all your suggestions. I am going to look into some kind of fan system to help keep the combustion healthy.

Is this clean enough? Someone told me carbonization is like a cancer and if you don’t get it all out, it will come back. But it was hard getting into those nooks and crannies. Is this going to get black and clogged again? Did this happen just because of the age of the boiler? Why does @EdTheHeaterMan have a cream color to his boiler picture and mine just looks like cast iron?

pecmsg

My biggest concern is how does a gas boiler get that bad in 2 years?

foresthillsjd

@pecmsg drywall and plaster dust?  They took the house to the studs, and I suspect they had the boiler on for a few weeks at the beginning of demo.

HVACNUT

That's an ok cleaning. He probably used a soft nylon brush. It looks pretty tight in there so a hard bristle brush probably wouldn't make it through the passes without bending.
Did the tech do a combustion test?
That really should've been caught on the first trip. It's kinda the first thing to look for.

JUGHNE

As suspected.....would the demo crew have run a powerful exhaust fan out a window during plaster removal and had the boiler firing for heat?

Between dust and down draft could this produce the soot??

I know you probably do not run the hood full speed, but just want to point out how much exhausting can remove the air that has to be made up from somewhere.

I read that a clothes dryer can discharge 150-200 CFM.....run time maybe 1 hour?

EBEBRATT-Ed

@foresthillsjd

Really need a combustion test on that boiler. You want to know the combustion is ok. The cleaning should have fixed the roll out problem

ChrisJ

Here's my issue with it and @JohnNY please correct me if I'm wrong.  I'm not a pro but I am concerned about those in that building.

I see comments about exhaust hoods and draft....
My understanding is a draft hood equipped boiler should burn properly without any draft at all.  Its part of the draft hoods job.  There should be no soot and no roll out with a completely blocked flue or even a down draft.  


The burner doesn't rely on draft from the chimney.

At least that's my understanding of how an atmospheric draft hood equipped appliance should operate.

Its also my understanding that NG and LPG do not produce soot unless something is really really wrong.

Please get that addressed NOW.

JohnNY

ChrisJ said:

Here's my issue with it and @JohnNY please correct me if I'm wrong

You're not wrong, @ChrisJ. I didn't read through the prior 39 posts here but there can't have been that much to say about this boiler. It takes a lot to activate a flame roll-out switch and when I see scorch marks over a burner tray, I know the boiler has been operating in an unsafe condition for a significant amount of time, and its problem is within the boiler jacket.

This boiler has to go in the garbage and if someone has to be held accountable for its failure that's secondary to the problem.