The Case of the Flame Rollout, You and Ray inside the boiler room can you solve it?

RayWohlfarth

Dan and I were talking and he suggested I post some cases and let you figure out the cause. This week's case is The Case of the Flame Rollout.
In this case, the maintenance tech warned, "Be careful, that thing has some wicked rollout." When the boiler started, the flames rolled out each side of the boiler base and then settled down and looked normal. I won't give the answer until Friday when my video is published. The games afoot.
Ray

JUGHNE

Gas regulator in the wrong location in the train.

Pressure build up between main gas valves.

A shot of high pressure gas hits the burners when main valves open.

IMO.

Or if the yellow valve closes quicker than the 2nd valve the reg has no pressure to it as all gas bleeds off.

When the valves open the reg over shoots pressure until it can modulate gas.

EBEBRATT-Ed

Agree with @JUGHNE that that could be the issue.

But

Has the problem always existed or is this something new? The boiler is old, it seems the issue would have come up years ago if the gas train was the issue.

Has the regulator vent been checked for obstructions? Looks like it's vented back into the burner as they did in the old days,

Also some of those old boilers had standing pilots which this looks like it does. Some of them had multiple pilots although not all of them are "proven", could be some pilot(s) are out.

HomerJSmith

A dirty HX or venting issue or misaligned standing pilot or dirty burners and slow crossover? I'm not very good at guessing. It seems obvious to me that there is a delay in lighting commiserate with a build up of gas that suddenly combusts. But whatda I know. If you guess right do you get a prize? Maybe a book by some guy called Ray Wohlfarth?

EdTheHeaterMan

I'm going with installer error.
The Honeywell V5055 valve with the V4055 actuator does not look original. at some time in the last 40 years that valve assy was replaced and perhaps the timing of the valve opening is not that which the original OEM specified for the burner / ignition combination of the boiler. Doing whatever it takes to get the heat on with the valve that was available at the time, some adjustments were made to get it operating. Those adjustments included inscorrect gas to ignition source alignment. Perhaps the pilot assembly is on the wrong burner, perhaps the pressure is insufficient on the start up, whatever the case, there is too much main valve gas open time befroe the ignition source reaches the raw gas.

WHOOOOPHhh... then all is well.

Get the ignition and the raw gas together sooner, and the wicked rollout will be reduced to something accepitble.

Stet

This is an old girl for sure. I know there were gas valves used on some boilers that opened in 2 stages. A low fire to start with and create draft,and after a delay would go to high fire. May be this old gas valve is just coming on with high fire.

mikespipe

I would suspect that the gas ports close to the pilot are clogged or covered with rust or soot causing delayed ignition

ttekushan_3

This one has brought me out of the woodwork-
The last time I worked on a Bryan water tube boiler I found it with several leaking 500 series tubes and it was packed with rust on top of the plane of tubes. Had it not had a Gordon Pyatt burner and was instead an atmospheric I would have expected huge flame rollout. As it was, the mini peeper flame sensor would fog up on cold start and sometimes lock out. That’s why I was called. Nothing was said about all the water around! Apparently it was “normal”. CO was off the charts! Shoveled it out, replaced 15 or 20 tubes, dialed in linkages and all was fine for a few years. 

So my vote is for a wet rusty bunch of water tubes creating combustion havoc. 

PS despite a gas train arrangement I wouldn’t expect to see the motorized valve should open slowly enough for the regulator to stabilize, unless, of course, the burners are collecting water. Still I think it’s the water. 

markysharky

If the house has been renovated and it's super tight, the kitchen fan (or even the bathroom fan) could be backdrafting through the boiler and chimney if there's no make-up air system, which usually there isn't.

maddog1950

roll out is always an air issue...what's cause insufficient air to draft up the vent....partially bocked or carbon up of heat exchanger.

PLONG

We have one of these boilers, circa 1964, and we have had various technicians clean the burners, and adjust the pilot and ignitor with only marginal improvements. The ignition speed from the pilot outward across the burners is slow compared to other boilers of this size.
The only thing that keeps the flame from constantly rolling out is to keep the air temperature warm in the boiler room, inducing a stronger draft.
I had newer Bryans at my last job and they fired off quickly and smoothly, makes you wonder if they were working out the design issues on these earlier versions.

EBEBRATT-Ed

All good comments. Just goes to show you can't fix it while driving you truck or sitting at your desk. Hands and eyes on the job LOL

RayWohlfarth

All right sorry to keep you all waiting.
@JUGHNE was the first one to correctly guess. The regulator was downstream of the electric gas valve. When the electric valve closed, the regulator would open wide trying to meet its set pressure. When the electric valve opened, the gas regulator was wide open and quickly closed to the set pressure. This boiler had been like it since it was installed.
@JUGHNE, You deserve a star for your forehead LOL
Thanks for playing along everyone. Next week is the Case of the Haunted Boiler Room

retiredguy

@ Raywohifarth, where do I start. There are many , many possible sources of potential problems with this unit causing the flame roll out.

#1) Is this a Pittsburgh Public School? Knowing this would be helpful in trouble shooting this problem.

#2) Is that Maxon Valve a 4800 series or a 5000 series. One of the 4800 series had a serious flaw in that it had a shock pad that would dislodge and cause the valve to fail open. (Not part of the problem but something to check.

#3) The Honeywell gas valve should have a slow open valve actuator coupled with a valve body that has a "characterized guide " and not a flat seated valve. The wrong valve combination will cause problems. See items #4 and #5.

#4) If the Honeywell gas valve is not the correct one for that installation, it will open before the Maxon valve allowing all the gas pressure to be be disbursed causing the Maxitrol gas regulator to go full open so when the Maxon valve opens the regulator does not have enough time to regulate the supply volume and thus flame roll out. This potential problem could be corrected by switching the position the Maxon gas valve to be ahead of the maxitrol gas regulator or with a "proof of open" switch in the Maxon valve that would only allow the Honeywell gas valve to open after the Maxon valve opens fully.

#5) The vent line on that regulator may be plugged, partially plugged or too small to allow the regulator to respond to a pressure change quickly enough. This could also be in conjunction with item #4.

#6) depending on the size of this boiler and the number of burners, it may be required to have more than one pilot. If that is the case, those pilots should all be supervised with some sort of pilot "cascading" . If the pilots are not supervised, and only the main pilot is lit flame rollout could happen.

#7) Could the burners be in need of cleaning and the burner runners or runner need cleaning also causing a delayed lighting.

This is not all the possible problems and only a physical inspection would need to be done to correct the problem. Thanks for the invitation to trouble shoot this burner problem.

RayWohlfarth

@retiredguy You had way too much coffee today LOL I agree, there are several possible causes. It was in a school an hour north of Pittsburgh. I spoke with the technical department of Bryan and they said the regulator was in the wrong location. I wished the owner would have let me try switching the valve and regulator to see if it worked better after but they decided to live with the flame rollout. Thanks for your suggestions.

mattmia2

If they won't switch the valve and the regulator perhaps they would be willing to pay for a time delay to delay the opening of the second valve until the regulator stabilized, like the kind that is used to delay a blower until the hx is hot

HomerJSmith

Thanks for the fun, Ray.

retiredguy

@ Ray, Yes, I did have a lot of coffee this AM but if they do not want to fix the problem correctly, and are looking for the cheap fix, you could recommend that the Maxon valve be equipped with a "proof of open" switch, if they are still available, ( I carried a few in my service truck). This of course is not the correct fix but it would work. ie; see the last part of item #4 above. I know that I have seen that boiler before. I worked for CS&E for 35 years and have been in almost every school system from the Ohio line to Harrisburg and beyond. Again, thanks for allowing us to answer your question.

mattmia2

Was the gas train set up like this from the factory or was it field installed?

EdTheHeaterMan

Have you posted the next case? This was a fun learning experience

RayWohlfarth

@mattmia2 This was from a long while ago Thanks
@HomerJSmith thanks I am having fun Glad you enjoy it
@retiredguy thanks I’m sure you were there You guys did work there This was a while ago
@mattmia2 it was installed on site
@EdTheHeaterMan i will post it next Wednesday Thanks

Solid_Fuel_Man

Keep these up Ray, it's fun!

RayWohlfarth

Thanks @Solid_Fuel_Man I will

EBEBRATT-Ed

Does @jughne gets the gold star n his forehead?

RayWohlfarth

@EBEBRATT-Ed I was thinking that or he could print out my reveal and post it on his refrigerator

JUGHNE

I told my wife (another Wall Widow) that I scored first place....she looked up from her book and said
"O good"....then back to the romance novel.

JUGHNE

The reason the answer jumped out right away was that I had studied some gas train piping for a problem I had.
Have a small Kewanee fire tube boiler with a power burner firing at 500,000 BTUH.

Always had problems with the pilot not holding. It was installed in 1998 by a dead man who one assumed followed instructions. I could not get past thinking he had done something incorrect.
He was a self taught, well respected repairman for many trades. Pearl Harbor survivor who may not have finished high school.

One lesson he taught me was "the local yocal never knows anything" in reference to discussing anything with the well schooled engineers we all know.....as years passed I came to learn what he meant by that.

He usually held his cards close to his chest, by the time he wanted to pass info to me about the pneumatic system that was connected to this boiler, he was starting to lose his memory and not much was gleaned by me.

........Lesson for us all and the entire hydronic industry......

However, I digress:

Staring at the simple piping connections for the gas train, it finally hit me:

The pilot was tapped after the main regulator.

So you could adjust the pilot reg correctly, but when the main valve opened the input to the pilot reg changed so much that it would snuff out.

Relocated the pilot feed connection ahead of the main reg and have had little problems since.

This system had been plagued by lock outs for over 10 years. Everyone in the building knew how to reset the Flameguard control.

The moral of the story is that just because something almost worked OK for years and to never question the original installer puts a mental block in front of you.....go back to the simple install instructions and check things out.

Would have made a good quiz, but I have no before pictures.

So you get the answer in advance.

RayWohlfarth

@JUGHNE lol well we know you’re special Thanks for the story That would be a good case to discuss it’s funny you say that My friend has a saying Don’t die with song still inside you which means we should share our knowledge before we pass

Tim McElwain

That was a good one Ray. It is amazing the things we find that have been the way they are for years - but wrong. That is what makes this business interesting

RayWohlfarth

Thanks Tim it is amazing why they would I think it’s because several companies before tried and failed to fix it He probably didn’t believe I could fix it