Burnham V8 "rumbles" when fired

joea99

Burnham V8, about put in new "a while back". Down fired to .85 to try and mitigate short cycling. It was oversized to begin with, due to my following bad "old timer" advice. "You don't want to not have enough capacity when it gets REALLY cold here".

Today I replaced a nozzle and the ignition electrodes that I kept telling myself I need to do for the last month or so. Fired right up and showed the usual "large flickering fingers" of flame. It also rumbles while fired. While it has always done that, it seems to bother me now and wonder if I should have a pro look at it, at least once.

I put this in myself, having maintained a V7 in another location, and set it up using a Bacharach kit, smoke and gas test. Still have the kit and use it too, once in a while anyway.

So, what am I asking? I guess is rumbling normal? Never really considered that as, as I recall anyway, the few I have dealt with all rumbled to some degree. And, if it is not "normal" what can be done about it, besides air adjustment maybe?

Steamhead

Start at the beginning. Which model V8? What burner is on this boiler? What nozzle did you put in?

EdTheHeaterMan

Rumble is a sign or incorrect nozzle. The flame is growing and shrinking based on the static pressure the burner is putting into the combustion chamber. When the flame grows larger, the added pressure of the larger flame causes a back pressure on the burner head > that back pressure causes the burner fan to reduce the amount of air to the combustion chamber > Less air but the same amount of oil makes the flame look for additional air to burn that oil out in the heat exchanger > This reduces the pressure in the combustion chamber > the reduced pressure in the chamber allows the burner fan to push more air into the chamber > With more air the flame increases in size using the new found air > then the larger flame causes the pack pressure > This reduces the amount of air the burner fan can push into the chamber > and the cycle goes on and on in rapid succession causing the vibration and noise you are describing.

Manufacturers do not want loud oil heating equipment in peoples homes. Bad for business. "Don't want the brand of heater in Joe's house, it's too noisy" So they do a lot of testing to find the highest efficiency with the lowest noise by testing different nozzles and spray patterns and different angles and different pump pressures. When you change that with a smaller nozzle, you need to try different nozzles also. Just going from a 1.00 80° solid to a .85 80° solid may not be the best fit. You need to find out if the Hollow or semi solid pattern or the 70° or 60°angle works better at that lower firing rate. You need a professional with the patience to conduct a nozzle application test or who has experience with down firing the Burnham V8. I would start with the professional getting it dialed in first.

joea99

Burnham V84WC-TBWN
Beckett AFG
Delavan .85 80A

Steamhead

joea99 said:

Burnham V84WC-TBWN
Beckett AFG
Delavan .85 80A

There's your problem. Assuming the AFG has the specified V1 head, you need to use an 0.85 x 60°A.

The head setting should be at 0.

Info from the Beckett OEM Spec Guide.

joea99

EdTheHeaterMan said:

. . . You need a professional with the patience to conduct a nozzle application test or who has experience with down firing the Burnham V8. I would start with the professional getting it dialed in first.

Thanks for the rundown. I only quoted that last part to mention that, in my area, none of the people I've dealt with and had in on service calls EVER did anything beyond maybe a smoke test. They were all "by ear and by eye" guys, by gosh. And would argue about it. One reason I try to do most of things myself, even to the point of buying test gear. Still experience is a big part.

I suppose I can put in the original size nozzle, adjust the air and see if that resolves it. If not, I suppose I live with it or survey the "big boys" to find someone game for the game. This is a rural (sih) area where, till recently, only one "commercial" outfit existed and charged accordingly. Now there are several.

joea99

Steamhead said:

joea99 said:

Burnham V84WC-TBWN
Beckett AFG
Delavan .85 80A

There's your problem. Assuming the AFG has the specified V1 head, you need to use an 0.85 x 60°A.

The head setting should be at 0.

Info from the Beckett OEM Spec Guide.

I just happen to have one of those in the cabinet. Several actually. I remember buying them, but don't remember why. Maybe for testing. Age has it's benefits. This is not one of them.

Now if I can remember what "head setting" means . . . or, if I can look it up. Either one is problematic today.

EdTheHeaterMan

That boiler is rated for a 1.35 GPH firing rate. and it is accomplished with a 1.10 GPH nozzle @ 140PSI. They also use a Hago (H) nozzle with a 60°B spray pattern.


My rule of thumb is never go lower than 15% of the rated firing rate. Your choice of a .85 GPH nozzle is much lower that 15% reduction. I might use the .85 nozzle at 160 PSI. I would also try the 60° nozzle from both Hago and Delavan. I find there is less pulsation with the Hago SS nozzle. (B on a Hago means solid spray pattern. same as Delavan)

Also... The higher pressure will form smaller oil droplets. This makes for greater surface area for the oil to vaporize (liquid oil will not burn... It must turn into a gas vapor) so more surface area will evaporate in the a gas fuel that can burn more efficiently with less excess air. Less excess air will make the flame hotter and also reduct the stack temperature. You end up with a higher combustion efficiency.

joea99

EdTheHeaterMan said:

That boiler is rated for a 1.35 GPH firing rate. and it is accomplished with a 1.10 GPH nozzle @ 140PSI. They also use a Hago (H) nozzle with a 60°B spray pattern.
. . .
My rule of thumb is never go lower than 15% of the rated firing rate. Your choice of a .85 GPH nozzle is much lower that 15% reduction. I might use the .85 nozzle at 160 PSI. I would also try the 60° nozzle from both Hago and Delavan. I find there is less pulsation with the Hago SS nozzle. (B on a Hago means solid spray pattern. same as Delavan)

Also... The higher pressure will form smaller oil droplets. This makes for greater surface area for the oil to vaporize (liquid oil will not burn... It must turn into a gas vapor) so more surface area will evaporate in the a gas fuel that can burn more efficiently with less excess air. Less excess air will make the flame hotter and also reduct the stack temperature. You end up with a higher combustion efficiency.

The only reason I deviated from 1.10 GPH was to attempt to get longer burn times as I understood short cycles were inefficient. Can't say I can really tell a difference in fuel consumption.

I see there is a notation on the burner itself "for V84 use 140 psi only 1.10x60B HAGO nozzle only for 1.35 GPH". Thought that was only "informational: as to how to achieve the advertisesd BTU rating and one could vary from that to cut down the firing rate. Which seemed like a good idea at the time.

The .85 was the smallest I found on some burnham document, somewhere, as to various nozzles for this boiler. I wanted to go smaller, but, there were "caveats" about doing that, so I didn't go any smaller.

I've given some thought to ripping it out and putting in a smaller unit, or going to propane or a mixed fuel system, but, payback seems iffy. Financial payback of course.

PS - as long as I'm being chatty, the only reason, I think, it short cycles is there are 4 heating zones, a "micro" climate someone said. If there was only 1 zone it might have to fire longer at any given time.

EdTheHeaterMan

Are all your zones Fin Tube type baseboard for heating? Is there an indirect water heater?

Steamhead

joea99 said:

EdTheHeaterMan said:

That boiler is rated for a 1.35 GPH firing rate. and it is accomplished with a 1.10 GPH nozzle @ 140PSI. They also use a Hago (H) nozzle with a 60°B spray pattern.
. . .
My rule of thumb is never go lower than 15% of the rated firing rate. Your choice of a .85 GPH nozzle is much lower that 15% reduction. I might use the .85 nozzle at 160 PSI. I would also try the 60° nozzle from both Hago and Delavan. I find there is less pulsation with the Hago SS nozzle. (B on a Hago means solid spray pattern. same as Delavan)

Also... The higher pressure will form smaller oil droplets. This makes for greater surface area for the oil to vaporize (liquid oil will not burn... It must turn into a gas vapor) so more surface area will evaporate in the a gas fuel that can burn more efficiently with less excess air. Less excess air will make the flame hotter and also reduct the stack temperature. You end up with a higher combustion efficiency.

The only reason I deviated from 1.10 GPH was to attempt to get longer burn times as I understood short cycles were inefficient. Can't say I can really tell a difference in fuel consumption.

I see there is a notation on the burner itself "for V84 use 140 psi only 1.10x60B HAGO nozzle only for 1.35 GPH". Thought that was only "informational: as to how to achieve the advertisesd BTU rating and one could vary from that to cut down the firing rate. Which seemed like a good idea at the time.

The .85 was the smallest I found on some burnham document, somewhere, as to various nozzles for this boiler. I wanted to go smaller, but, there were "caveats" about doing that, so I didn't go any smaller.

I've given some thought to ripping it out and putting in a smaller unit, or going to propane or a mixed fuel system, but, payback seems iffy. Financial payback of course.

PS - as long as I'm being chatty, the only reason, I think, it short cycles is there are 4 heating zones, a "micro" climate someone said. If there was only 1 zone it might have to fire longer at any given time.

I think this is what you saw (attached). This boiler has had several firing rate specifications over the years. Where possible I like to use the lower rates as long as the combustion numbers are good, since a lot of boilers are oversized.

With the 0.85x60A nozzle the firing rate is 1.00 GPH. With a 1.00x60B Hago it is roughly 1.2, and as @EdTheHeaterMan says the highest spec is 1.35 GPH.

If you use the lowest firing rate and it heats the house properly on the coldest day of the year, and doesn't soot up, you win.

BTW, where are you located?

EdTheHeaterMan

When you go too small on the firing rate, you may find the stack temperature gets too low. Stack temperatures below 300° with return water temperature below 135° can lead to condensation of the flue gas in the cast iron heat exchanger. This may cause the condensation droplets with higher concentrations of carbonic acid to eat away at the boiler resulting in premature failure

MaxMercy

EdTheHeaterMan said:

My rule of thumb is never go lower than 15% of the rated firing rate. Your choice of a .85 GPH nozzle is much lower that 15% reduction. I might use the .85 nozzle at 160 PSI. I would also try the 60° nozzle from both Hago and Delavan. I find there is less pulsation with the Hago SS nozzle. (B on a Hago means solid spray pattern. same as Delavan)

I'm in the same boat as OP: I replaced my boiler based on the original boiler's BTU.

I ordered a prepackaged Slant TR30-1.10 with the AFG. Short cycled with the stock 1.10 nozzle (it also came with a 1.25 in a bag - over-firing?)

I contacted Slant (remember them?) and asked them about down firing, and said the lowest to go with the TR-30 was .85 gph, so that's what I put in. Still short cycles 95% of the time but is smooth and quiet. The only time it doesn't short cycle is when both zones are calling (hydro-air) on a very cold night, and even then, it will only run a bit more than 15 straight minutes. I'm afraid that enclosing my attic (where my upper air handler is parked) will just make this worse, but I'm stuck for now.

So .85 is a bit more than 15%, but it seems the 15% rule is a good one to not under fire.

Steamhead

EdTheHeaterMan said:

When you go too small on the firing rate, you may find the stack temperature gets too low. Stack temperatures below 300° with return water temperature below 135° can lead to condensation of the flue gas in the cast iron heat exchanger. This may cause the condensation droplets with higher concentrations of carbonic acid to eat away at the boiler resulting in premature failure

This, of course, is why we test!

joea99

I think this is what you saw (attached). This boiler has had several firing rate specifications over the years. Where possible I like to use the lower rates as long as the combustion numbers are good, since a lot of boilers are oversized.

With the 0.85x60A nozzle the firing rate is 1.00 GPH. With a 1.00x60B Hago it is roughly 1.2, and as @EdTheHeaterMan says the highest spec is 1.35 GPH.

If you use the lowest firing rate and it heats the house properly on the coldest day of the year, and doesn't soot up, you win.

BTW, where are you located?

I'm located near Kingston NY.

So, I should be OK with a .85 maybe change to a "B" (Delavan), as long as smoke, co2 and stack temp are OK? I forget what my last tests showed, but seems I really wanted stack temp to be lower, it was 500-600 degree range if I recall.

joea99

EdTheHeaterMan said:

When you go too small on the firing rate, you may find the stack temperature gets too low. Stack temperatures below 300° with return water temperature below 135° can lead to condensation of the flue gas in the cast iron heat exchanger. This may cause the condensation droplets with higher concentrations of carbonic acid to eat away at the boiler resulting in premature failure

Well above 300 last I checked. It's easy enough to do, I should check it again.

Steamhead

Well, you already have the 0.85x60A so try that first. It may be the air pattern at that rate favored the A. Post the numbers here.

joea99

Steamhead said:

Well, you already have the 0.85x60A so try that first. It may be the air pattern at that rate favored the A. Post the numbers here.

Seems I lied, only have .85 60B. I do have a Danfoss 1.20 x60AS and 1.10x 60AS.

I'll check what I can pick up next couple days.

Steamhead

Reminds me of a somewhat similar boiler I worked on a few years ago. Same problem- a rumbling, noisy fire. This was a V-13 with an AFG, but it had a fixed head rather than your V-84's adjustable one.

Turned out this boiler/burner combination needed an 80° hollow nozzle, but some flamehead had used an 80° solid, which did NOT match the air pattern well. The owner was ready to replace it because of the noise.

I checked the OEM Spec Guide and put in the proper hollow nozzle. No more noise, and better combustion after I tuned it with the analyzer. It's still working.

joea99

Steamhead said:

Reminds me of a somewhat similar boiler I worked on a few years ago. Same problem- a rumbling, noisy fire. This was a V-13 with an AFG, but it had a fixed head rather than your V-84's adjustable one.

Turned out this boiler/burner combination needed an 80° hollow nozzle, but some flamehead had used an 80° solid, which did NOT match the air pattern well. The owner was ready to replace it because of the noise.

I checked the OEM Spec Guide and put in the proper hollow nozzle. No more noise, and better combustion after I tuned it with the analyzer. It's still working.

I need to look into how to adjust the head, Don't think I've ever touched it.

joea99

OT - can anyone recommend a good forum, etc, to discuss kitchen range hood venting? Installing an island range hood and rethinking recirc vs vent to outside.

EdTheHeaterMan

joea99 said:

OT - can anyone recommend a good forum, etc, to discuss kitchen range hood venting? Installing an island range hood and rethinking recirc vs vent to outside.

Too bad that @DanHolohan or @Erin Holohan Haskell are not also Epicurean devotees or we might have also had CookingHelp.com for this query.

joea99

EdTheHeaterMan said:

joea99 said:

OT - can anyone recommend a good forum, etc, to discuss kitchen range hood venting? Installing an island range hood and rethinking recirc vs vent to outside.

Too bad that @DanHolohan or @Erin Holohan Haskell are not also Epicurean devotees or we might have also had CookingHelp.com for this query.

Yeah, pity. Well, heating help is not too far off from HVAC help. And stoves make heat, so . . . , Why yes, that is my coat and OK, Ok, I can take a hint,
it is time I was going . . .

Steamhead

joea99 said:

EdTheHeaterMan said:

joea99 said:

OT - can anyone recommend a good forum, etc, to discuss kitchen range hood venting? Installing an island range hood and rethinking recirc vs vent to outside.

Too bad that @DanHolohan or @Erin Holohan Haskell are not also Epicurean devotees or we might have also had CookingHelp.com for this query.

Yeah, pity. Well, heating help is not too far off from HVAC help. And stoves make heat, so . . . , Why yes, that is my coat and OK, Ok, I can take a hint,
it is time I was going . . .

In general, venting to outside is preferred. But some hoods have filtration systems that can remove smoke from cooking. First thing to do is check local Codes to see what they say.

joea99

EdTheHeaterMan said:

Are all your zones Fin Tube type baseboard for heating? Is there an indirect water heater?

Sorry I missed this earlier. Yes all zones are fin tube baseboard, except for one zone that serves an indirect "superstore" type water heater that now functions as a "standby", with a propane Takagi TK3 as the primary domestic hot water heater. I did have to use it once when the TK3 heater core sprang a leak and required replacement. That was a pain to replace even at no cost for parts. Would have been a week without hot water as they refused coverage at first.

EdTheHeaterMan

This is the instruction booklet for the AFG oil burner when it is not attached to a particular brand of equipment. OEM instructions (like Burnham Boilers) are brand specific. https://5476519.fs1.hubspotusercontent-na1.net/hubfs/5476519/2022/Manuals/PDFs/Burner Manuals/Residential Product Manuals/6104-Burner_Manual_092120.pdf?__hstc=&__hssc=. In this booklet there are 3 different burner heads mentioned. The F head is a fixed head that is not adjustable and is attached to the end of the burner air tube. The OEM (or installer of a retrofit burner) selects the proper size head to match the firing rate of the burner. Notice the different secondary air openings around the parimiter of the slotted cone. The larger the number the more secondary air


The L and V1 heads are adjustable You can tell the difference by the shape of the section that is attached to the nozzle adaptor. (outlined in Red)

Look at your nozzle assembly to determine if you have the proper head for your boiler/burner combination. If your burner, or any of the parts of your burner, was replaced over the life of the boiler then using the OEM guide to select the nozzle may not help.

joea99

EdTheHeaterMan said:

. . .
Look at your nozzle assembly to determine if you have the proper head for your boiler/burner combination. If your burner, or any of the parts of your burner, was replaced over the life of the boiler then using the OEM guide to select the nozzle may not help.

Thanks. Nothing has been changed since install, save filter, nozzle and electrodes. And a clean out cover gasket or two.

Which does not mean the supplier (or the factory) didn't do something iffy. Figured no need to check something fresh out of the crate. If putting in the "correct" nozzle does not help, looking into that is next.

EdTheHeaterMan

Figured no need to check something fresh out of the crate.

The first thing you learn in oil burner school is that the factory settings are never correct. They might be close but you need to check the settings with instruments. Smoke reading, CO2 or O2, Draft, and Stack Temp. Based on those numbers, you adjust the flame settings accordingly. Air Band and and Air Shutter, The V1 head adjustment. and the fuel pump pressure will all make a difference. If this was a steam boiler you could down-fire with a .85 60°A nozzle according to this line in the book that Steamhead posted.
Pump pressure at 140 PSI
Air band at 1
Air shutter at 10
V1 adjustment at 0
Those settings are the starting point. Then you need to do the smoke test to make sure the fuel is all burning clean.

The steam boiler will not have a flue gas condensation problem like a water boiler can, so the boiler can be down fired more than the water boiler (like you have). But since those numbers are in the book, I would try them and see if you get at least 350° stack temperature

joea99

It is a V1 head. As far as settings it matches what is shown in Figure 12 above. What I cannot see is how to set the "Z" dimension unless it is out of the burner and what that has to do with the "acorn nut" on the side of the burner. I must be missing something.

In any case, I changes to a .85 60 degree B nozzle (I know it should be an A, but, that is the only 60 degree .85 available. I set the band to 1 (it had been open a tad) and opened the shutter all the way as it had been closed a bit.

Smoke test came at 10+, i'd say. had to open the band up a crack and set the shutter about 1/4 open to get to "trace" in order to take CO2. Which ends up at 9 (red fluid test) and seems not to vary. Shutter was quite touchy to get "0" smoke. Stack temp is at 550 degrees.

Seems quieter, but I really should go listen to some other burners to get a comparison. I may just be chasing my tail.

I does trouble me that CO2 seems a bit low. Got no way to test 02. Asked at a community online forum for my area for someone that has test equipment, knows how to use it and actually uses it. So far the only replies have been, "yeah, I want one of those guys too".