Which nozzle to use and how to clean firebox

D_I_Why

Hello!
I have a 'Manufactured home' with a Miller CRF100-PO furnace (I find info online about the CMF series but not the CRF for some reason). I believe it is original to the house (1983 or 4). The furnace has a Wayne M-SRH-1 burner.

The original Miller service info label in the Furnace says to use a .75GPH 80 degree Solid nozzle.

I am looking to do service on it myself this year (filter, pump screen, nozzle, cleaning burner, reset or replace electrodes if necessary)

I saved the nozzle from the last service I had and it was a Delavan .75 80A, which is a hollow cone nozzle. It seems to me that the furnace was running fine with it, but I don't really know (I don't know how to determine if it's a problem or not, I never even lifted the little spring loaded door on the combustion chamber to look at the fire and I don't know how to check the efficiency). I don't know what nozzle is in there now, either (I'll find out when I open it up to replace it)

Question 1- Does it matter much if I use a solid or hollow cone nozzle? I don't know if the nozzle left over from the last service was hollow because the tech felt it would work better, or if it's just what he had on the truck.


Question 2- I've heard you should vacuum out the firebox but it's extremely delicate. Never having done this before, what's the procedure? Remove the burner and try to delicately vacuum out any soot/debris in the chamber?


Thanks for any suggestions.

lchmb

Playing with fire in a home is not the best option. I can understand trying to save money in this day and age but sometime's the best option is to have it done by a pro. Safeties need to be tested, the heat exchanger checked... Do yourself and your family a favor and call someone who does this for a living..it will be the best money you spend

D_I_Why

Thanks- but I'm going to do it anyway. I'm not trying to save money. I've tried every service provider in the area and none of them seem to know what they're doing, they refuse to answer questions about what they actually did and whether or not they changed any parts in particular or did any testing ("Yeah, everything's running great"). So-I'm better off doing it myself. Obviously I understand fire, CO, and other combustion products are dangerous, that's why I'm here asking, instead of just taking a wrench to it.

KC_Jones

You will need a combustion analyzer and learn how to use it in order to do the servicing properly. It's not just about cleaning and changing a nozzle the burner has to be tuned as well. This also means you will need to learn how to do all the burner adjustments to be able to tune it.

Not sure if there are any classes available to learn all this? Perhaps a pro could chime in on that?

lchmb

well..I wish you the best of luck...with that said, I know many miller furnaces running with a hollow nozzle that have never had a problem. One question though, how about a picture of the furnace? I cant find any information in my library about this unit...

Jamie Hall

I can understand your frustration; good techs are hard to find and they aren't cheap.

However.

To do the job right, you absolutely must have a combustion analyser and you must know how to use it correctly. You are not changing the spark plug on a lawn mower here. Even if you were to use exactly the same nozzle, it will behave slightly differently and you will have to adjust the air to get the unit to perform properly, never mind safely.

I will do pretty much anything else in terms of maintenance on the place I care for, and I'm licensed to do most of it -- but play with the boiler's oil burner? No way. That's a job for a pro.

STEVEusaPA

From Hat:
And, no, you don't need a combustion analyzer to clean an oil fired boiler. In fact, I'd make a guess that not a single tech from any oil company has ever owned or operated one. If you have one, you can optimize the air for better efficiency but it isn't mandatory.

Finally, if you clean and vac it yourself, it will be far better than anything the oil company offers to do. A lot of them don't even want to bring the vacuum inside.


This is completely false and untrue. Please only offer facts based on your experience instead of perpetuating this myth.

STEVEusaPA

Hat
How many annual cleanings have you completely observed, how many service calls in these 30 years? Was it your job to observe all these incorrect cleanings, and incorrect repairs where no one does anything right, then do nothing about it but report it 30 years later?
You've never seen a tech use an analyzer?
All bull crap. I stand by my original statement. I only responded because I am personally getting annoyed with all the oil bashers who just don't know what they are talking about.
I'm not interested in getting into with you. I know you have a lot of knowledge about a lot of things-but not with this.
I also know you like to derail a thread and have to get in the last word--but I'm not playing along.
So I'll post this, you'll quote this and say something more ridiculous than your last statement, and I won't respond.

Jamie Hall

Calm down gentlemen. In a sense, you are both partly right. It is quite true that many times the people sent out by the oil dealers don't use a combustion analyser. However, only the real clowns -- who, unfortunately, do exist -- don't bother to at least wave a vacuum at the firebox (but they don't open the door!), And the burners continue to run. Sometimes better, sometimes worse. It is rather astonishing how far out they can be and still run (rather like an old car that way!).

It is also true, however, that you can get much better results from a boiler or furnace by cleaning it up and tuning it up properly. Again, rather like that old car. Further, you will avoid problems down the line, like a heavily sooted heat exchanger or, worse, a heavily sooted chimney.

KC_Jones

I can add another to the list. My parents have always gotten a combustion analysis, burner tuning and the readout off the analyzer as proof. If I asked my mother it wouldn't surprise me if she saved them all. Same oil company since the early 1980's, first furnace lasted 33 years before it cracked in 2010. The tech is usually there for a couple of hours. They started as only an oil company and now merged with an HVAC company, but the service has always been the same.

Not sure when the analyzers first came out, but as far back as I can remember they were getting the print out from one.

My mother had an issue with them one time and the tech was an idiot, the furnace was noisy. She complained and they came back and did it over on their dime, we later heard the tech was let go for incompetence.

lchmb

I cant speak for any other's at the company I work for (other than my son) but I use a digital analyzer every tune up as well as my son who has been in the field a little over a year. We also use it to set up all the installation's we do and leave the print out with the service manual attached to the boiler.
I've been in the field going on 22 years now and know plenty who don't. I also know plenty who take great pride in their work and do it right....

btw 30 tuneups in 30 years? so that's maybe 1/10th of 1 percent of the tuneups done in 30 years and that means no one else does them?

D_I_Why

I have gone through ALL of the service providers in this area in the past 15 years. It was kind of an experiment. I have used big companies and one-man shows. In 15 years, I have never seen a tech use or even mention a combustion analyzer. They pull the burner, scrub it clean and replace the nozzle. I believe the electrodes were replaced only once (when chasing a problem that turned out to be the transformer). Only one vacuumed the box out.

Jamie Hall

I would probably agree that many, if not most, companies don't do a proper tune up or cleaning. I would point out that most companies can't figure out how to pipe a boiler to save their souls, either.

Doesn't make it right. Craftsmanship is not defined by majority vote...

rick in Alaska

24 years of tune ups and installations. Went through two wet kits and two electronic analyzers over the years. I check every installation with it, but I only clean out boilers and furnaces when they need it. If they are only a little dirty, I usually leave them alone.
And, I have to say, there are three companies in town that do burner work, and we all use analyzers on the job. Not sure about the un-licensed ones though. Probably don't.
Rick

Solid_Fuel_Man

In my area we are about 90% oil. It is standard practice to leave a printout from the analyzer, or a card with all the specifics like stack net, CO, o2, of draft, etc.

How much soot is actually in the combustion chamber is a good indicator of the previous burner tune. For a typical residential job with 500-1000 gal annual usage.

Taylor

Bob Bona_4

Always did a combustion test after cleaning. It's part of the tune. Nozzles can vary slightly between mfrs. Cleaning burner fan, chamber wear, turbolator wear etc etc. Heck, even a leaky transformer plate seal Can change settings. Perhaps prior nozz/settings were off. I could not walk away from a clients appliance unless I was sure about how burner was performing. You have to know your draft, over fire vs. Breech. Not dking this is dangerous, IMO.

ChrisJ

From what I've seen, albeit a very small sample you're lucky if the guy actually cleans the boiler and changes the filter. My guy did nothing and charged a lot for it but it only happened once as I ripped the boiler out after it.

My friend and neighbor had an oil company service his boilers and at one point one of them was totally plugged up so he asked me to come over and get it going for him late at night. We cleaned it, swapped nozzles and filter and I opened the air shutter a tad to lean it out some. I asked him to please get someone in with an analyzer to set it up correctly.

Well, him being him, never called anyone (if it was working, he ignored it) and after two years of heat and domestic hot water that boiler was still spotless inside. I guess I got lucky. I have no idea how efficient it was running, but it was burning a lot cleaner than before. In fact, I think it's still going and still hasn't been touched so we're probably over 3 years now which is a shame but nothing I can do about it. He passed away a few months ago.

If it was mine I'd want it cleaned, nozzles swapped and filter changed every 6 months, 12 months tops. I'd also insist an analyzer is used, but apparently I'm extremely picky.

In general, I agree that most oil guys don't have an analyzer but I would also say it really should be done. Doing it by eye works, but it certainly isn't the correct way, not in 2016 when we have the tools available to do far better.

Bob Bona_4

When I began this trade I went from a Honda factory trained motorcycle mechanic and service mgr, to oil appentice. The oil co. I worked for had about 6-7 techs. All had wet kits provided by the co., and all were expected to use them and report readings on annual service. I did find it curious how certain guys seemed to have the exact same readings every single year if they were the consecutive tech. Although it is possible.

I'd be driving blind without combustion readings. Could I get things close? Sure. 8 years of 5 cleanings a day, installs mixed in, plus night calls, you get proficient. Today? With positive pressure boilers, often you can't even see the flame. And what is the over firedraft? Burning your knuckle hair doesn't really cut it

Rusty2

The house we moved into has one pipe steam and a Peerless oil boiler. Whoever installed it piped the drain from the Low Water Cut Off so that you could not open the boiler door without removing the bolts and taking it off its hinges or removing the drain pipe(s) from the LWCO. What they were thinking to do this, I haven't figured out. I'm guessing that's why in those 3 years I've never seen anyone clean or vacuum the firebox. It was too much trouble to get the door off. Recently I serviced and re-piped the LWCO so that the door will now open. There was a lot of stuff in the firebox so I carefully moved it into a dust pan, then vacuumed and made sure I didn't tear the blanket. I used the nozzle on the chart specified by Peerless for this boiler. For some reason there was an undersized nozzle on there maybe from the guy who made sure you couldn't open the door. If you also get new electrodes they sometimes come with a gauge to set them the proper distance from the nozzle. I was lucky to eventually find an excellent guy in our area who is very familiar with Dan Holohan's work and the body of knowledge he's been so generous to share with us. The more I can learn makes me appreciate how things work and makes it easier to communicate with a professional tradesman. I have to know my limitations.

cableman

So i asked a couple of guys at work if their boiler guys use a combustion analyzer, their response was im over analyzing it!
Does anyone have a recommendation on longisland for tuning up my burner?
Ive already cleaned it, just wanna lower nozzel and make sure its running how it should.
Thats!

STEVEusaPA

You couldn't go wrong starting here:
https://heatinghelp.com/find-a-contractor/detail/technical-heating

D_I_Why

Turns out the heat exchanger has a hole in it. You can see it from the inspection port. Furnace is 30+ years old so I guess I'm OK with just replacing it.
I got a recommendation on an HVAC guy and he is working up some prices for me. What should I look for (remember this is a Miller 100KBTU downdraft, mobile home type furnace) with the installation? Does it need anything special when it's being set up? Should the installer be doing anything beyond dropping the new one in place of the old (I assume there should be some kind of analysis done).

lchmb

take a close look at the roof jack to make sure it's not rotting out..

D_I_Why

During very heavy rain there is some water coming down the outside of the pipe and settling on top of the (old) furnace. Is this normal?

D_I_Why

PS The old furnace is a 100KBTU unit and the replacement is supposed to be an 80KBTU (I was told Miller doesn't make a 100KBTU furnace any more?). Does this make a significant difference? It's a 'manufactured home' so I would expect that not only was the furnace size engineered to match the layout of the house, but that they used the cheapest (smallest) one possible, so going smaller yet may not be a good idea.

I found that Nordyne makes an 80 to 100KBTU conversion kit (PN 903102) but I can't find a picture of it or description of what it contains. What do these kits normally consist of?

Solid_Fuel_Man

Without even having the proper heatloss calculation I can speak with 99% certainty that an 80,000 btu unit will be more than double oversize.

Taylor

D_I_Why

Dang- this goes against my assumption that the builders used the cheapest possible parts to get the job done. Was there some misunderstanding in the previous century about how to size HVAC? Are today's units designed and intended to run with longer on-times?

Solid_Fuel_Man

Yes, longer run time is better efficiency wise. But the sad reality is that most HVAC guys just "drop in 100,000 btu or more" and call it a day. With the owner ultimately paying for that mistake over and over again.

Taylor

D_I_Why

I started off with this, wanting to do my own service. I went to a local big-box store for parts but couldn't find the right stuff. I was researching local plumbing supply stores and found some online sources (Amazon has a surprising amount of service parts) but ultimately I ended up getting too busy at work to do it and had to hire a tech to come out and get it done.

He had changed the tank filter and finished performing cleaning service on the gun before he realized the HX had a hole in it.

In retrospect, my wife started complaining last year that the heat 'smelled different' so we've been running the unit with a hole in the HX at least since last winter.

During the cleaning process he said these units like a special MH (Mobile Home) nozzle and had replaced the .75GPH nozzle which was in it (and which was recommended on the factory label) with a .579GPH nozzle. I am running the unit right now ( my wife and kids happen to be out of the house this morning... and I've got two CO detectors running in different rooms just in case. I'm only running the heat to warm up the house a bit until Monday when the contractors are coming to put the new unit in) and it feels to me that the air coming out of the registers is less hot. Am I imagining things or does the oil spray rate from the nozzle affect the output air temperature that significantly? I was thinking maybe the house (and ductwork, etc) cooled down more than usual but the thermostat was at 65 degrees which is where the heat normally kicks on anyway. I don't think it's the air leak in the HX since we had that last winter and the output air at the registers was hotter then.

PS .579 sounds needlessly precise to me; why not .58? Are things really that precise when it comes to oil nozzles?

rick in Alaska

I hope he at least told you not to run this thing and disconnected the lines and you hooked it back up and are running it anyway. If not, then he is in for a big liability if something goes wrong. PS, unless you have really good (expensive) CO detectors, most of them take a very long time to respond with lower levels of CO.
Warning done.
The nozzle gph does affect the amount of heat going in to the firebox, so the lower nozzle will affect the heat output, which will make the air feel cooler.
Not sure about a .579 nozzle. Never heard of it myself.
Rick

D_I_Why

Just to clarify- He just flipped the switch off and strongly suggested only running once or twice to get the house warmed up. I did tell him I had CO detectors. I am aware they can be slow to alert. One is a plug-in unit that only beeps on high levels of CO (400 PPM for 35 min) and the other is a digital readout unit that won't alert until there's a sustained 200PPM but you can press a button and see the concentration at any time. I have them low in the room but not in direct airflow of the registers (I doubt hot air is good for the sensors). It was warm enough yesterday and today that I only needed run the furnace once, and the new furnace is coming tomorrow.
At any rate, a hole in the HX doesn't guarantee CO entering the house. It's not a great thing and should be remedied ASAP but it doesn't mean CO is being put into the house. It didn't kill us last year

The guy also suggested that running .75GPH was heating things up too much which could have caused thermal stress which resulted in the hole in the HX. Now, that might be, but why would Miller have spec'd that size nozzle then? It's listed right on the sticker inside the service door.