The orifice on the long horizontal burners is nowhere near where the flames are combusting. These orifices are mounted right to the fuel rail-pipe coming off the gas valve, where the burners are loosely inserted over them. It's cool to the touch.
The orifice on the long horizontal burners is nowhere near where the flames are combusting. These orifices are mounted right to the fuel rail-pipe coming off the gas valve, where the burners are loosely inserted over them. It's cool to the touch.
So is your brain.
He's an "idjit", but surprisingly enough, it actually CAN work - since the flame does NOT occur at the jet. It would be very unlikely, in many furnace designs, for the jet to approach anything close to 300 degrees F.
Hey. I hate to agree with Home-guy - but in this case he IS RIGHT.
Sure, you can "control" the flame, but accuracy and repeatability are not really in your lexicon when you do this. Soldering the "jet" and re-drilling it is a much more "scientific" , repeatable, and accurate way of doing it. (and getting a jet of the same size/format as a permanent replacement is even better) It's not just the size of the jet either - the "format" of the jet - the taper on the inlet side(if any) and or the outlet side, can significantly affect the volume of gas flow through a jet of a given "bore"
True - and it's STILL a dumb-ass thing to do in a combustion chamber. Can you say 'roll out' ?
No, he's not. He's talking about 'some asshole DIY'r could get away with it', not 'the correct and safe way to do it'. Which said 'correct way' , as it happens is also very inexpensive and easy to do.
And it 's total bullshit.
Thank you. Why not skip the bullshit DIY'r crap and just give the correct answer ?
And the velocity and pattern of the outlet gas, and the quality of the air / fuel mixture, thus the quality and efficiency of the flame. So why not just do it right ?
Accuracy is not called for here.
Anyone dialing-down the gas supply to the burners will not know ahead of time what the exact precise flow rate should be that they are intending to achieve. Much the same way that you won't initially know what setting your barbeque's controls or gas stove need to be in order to get a certain temperature on the grill.
In this excercise, you dial the gas down, you let several hours (or days) pass, you note how the duty cycle of your furnace has changed, and you either leave it alone or you adjust it up or down as needed.
And also more effort for no real, effective gain in terms of the desired end result.
If the furnace has a variable dial on it's gas valve/regulator, then use it. If it doesn't, try the main shut-off valve.
Yes, you know that changing the jets by getting smaller ones (or making them smaller with solder) will give you a smaller flame and less BTU's. But you really don't know by how much until after they're in place. And if the new jets are too small or not small enough, then you've got to partially dis-assemble your burners and change the jets.
Makes about as much sense as saying that replacing the potentiometer in my stereo's volume control with fixed resistors is a better way to control the intensity of sound coming from my speakers. Does it matter if the fixed resistor is "more accurate" ?
Yes, I am.
No.
I'm saying that the orifice jets do not experience high temperatures because of where they are mounted, so your claim that their size can't be changed by filling them in with solder is wrong.
I never said that modifying them with solder is good or bad or risky or safe.
But if you want such an opinion from me, then I would say that filling them in with solder and re-drilling them to a smaller size is perfectly acceptible. Solder is dimensionally stable in this setting, and the distance between the orifice and the combustion site is such that there is no fine detail in orifice shape or construction that can have any meaningful effect on downstream combustion other than the size of the opening.
You see, this is what happens when you have no real experience with 25+ year-old furnaces, other than to tell the customer that "yup, yours needs to come out and you need to fork over $4k to me for a new-fangled one".
After all, that's what you tell people when their pilot light blows out
- isin't it?
Your stereo doesn't need a specific fuel/air mix to operate the way it was designed to. FWIW, I have *NEVER* seen a furnace gas valve with a "variable dial" on it.
Oh, and while I am at it, HomeBoy.... you sure that your name isn't really Homer Simpson??
Steve followed poor usenet message-construction style by unnecessarily full-quoting:
We already discussed adjusting the primary combustion-air baffle plates, which are most likey already in the incorrect (lean) wide-open position in your average open-burner, standing-pilot furnace anyways, making your observation somewhat irrelavent, but still easily remedied.
Here ya go:
Using a proper sized jet is the RIGHT way to do it - but what he did works and is often done to determine what the right jet size is.
It would take one heck of a rollout to get the jet hot enough to melt the solder - - -
That is *NOT* a variable dial.... it strictly turns the gas valve on or off.... it is *NOT* variable.
Now do you want to pull your head out of your ass??
You are on drugs. See that blue dial? That's a variable-position dial. You get more or less gas going to the burners depending on it's position. Try it some time.
What is wrong with you people anyways?
You want to so hard to believe that it's not possible to dial-down the BTU output of old furnaces.
I don't know what your problem is.
They make em steve. They have a sensor that goes in the supply air and you set the valve according to the supply temp that you want. Usually see them on direct fired make up air units. Seen them on Reznor gas fired duct heaters too.
The King is dead but not forgotten.
That's true. But with the induced draft they can safely operate at high efficiency because they can better control how much air goes up the stack.
Last summer we changed out an "old style" gas furnace with an induced draft unit. Tremendous difference in gas usage.
Because we have also switched over to nearly 100% CFL for lighting, we have saved so much electricity that we just don't notice the extra 80 watts used for the draft blower.
But I agree with your main point: the old style motors in gas furnaces do waste quite a bit of power. But the main power hog is the air circulation motor. That can easily cost $.05/hour. That may not seem like much but if that blower operates 24/7, it adds up to over $30/month. A good reason to keep the fan on "auto" rather than "on."
You furnace should be sized so that it can keep you comfortable on a very cold day by operating continuously. You can pick your own numbers but your furnace shouldn't be expected to operate 24/7 more than a day or two each year. That's an extra $1 or 2 or so.
Maybe the next generation of furnaces will also take account motor efficiency. Right now the 90 (plus) % efficiency systems are much, much more expensive than the 80% (the condensation feature adds to the complexity and cost). But like so many other things, prices will come down with competition. It may end up being less expensive to buy a high efficiency HVAC system than to "super insulate!"
As the Idjit who filled in the orifice and then redrilled it, I can assure everyone that I did calculations on what size orifice I needed to get a certain BTU flow. I did this 20+ years ago and don't remember the details any longer, but it was not strictly based on cross-section of the orifice opening, but also included the effects of friction of the gas with the orifice walls.
If the flame ever gets close to the orifice opening, there will be major problems as at least in my furnace, the actual flame is several inches into the furnace from where the orifice is located. The is an air-mixing tube that goes between the orifice and the burner, and that is where you adjust the airflow to match the gas flow. It may not meet some PhD type of analysis, but it cut down the gas consumption and we stay warm on -10 degree nights and days so I guess I did something right.
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