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General => Mr. Fix it => Topic started by: Wingdreamer on Dec 15, 2009, 10:16 AM

Title: Get more BTU'S out of Stove???
Post by: Wingdreamer on Dec 15, 2009, 10:16 AM
I have a factory inside/outside stove that I use exclusively outdoors, attached to the side of the camper. Problem is, on a cool day, it takes forever to get water to boil, as it appears to be a low BTU stove. Is there a way to increase the flow of propane through these burners? Can I drill and enlarge the actual holes in the burners, or modify the valves, line or regulator to get more volume/heat?
Bottom line, how do you get more BTU's out of any propane stove or BBQ?
Thanks!!!
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Post by: Hoagie on Dec 15, 2009, 10:30 AM
Definitely DO NOT drill out the holes in the burner. What is regulating the gas flow is the orifice which is in-line before the burners. The hole in this piece is precisely drilled to provide the gas to air mixture for you stove.
 
My advice would be to stop in at your local propone supplier. Not the gas station of the local big-box store, but the dealer with the tank farm and the trucks used to deliver propane to rural residences. Talk to them about what you want to do and see what they recommend. They may be able to switch out the orifice. It may be that you stove cannot be safely modified, in which case I can recommend the Camp Chef line of stoves as a great alternative for outdoor cooking.
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Post by: Recumbentman on Dec 15, 2009, 12:25 PM
My understanding is the gas is controlled by the regulator located next to your propane tank. You would have to put a "Tee" at your tank and place a high volume regulator on one end and the original regulator at the other end and then a separate propane line to wherever you want it to go.
It would be a lot easier & cheaper to just buy a table top stove ;)
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Post by: coach on Dec 15, 2009, 12:41 PM
The BTU is limited by an orifice ~6500 BTU.

I wouldn't, but it could be precision drilled larger!
In/out stoves have limited BTU since they are so close to flammables.

Get a 'outdoor' stove, one designed to be solely used outdoor
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Post by: flyfisherman on Dec 15, 2009, 04:26 PM
Yeah ... I hear ya!

First off, just toting that inside/outside stove in and out is a hassle!
Secondly, it's performance outside leaves much to be desired.

Our solution has been to use a Coleman two burner camp stove (a left over from the canoe/camping days), outside, where all the serious cooking is done ... either on the C/G picnic table or on a 2'X3' folding aluminum table that is set-up under the awning. The inside stove is used for perking that morning coffee (which also helps to take that morning chill out of the camper) or simply to heat something up, like soup for instance.

That inside/outside stove, like all RV appliances, is designed to operate at 11" WC pressure (28" WC pressure = 1 psi), whereas that Coleman camp stove does it's business at 10 psi. No comparison in performance, but it should be noted that the Coleman camp stove is never used inside the camper.  And the Coleman camp stove can operate using those 16oz disposable propane canisters or it has it's own regulator where it can be hooked directly to a regular refillable L/P tank. I carry an additional tank (in the truck) just for this purpose.

Here's a pic showing the Coleman camp stove set-up under the awning. You can see how we sprawl out all over that C/G picnic table ... all kinds of things are done there! Especially washing the dishes as you can see right in the fore ground.




(http://i65.photobucket.com/albums/h226/dww0825/section1012.jpg)
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Post by: coach on Dec 15, 2009, 08:04 PM
Please stop blaming low pressure for low BTU!

Many CampChef stoves offer 30,000 BTU/burner and are also low pressure. Or the 20,000 BTU furnace or ...

The in/out stove is limited due to the closeness of flammable material inside the PU.

A Coleman is a good alternative, not because it operates on 15 psi but because is has 10,000 BTU/burner versus the wimpy 6500 BTU of the in/out stove, costs about $50 and can be moved to block the wind!
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Post by: flyfisherman on Dec 15, 2009, 11:13 PM
And, please, let's not get into any more voodoo physics on how your going to get more BTU performance out of less fuel. No doubt a better engineered stove with the right jets will out perform an inferior design, but all things equal, the more fuel at a higher psi will produce more BTU's.
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Post by: coach on Dec 16, 2009, 07:57 AM
It is code that limits the BTU of the stove not pressure.
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Post by: flyfisherman on Dec 16, 2009, 09:29 AM
No doubt that the Suburban cook stove that came with my Starcraft meets the criteria of the standard for rec recreation vehicles ANSI A119.2/AFPA 501C and the national gas code ANSI Z223.1, part of which sets the minimum gas supply pressure at 11" W.C. and the maximum at 14" W.C. ~  (no doubt fire safety is the primary goal of these codes), and I'm sure the good folks at Suburban have engineered their stove to deliver optimum performance while meeting that criteria. And I'm also sure that this stove can be "modified" to give more performance (BTU wise) but would exceed the limitations of those  codes.

Coleman, who has been in the camp cook stove making business for many years, I'll bet knows a thing or two about stove performance, fuel efficiency and BTU's as well. Since their propane camp stove I have (Model 5400 A 700) is not encumbered with the recreational vehicle code already listed, do they restrict the fuel intake to 11 to 14" W.C. pressure ...? Of course not, they engineered it to receive 20 times that amount of fuel and the result is the stove will blow the wind shields off the restricted intake stove. In the realm of propane fuel deliverance, higher psi equates to more fuel and more fuel equals to more BTU's; and I'm sure a good engineered burner/orifice set-up increses the performance of the proportioned fuel recieved.
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Post by: AustinBoston on Dec 16, 2009, 10:20 AM
Quote from: flyfisherman;213460And, please, let's not get into any more voodoo physics on how your going to get more BTU performance out of less fuel. No doubt a better engineered stove with the right jets will out perform an inferior design, but all things equal, the more fuel at a higher psi will produce more BTU's.

The point is, it's more fuel, not higher PSI.  They are not the same thing.  I once had a small, single-burner camp stove that ran on a 1-lb bottle of propane, without a regulator - 150 to 250 PSI - and by design only put out 6,000 BTUs.

Now if you wanted to force more BTUs through a system designed for 11" WC, you could do that by jacking the PSI, but you could also do it by switching out the orifice.

Austin
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Post by: coach on Dec 16, 2009, 10:30 AM
You don't need higher pressure to get higher BTU.

Many a bakery operates at even lower pressure than 11" wc (7" wc) and with a gas that has less BTU. They use large supply lines.

Now if the this high pressure existed at the burner (15 psi for Coleman) the flames would shoot out a long way!

Check how small the supply lines under the burners are!


RVIA adopts NFPA standard (//%22http://www.nfpa.org%22)s, NFPA 1192 Rec Vehicles
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Post by: flyfisherman on Dec 16, 2009, 10:56 AM
Quote from: AustinBoston;213466The point is, it's more fuel, not higher PSI.  They are not the same thing.  I once had a small, single-burner camp stove that ran on a 1-lb bottle of propane, without a regulator - 150 to 250 PSI - and by design only put out 6,000 BTUs.

Now if you wanted to force more BTUs through a system designed for 11" WC, you could do that by jacking the PSI, but you could also do it by switching out the orifice.

Austin

Again ... no doubt a more efficient burner/orifice/jet assembly on a stove receiving "X" amount of fuel will out perform an inferior design receiving the same amount of fuel. However, a pound or a gallon of propane only contains so much energy (BTU's if you will) and if you deliver say one quarter of that amount in one hour vs half ... the later will obviously have delivered the more BTU's, with all things being equal.

As for your single burner stove, it's regulator was located right where you screwed in the disposable tank and only allowed so much fuel to come out of the tank and be consumed. In other words, it restricted the psi just as a propane regulator does on the camper. Like the water hose with 45 psi, barely crack the valve and only so much water comes out at a lower pressure. Open the valve fully and it comes out gang busters. In other words, it delivers more water. Yes, we can stick an adjustable nozzle on the end of the hose and do all kinds of things with it, but we need pressure to deliver optimum supply.
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Post by: flyfisherman on Dec 16, 2009, 11:19 AM
Quote from: coach;213468You don't need higher pressure to get higher BTU.

Many a bakery operates at even lower pressure than 11" wc (7" wc) and with a gas that has less BTU. They use large supply lines.

Now if the this high pressure existed at the burner (15 psi for Coleman) the flames would shoot out a long way!

Check how small the supply lines under the burners are!


RVIA adopts NFPA standards, NFPA 1192 Rec Vehicles

Ther are other factors involved in your bakery example. Like my Suburban cook stove in the camper, it was designed to operate (max) at a certain level. As already posted, no doubt it can be bumped up in performance but that would be contrary to what it was designed for. But no way, under the sun, will it ever operate on the scale of the Coleman camp stove, with only 11" WC pressure. Impossible.

Now, my Coleman camp stove uses 10 psi ... you keep saying 15 (unless you know more than Coleman?) ~ it has a regulator on it to ensure the burners will receive that max amount ... and obviously that 10 psi can be regulated further by the burner valve. But the fact is that stove, as presently designed, can only deliver so much heat (BTU's). Maybe someone real knowledgeable could boost it a tad with bigger jets as it is presently set-up. And here's the point ... in order to achieve a higher BTU level, assuming one where to have the proper burner/orifice set-up, would be to increase the supply of fuel and with propane that would be a higher psi.
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Post by: Wingdreamer on Dec 16, 2009, 11:42 AM
Wow, we're getting some great discussion on this topic, thanks! So far, I've learned that the manufacturer deliberately keeps the output on these stoves low as they are used inside or outside,close to the camper. Ok, makes sense. As I never use the stove indoors, it wouldn't be big deal for me,  not mount it on the outside, but rather set it on a table close to the camper. (I presently place a glass cutting board between the stove and the camper to deflect excessive heat and it has worked well for the last 2 years.) I'd still like to tweak the orifice a little (replace or slightly oversize it) if you think it will increase BTU output.
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Post by: AustinBoston on Dec 16, 2009, 04:46 PM
Quote from: flyfisherman;213470Again ... no doubt a more efficient burner/orifice/jet assembly on a stove receiving "X" amount of fuel will out perform an inferior design receiving the same amount of fuel.

This is totally and utterly irrelvant to the point.  At 11" water column, you can deliver 50,000 BTUs.  It's not about efficiency.

QuoteHowever, a pound or a gallon of propane only contains so much energy (BTU's if you will) and if you deliver say one quarter of that amount in one hour vs half

And this has to do with PSI how?

QuoteAs for your single burner stove, it's regulator was located right where you screwed in the disposable tank and only allowed so much fuel to come out of the tank and be consumed.  In other words, it restricted the psi just as a propane regulator does on the camper.

Misuse of the term "regulator."  W/R/T propane, a regulator sets the pressure, not the rate of flow.  This stove did not regulate pressure, only the size of the opening through which propane could flow.

QuoteLike the water hose with 45 psi, barely crack the valve and only so much water comes out...

OK so far...

Quote...at a lower pressure.

Analogy FAIL.  You are comparing a valve to a regulator.  Different animals entirely.

1) The hose will build to 45 PSI if the nozzle is all the way off, no matter how little the valve is turned on.  The propane line will not exceed 11" WC, even with everything off.

2) The hose will drop to near zero pressure when the nozzle is turned all the way on.  The propane line will remain at 11" WC unless there is a catastrophic failure (i.e. major leak).

3) If the hose has a "Y" in it with two devices connected, turning one of the devices on and off will affect the amount of water going to the other device, because the pressure will fall when the device is on, and rise when it is off.  This does not happen with a propane regulator.  The regulator will allow more gas to flow when there is more demand in order to maintain the 11" W.C.

A valve (faucet) linits flow rate.  A regulator (below a certain flow rate) does not.  You will hit the tanks OPD leak limit before hitting that limit with an 11" W.C. regulator.  You would hit the very same limit if the regulator were for 10 or 15 PSI (220 or 330" W.C.).

QuoteOpen the valve fully and it comes out gang busters. In other words, it delivers more water. Yes, we can stick an adjustable nozzle on the end of the hose and do all kinds of things with it, but we need pressure to deliver optimum supply.

And indoors, 11" WC is optimum pressure.

Austin
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Post by: AustinBoston on Dec 16, 2009, 05:03 PM
Quote from: flyfisherman;213471Ther are other factors involved in your bakery example. Like my Suburban cook stove in the camper, it was designed to operate (max) at a certain level. As already posted, no doubt it can be bumped up in performance but that would be contrary to what it was designed for. But no way, under the sun, will it ever operate on the scale of the Coleman camp stove, with only 11" WC pressure. Impossible.

Now, my Coleman camp stove uses 10 psi ... you keep saying 15 (unless you know more than Coleman?) ~ it has a regulator on it to ensure the burners will receive that max amount ... and obviously that 10 psi can be regulated further by the burner valve. But the fact is that stove, as presently designed, can only deliver so much heat (BTU's). Maybe someone real knowledgeable could boost it a tad with bigger jets as it is presently set-up. And here's the point ... in order to achieve a higher BTU level, assuming one where to have the proper burner/orifice set-up, would be to increase the supply of fuel and with propane that would be a higher psi.

Please, please, tell me why my furnace, three burners of my inside stove, and my hot water heater can all run off the same regulator and not have their BTU output affected?  Does your stove put out 30,000 BTU's like the combined output of my three devices (all running off the same regulator)?

I'd bet an oven in a large bakery, running at 11" W.C., could put out 100,000 BTUs.  Could your stove do that?

You clearly have no idea how this stuff works.

Austin
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Post by: flyfisherman on Dec 16, 2009, 07:02 PM
Quote from: AustinBoston;213476This is totally and utterly irrelvant to the point.  At 11" water column, you can deliver 50,000 BTUs.  It's not about efficiency.



And this has to do with PSI how?



Misuse of the term "regulator."  W/R/T propane, a regulator sets the pressure, not the rate of flow.  This stove did not regulate pressure, only the size of the opening through which propane could flow.



OK so far...



Analogy FAIL.  You are comparing a valve to a regulator.  Different animals entirely.

1) The hose will build to 45 PSI if the nozzle is all the way off, no matter how little the valve is turned on.  The propane line will not exceed 11" WC, even with everything off.

2) The hose will drop to near zero pressure when the nozzle is turned all the way on.  The propane line will remain at 11" WC unless there is a catastrophic failure (i.e. major leak).

3) If the hose has a "Y" in it with two devices connected, turning one of the devices on and off will affect the amount of water going to the other device, because the pressure will fall when the device is on, and rise when it is off.  This does not happen with a propane regulator.  The regulator will allow more gas to flow when there is more demand in order to maintain the 11" W.C.

A valve (faucet) linits flow rate.  A regulator (below a certain flow rate) does not.  You will hit the tanks OPD leak limit before hitting that limit with an 11" W.C. regulator.  You would hit the very same limit if the regulator were for 10 or 15 PSI (220 or 330" W.C.).



And indoors, 11" WC is optimum pressure.

Austin


What we are discussing here is a small volume regulated propane system for an RV and the appliance efficiency (i.e., cooking stoves) operating on 11' WC pressure.
We are not talking a large bakery with maybe a 3" incoming supply line and with volumes and volumes of fuel source, like maybe enough to perhaps heat a city. An entirely different animal.
I've laid out how the system works and have answered your baiting questions in about as simple terms as I know how.
But I'm not about to indulge in any of your well known, AustinBostin, pseudo intellectual, put down, question and answer nonsense.

Comprende?
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Post by: flyfisherman on Dec 16, 2009, 07:10 PM
Quote from: AustinBoston;213477Please, please, tell me why my furnace, three burners of my inside stove, and my hot water heater can all run off the same regulator and not have their BTU output affected?  Does your stove put out 30,000 BTU's like the combined output of my three devices (all running off the same regulator)?

I'd bet an oven in a large bakery, running at 11" W.C., could put out 100,000 BTUs.  Could your stove do that?

You clearly have no idea how this stuff works.

Austin



Your three burner stove and water heater all work off the same regulator with the same line pressure and appliance performance because the regulator is doing exactly what it was designed to do.

Again, we're not talking about a bakery, the topic is popup campers.

I may very well have limited knowledge on how things work (especially bakeries), but I do understand how my popup camper propane system works; and that's got to be more than you know.
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Post by: JohnandLeann on Dec 16, 2009, 09:34 PM
Find the orface that regulates the flow of fuel into your stove.  It will be inline probably after the connection where the supply hose connects to the cook top.  It will have a very small hole in it to reduce the fuel flow.

If you don't have some, get some small pin drill bits.  I got mine at harbor freight.  Find out which of the small drill bits from this kit fit the very small opening.
When you find which one goes through the orface without much resistance, go to the next size bigger pin drill bit.  Do this with your hand only and not with a drill or any thing else.
I would not recommend going more than 2 or 3 sizes bigger than "stock".
Try each "adjustment" after you have done this and see what if any improvement has occurred.

Remember to think safety here and have a fire extinguisher at the ready if needed.
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Post by: coach on Dec 17, 2009, 09:22 AM
A mole of propane has the same BTU available no matter what pressure or state.

My Coleman stove regulator is set at 15 psig, written right on the lid/wind guard.
Coleman/Fleetwood/FTCA PU use a 16 psig regulator for the outside stove high pressure stove which at on time was a Coleman 2 burner stove and later changed to an Atwood.

Many a stove top have an internal regulator set at 10" wc.

Coleman? 15 PSI Regulator (//%22http://www.shopwiki.com/_Coleman%C2%AE+15+PSI+Regulator?o=14844439&s=153172&%22)

So I'm filling my pool with a garden hose. Then I put my finger partly over the end of the hose cuz some one suggest higher pressure would fill faster. The water shoots out farther, the pressure in the hose goes up but the pool don't fill as fast as when the hose had lower pressure.
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Post by: coach on Dec 17, 2009, 10:33 AM
Coleman warning sticker and close up - preset to 15 psi.

(http://inlinethumb10.webshots.com/44617/2466998660105984492S200x200Q85.jpg) (http://outdoors.webshots.com/photo/2466998660105984492SrVyeN)


(http://inlinethumb58.webshots.com/6905/2998083020105984492S600x600Q85.jpg) (http://outdoors.webshots.com/photo/2998083020105984492bzHQhA)

Same sticker on the PowerPack™ 1-Burner Propane Stove 7,500 BTU max (//%22http://www.coleman.com/coleman/colemancom/detail.asp?product_id=5453A700&categoryid=2010&brand=%22).
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Post by: AustinBoston on Dec 17, 2009, 01:25 PM
Quote from: flyfisherman;213479I may very well have limited knowledge on how things work (especially bakeries), but I do understand how my popup camper propane system works; and that's got to be more than you know.

The fact of the matter is, you claimed pop-up stove BTU rate is the result of low pressure.  When someone else pointed out that you were wrong, you tried to defend yourself with a an analogy that just doesn't compare.

Several people (not just me) have tried to point the truth out to you.  They all agree with me.  But for some reason you think I'm the one who doesn't know how it works?

Have a nice day.

Austin
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Post by: oreo57 on Dec 17, 2009, 02:18 PM
Remember, theres a BIG differance in what you 2 are talikng about. ones talking pressure and one volume, and the regulator is designed to keep a consistant volume regardless of the pressure to the stove,heater or whatever it may be or btu rating, thats why its called a regulator.
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Post by: coach on Dec 17, 2009, 03:25 PM
Quote from: Wingdreamer;213473Wow, we're getting some great discussion on this topic, thanks! So far, I've learned that the manufacturer deliberately keeps the output on these stoves low as they are used inside or outside,close to the camper. Ok, makes sense. As I never use the stove indoors, it wouldn't be big deal for me,  not mount it on the outside, but rather set it on a table close to the camper. (I presently place a glass cutting board between the stove and the camper to deflect excessive heat and it has worked well for the last 2 years.) I'd still like to tweak the orifice a little (replace or slightly oversize it) if you think it will increase BTU output.

Knowing the risks, I suggest you find numbered drill set.
The numbering seems backwards.

I'm guessing your control valves have hole through them (might find a disc orifice). Find the drill that fits the hole ( a 65 or so). See PROPANE ORIFICE CAPACITY 11 INCH WATER COLUMN, scroll to see. Drill away, a tad larger and pray! There is a limit of how much bigger you can go and still have a blue flame. One burner may use a different size than the other as they may not be rated the same. I disavoy any knowledge of this!

When the wind blows from the PU's side it blows much of the energy toward the PU.

Is it worth the risk?



BASIC CONCEPTS FOR LP GAS REGULATORS
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Post by: coach on Dec 17, 2009, 03:46 PM
The propane supply tubing in an RV is designed to carry the entire load of all appliances on high with only a 0.5" drop in pressure.

The green ACME  (//%22http://store.uhaul.com/Propane__Grilling/Propane_parts_and_accessories/Propane_Acme_Nut_(Green)%22)is rated to 200,000 BTU capacity.
Model 299 Marshal integral two-stage regulator has an 160,000 BTU/hr capacity. Both in excess of a PUs requirement.
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Post by: hoppy on Dec 19, 2009, 11:17 AM
Quote from: Wingdreamer;213473As I never use the stove indoors, it wouldn't be big deal for me,  not mount it on the outside, but rather set it on a table close to the camper...... I'd still like to tweak the orifice a little (replace or slightly oversize it) if you think it will increase BTU output.

 The only problem I see with this senerio is if or when you lend the PU to a friend or family, or you decide to sell the PU to some unsuspecting soul, the unsafe condition will not be known by these individuals, since that stove will be stored inside the PU during transit or sale. This is all dependent on your memory to inform all parties of this modification. You may also need to de-mod this in the event of a possible sale in the future.

 IMHO, Me thinks just purchasing an outside stove is the way to go for efficiency and safety in the long run. (Esp. if you have CRS syndrome like me)