high altitude oven oriface

Hi Craig,

Not enough information!

What kind of oven? Industrial? Domestic? Gas-fired? Electric?

Does the manufacturer explicitly declare the altitude range in which it will operate?

What are you using it for?

How would we even know what the warranty is, let alone if you voided it, if we don't know the Make and Model?

If you answer these questions, maybe we can help.

Mike

Hi Mike, Sorry for not getting back to you sooner, but.........Just to refresh, domestic range /oven installed at 8'000 ft., 1000 BTU rated Nat gas at 7" w.c., oven burner 13,000 BTU . after 1 yr it was tested using a combustion analyzer. On start up the CO reading was 750 PPM, then after 15 Min's. it dropped to 450 PPM. At that point, precise calculations were done and the orifice taken out and modified. the range/oven operating and conversion instructions say that it will operate (no efficiency numbers) up to 2,000' ft. then must be de-rated for altitudes above 2,000'. instructions were followed for conversion from Nat to LP. But there were none about HOW to re-rate for 8,000'. called around to the manufacture,installer,gas co., no luck, all said it's fine. After the modification, the oven was tested again under the same parameters. First 15 mim. 240 PPM, then DOWN to 7 PPM............Re tested the unit, calibrated the equip., and tested again, same/same. At this point we thought since the oven burner had to be taken out to unscrew the hood orifice, and modified and reinstalled, and no place in the book or manufactures specs. (fax & phone calls) did it say this could be done, that it may have voided the warranties which came with it. The installation and the modification were done by a Colo. master plumber. do you think that all gas appliances are putting out way too much CO over 2,000'?. Mine is putting out 7 PPM , takes a bit longer to get to temp. But cooks the food much better. How can this be?

Wow! That's an impressive improvement! I'd think your local Air Pollution Control District would be interested, and should verify your tests. If their results agree with yours, they ought to encourage others in your locale to do the same modifications, and might even have enough clout to force manufacturers and/or distributors to publish appropriate data.

"have enough clout to force manufactures and distributes to publish APPROPRIATE DATA", just like they used to. C O is very, very bad for those who breathe

hi I am wondering if you mean your plumber has reduced the size of the jet (injector), to compensate for the lower oxygen content at this altitude to get a better combustion reading.(assuming gas oven) this would lower the gas rate to the oven and make it slower to heat up, but dont know if this would affect any warrentee, please give some more info

Hi Pete. Good first post! Welcome to CR4!

Dick

hi and thank you Dick

Hi yes my old plumber re rated the hood oriface, and it does take longer to heat up, but is working so perfect. CO at 4-5 PPM. He said in the old days the gas co. used to re rate all the time by the book. they could tell you exactly what size the hole should be at altitude (8'000') and 10" l p gas. Why did they stop doing this?????. They protected peoples health and safety. Is there any new ranges out there that are redesigned to optimum spec's? Thank you for responding. craig

Yes. But the "book" does not tell how to do this. very old timers used to get the exact size from the appliance company. (30 yrs ago) The other way to do this is brain surgery, and young plumbers have not been taught, and the appliance company (sears etc.) have an extra charge for a Nat to LP conversion kit with instructions. Nothing available for high altitude conversions.

The inspectors and the gas company should (and used to) inspect the efficiency of the flame before certifying the home for C O (Cirtificate of Occupancy or Carbon Monoxide, take your pick).

The two ways to adapt a burner to high altitude, are smaller orifices or lower manifold pressure. With out proper information both are a shot in the dark.

Some manufacturers do offer a high altitude kit for there product. Start with them.

on Nat gas, lower press. is not an option, exact math is.

I have found not one manufacturer of range/oven that will tell me exactly how to re rate the oven burner to 8,000' L P. They all say "use a 1/2" open end wrench and crank down the hood orifice ,but do not over tighten it, change the regulator to lp and thats it. Not one will tell me exactly how to lower CO output at 8,000'........