Gas Range Smells and Smokes

[dhodson2004]

Hello. I have a Kenmore gas range, model # 790.78511400. I got it new almost two years ago. The burners would blacken pots and pans. I changed the orifices with smaller ones that came extra with the range. They don't blacken pans anymore, but it takes a lot longer to boil water. I cannot use the oven part without having to turn the exhaust hood on. It has always smelled real bad. Not like propane, but it will burn your nose. There is always smoke coming out of the rear vent. There is nothing to burn like splattered food inside. There is a THICK layer of black buildup on the inside of the oven after a couple uses. Someone told me that it could be setup for natural gas. I don't know what the problem is. I figured I'd see if anyone could help before I have it serviced. I'd hate to pay for a fix that I could have done myself. Thanks!!

-Dan

[Dan O.]

Call a *licensed* gas appliance service technician!

Kenmore gas range, model # 790.78511400. I got it new almost two years ago. The burners would blacken pots and pans.

And it is running on natural gas now or propane?? Has it always been??

It sounds like you may be running it on propane but haven't set it up properly to do so. That can be very dangerous!

I changed the orifices with smaller ones that came extra with the range.

Those are to convert the range to run on propane but there's more that needs to be done as well. Did you read the instructions which should have been packaged with the propane orifices or the range's installation instructions??

it takes a lot longer to boil water.

Yes, running on propane will not generate as much heat and thus take longer to cook. The heat output may be reduced by as much as 20% when running on propane.

I cannot use the oven part without having to turn the exhaust hood on.

Than I would assume no one had bothered to set up the oven for propane either.

Someone told me that it could be setup for natural gas.

Almost all ranges these days leave the factory set for natural gas. They have to be properly converted to run on propane.

I figured I'd see if anyone could help before I have it serviced. I'd hate to pay for a fix that I could have done myself.

If you don't know what you're doing, call a professional. Incorrectly set up gas granges can give off carbon monoxide which is poisonous!!!

JMO

Dan O.
www.Appliance411.com
The Appliance Information Site
=D~~~~~~

[dhodson2004]

Thanks Dan O. Would I be better off calling my propane company or sears for the service? What would they do to convert it to propane? Any idea of what they might charge? Thanks again.

[Dan O.]

Would I be better off calling my propane company or sears for the service?

Either one could probably do it as well as any other *licensed* gas appliance service technician. That range was actually manufactured for Sears by Frigidaire so one of their *factory service* depots would likely be a good choice as well.

What would they do to convert it to propane?

Whatever the conversion instructions say. Usually change the orifices, screw down the orifice hoods(s), switch the regulator, adjust the air shutters.

Any idea of what they might charge?

I have no idea of the going rate for home service wherever you are. Call and ask for a rough estimate.

JMO

Dan O.
www.Appliance411.com
The Appliance Information Site
=D~~~~~~

[dhodson2004]

Thanks. I found a site with directions to convert it. Followed the pictures that are included on the page. The only thing I did not do was switch the thermostat from N to L. I couldn't locate it. I'll call Sears tomorrow to find out where it is located.

[Dan O.]

I found a site with directions to convert it. The only thing I did not do was switch the thermostat from N to L. I couldn't locate it.

You mean you just found some range conversion instructions.

Different ranges get converted differently. If the instructions were not for your specific model, not all things mentioned may be applicable to yours.

JFYI

Dan O.
www.Appliance411.com
The Appliance Information Site
=D~~~~~~

[HayZee518]

propane ranges have a larger orifice hole in them - the air to propane ratio needs to be adjusted so the flame has blue tips no orange - the inner flame is a deeper blue glow. all ranges give off carbon monoxide.

[dhodson2004]

You mean you just found some range conversion instructions.

Different ranges get converted differently. If the instructions were not for your specific model, not all things mentioned may be applicable to yours.

JFYI

Dan O.

Sears sucks when it comes to owner's manuals. It also helps if they include the PROPER conversion directions. I cannot find any directions for converting this particular range. So it was on to gas range conversion manuals. If Sears was at all concerned about their ranges being properly converted, they would supply the materials.

[dhodson2004]

propane ranges have a larger orifice hole in them - the air to propane ratio needs to be adjusted so the flame has blue tips no orange - the inner flame is a deeper blue glow. all ranges give off carbon monoxide.

I have adjusted the burners so that they are now blue, no orange. I don't think that the oven is supposed to normally give off excessive CO. Improper combustion as I have experienced, has left a nice layer fo black soot all throughout the range. The layer is about 1/8" thick. The level of CO this range gives off is nowhere near normal. The smell from a gas range is not supposed to be smelled throughout the house and eye/nose burning! I should have kept my old oven. Sure, it was around 30 yrs old, the door didn't quite shut, the oven temp was off, and the occasional relighting the pilots. I could live with that. Not a $600 stove that should have been thrown from a moving truck back into the Sears parking lot.

[JCA1]

This is a little late I guess, but anyway.

The conversion process from natural to LP involves a few things. The appliance regulator has to be changed over first cause lp runs on higher pressures than natural because of it's settling tendencies, where as natural just floats up into place, propane has to be pushed harder. Because of this and other characteristic differences the orifices have to be changed. The Lp orifices will be smaller than the natural. Orifices come in many styles, some have spud type orifices that must be changed or respuded, and some have adjustable orifices. This is most commonly seen in ovens and broilers. If these orifices are not changed/adjusted then you will have way way way more gas than needed. Usually fire can be seen blowing up into the oven by the side vents in the bottom drip pan. Because there is so much gas there is no way to get enough air to complete the burn, so a yellow nasty flame is produced which produces soot and a lot of it, CO, as well as other nasty poisonious gasses. Then if everything but the regulator is changed you get the opposite, not enough gas and too much air which still leads to an incomplete burn which puts off the same gasses but not the soot, as well as a lazy flame. If you ever buy another gas appliance read the instructions! If a conersion kit is included with the range the owners manual will have conversion steps included, if the kit is not included the manual will tell you to get one which will include instructions for installation. Honestly your range is probably close to ruined now from all the soot damage and if not, it's in desperate need of a thourough cleaning which is almost impossible in todays ranges.