Conversion from natural gas to propane

[sambolina20]

Hi just wondered if anyone can chime in on this, I recently purchased a Tappan gas stove roughly 1948-1953 not sure of its age, I had to convert it to propane, I had the propane company that brought the tank help me find all the offices and air shutters and we got it adjusted and the burners are spot on, but the oven is burning at 450 degrees on low, and VERY intense gas smell. Of course this was realized after the service man had left, so I shut the gas off. It was bad enough that my carbon monoxide alarms were triggered. The regulator inside the stove had been removed, I'm wondering if that would make the propane smell go away if I hook one up, or if I've got a bigger problem on my hands. We called around and the one applIance store owner who said he was very knowledgable on older Tappan stoves said I didn't need a regulator. Thoughts?

 

[kenmore71]

You shouldn't need a regulator to use it on propane. If it's running that hot i would suspect a thermostat issue as opposed to a regulator issue. Is the flame blue with yellow-organge tips?

 

[sambolina20]

Yes, and again the top burners are perfect, the propane service man checked those and the oven. When you start the oven its a big intense blue and orange but after 30 seconds or so it calms down to a very small blue flame

 

[kenmore71]

Do you know if the oven thermostat worked properly when on natural gas?

 

[gizmo]

I have a similar issue (but not as bad) with my 1980s (Australian) Modern Maid Ultima stove.
I love these stoves, we bought a new, middle model one during the clean out when Modern Maid went bust in 1987. Got it for less than half price. Liked it so much that when we moved to the sticks, we bought a used one and converted it to LPG (propane), it worked perfectly.
When building our new home I tracked down a TOL version in 600mm wide (our earlier ones were 540mm) and had it converted to LPG again. This latest one runs a little too hot on the lowest settings and I think I understand why, hopefully the same applies to your stove.

Electric ovens have an "On/Off" thermostat - it turns on till the oven is up to temp, turns off till it has cooled a certain amount, then turns on again.

Gas generally works different (though a few gas ovens work the same way as electric).
Gas ovens don't cycle between on/off - they cycle between high and low. When you first light the oven, it runs on a high flame till it gets close to temperature, then the thermostat gradually lowers the flame till it maintains a constant flame that is just enough to maintain the set temperature. This depends on the low flame being low enough - if the low (minimum)flame is too large, the oven will run hot even if the thermostat is trying to turn it down.
When you convert from Natural Gas to propane, you not only have to change the burner jets, but you also have to either replace or recalibrate the oven thermostat. The "low flame" orifice for Natural gas is larger than the one for LPG, so it's no surprise that it is running hot if the thermostat hasn't been swapped, or its low flame jet replaced. It depends on the particular thermostat in your oven as to whether it can be adjusted (low flame turned down); a low flame orifice replaced; or if the thermostat has to be replaced.

On my stove the low flame is just a tiny bit too high - the old stove could maintain the lowest temp on the dial which is 110 degrees C, the newer stove creeps up to 130 or 140 which is too hot for my annual batch of Christmas puddings.(though strangely it behaved itself last Christmas.)

so if you're very lucky you can turn down the low flame.

the "intense gas smell" worries me - I suspect you might also have a leak. There could be a leak in the pipe from the thermostat dial to the burner, or maybe the oven burner orifice wasn't changed (even the high flame orifice, called the main jet) or not tightened properly, it could be a loose connection.
I wouldn't use the oven till it's fixed.

good luck with it.

 

[sambolina20]

Thanks so much!

Well I found out that I did indeed have a leak or rather leaks! 4 of them inside behind the right door where all the piping is to the burners and the oven, I had the propane company come back and a different service man was able to locate the leaks and tighten the fixtures. Your advice about the thermostat may be what I'll have to investigate next because tonight, on low, the oven is burning again at 350-400. This may require more than I can handle but at least I'll know what to ask about when I locate an appliance store who might be able to help me. Thank you for the advice!

 

[combo52]

Old gas Oven Running Too Hot

These older [ before 1960 ] gas oven thermostats are usually modulating designs and in addition to changing and or adjusting the main burner orifice you must make a bypass flame adjustment on the front of the thermostat control for the oven to work properly, otherwise the temperatures will soar above the set temperature.

 

For the life of me I can not understand why any one would want to cook on propane, it is like cooking on natural gas but twice as bad. It smells worse and costs far more than cooking on electricity and is MUCH more dangerous, especially on an older stove without 100% safety controls on the top burners [ European style ], please be careful. John

 

[gizmo]

"For the life of me I can not understand why any one would want to cook on propane, it is like cooking on natural gas but twice as bad. It smells worse and costs far more than cooking on electricity and is MUCH more dangerous..."

My last stove (apart from gas) was a wood stove - lpg is sure easier than chopping firewood! A decent LPG stove should operate exactly the same as the same model on natural gas. If not, the burners aren't set up right. Often stoves are "designed" for natural gas and when re-jetted for LPG they err on the side of too much gas, which produces an over-rich flame causing sooting of the bottom of the pots. The stoves where I work are like that. My stove at home burns beautifully clean.

I hate electric stoves - too slow to react. The only electric cooking I like is induction, it's my absolute fave. The wood stove is great too, though. Horses for courses.

Electric is not an option for me as I'm not on mains electricity (I'm on solar) and regular electric elements use way too much power. On sunny days I can use my little induction cooker, otherwise I'm happy with gas.

 

[kb0nes]

First off, welcome to AW Sam! Hope you find the answers to your questions here.

I think Chris has hit on a pretty valid reason to use gas. Life off the grid means limited power availability. A bottle of LP equals a lot of watts...

Looking at Sam's profile it states that "His great grandmother had a stove like this". Its clear this stove is being installed where there isn't natural gas or one wouldn't consider the hassles of LP. Because of the great emotional attachment to this specific appliance it appears that Sam has a very valid reason to consider LP. It is good that you are enlisting the help of the LP professionals to get you up and running safely. Hopefully someone can get the thermostat regulation problem of this vintage appliance ironed out for you!

Bottom line is that we can't discount personal preference, we all likes-what-we-likes. For me I dislike gas, unless cooking outdoors. Unless its a commercial range with a big burner there just isn't enough heat. Boiling water takes patience. Years ago I won a bet with a buddy who claimed his gas range would beat my electric in time to boil 6 quarts of water. Even with the slower initial warmup of my electric it still won by better then 8 minutes... It was a quick $20 !!

 

[combo52]

Propane vs induction vs resistance electric surface elements

 Hi Chris  and yes welcome aboard, and I hope I wasn't too hard on your choice of having a propane range. And you do have a reasonable reason for not using electricity for your primary cooking, but I did not consider that you might be one of the 1/10th of 1% of Americans that are living off the electrical grid.

 

Some things to consider about cooking on propane, when 90% of natural gas ranges are converted properly to propane the BTU output is reduced around 20% or so, just look at the specifications for the product.

 

Resistance electric cooking is very little less and in some cases more efficient than Induction and if you can run an induction hot-plate on solar you can run an electric surface element on solar. I am a huge supported of induction and have used as my primary cook-top for over 25 years here at home, but I also have another 7 resistance surface elements that I enjoy cooking on.

 

Another mith [ electric is not responsive ] if your electric coot-top element can't go from a rolling boil to a simmer in about 60 seconds you aren't using it correctly.

 

I would still get a sealed cook-top with 100% safety shutoff if I was going to use propane indoors, I have been in kitchens where the propane fueled cook-top [ non-sealed cook-top ] exploded, propane being heaver than air makes it much more dangerous than natural gas for cooking.

 

Did you find the instructions for adjusting your thermostats by-pass flame? this should be an easy adjustment if you find the instructions or a tech old enough to remember working on pre 1960 gas ranges.

 

[sambolina20]

Still Working on the Oven!

I have not found the instructions on how to adjust the bypass flame on the Thermostat yet, meaning im still looking for a well experienced repair man! As soon as I get this figured out ill be glad to share what the final results are!