Propane question

[joshuabardwell]

I am running a gas range off a 20 lb propane tank. I've got a two stage regulator on the tank and have converted the stove's regulator, orifices, etc... Everything was working fine up until yesterday, when the stove began acting starved for fuel. The burners have small flames. The oven looks like only one side of the burner is on. Most tellingly, if I turn on a top burner and then turn on the oven, the top burner shrinks near to nothing.

When I was first testing this setup, I ran the stove on a nearly empty tank to ensure that the pressure would be adequate. It worked fine. The tanks I'm using are both full. Same issue on both tanks. The only thing I can think of that's changed is it was a little colder last night than the night before, and all my testing was done in the summer. Would a ten degree difference in ambient temperature make enough difference in the tanks' vapor pressure to cause this effect? The only other thing I can think is that the regulator or stove has malfunctioned, but that really seems unlikely. Nothing else changed between when it was working last night and now.

I really want to figure this out if possible. I have a bunch of people to cook for tomorrow. I limped through tonight, but it was slow and the oven didn't get hot enough to cook the food like it really should.

 

[SPIKER]

COLD will cause this as the propane liquid can not turn into vapor fast enough to maintain the pressure without freezing up. The regulators and lines and openings will form solid crystals if there is not enough area above the liquid to dissipate the cold when the tank/liquid is already cold from lower temps. heating the tanks up can help but would suggest a 30 or 100 lb tank for regular house size stove. Most BBQ's have the tank rather close to a lot of the heat so that helps, very short hoses and the like topped with cookign outside in heat (usually.)


Mark

 

[mikehaugen]

COLD will cause this as the propane liquid can not turn into vapor fast enough to maintain the pressure without freezing up. The regulators and lines and openings will form solid crystals if there is not enough area above the liquid to dissipate the cold when the tank/liquid is already cold from lower temps. heating the tanks up can help but would suggest a 30 or 100 lb tank for regular house size stove. Most BBQ's have the tank rather close to a lot of the heat so that helps, very short hoses and the like topped with cookign outside in heat (usually.)

Mark

Would 10º be enough to cause this?

I would think it could also be your tanks maybe? Some tanks will shut off if the gas flows too fast, maybe some have flow limiters on them. Just a guess.

BTW... where have you been? I haven't seen any posts from you in a while.

 

[mrmikey]

Some tanks will shut off if the gas flows too fast, maybe some have flow limiters on them

I was thinking that also, might be a combination of the temp and the tank freezing up and it was just working at it's max before the temp drop. If it is the flow check in the nipple, you can drill it out, I just did to use a 20lb on my cutting torch using an acetylene regulator.
I unscrewed the acetylene nipple from the regulator and used the nipple from an old barbecue, they're both 1/4" npt. Couldn't get a thing thru the regulator as there was too much flow until I removed the check by drilling out 3/16", from the nipple......Mike

 

[IXLR8]

I run a 5 burner cooktop off a 20 propane tank outside, no issues down to -10dF. Not sure if it would handle an oven as well though. I have had issues with the regulator at the cooktop sticking closed. I have had to remove the cover from the valve so I could push on it to unstick it. It does seem to stick more when the bottle pressure is getting low.

 

[joshuabardwell]

A little more information, guys: tried opening the valve slowly and no difference. Ambient temp is only 50 degrees, so I'd be surprised if temperature was the issue. The oven burner is rated for 16,000 BTU. Seems like it should really be working.

 

[joshuabardwell]

I run a 5 burner cooktop off a 20 propane tank outside, no issues down to -10dF. Not sure if it would handle an oven as well though. I have had issues with the regulator at the cooktop sticking closed. I have had to remove the cover from the valve so I could push on it to unstick it. It does seem to stick more when the bottle pressure is getting low.

Do you mean then cap that you flip to convert the regulator from natural gas to propane and vice versa? With the spring and diaphragm under it?

 

[jinman]

I would think it could also be your tanks maybe? Some tanks will shut off if the gas flows too fast, maybe some have flow limiters on them. Just a guess.

That's my guess. The tanks flow limiter is closing down the flow. Most bbq tanks have a regulator very close to the tank. An oven probably has a regulator very far from the tank. When the valve is cracked open, the tank valve senses too much flow and shuts down. I would try a double open procedure. Open-close-slowly open to see if the 2nd time around didn't do the trick. I had that happen to me before I knew about it and was super frustrated to have a full tank and hardly be able to cook four burgers. I was ready to throw that grill off the cliff before I discovered the tank valve was shutting down.

 

[charlz]

I have had something similar. I had to close the tank valve, disconnect what I had attached to it, reattach and open the valve. I believe part of the design on the new tank valves is something has to be attached before it will open. If not seated correctly it won't open or open fully. I know horizontal tanks are exempt, 100lb tanks might be exempt from the new valves as well. If this happens now and then it might be worth a tank upgrade just to avoid it.

 

[user.69169]

You got the triangle valve blues going for yourself there.
The new propane tanks with the triangle valve handle only let out so much propane per minute, some government genius design made for a fool reason.
Lot of people with the turkey cooker burners find out about them new tanks with the built in limiter every year and give up turkey frying.
Them dang triangle valves on everything short of 100 pound tanks now.
Might too have you case of undersize propane hose. The gas at very low pressure after leaving the regulator, and the hose has plenty of friction to add to the problem.

Far as temperature concerned, you need to get down to about 10 degrees to notice any lack of boil in the tank.