Propane Stopped Flowing

jakenjulie · 10-18-2010, 09:54 AM

Hi guys,

We're in Northern MT and last night we had 23F. Sometime in the middle of the night I noticed the furnace was making a whistling sound. It was about five seconds long repeated about every ten seconds. Shortly after that it stopped putting out heat. I tried the stove-top burners and they would barely light and then go out. So I went out and switched the tanks (BTW, the tank that had been in use had frost on the bottom half which tells me it was still about half full) with no result. I started reading forums and saw that some have been able to restart their flow by pouring water on the regulator which I did and was able to get the furnace going again.

My questions are: What made the whistling sound and what is causing the regulator to freeze up? Why did it not freeze up before now? We have had similar temps the last few nights.

Thanks,

NWJeeper · 10-18-2010, 10:11 AM

I can only assume that it's latent moisture in the propane that causes it to freeze up and usually it does so at higher flow rates like the furnace will use because the propane is flowing through at such a high rate. The faster it flows the colder the propane will cause the regulator to be. I think also it has a bit more to do with the humidity rate than the temperature as I have experienced a frozen regulator at ambient air temperatures way higher than freezing. Much like carburator icing in normally aspirated aircraft engines can occur at temps above freezing too.

I would try an insulate the regulator. Pouring the water over it is a quick but temporary way to get the gas flowing but it won't solve the problem. If anyone else has a more permanent fix to this I am sure they will post here and I would love to hear it.

The_Stuff · 10-18-2010, 10:43 AM

heh.. might be why sometimes the flames for stove etc come to a crawl if the furnace has been running..

camprat · 10-18-2010, 04:01 PM

IT like NWJeep said moisture. Now what percent depends on dealer sometimes. I have had freezing @ 40 degree & run fine below freezing. All propane is not the same. Also the lower your tank the more vapor which drops the temp on the regulator. Just about all my freeze up were with half a tank or less.

**KyDan** · 10-19-2010, 06:45 AM

Next time you refill your tanks ask the LP guy to purge them.
It can't hurt.
Good luck!

jimh · 10-25-2010, 10:02 AM

Quote:

Originally Posted by jakenjulie

Hi guys,

We're in Northern MT and last night we had 23F. Sometime in the middle of the night I noticed the furnace was making a whistling sound. It was about five seconds long repeated about every ten seconds. Shortly after that it stopped putting out heat. I tried the stove-top burners and they would barely light and then go out. So I went out and switched the tanks (BTW, the tank that had been in use had frost on the bottom half which tells me it was still about half full) with no result. I started reading forums and saw that some have been able to restart their flow by pouring water on the regulator which I did and was able to get the furnace going again.

My questions are: What made the whistling sound and what is causing the regulator to freeze up? Why did it not freeze up before now? We have had similar temps the last few nights.

Thanks,

if u have an unfrozen area above the liquid in the tank, it sounds like the regulator is the problem. if u are dropping pressure there, it may freeze externally. if pressure is low in trailer, i would suspect the regulator is stuck almost closed. i would replace the regulator.
propane cannot be sold if the moisture content is very high...believe me, it is very very low. the propane may have turned to (propane) ice within the reg but i wouldn't suspect this.
a guess on the whistleing noise would be the propane squeezing thru a almost closed reg.

Bushman512003 · 10-25-2010, 10:48 AM

You may have some southern Propane or Butane it will freeze first think of the cig.lighters people had to hold in hand to warm a little to light same thing winter propane is now getting shipped up in the north I hate to say it but winter on the way right I go south but have My winter propane for the trip down Heat will be needed.I found a full 20lb tank of propane in a dempster last winter some one must have thought the valve was broken but was just frozen I used it up, so have a little luck it will straiten out as it warms up also open the valve very slow as they freeze or are tripped to safety shute off very easy in the cold Good luck

The_Stuff · 10-25-2010, 11:03 AM

Quote:

Originally Posted by Bushman512003

You may have some southern Propane or Butane it will freeze first think of the cig.lighters people had to hold in hand to warm a little to light same thing winter propane is now getting shipped up in the north I hate to say it but winter on the way right I go south but have My winter propane for the trip down Heat will be needed.I found a full 20lb tank of propane in a dempster last winter some one must have thought the valve was broken but was just frozen I used it up, so have a little luck it will straiten out as it warms up also open the valve very slow as they freeze or are tripped to safety shute off very easy in the cold Good luck

I have NEVER heard of such a thing before. Propane's gelling point is -42c.

also lighters are butane, which gell at -0.5C or 32F

jimh · 10-25-2010, 11:36 AM

yep propane is propane C3. at -35f should still be boiling.
my point was that if it stuck once, it could do it again. they aren't that expensive, i'd just replace it.

may be thinking of climitized fuel; diesel is lighter when sold in cold climates. diesel marketed for summer months, can give problems when it gets cold.
i'm not sure abt gasoline, it has a ignition temp down in the -40's F anyway.
propane was one of those things that had a very strict spec year round. the pipelines, that accept propane, do contineous monitoring and will shut a source down until they correct the problem.

Bushman512003 · 10-25-2010, 01:18 PM

I was told that about 10 years ago and think there is some truth to it .Would not think some one would disgard a full bottle would You that?That said is also why I think it is true and where I worked 33 1/2 years used propane fork trucks but the gas was a different mix in summer I still think it was Butane I wonder if Butane was less money to buy.But I care less if You want to beleave Me or not have it Your way I was just thinking I would not change out a thing on some ones say so.My old 2001 Motor Home diafram stuck every winter I would turn the gas on then tapp it with a cut off broom handle and away it would go every year never stopped working again. Till it sat waiting to go south about 2 months the next year.lol I have no reason to tell You a pile of crap but some think it is I was just trying to help.........Bushman

Willis · 10-25-2010, 03:04 PM

Propane must turn to gas from its liquid form to be usable in an RV system. As the liquid turns to gas it forms vapor pressure within the tank. In cold temperatures the conversion process is less efficient. Thus lower than normal vapor pressure will result from either colder temps or lowered levels of liquid propane in the tank. If both of these factors exist the effect will be compounded. This lower pressure contributes to excessive release of water vapor present in the propane which can freeze when it hits the valves or regulator.

jimh · 10-25-2010, 04:12 PM

i would replace the reg more as a safety issue....what if it stuck open. it could put between 50 and 100 lbs pressure on orifaces designed for proper flow at a few oz.
check out MSDS for propane PROPANE MSDS

The_Stuff · 10-25-2010, 11:36 PM

i found out everything from my 88 plymouth voyager thats ex CFB moosejaw's experimental vehicle that was on propane.

camprat · 10-27-2010, 09:37 PM

I have had dealer tell me sometime they have had problem with there load . I have had to call the dealer out for emergency generator set that had freezing regulator. that they change out.

jimh · 10-29-2010, 01:09 PM

more than likely, if the reg stuck open, it would rupture the diaphram, after a short pressure burst. the propane would probably vent to atmos instead of overpressuring the system. i guessing, i would suspect there is some safe guard built it in case of a failure.
i would suspect any freezing to occure on the atmospheric side of the diapharm. there shouldn't be anything in the propane to cause freezing.

if u request a MSDS where ur buying ur propane, it will tell u for sure what ur getting. whoever sells it to u is required to have an MSDS sheet. look for the purity. it should be somewhere around 99% min. If someone is blending it for use as a motor fuel, the % will be disclosed in the MSDS. When it leaves the refinery, it is 99%+ pure.

camprat · 10-29-2010, 08:52 PM

Most of the regulator have a screen in them to keep form damaging the reg, but this where the ice builds up to & can plug up. Like Willis said. I would agree with you about MSDS & 99% pure if this was a perfect world. But we are getting vary % of purity of propane. When I have had my problem was coming out of summer with propane left over & going in to fall winter. Why ? Would be nice if anyone else has had this problem post it.

jimh · 10-30-2010, 07:46 AM

possible explamation for the propane giving more problem with freeze up at a lower level than a full bottle is as the propane evaporates, it reduces the temp of the liquid. the amt of liquid in contact with the tank is less so is unable to keep the liquid warm. the lower the level gets, the colder it gets. the colder the gas entering the reg, the colder the gas after the pressure drop in the reg.
i'm having a problem with water being in the propane. an easy way to see if it is water is (if the outside temp is in the 20's) to shut off the system for abt 30 minutes. propane will evaporate and all will work again. water will remain frozen.
when manufactured, we had strict specs for moisture, purity, and sulfur just to be able to sell it. off spec had to be reprocessed or sold at a reduced price to someone that used it in their process.
i know that if u get a leak in a liquid propane line, it will ice over so the temp can drop quiet a bit in the transformation from liquid to gas.
what happens in the handling of the propane beyond the refinery isn't something i'm firmiliar with. would be equivlent to me saying that gasoline doesn't have water in it leaving the refinery and someone gets a tank full of water at the gas station. both statements can be true.
i can say that propane left us on spec. what it goes thru beyond us i can't say.
i live in the deep south. we don't have that many days where it drops below abt 26 and then it is only for 6 hrs or less. i did use propane at home to dry clothes and never experienced icing of the reg. could be that the volumn of liquid propane didn't get cold enough to cause the extra cooling at the reg.

The_Stuff · 10-30-2010, 12:50 PM

if the regulator is exposed to wind that plays a factor to. try wrapping a towel around it.

jimh · 10-31-2010, 07:07 AM

if this is the reg that switches the tanks, try switching the tanks. the warmer (relatively speaking) propane may solve ur problem.

camprat · 10-31-2010, 08:58 PM

What work sometime is just warm water over regulator & then switch.

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