Where did the propane go?

[stppinz]

So the family went out on a great long weekend a while ago. It was cold at night so we used the furnace each night. The last night the furnace quit, kind of expectantly because we used so much propane through out the week. We get home and I don't get to fill the propane back up until we go back out about a month later. I go to fill up the propane tank and was expecting at least 10 gallons or so....the guy could only get 2.5 gallons to go in my tank.

I am a bit confused. Everything is working, fridge, furnace, stove range....Could there be a blockage in the propane system? I am at a loss. Haven't had time to really trouble shoot but I don't really know where to start other than evacuating all the propane and trying to fill it again.

Again, Any ideas would be great.

Thanks 

 

[Ray D]

When I'm looking for "how much propane do I really have," I use my laser, remote thermometer, to check the side of the tank for a fluid level. It is determined by a sudden change in temperature. The height of the change determines the level of the fluid, inside. Kind of a lie detector for tanks with liquid in them.

Ray D

 

[Larry N.]

When I'm looking for "how much propane do I really have," I use my laser, remote thermometer, to check the side of the tank for a fluid level. It is determined by a sudden change in temperature. The height of the change determines the level of the fluid, inside. Kind of a lie detector for tanks with liquid in them.

Ray D

I presume you mean infrared, rather than laser?

 

[wannabfree]

from RAY D ," I use my laser, remote thermometer, to check the side of the tank for a fluid level. "

What an Excellent idea!  Thank You

Dave

 

[John From Detroit]

You said the furnace quit: Were you on shore power or batteries only?

The furnace contains something called a Sail switch.. this switch has a plastic paddle (Sail) on it, as "Wind" blows on the sail it closes the switch.

When the thermostat calls for heat the blower starts, the "Wind" from the blower is what blows on the sail

If the batteires are low and either there is no shore power, the converter's breaker is tripped or off, or the converter has failed... There won't be enugh wind to close the switch.

When the switch closes.. the furnace passes gas to the burner and sets it to burning.

 

[Ray D]

I presume you mean infrared, rather than laser?

Thanks, Inuss.

Senior moment. Gets worse as time passes.  :-[  It's an infrared remote thermometer with a laser dot aiming assist. The dot tells me the location where the temp is being measured.

Ray D 

 

[Gary RV_Wizard]

Several questions come to mind...

1.What size is the LP tank? How much does it hold when full? Either pounds or gallons.
2.Why do you think the furnace ran out of LP, if everything still works on LP gas (stove, etc.)?
3.Were you running on battery at the time (John's question about the sail switch)?
4. How many hours did the furnace actually run?

 

[John From Detroit]

Thanks, Inuss.

Senior moment. Gets worse as time passes.  :-[  It's an infrared remote thermometer with a laser dot aiming assist. The dot tells me the location where the temp is being measured.

Ray D 

I'm going to help you out here a bit Ray

THe IR pyrometer has a LASER spotting diode, you turn on the light and scan the tank, when the temp changes drastically the red dot of the laser is the liquid/gas interface on the tank.

So the thermometer is Infra Red

But it's the LASER that tells you how full the tank is.

 

[Ray D]

Thanks, John. I feel better now. 

 

[DearMissMermaid]

Where do I get one of those newfangled laser infrared temperature things?  Will it work on poop tanks too? 

My poop tank and propane tank always read full on the inside gages. So basically, I dump every month or whenever I come across a hookup or dump station, I fill up the propane randomly, like when I see a big propane place and I can actually stop and turn to get in the place.

So far the poop hasn't overflowed and the propane hasn't run out. But a more serious approach would be handy, I guess.

Occasionally I've filled the propane at campgrounds, but the prices seem double to triple what a regular propane place charges, so I learned my lesson on that one. 

By the way, a mattress warmer does wonders for a motorhome in cold weather. 
http://tiny.cc/rrwrv

 

[Ray D]

DearMissMermaid, I got mine at an auto parts store. Don't remember which one. Yes, they work on poop tanks and gray tanks, too. Also work on tires and wheels and whatever else you'd like to know the temperature of. Very handy.

 

[Jammer]

There are only two foolproof ways to figure out how much propane is in the tank:

1) Look at the float gauge, if the tank has one.
2) Take the tank off and weigh it.

In general you can't add a float gauge to an existing tank, but you can buy a new tank that has a float gauge.  They're several hundred bucks but over the lifetime of the tank that's a lot of hassle and running out of gas that it saves.

Many reasons a furnace might shut off and without more information, it's hard to guess.

 

[powderman]

If you have 2 tanks, you can only read the level on the  one you are drawing from with the temperature gauge,  as the liquid only cools when it is being consumed.
I like to use the gauge to keep tab on the tire temperature.  However if you pick up something from the road like I did, you will only know it when you hear the explosion unless you have a tpms system which I am getting soon. 

 

[700renegade]

saying "the temp changes drastically" may be a bit misleading.  I haven't tested a tank this way with my IR thermometer, but I'd be startled if the temp changes by more than 5 degrees F at the liquid/vapor line.  I doubt a typical RV appliance would pull enough flow to measure the effect of vaporization, unless you are using a really small tank like a 20#.

If the top of the tank is warmer than the bottom, you are NOT measuring the effect of fuel vaporization - you are measuring the effect that the whole tank cooled down overnight ( say 50* ), and the steel skin above the liquid line can heat up to ambient temp ( say 75* ) by mid morning easier, as it is not in direct contact with the cool liquid LP.  Since steel is a pretty good heat conductor the transition between cool and warm will be a few inches wide.

Since polyethylene is a bit of an insulator, my guess is you could not get a reliable reading on grey or black tank levels that would make it worth buying a $30 or $100 IR gun.  No disagreements on their use for tire temps and they are generally a fun widget to have around if you are the inquiring type.

 

[tennsmith]

Well stppinz, it appears your thread has been hijacked by the metrology group.   If other things that use propane like the stove top or the refrigerator in the gas mode, then your problem is likely one associated with the furnace, not the propane supply.  However, if all LP appliances are inoperative, then I'd suspect you have a problem with your regulator.

Having said that and keying off John's sail switch theory, maybe your batteries became too low to operate the furnace fan, thus failing to activate the sail switch.  Then, on the drive home, your batteries were recharged by the engine alternator, and after filling the tank albeit only 2.5 gallons, everything worked again!  If you were plugged into shore power, this is NOT the problem unless you have a bad converter and then things like lights wouldn't work and you would certainly notice that.

I don't think anything would be gained by emptying the tank and refilling it other than losing money.    You did not address whether or not your LP tank indicator said it was EMPTY when the furnace quit.  If it indicated empty and it took only 2.5 gall to fill, then I am truly baffled.  However, if it indicated 5/8 to 3/4 full, then it sounds like the tank and associated indicators are working properly.  That morning when the furnace had quit working, did you try other propane appliances?  Did they work?

The vibration associated with driving home could have fixed a lot of gremlins.  Stuck regulator on the LP tank, poor contact in the furnace thermostat, loose connection somewhere in the electrics.  You may have to just go RVing again, prepared to do some troubleshooting in order to find the problem.

 

[Gary RV_Wizard]

Thanks for getting this thread back on topic, bob.