Propane question

[Allen in MT]

Both of my tanks are full and have been emptied and refilled thru normal use and still my indicator reads about 1/2 to 3/4 red all the time, The indicator will go completely red when empty. I think I need to replace the valve, was told that if they stick might give a shot od wd40 into one port, but not sure of doing that, might be simpler to just replace to be sure
Allen

[MacDR50]

Good primer on propane.

http://www.rvst.org/frames/propanedemoframe.htm

For those who want to know more this is the handbook we use at work.

http://www.fisherregulators.com/lp/pdf/handbk.pdf

From both references you will quickly realize that the temperature of the propane has an effect on it's efficiency. The other factor often overlooked is the propane/air mixture which is usually controlled by an sliding sleeve gate on the mixing tube.

[sreigle]

I don't know about using wd-40. I've never heard that. Maybe someone who knows about that will reply.

It sounds like either there is a restriction in the line to the regulator from the bottles or there may be oil in the regulator. Since it does it on both bottles it's probably not a restriction. You might try disconnecting and removing the regulator and see if any oil runs out. I'm not sure whether you can clean the regulator inside other than draining any oil. Anyone know?

It may also be there's a problem with the regulator itself.

[Charlie]

When I had oil in my regulator I used WD-40 to clean and then blew dry with an air compressor. Repeated it a couple times to make sure all the oil was out.

[Icehouse]

Taking all of the above into account, we are having an issue. Current Conditions: outside temp is about -15, switchover regulator seems to switch tanks properly, but my red/green flag indicator is stuck on red, I have 1 empty tank and 1 almost full tank - both are very icy with crystals. My heater is running and producing some heat (appropriate steam from vent since it is so cold outside, feel some heat from the floor vents. I turn the full tank to OFF. Heater turns off, steam stops. I turn tank back on - heater ignites, steam re-starts, heat flowing in vent. However, the heat coming from the vents is WARM not HOT. I changed to a totally different tank (this tank is cold but not ice crystals) - switchover valve does not change, but heat coming from the vents is now HOT. Any idea why come? I am aware temperature affects propane efficiency but the two tanks should be close in temp. Valves bad or partially plugged? Is this possible? Regulator partially plugged? I would assume we are either flowing propane or not. The variability of the heat has me confused. Suggestions?
Thanks

[SlickWillie]

quote:Originally posted by Icehouse

Taking all of the above into account, we are having an issue. Current Conditions: outside temp is about -15, switchover regulator seems to switch tanks properly, but my red/green flag indicator is stuck on red, I have 1 empty tank and 1 almost full tank - both are very icy with crystals. My heater is running and producing some heat (appropriate steam from vent since it is so cold outside, feel some heat from the floor vents. I turn the full tank to OFF. Heater turns off, steam stops. I turn tank back on - heater ignites, steam re-starts, heat flowing in vent. However, the heat coming from the vents is WARM not HOT. I changed to a totally different tank (this tank is cold but not ice crystals) - switchover valve does not change, but heat coming from the vents is now HOT. Any idea why come? I am aware temperature affects propane efficiency but the two tanks should be close in temp. Valves bad or partially plugged? Is this possible? Regulator partially plugged? I would assume we are either flowing propane or not. The variability of the heat has me confused. Suggestions?
Thanks

I found the regulator on the secondary tank was packed with thread sealant compound. I was getting about half red when on that tank. Cleaned to no avail. I think I will do away with the single stage regulator on that side; at least temporally.

[MacDR50]

Try a hair dryer on the regulator. If it frees look for ice or oil. The temperatures outside can make oil turn into waxy sludge. Ever hunted rabbits in the winter with a pump gun that still had gun oil on the block? Dry as the bone and clean as a whistle are best in cold weather. Methanol can be used to clean oil and is also an antifreeze. So can denatured alcohol and it is less toxic.

[Icehouse]

Thanks for the advice. I have tried the slow open process after filling the tanks. I discovered there is slow and then there is sslllooowwww. I assume because of the cold, but if I take about 60 seconds to slowly open the valve, I can here the propane flow and all is well. My switchover valve also registers correctly and switches well. Never had this issue before, but never tried changing LP tanks at 0 degree before either...

[Katja_and_Michael]

Hi everyone,

This may not be exactly on topic, but we've had some problems with the LP changeover valve - it can say that it's emptying the driver's side tank, and it's actually emptying both tanks. Could this be a faulty valve? This is a replacement that my DH installed a couple of weeks ago, since the original valve was doing the same thing. Has anyone else had this problem and found a way to solve it?

Thank you!

Katja

[racerjoe]

Dennis,I don't know how cold it is where you are right now having this problem, but I have found when at home in a workshop area I have,I use a 100,000 btu propane heater. If I run it on a 30 pound bottle like we use in our trailers,at about 1/2 tank it ices up and pressure drops off and flame gets smaller. What I had to do is go to a larger tank so it would not ice up and lose tank pressure. Is it possible that due to the cold conditions your tank pressure is falling off to fast? i am far from an propane expert but this fixed my heat problems.I have used both a 100 pound tank and now I have set up a 100 gallon tank in a fixed location and use in two buildings.

[MacDR50]

racerjoe:
That is the ticket for propane use in really cold weather. The 100 lb tank has more liquid in contact with the tank sides where it gets the heat necessary to boil off into gas. As temperature drops the amount of gas produced per square inch of surface contact decreases. The solution of choice is to add additional tank capacity.

[richfaa]

You guys will be able to write a new book on "cold weather and its effects on a RV".. I will bet that most if not all of your problems are a result of the effects of extremely cold weather on all systems in your rv.... Have you tried talking to Team Montana about this..they just might have a interest in your experiences and maybe have some cold weather suggestions. I believe they said they tested these things to -20 degrees???

[sreigle]

It should turn green very quickly. If not, there are a few possible problems. One is very low ambient temperatures lowering the pressure. Another is a faulty regulator. However, having just had this same problem and having to diagnose the cause, I found another possibility and this one is what caused ours to do as yours is doing. Ours has, on the off regulator side, a small red regulator. It's purpose is to keep the safety valve in the tank from tripping should you open the tank too quickly. If you open too quickly, the gush of propane going all the way to the other side makes the valve think there is a leak. It thus trips the valve to stop the flow of propane. If this happened to you, close the valve on the tank, let it sit a few minutes, then open it verrrryyyyy slowly.

Back to the red regulator. Ours has been replaced and it again started acting up. This time I just removed it. After all, we used to not have that regulator and learned to open the valve very slowly. I can do so again. In removing the regulator I found the hose does not mate exactly to the pipe where the regulator was screwed in. You have to go to your hardware store and get an adapter. I forgot the exact size, but take the red regulator and get an adapter where the male end mates on one end of the red regulator and the female on the other end of the regulator. Now my normal regulator green flag comes up as it should.

Good luck.

[werhapy]

MacDR50 - great links! For the techies, we can put the numbers together and estimate the heat tape or blanket wattage rating needed to keep the pressure to the first stage regulator reasonable ( say 10-15 PSI requires the liquid propane temperature between -25F and -15F).

The key table is the vaporization rate table that shows that you can only count on 50000 btu/hr from a 100 lb tank at 0F
"For continuous draws, where temperatures may reach 0°F,
assume the vaporization rate of a 100 lb. cylinder to be
approximately 50,000 BTU/HR Therefore the:
Number of cylinders per side = total load in BTU/HR / 50,000"

So with a 35000 btu/hr furnace running full time, the 30 lb tank will not come close to supplying the needed flow without significant propane cooling and even lower vaporization rates.
Putting the numbers together for a 35000 btu/hr furnace load, you need to add heat at 88 watts to vaporize the propane without lowering its temperature. Any less will lower the liquid temperature till ambient heat from the air will supply the heat for vaporization. The larger the tank, the more surface and the less the propane temperature drops below outside temperature to supply the vaporization heat. Since a 100 lb tank would only supply 28000 btu/hr at 0F with 30 lb, our small tanks would need to have some warming for these very cold conditions to keep 10-15 psi pressure to the first stage regulator inlet. Remember that any blanket would block the outside air flow and require more of the vaporization heat to be supplied from the heat tape.
Sorry for the long discussion but the numbers point to adding some heat without insulating the propane tank from the outside air when temperatures drop to these extremes. Full tanks will work better than 1/4 full tanks. and adding the heat to the bottom of the tank would be better than adding to the sides. Is there a small blanket that could be attached below the support plate and be out of the way for removing the tanks? This would warm the liquid in the bottom of the tank as the tank empties so would be as convenient as possible.

[kingrving]

I was at the RV show here in Austin Tx last weekend and attended a seminar on maintenance for your RV here is a great link that has repair and maintenace tips. One of the items he covered was propane and the fact that in cold weather if the tank was over filled it just won't work correctly. Here's the link the ask the Professor was a guy name Terry who runs the RV Technicans program at the Tech school in Waco Tx.

http://www.everythingrvtv.com/

Hope this helps