Propane tank issues (low pressure)

[GaHighPockets]

I was away from my 5er (Carriage) over the holidays and on my return my furnace which has always worked would not come on but storve top and hotwater would both work on gas.
1) I first checked my gas, one tank empty, the other with a little gas (red-green indicator was half green & half red).
2) I filled both 40# tanks ( did empty one first then went back and filled other.
3) Opened valve very very slowly so as to not trip excess flow valve and sytem presureise but only a little green showed on indicator. I repeated this over and over with one tank then the other , same result.
4) closed both valves, went inside lit stove and bled gas pressure then turned stove off.
5) repeated slow tank valve opening process, still only a little green on indicator, repeated process numerous times with no improvement.
6) went in side, and tried hot water heater, lit up with no issue.
7) pig tail hoses from tank seemed hard so I changed out both, still no luck.
😎 during this whole time I would try the furnace, it would cycle, 9I could hear gas solinoid valve click up when fan flow was up to speed, hear igniter clicking) but would not fire.
9) I suspected low gas pressure so I turned furnace back on, went out side and put hand over the fresh air intake for the furnace, it would light right up and make heat as long as I kept intake mostly obstructed.
10) Read that cold temp might be an issue so I warmed up the lp tank locker with a 100 w bulb....no change.
11) I have read about hoses and regulators but all of this is down stream of the red green inicator so issue appears to be between tank and the indicator fixture and not down stream.
12) I also have a 39' Sundowner with lQ and a surburban furnace, those tanks are outside, not in an enclosure, the only difference being that the pig tails for those 20# tanks do not have the new type connectors (they screw in utilizing the internal threads of the tank valves and have worked fine with the same outside temps. Horse trailer is in mid ga. and I have RV in NW ga.

I have been rving for many years and finally and begrudginly admit defeat, any advise or comment would be appreciated.

[NC_Hauler]

GaHighPockets wrote:
Thanks for all advice, best was the regulator....got and installed New one today and success.

yep, sounded like it, but there were other probabilities, glad you got it fixed:)

[GaHighPockets]

Thanks for all advice, best was the regulator....got and installed New one today and success.

[C_Schomer]

You need to find a point where you can check the pressure in the lines. I have w.c. gauges but you can make a manometer with about 3-4' of tygon tubing. Double it over, tape in together, put about 1' of water in it and viola, you have the gold standard for measuring w.c. I've done that several times when my gauges broke or I didn't trust them. The line pressure should stay up to ~9" when all the LP appliances are lit. That rarely happens but the pressure should stay up to 10" when about half (btus) the appliances are lit. I've dissected my old RV regulator before and it wasn't the best designed thing I ever saw. The pin that pushed the diaphragm open rested against the soft rubber disc and over time the pin sunk into the rubber and essentially reduced the out going pressure. I cut new Viton discs and put it back together and I'm still using that same 15 yr old reg. The red/green tank indicator isn't the best thing to judge line pressure by cuz it is going by the first stage pressure but it's still a sign that something isn't right. Very possibly what I said about the pin sinking into the rubber. Internally, each tank has it's own first stage reg and the changeover knob simply adjusts the lead tank reg to a higher setpoint than the lag tank. The lead tank has a higher setpoint so it keeps the lag tank reg from opening til the lead tank can't deliver and the lag tank reg opens to deliver pressure to the 2nd stage reg. There will be a test on this, later! Normally, that variation in first stage pressure doesn't affect the 2nd stage pressure too much but I wouldn't count on it. Also, I always take the tank connectors off the pigtails and neuter the over flow ball and spring and put the connector back on the pigtail. I don't deep fry turkeys under wooden decks or heat my house with a BBQ grill and I don't need that over flow POS to cause me grief! Craig

[thomasmnile]

For fun, I read the Wikipedia entry for propane. It is a mix of propane and butane, and the quantity of each does vary with the season or climate. In winter or colder climates, there is more propane than butane, in summer months or warmer climates, there is more butane than propane in the mix. Didn't know that. Guess in the South, must be the butane 'heavy' blend most of the year.

[NC_Hauler]

My bad, not relevant.

[mustangglp]

sljkansas wrote:
I remember hearing something a while back about LP dealers down South uses butane instead of propane, and that butane doesn't like being real cold.

maybe someone can chime in on this. My memory sometimes mixes things up.

We run in to this here some place sell butane in the Summer and it does not work when it gets cold! This what I would suspect isn't much colder than normal in Florida? I bet they pass butane off as propane all the time.

[Jerry_B]

Just had the same problem. All other gas appliances will operate with low gas pressure. At night at the coldest, the furnace would fail due to the lower vapor pressure. Switched to a full tank it was ok.

[GaHighPockets]

The excess flow valves in each of the pigtails are designed to allow a small flow of gas so that you can leak check. Another way of stating would be that if you had a leaking line and if the excess flow valve close off completely you would not be able to easily check for leaks, they are designed to pass a small amount of gas which would allow appliances with small consumption to operate but not a gas hog like a furnace.

[NC_Hauler]

I have two 40# propane tanks in my 5er....My furnace wouldn't stay lit with tank on the drivers side.....but would run with the curbside tank.....With the drivers side tank, I could turn on and run my stove, my gas water heater would run, (though I run it mostly on electric, I checked to see what would happen)...BUT, the stove wouldn't STAY lit.....The drivers side of the 5er where propane tank is has a regulator, as does the curb side....I changed out the regulator on the drivers side and now the furnace will work on either propane tank....

It was mentioned earlier and no one made a comment on it, but I'm here to tell you that it "could" be the regulator as mentioned by newman fulltimer, because it was the regulator in "MY" case.

On edit..I camped over Thanksgiving when temps were zero with a windchill below zero and never had an issue with either tank....

[Ka_Ron]

rhagfo wrote:

Ka Ron wrote:
This does not sound like a propane issue, it sounds like a furnace issue.
Probably a sail switch??

GaHighPockets wrote:

9) I suspected low gas pressure so I turned furnace back on, went out side and put hand over the fresh air intake for the furnace, it would light right up and make heat as long as I kept intake mostly obstructed.

I believe it to also be a propane supply issue, if chocking off the air supply makes it work, most likely not enough propane for combustion.

If this was a pressure issue the hot water tank and the stove would not operate normally as the OP said they did.
a sail switch in the furnace is proving airflow before firing and with the combustion air partially obstructed could be creating a false pressure reading which allows the sail switch to let the burner light.
Would recommend having the furnace checked.

[sljkansas]

I remember hearing something a while back about LP dealers down South uses butane instead of propane, and that butane doesn't like being real cold.

maybe someone can chime in on this. My memory sometimes mixes things up.

[GaHighPockets]

I think if it were a regulator problem, the red/green indicator that tells you that you have tank pressure would be green. As the regulator is down stream of the indicator I suspect it to be a tank pressure issue as I changed the pigtails (which have a excess flow mechanism and a fusible link) It is also possible that the tank has too much pressure ( had the tanks filled early this week when the previous nights temp was around 5 degrees) thus every time I crack the valve it is triggering the excess flow valve in the pig tail. When I go home for the weekend I am going to make me up a pressure gauge to check.

[wandering1]

Based on everything you have done, the only thing not eliminated as a problem is the furnace. Get an RV tech to check it out, it could be the sail switch, heat sensor, or the furnace circuit board (computer), ignitor or needs cleaning not the regulator.

[rhagfo]

Ka Ron wrote:
This does not sound like a propane issue, it sounds like a furnace issue.
Probably a sail switch??

GaHighPockets wrote:

9) I suspected low gas pressure so I turned furnace back on, went out side and put hand over the fresh air intake for the furnace, it would light right up and make heat as long as I kept intake mostly obstructed.

I believe it to also be a propane supply issue, if chocking off the air supply makes it work, most likely not enough propane for combustion.