Bad propane? Bad tank? Gas, but at low pressure...

[almcate]

Filled a propane tank yesterday (we've been drinking propane this week) and this afternoon, furnace would not heat and shut down. Assumed 2nd tank had emptied so switched to the new tank, but still the furnace fans would kick in and off again without igniting the furnace. Several cycles, but no heat and shut down. Gas pressure was so low that burners on stove would burn only very weakly on high. Water heater would fire, but exhaust was warm, not hot. Figured there must be a failure of the regulator, but as double check just refilled the newly empty tank, switched back and I have full pressure, and hallelujah, heat.

Now, I'm perplexed. supposing the switch valve on the regulator could still have failed. but am wondering if there is such a thing as a bad propane refill? Maybe the station filler tank was near empty? Perhaps my 30# tank has a problem or blockage affecting the valve? Replaced a tank a year ago when the valve would not accept a fill. Refill is always 7 gallons, and yesterday was only 5 gallons. Come daylight, will reverse the tanks and test to see if tank position on the regulator makes a difference.

My speculation aside, anybody have similar problems?

[Silver Goose]

Is there any chance you were sold butane instead of propane?

http://www.avantigas.com/propane-butane/

[Al and Missy]

I have seen refill stations that go by a gallon flow gauge and some that go by weight. Either way, it's hard to see how (assuming the attendant was awake) you could get a bad fill. One of my tanks went empty and when I tried to fill it, it would only take a little gas. The guy tried everything, opening the bleed valve, banging the tank on the concrete, slowly opening the fill valve, changing the order of which valve to open first but nothing would get the tank to take any gas, but it was obvious to the attendant.

Al

[idroba]

Probably what happened was an automatic flow restriction or shut down when you turned the newly filled tank on. The OPD fill valves will shut down automatically and deliver almost no gas it they think there is a massive leak in the system (high flow rate). When you first turn a tank on, in an empty system, there is a high flow rate, which may have triggered the valve to shut down.

Turn the tanks off, relieve the pressure by turning the stove on. Then shut the stove off and open one tank valve very slowly. You will hear the gas flow into the system and possibly a click. Then open the valve fully and check to see if things are working properly.

I bet you will find it working right.

[OTRA15]

The newer regulators have a safety feature that restricts flow if it senses a leak in the line I believe. There have been discussions here, but this is all new to me since my 1990's AS 25.' Until someone more knowledgeable can chime in, I would:

-- turn off both tanks and all appliances
-- open a burner valve on the cooktop to verify that the line is not under pressure
-- you could hold a sparker or match there to verify
-- turn off the burner valve
-- VERY SLOWLY open the main valve on the tank you think has propane in it and let the system reach equilibrium until no gas is flowing
-- try lighting a cooktop burner again
-- hopefully it will light and sustain a flame
-- open other cooktop burners and light them

If this works, maybe report back or detail problems.

Again, just a guess on my part. YMMV.

Edit -- idroba beat me to the punch!

[almcate]

As I said my (cockamamie) speculations aside...always get good insights here. I'm warm now, so come daylight, figure I'll reverse the tanks left to right and see if the regulator properly feeds gas at pressure from the "problem" tank. And if pressure is low, try relieving the pressure as noted and see if the valve responds. Figure if problem persists and I then switch the primary tank back to the "good" tank with good pressure, I can stop worrying about the regulator and see if the tank valve can be repaired or if the tank needs to be replaced. Thank you all. Will let you know what happens...

[GammaDog]

Great suggestions above. One not mentioned (apologies to anyone who mentioned this if I missed it) is to have each tank "purged" on its next fill. AS recommends that annually for the 30 pounders on my trailer. I've asked numerous propane guys about that and the consensus opinion is that after repeated fill/empty cycles tanks start to fill slowly and empty slowly and are due for a purge. The AS guidance seems excessively often (one guy I asked in Maryland said that in 20 years of propanery he had never seen a tank that needed purging) but yours may improve with the procedure.

[Ray DeBaets]

The new (last 10 years plus ) that are used to connect to the LP tank have a high flow check valve in them. This is a small steel ball with a coil spring behind it. When you open the tank valve and there is low preasure downstream from the tank the check valve seats and reducces flow to a mere trickle untill the preasure downstream returns to noemal, it then opens for normal flow. If ths problem is happening, just shut stove, refridgerator, water heater, and furnace for about 10 minutes and the try one appliance at a time starting with one burnner on the stove.

[MissingLink5]

We go south for the winter and most park model homes use propane for furnace, hot water and cooking. When the propane tank trucks come around to fill tanks one operator said you sometimes, after the tank has been filled, need to unscrew the connection to the tank, take a screwdriver smaller than the opening going into the tank, open the valve on the propane tank, and quickly jam the screwdriver into the opening to release a jammed ball valve. Make sure you wear gloves and stand to the side of the valve, perhaps even wearing some protective clothing. I saw him do it with the palm of his hand and it worked in my case!

[cwf]

Same problem.. so, I shut off all propane, opened my stove valve, closed stove valve,
Next, I removed the propane hose from each tank...

Now, connect the hoses, then turn on your propane valve at the 'suspect' tank verrrrrrrry slowly.... If you 'crack open' quickly (like in the old days), the 'flow' necessary to fill all the hoses and pressurize the system requires enough LP to cause the 'flow' valve to 'check'. When that happens, you need to remove the hose with the valve off then replace the hose and try again... hose, verrrry slowly open the OPD/LP valve....

I have seen this primarily on 'fresh' fills of our large tanks... the key being, slow pressurizing ...

Finally, go the the range, flush and light up the range... then see if you water heater will light.. recycle several times... till it lights...

[almcate]

Well, campers, all is well and it does appear to be a valve on my old tank was thinking that it had detected a leak and shut off (most) of it's gas flow. Switched regulator over to the old tank as primary and closed off the newer tank. Good pressure to stove, water heater and furnace operating as if nothing happened. Hadn't been aware that the valve had the pressure sensitivity built in, so advice here saved a service trip. Had a dead fridge about a year ago and again helpful advice added one last troubleshooting tip after I exhausted all of my "speculations"... fridge computer was in need of a reboot and turning off the fridge didn't work, but shutting off ALL power from the batteries to clear the computer chip did the trick. It's all the little things that only hard experience (happily someone else's) answers. Thanks all.

[almcate]

Notice that I wasn't clear about the initial resolution last night...refilled the tank that had just emptied and it returned normal pressure. Didn't want to chance screwing around troubleshooting again until today. Tank that shut down last night is now functioning as normal, but as primary we'll be repeating the test in 10 days or so and see if it behaves any better on the next refill.

[almcate]

A followup question. Since I had the low pressure episode, furnace has been working properly, but consumption has really skyrocketed. Have been going though a tank every 3-4 days even with some supplementary heat from a small ceramic heater. Weather here has been from high 20s to mid 40s, but I have never refilled so frequently. Am beginning to wonder if the regulator is not functioning correctly or if I might have a leak. Any thoughts?

[xrvr]

Twenty pound tanks can go away quickly. Check the regulator with soapy water.

[cwf]

Our 30# was consumed in about 4 days with temp near freezing and windy.. Rain also pulls more substantial heat than a breeze.

We added the reflectix to all windows and skylights... Big difference!!! Much warmer. Far less propane use.

[Silver Goose]

The LPG furnace in our Airstream is rated at 30,000 BTU/hour. A pound of propane has roughly 21,000 BTU. In theory, a 30# bottle should feed the furnace for 21 hours non stop. From recollection, I think I got about 3-4 nights max out of a tank when it was getting into the 20’s overnight. I know it runs a lot when it's cold.

[almcate]

Part 3: interestinger and interestinger...

Okay, solved the low pressure. Rain, wind, significant chill, and being a bit "house" bound seems a more reasonable explanation to the sudden upsurge in propane consumption than a leak.

NOW, furnace fan again cycles on but burner doesn't ignite (again, and of course, on a Friday night). Couple on/off cycles on the thermostat and same result. Two hours later, furnace starts up. Then doesn't. Then does. Was thinking a bad thermocouple but I don't think they fail intermittently. Same with the thermostat. Good gas pressure and fire to burners and water heater.

Opening up the furnace enclosure (while it's working for now), as I expected, nothing jumped out as an obvious problem except that there were at least two dozen stink bugs nesting inside the space between the metal access door and the plastic component box door. An absolute explosion of the critters here in Oregon over the last couple months. Now me thinks, maybe this is just a couple suicidal stinkbugs crawling up into the combustion tube? Good dose of insecticide as a preventative, maybe? Thoughts, comments, howls of derision?

Sigh.

[dennis3751]

If you are not hooked up to 110v it may be a low battery. Our furnace won't light if the voltage is low. Fan starts when heat is turned on but the sail switch won't energize if blower is slow. Maybe a good cleaning of fan area and some lube on fan shaft may help.

Dennis

[afk314]

Just got my furnace cranking on a cold night after switching tanks. All the same symptoms - low propane flow, red blinking light on furnace controller, but I had a full tank! This thread saved the day - especially Otra15's post above. Hard to be patient and detailed in the middle of the night with a freezing trailer, but I recommend you do - I ran through the process a couple of times and it only worked when I slowed way down.



Airforums rocks, thanks all.