Visit our Popular Forums

Jeremy9107 · 07-14-2013, 10:38 PM

So I wanted to pressure test my propane lines and find out that there is a very slow leak somewhere more obvious with higher psi. Just curious, what is the acceptable leak rate if any?

awryawry · 07-14-2013, 10:54 PM

None.

idroba · 07-14-2013, 11:15 PM

At only 11 inches of water pressure, there should be no leaks at all in your propane system, that is none are acceptable.

wahoonc · 07-15-2013, 04:02 AM

None at working pressure.

Use something like Big Blue leak detector spray to find it.

Aaron

Jammer · 07-15-2013, 12:56 PM

Quote:

Originally Posted by Jeremy9107

So I wanted to pressure test my propane lines and find out that there is a very slow leak somewhere more obvious with higher psi. Just curious, what is the acceptable leak rate if any?

If you do air test, be sure to physically disconnect and cap the lines to each appliance -- don't rely on a valve. Purge the lines of gas before pressurizing.

I typically pressure test at 30 PSI and consider the system to be leak free if the gauge doesn't show any pressure drop after 15 minutes. Sometimes there can be a slight drop due to the effects of temperature change, and if that happens, I'll watch it for another 15 minutes or more and see if the gauge continues to drop.

But the higher quality non-drying leak test solutions work extremely well, too, even at service pressure. With the better test solutions you can leave them overnight and look for bubbles in the morning, which turns up problems you might not find otherwise.

cwf · 07-15-2013, 01:16 PM

I didn't read all, but are you concerned about "possible" or "actual" leaks?

Splitrock · 07-15-2013, 05:15 PM

This is what I used. I had all the shut off valves shut off. I pumped the tester up with a bicycle pump.

Mine held 15# pressure for 3 days. I ended the test at that time.

I replaced all the lines except the first leg of 5/8" and I replaced all the shut offs before the test.

I got the bicycle stem with pipe thread at the auto parts store. It's an air conditioner part.

`

Jeremy9107 · 07-17-2013, 11:52 PM

CWF, I have an actual leak, just can not find it and it is very slow. I have sprayed the lines and connections and can't seem to see it. I am using a similar test set up as Splitrock. I have turned off the shut off valves to the stove, fridge and hot water tank. I can't find a shut off valve to the Suburban furnace I have though. I also have an additional heater mounted on the kitchen cabinet that I assume is an after market install that definitely does not have a shut off valve. Does the Suburban furnace typically have a shut off valve?

perryg114 · 07-18-2013, 05:34 AM

You can start capping off branch lines and figure out where the leak is that way. If you put several psi of pressure on gas valves that are designed for a fraction of a psi then they might leak. The copper lines are not an issue as far as pressure. Probably 5 psi would be enough pressure. Soap and water will find the leak if you have some idea where it is. Try tightening all the joints and go from there.

Perry

cwf · 07-18-2013, 06:06 AM

Do NOT use fire to locate leak....even tho spectacularly effective.

Have you replaced all flex lines, have you soaped the full hose length?

Have you checked valve and tank and regulator?

Silverflames · 07-18-2013, 06:28 AM

That alerted you to the fact that you have a slow leek?

cwf · 07-18-2013, 06:35 AM

Also, should you have a leaky shutoff valve leading to leaky control valve the leak would still show up.

How long does leak down take?

Silverflames · 07-18-2013, 06:42 AM

Quote:

Originally Posted by Jeremy9107

CWF, I have an actual leak, just can not find it and it is very slow. I have sprayed the lines and connections and can't seem to see it. I am using a similar test set up as Splitrock. I have turned off the shut off valves to the stove, fridge and hot water tank. I can't find a shut off valve to the Suburban furnace I have though. I also have an additional heater mounted on the kitchen cabinet that I assume is an after market install that definitely does not have a shut off valve. Does the Suburban furnace typically have a shut off valve?

My 1969 had the shut off valve inside the cabinet next to the suburban. Not on the outside.

HowieE · 07-18-2013, 08:17 AM

Get a bottle of AC Lead Detector solution and spray on ALL points. By ALL point I mean the regulator, the gauge on the tanks, the tank valves. Short of a ware through on the copper lines the leak will be at a connection point and the test above leave out half of the likely points. You have to go all the way to the output side of every shutoff valve to complete the test. Small pieces of dirt may become affixed to the seat of one of the control valve. Remove the line after each valve and test at that point with solution.

I have seen the tank gauges, flare connection where the hose to copper connection is made, the hose itself leak, and a failure of a double seated shut off valve on a heater.

Keep in mind that gas may have a smaller molecular size than air and those pass through at 11 in. of water where air may not pass through at 30lbs.

Lucky Tom · 11-29-2013, 07:37 PM

I have just recently purchased an Airstream and I keep the gas furnace set at 45 degrees while in my yard during cold weather. In the last few days I have had a "Fault" alert on the LP gas detector. I do not know what this means but I have ordered a really good combustible gas test meter. It was expensive but so is my life. I have invested a lot of myself and my money to have great retirement years. The LP gas test meter is costing me just under $200. But isn't my life worth a whole lot more? We all have to make decisions on how we spend our money. Nobody else can tell you how to do that. This gas leak detector can be used both on my Airstream and my home. I have three gas appliances in my RV and also in my home. Do any of you ever have the "Fault" alarm on and if so, what causes it?

HowieE · 11-29-2013, 08:00 PM

Save your money for now. Turn the heater and all other gas units off and leave the off for a day while the tanks are left on. After a day go to the tanks and turn one on, make sure the selector valve is open the that tank. If you hear gas move as the valve is open you have a leak in the system. If not I doubt a gauge will tell you anything more.

Leaving the heater on, even in Al., all winter will be a costly venture.

If you turn the heater on on those nights that it will go below 28 degrees and remain below freezing for the following day and night you should be OK.

The trailer has quite a thermal mass and it really take a while to pull all the heat out of the trailer to the point of freezing.

Michigander · 11-29-2013, 08:05 PM

Quote:

Originally Posted by wahoonc

None at working pressure.

Use something like Big Blue leak detector spray to find it.

Aaron

Big Blu sounds good. I've always relied on dish soapy water, but this stuff sounds even better. I agree that NO leak is the only acceptable result.

Nuvite-F · 11-29-2013, 08:47 PM

Quote:

Originally Posted by hentom

I have just recently purchased an Airstream and I keep the gas furnace set at 45 degrees while in my yard during cold weather. In the last few days I have had a "Fault" alert on the LP gas detector. I do not know what this means but I have ordered a really good combustible gas test meter.

<snip>

Do any of you ever have the "Fault" alarm on and if so, what causes it?

Welcome to the forums!

Before you get too far, you need to read the owners manual for your LP gas detector or, if you don't have a manual, see if you can find one online or call the manufacturer. I suspect that a "fault" indication means that the gas detector has failed its internal self-test and is telling you that it's not working right.

If I remember correctly our LP gas detector has four possible states,

Normal - detector working and not detecting gas - flashing green LED
Low battery voltage - intermittent beeping and flashing red LED
Malfunction - intermittent beeping and flashing yellow LED
ALARM - gas detected - horn blowing continuously (loud enough to wake the dead!) and red LED.

We have seen 3 of these 4 conditions at one time or another - normal, low voltage, and ALARM. If your LP gas detector is detecting gas, it will let you know! (We accidentally left the oven pilot on, but not lit.)
.

Protagonist · 11-30-2013, 08:45 AM

Quote:

Originally Posted by hentom

In the last few days I have had a "Fault" alert on the LP gas detector.

That happened to me just this morning in my Interstate. Must have kicked it or something. But there is a "test" button on mine that also functions as a reset switch. Press and hold until the normal green light comes back on, and good to go.

Lucky Tom · 11-30-2013, 10:26 AM

My indicator was number 3 on Nuvite-F's list. I did the reset by pressing in on the test button. I will get a butane lighter and test to see if it can sniff gas.
I am a retired repair technician so I like the test equipment approach to problems. I have testers to test about everything. From the megger to test your ground rod connection to the surrounding dirt to about everything else you can imagine. I even have the vacuum tube tester I purchased in the sixties, still works, even still have an assortment of vacuum tubes. If you know someone who collects old vacuum tube radios I could be their best friend! So I am looking forward to using my new gas leak tester when it arrives! I hope it is a waste of money! Like the money we all spend on smoke detectors for our homes and RVs. We always hope that is a waste of money. That we will never hear them in the middle of the night! I will post here if I find even the minutest leak with the handy dandy tester! This is the one: General Tools NGD8800 Combustible Gas Leak Detector.