Low Propane Pressure

Dennyha

Well-known member
I recently bought a manometer after taking some of the RV Professor's classes. I hooked it up to the gas outlet on the stove, as he advises, and I'm only getting 6 inches of water column of pressure. I lit the other burner, turned on both propane tanks etc. It stays at 6" water column. I tried to adjust the regulator higher (clockwise turn), and it is bottomed out. If I turn it counter-clockwise, it drops down to 5" and lower of pressure.

I'm buying a new regulator, but I'm surprised that, at 6" of water column pressure, my burners would light. My wife did notice the smell of propane by our refrigerator a couple of times, but the gas detector never alarmed. Should 6" of water column be functional? Should I suspect my manometer, which I just purchased from Amazon? It is a Yellow Jacket brand. Is this a common issue?
 

dave10a

Well-known member
Beware that the stove most likely has a regulator of its own. Therefore measure the propane pressure before the stove with the water heater, refrigerator and heater on. Also makes sure the pressure drop and leak down are in spec as well. If you are not familiar with propane regulators and functioning I highly recommend that you have a licensed pro do perform the tests and settings for safety reasons.... It looks simple and is invited to do it yourself, but looks are deceiving :)
 

Dennyha

Well-known member
According to Terry Cooper, the appropriate place to check the propane pressure is at the stove top.
 

CDN

B and B
Hello
Terry and you are correct. Only 1 Low Pressure Regulator in the system (high pressure regulator between tanks).

It will light at 6 inches but the BTU output easily said is half. The biggest problem would be the Fridge. Uses so little propane the pressure being lower would result less than ideal ammonia vapour creation in the boiler if you have a propane fridge.

Yellow Jacket are good test equipment, Just to be certain you have the correct range unit, reading the outside scale.

Brian
 

Dennyha

Well-known member
Hello
Terry and you are correct. Only 1 Low Pressure Regulator in the system (high pressure regulator between tanks).

It will light at 6 inches but the BTU output easily said is half. The biggest problem would be the Fridge. Uses so little propane the pressure being lower would result less than ideal ammonia vapour creation in the boiler if you have a propane fridge.

Yellow Jacket are good test equipment, Just to be certain you have the correct range unit, reading the outside scale.

Brian
Brian, thanks for your feedback. Yes, I double checked to make sure I was reading the outside scale. I kept telling myself that I had to be doing something wrong, but at this point, I don't think so.

Could the low propane pressure account for my wife smelling propane near the refrigerator. We do have a 2 way refrigerator, and it uses propane when we boon dock and during travel.
 

CDN

B and B
Brian, thanks for your feedback. Yes, I double checked to make sure I was reading the outside scale. I kept telling myself that I was had to be doing something wrong, but at this point, I don't think so.

Could the low propane pressure account for my wife smelling propane near the refrigerator. We do have a 2 way refrigerator, and it uses propane when we boon dock and during travel.


Possibly, It may not light correctly with low pressure causing propane to mingle after non combustion. Could be a bad connection or spider nest in the venturi that feeds the burner.

Standard Disclaimer- I would get it checked out by a professional to make sure.

I have worked on propane on my trailers for many years. With todays litigation based response to anything just about anyone does I use my extended warranty when required. If I have a emergency repair gloves off and look after it.
 

JohnDar

Prolifically Gabby Member
Do not explicitly trust the LP gas detector to alarm on low quantity leaks that you occasionally smell inside. We had a small leak at the furnace connection that we could perceive. I could not easily isolate it until I went around with my little handheld detector. Fitting had not been fully tightened after having it serviced for a defective control board. They cost less than $30 and are great for checking the lines and fittings.


Sent from my iPhone using Tapatalk
 

dave10a

Well-known member
According to Terry Cooper, the appropriate place to check the propane pressure is at the stove top.
That was true for older stove tops but most of the later models have regulators built in. Is Terry a licensed and properly train individual? Again the proper place to check the tank regulator is before any appliance with normal draw from each.....
I would suggest you get a pro involved.... Just saying :)

Just curious, could you describe the pressure monitor you are using. Is it home built. Your measurement of 6 inches of water makes me curious....
 

Dennyha

Well-known member
If you look at the Yellow Jacket link in the first post, you'll see the manometer I'm using. It is not homemade.
I don't think I'm going out on a limb when I say that Terry Cooper is qualified.
 

dave10a

Well-known member
If you hook the manometer before the stove regulator, which requires a special brass fitting that will be a good measurement place that is directly from the main propane tank. When you measured 6 in of water, it got me thinking that is approx. 1/2 what the stove regulator is set for. Home made units some times make a mistake of 1inch scale graduation instead of 1/2 inch graduations which would give a 6 inch water reading. The fact that you are asking these question is making me think you are not certain of what to expect or how to perform ALL of the required measurements to do the job correctly, and maybe you should get a pro involved. Propane is dangerous to mess with one mistake could be your last.........

The best place to make all of the necessary measurement is before all appliances with a normal draw from each. There are kits available that allow hooking to those locations and require special adaptors.... In the early days before stove tops had regulators is was easy to connect a rubber hose of the manometer to the stove office to make all the necessary readings, but those days are gone.... Using those old ways on newer cooktops could cause improper readings and allow one to set the main regulator too high which is dangerous.
 

Dennyha

Well-known member
I bought a new regulator today, and swapped it out tonight. After installing the new regulator, I'm getting 12" of water column with no other open draws, and exactly 11" of water column when I light a stove burner. The stove burners burn much better, with a more solid blue flame. Apparently my old regulator was the problem.
 

dave10a

Well-known member
I bought a new regulator today, and swapped it out tonight. After installing the new regulator, I'm getting 12" of water column with no other open draws, and exactly 11" of water column when I light a stove burner. The stove burners burn much better, with a more solid blue flame. Apparently my old regulator was the problem.

I am not sure you are out of the woods or not, but here is a good article to consider. http://www.rvdoctor.com/2002/01/what-pros-do-propane-system.html
 

wdk450

Well-known member
Do not explicitly trust the LP gas detector to alarm on low quantity leaks that you occasionally smell inside. We had a small leak at the furnace connection that we could perceive. I could not easily isolate it until I went around with my little handheld detector. Fitting had not been fully tightened after having it serviced for a defective control board. They cost less than $30 and are great for checking the lines and fittings.


Sent from my iPhone using Tapatalk

I would 2nd John's post above on the propane alarm being next to useless. The standard mounting location for the alarm is far from any propane sources.

The best way to first see if you DO have a propane leak is a pressure leak down test done at the tanks. The tanks are turned off, a gas pressure gauge (like what is sold to measure gas left in a propane tank) is connected to 1 tank, the tank hose is connected to the output side of the gauge. The tank with the gauge is turned ON, then OFF. The gauge will now read the pressure remaining on the propane system, and if there are any leaks anywhere the pressure reading will bleed down. If the system is leak free, the gauge will hold steady. You can repeat this with the 2nd tank to just verify its hose and connections to the tank selector.

EXACTLY finding the source of the leak involves crawling around and tracing out all of the propane piping. The amateurs use bubble solution looking for bubbling on the piping and fittings. The pros use an electronic hydrocarbon gas detector (like what they use for automotive air conditioning freon leak tracing) that acts like a geiger counter for gas leaks. They then verify the suspected leak location with bubble solution.
 

Dennyha

Well-known member
After installing the regulator, I did perform a leak test. I shut off both tanks, and then opened a second burner to bleed off gas to bring the pressure down to 8" water column. The system held the 8" water column pressure for 10 minutes. After 10 minutes, I closed off the burners, removed the manometer, and reassembled the stove top.

I'm still convinced my problem was a bad regulator.
 
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