What's wrong with my manometer?

[adarklake]

Sorry I don't have pictures, but I built a manometer taking direction from various websites about how to build one. I used 1/2" clear PVC with 3/8" ID. Mounted to board, drew 1" marks, added red water. When I hooked it up to the stove burner, the water only climbed to the 7" mark. I don't think my regulator is putting out 7" of pressure rather than the standard 10-11". I'm too unsure of my manometer build to trust it. There were some conflicting designs online, one had you totaling the drop on one side with the rise on the other?


Regardless, I have a propane leak somewhere in my brand new 2019 Widlwood 171RBXL. I can smell the mercaptan inside and the manometer pressure very very slowly drops after the tank is shut off. I have a trip this weekend and need to get it repaired fast. Where should I look first, what is the most common leak location? The stove coupling? The propane alarm inside isn't going off and the rotten egg smell is extremely faint (yes, the drain traps are full).


Also strange is that after the tank is shut off and the system is bled 3" to equalize pressure, the pressure slowly rises about 1" until it starts to drop slowly to almost 0. It takes a little over an hour to depressurize.

[jeff64]

You should be testing with a spray bottle and soapy water. Looking at fittings and connections and where they would be swedged on to the tubing. On a 2019 unit it would be unlikely but not impossible cracked hoses. Anything obviously pinched?Lp gas connections for grill, maybe? Mine pushes inside the coach behind a door/plate and has a shut off valve on the quick connect.
Sounds like you constructed the manometer OK. When nothing is on( incl Lp) or it's disconnected the "0" of your drawn scale should be at the static position. Graduations to either(both) sides of the zero are drawn in inches. Add both readings together for a total in inches WC. Once you've run the system with a couple gas appliances operating, and see you can maintain the 11" WC, you know your regulator is doing what it's supposed to do and from my experience you can remove the manometer and just go to the leak checks without it, just lp on and nothing lit. Don't know how your TT is laid out but with mine, in a 3 ft area resides the refer, furnace stove/oven, WH and the outside grill line. Once you've exposed the areas from removing access panels, the testing should go quickly. But, you need to look from the propane bottles, hoses and regulators back to the appliances( up to gas valves). Just like you were troubleshooting electrical... one end of the circuit from source to finish You lost me on on what you're seeing/doing on your last paragraph, sorry. Good luck!

[Iwannacamp]

Not an expert.... I don't think that is a "true" measure of Inches of WC. I will try to research and post back.

[Paulie1138]

While I cannot comment on your manometer build, I tried making one, and was not happy. Yes, as I recall, you have to add the movement from both sides. May have needed someone familiar with them show me how.....but...

With a leak as you describe, I would get out the soapy water at the connections and look for bubbles. It is possible that you may even have a chafed line somewhere. Be careful....you can get “nose blind” to the smell, and it may seem like it is dissipating, but is still building up.

I was having pilot lights flame out only to relight and run a while, then kick off. It seemed to me that I had too much pressure, as the flame seemed ‘ratty’ sounding and not even, nor was it yellow-ish.

I bought a digital one from Amazon for...24? Turned out that my main regulator was set at 14.4”. Set it for 11” and all is fine now. Tossed the meter into the electronics kit I keep.

Hope you find the leak for your weekend.

[adarklake]

So if you're supposed to add the inches from both sides, I'd have 14" of pressure (7" rise + 7" drop). If that's the case, then I probably have a regulator that's turned up too high? Maybe it's overpressurizing the system and causing leakage?
The 171RBXL doesn't have an outdoor LP quick connect, I wish it did. There's 4 endpoints, furnace, fridge, hot water and stove/oven. I'd be curious as to which connections fail/leak more often than the others, so I don't have to dig around as much.
My last bit was about the tutorials which tell you to pressurize the manometer and then bleed off a few inches before you let it sit for a leak test. When I did this, the pressure briefly rose back up a small amount after being bled. I can't figure out why, both tanks were fully off.

[dustman_stx]

Here's a quick basic paint drawing I threw together to show how the manometer works. I built one myself and have used it several times. Had a regulator putting out 5psi at 50% flow- not good. And it wouldn't adjust. Had it replaced under warranty- so they do go bad- and this was on a less than 1 year old camper. One more thing to keep in mind- some appliances have a regulator that reduces pressure to less than 11"WC.

[adarklake]

Originally Posted by Paulie1138

I bought a digital one from Amazon for...24? Turned out, my main regulator was set at 14.4”. Set it for 11” and all is fine now. Tossed the meter into the electronics kit I keep.

Which one did you buy? I poked around on Amazon previously but didn't find anything that looked like it would work.

[Iwannacamp]

This might help...
https://vignette.wikia.nocookie.net/...20150806001423

[dustman_stx]

Couple other things:


1. Make sure the temp of the lines has "normalized". Change in temp during the test can give inaccurate readings.



2. Regulator lockup occurs at a max of 14" WC. So, if you're turning off the appliance and then going out to turn off the gas, you might see as high as 14". On this note, you should check regulator lockup pressure as well. Keep the gas on at the cylinders but off at the appliance for a minimum of 3 minutes and make sure the regulator isn't allowing the pressure to rise too high during lockup. Once again, make sure you don't have a secondary regulator at the appliance you're testing or this won't be an accurate reading.



3. Make sure you are dropping pressure to 8"WC to do the time pressure drop test. This is to make sure the regulator is out of lockup.

[adarklake]

Originally Posted by dustman_stx

Here's a quick basic paint drawing I threw together to show how the manometer works. I built one myself and have used it several times. Had a regulator putting out 5psi at 50% flow- not good. And it wouldn't adjust. Had it replaced under warranty- so they do go bad- and this was on a less than 1 year old camper. One more thing to keep in mind- some appliances have a regulator that reduces pressure to less than 11"WC.

Thanks, the drawing is similar to one of the ones I saw and makes a lot of sense. The side text about running another gas appliance is good info too.


I'm running my manometer off the Suburban 3 burner stove/oven combo that's in practically every camper you see with an oven. I don't think they throttle the pressure, but it does have the additional regulator.

[dustman_stx]

Originally Posted by adarklake

Which one did you buy? I poked around on Amazon previously but didn't find anything that looked like it would work.

Only thing you'll find online will most likely be the dial type- this was my experience. The true water column type like you built is the best and most accurate. I have a dial type, but I have to confirm it's readings occasionally using the true water column I built because they can get out of spec.

[dustman_stx]

Originally Posted by adarklake

Thanks, the drawing is similar to one of the ones I saw and makes a lot of sense. The side text about running another gas appliance is good info too.


I'm running my manometer off the Suburban 3 burner stove/oven combo that's in practically every camper you see with an oven. I don't think they throttle the pressure, but it does have the additional regulator.

Your fridge and water heater both have gas ports at the valves you can use if you want to take readings at a different location. Think they both are 1/4"MPT fittings.

[rockfordroo]

What Dustman said: It's the DIFFERENCE in the two heights, not the single height.

[jeff64]

Originally Posted by adarklake

So if you're supposed to add the inches from both sides, I'd have 14" of pressure (7" rise + 7" drop). If that's the case, then I probably have a regulator that's turned up too high? Maybe it's overpressurizing the system and causing leakage?
The 171RBXL doesn't have an outdoor LP quick connect, I wish it did. There's 4 endpoints, furnace, fridge, hot water and stove/oven. I'd be curious as to which connections fail/leak more often than the others, so I don't have to dig around as much.
My last bit was about the tutorials which tell you to pressurize the manometer and then bleed off a few inches before you let it sit for a leak test. When I did this, the pressure briefly rose back up a small amount after being bled. I can't figure out why, both tanks were fully off.

When you leave it set with tanks off and connected the drop will tell you IF but not where. The 11" WC is very slight in psi, like .397 psi. Don't understand the bled off portion of your tutorial, but like many YouTube things...
Regulators are designed to maintain pressure/flow relative to demand

[Paulie1138]

Sorry for the jingle My Sharona will never be the same!...LOL

At the fridge, was a 1/4’ fitting. The adapter came with the one I bought. The brand is RisePro. Verified my regulator was not in lockup mode, ran the stove with all 3 burners running. Set pressure, good to go. Pilot has stayed lit now for a few days. Problem solved.

[adarklake]

So if I'm reading right, my 7" on one side means I have 14" WC total running through my system and I should probably turn my regulator down right away.


The bleeding to 8" WC that Dustman said in his point #3 is what I did. When I depressurized down to 8" WC and then closed the system, the pressure rose slowly back to 8.5" WC before dropping again. (dropping from the leak) I found the rise to be strange because none of the tutorials showed this happening. Theirs just dropped down to 8" WC and stayed there, mine did not. My tanks were closed before I dropped the pressure.

[Paulie1138]

By the way, Thanks Dustman for the information on lockup. I will repeat my test and check lockup pressure.

Thanks to everybody on this forum! Great place to learn new tips! (Hopefully without flaming each other!) But then, this topic is why we are here....lol.

[gasman6674]

Your pressure climbed because you shut off the tanks and still had tank pressure at the inlet of the regulator and with your leak you still had flow. Lock up is 120% of flow pressure so if your regulator is set a 11" flow lock up should not exceed 13.5" . Rego Products (reguLator manufacturer) has some you tube videos on regulator flow and lock up.
Find your leak and repair it, set your flow pressure and then check lock up.
if you want to use air to test your lines you can but do not exceed 2 psi without isolating /disconnecting the appliances or you will damage the controls.
Good Luck

[llr]

I had leaks in both of our pigtails form delivery or very shortly after. I did not see them with soap so got a gas detector and found it.

Of course the dealer couldn't find the leak.

[Witch Doctor]

I take my hat off to you for trying, and for building one, but if you still have questions, take the unit to a propane company and have them check. Propane is nothing to play with, good advice from members, what bothers me is that you didn't know how to read one, also you have additional pressure valves at each appliance such as your gas valve for your water heater, stove and furnace. The 11" you are talking about is the pressure of your main regulator only, you need to read all the manuals for each appliance. Good Luck, and be careful playing with Propane and making adjustments just some advice, did HVAC repair for many years,