I bought a manometer to chase down what I think is an over fired furnace.

I hooked up my manometer to the test port on the regulator, at the top where it says “gauge”

when I cracked the valve for the propane tank, my gauge instantly maxed out.

is this test port supposed to show the pressure after the low pressure regulator? Or does it just show the pressure after the high pressure regulator?









I don’t see anywhere else to hook up a manometer. Do I have to build a test port after the output line on the regulator?

im supposed to run 11” wc and my gauge maxes out at 89” wc, so the pressure at the port on the gauge was stupid high.

 

As far as I know, the first regulator is high pressure. So that test port would be used to ensure you're getting something like 100 to 200. Any test for a "normal" WC would be done on the final output port at the bottom. At least, that's where I would do it. When I tested mine, I did it at the stovetop.

The one time I questioned what my propane regulator was doing, I replaced it altogether. It was probably 14 years old at the time.

 

I think that is where I’m at. This one is about that old, I think the camper is a 2007 or 2008.

going to the local propane dealer later today to see what I can find. The camper dealer just had one for a dual tank set up, so hopefully I can find more of a direct replacement.

 

You have a single tank? The front of your trailer looks like it has dual tanks.

I bought a Marshall Excelsior MEGR-253H regulator back in 2017. No problems so far. As I recall, it has a higher flow rate, but the same pressure as the one it replaced. At the time of purchase, it was made in the USA.

 

The big camper in the pic below has dual tanks, yes.

this is for my in-law’s pop up camper that we use for trips far away from home.

got a dual stage single tank regulator at the propane store for $48. And it has the test port for the low pressure side as well. That almost feels like winning.

now just have to get it installed and check the pressure level. I’m guessing it is going to be about perfect out of the box, but at least now I can check it and verify.

 

Got the new regulator in. It is a Marshall excelsior also and it labeled as made in USA.

pressure was set to 14” right out of the gate. I dialed it down and ended up with about 11.3 with the fridge running. I can adjust from here to see what happens. Had to back the screw all the way out almost to get it down around 11.

 

That's a handy little testing device. Beats the heck out of the water tube, which is what I used.

I read that due to the mechanical nature of the regulator, it should always be oriented up/down. But I read that on the Internet, so...

 

I’m definitely going to recheck it now that it’s is mounted in its permanent home. I just didn’t want to mount it and then find out there was something wrong and it wouldn’t work.

it will definitely be interesting to see if it makes a difference in the reading. I did hold it more vertically when adjusting it and it didn’t seem to change enough that I could tell in the reading, but it will definitely be interesting to see.

I was also surprised how much the reading dropped just from the load of the refrigerator. The burner on that isn’t much more than a pilot light but it pulled the reading done more than 0.5” at the regulator.

I’ve got it set at about 11.3 with the fridge running. I’m fully expecting to see lower with the furnace or water heater running. I’m targeting as close to 11 with the furnace running as I can get to see if that lowers the combustion temps. I’ll go back and update that thread when I get to that point. But for now, I at least have a known good regulator and a way to adjust it.

that tool is pretty slick. Not bad on price either. A touch over $40 at the time of purchase.

Manometer, Professional Air Pressure Meter, Dual-Port Manometer Gas Pressure Tester,12 Selectable Units Differential Pressure Gauge, HVAC Digital Manometer, Gas Pressure Tester (Included Battery) https://a.co/d/4OicC7k

 

The furnace has a valve that regulates pressure too, doesn’t it? I assume it’s just like a residential furnace. There should be a sticker on one of the furnace covers that listed the inlet and outlet pressure settings. You should check the inlet and outlet pressure there as well, if you are concerned about over firing.

 

Thanks for the link. That is a great price. I thought it would be a lot more.

 

As far as I know, there is no regulator on the furnace itself. To the best of my knowledge, the pressure at the furnace is dictated by the pressure at the line.

I could be wrong though. I’m still learning, and much more than I ever wanted to know.

this is the manual I’ve been using. If you see something in there that regulates the pressure, please point it out to me so I can figure it out and check it.
https://myrvworks.com/wp-content/upl...HydroFlame.pdf

 

It has a white-rodgers gas valve. I am familiar with them in residential furnaces. They have an upstream and a downstream port to test from and an adjustment for burner manifold pressure. I don’t see any reference to adjust the gas valve in the manual though, so I am be wrong. It does say you want 11” wc with all appliances running. I would test at the gas valve inlet port if it has one , because there will be some pressure drop in the lines.


post edit: I do see that outlet test port on the drawing. There may be a sticker on a furnace cover that will tell you the manifold pressure. That is what you are after, if it is adjustable.

 

Wow. That is super helpful.

even if it is not adjustable at the furnace, I can use that port and adjust for 11” while it is running.

I’ll peek at it again tomorrow night and see if I can locate that test port.

 

What you need is an LP Tap Jig. You can make one yourself that will simulate a 50% load on the LP system.

Darren with MyRV Works makes some very informative videos and he explains the LP Tap Jig and how to set the correct inches of water column in this video.

 

Researching regulators. Ours does not like to use all the gas in second tank. It does not have a flow lever. Meborder are you still happy with your 253h?