No gas to cook top

Bought a Yellow Jacket manometer – not expensive. With stove burners and water heater running it showed a fat 11.5. Marshall engineer said even 12 qwould be ok but to watch for poor flame at high altitude (due to lower oxygen). He also emphasized that all regulators are affected by altitude pressure, My instinct would be to set the main regulator up a bit for higher altitudes due to lower pressure. Kids have a new Escape trailer and others owners have reported that the OE regulators supplied are all over the place. So the easy and inexpensive thing to do was replace the regulator with a highly regarded one.

enahs wrote:
the main RV regulator was replaced with a Marshall 253H, which a Marshall engineer said was fine. Did a manometer check on the Marshall with stove burners and water heater running. It showed 11.5 at home (2500 feet elevation).

That's the same regulator I put in the camper 2 years ago. now the literature says it should be set for 11" WC from the factory not 11.5 so I wonder if they set them a little high on purpose. Which Manometer did you get?

When I bought mine to replace a failed one the spec, I was looking at was the BTU output as it was 350000 instead of 220000 so I figured having more volume would help prevent pressure drop better if you were running a bunch of stuff.

Great news! And a good follow-up, thanks for reporting back.

Some folks reported they had no issue above 5,000 ft with their stove, but they may not have known what their main tank regulator was set at. It could be possible their main tank regulator drifted up, allowing their setup to work. The quality of standard RV regulators is not the greatest, and they can get worse when they age. I have seen this firsthand, restoring older campers.

Thanks again,

John

Thanks for getting back.
Both my campers had main regulators that required adjustment when checked with a manometer. Simply unscrew the cap to find the adjustment beneath. Clockwise increases pressure.
We've camped at 10000 ft at Great Basin with all appliances working fine, although the rice stayed rather crunchy at that level.

Solved! Back to high elevation (over 6000 feet) and all appliances, including Dometic cook top working fine! Unfortunately two changes were made, so I can't say with certainty what the fix was, but here goes. First, the cook top part with the at appliance regulator was replaced. Factor replacement part, same little regulator. In addition, the main RV regulator was replaced with a Marshall 253H, which a Marshall engineer said was fine. Did a manometer check on the Marshall with stove burners and water heater running. It showed 11.5 at home (2500 feet elevation). Made no changes to that setting. Now with all at just over 6000 feet everything is fine! Clearly, Dometic was lying when they repeatedly said that the cooktop would not operate above 4500 feet and were entirely unwilling to help. Bad company. IMO both changes I made contributed to the fix. If others encounter this issue, I would first change the main regulator to a Marshall 253H. That's the easiest and least expensive thing to try. Be sure it shows at least 11.5 WC. Or, before replacing the main regulator, make sure existing regulator is consistently delivering 11.5. I bought a Yellow Jacket manometer to do the checking. Check with gas flowing, say, to the stove burners.

Finally talked to a very knowledgeable engineer at Marshall regulators (which was not the initial contact, had to ask to be transferred for reasons that quickly became obvious). Going to install a Marshall regulator at the tanks. He acknowledges that ambient air pressure does affect the regulators. And insufficient WC may prevent the stove regulator from opening due to decreased atmospheric pressure above 4500 feet elevation. He sees nothing wrong with bumping up the WC setting on the main regulator by 1/2" or so. The only problem will be if too much increase is necessary to get gas flow at the stove, the appliance flames will be poor due to too much gas and insufficient oxygen at that altitude — it's a balancing act. We'll see. He reports, too, that the Marshall 253HP and 253L will both work just fine in an RV application. Both produce 11 WC output. But final installation should be tested and set with stove burners, etc. running.

The Seven Universe R60 regulator at the cooktop specifies 1/2 psi as the maximum working pressure. What might that mean. It also specifies the normally anticipated inlet and outlet WC specs seen in RV applications. I understand that 1/2 psi = 13.75 CIW.

Your welcome Shane, Glad to try and help. And really curious on how this comes out.

If your R60 stove regulator does not open after your testing at higher altitude, I have a surplus of new ones that do not close up... PM me I'll send you one.

For sure, report back your findings.

John

Yes, that's the tester I am using. You have been very kind and patient in sharing you expert knowledge. I did tap the gauge before finally reading. But I am now going to go back at this armed with the insights you have provided. The aim is to examine the trailer's system to see if anything other than the stove regulator could be contributing to the stove issue. The new part has been installed in the stove, but it will have to go back to high elevation to really be tested. As you might surmise, I am retired with too much time on my hands!

Many thanks,
Shane

Ok, you interpolated. I was going on the words you posted. I looked up a Yellowjacket Tester, I'm assuming it is this one? https://yellowjacket.com/product/gas-pressure-test-kit/

Did you tap the gauge lightly once the pressure was to be read? These types of gauges need a light tap to settle them, then read the number. Many times they drop slightly, but not always.

There is also the regulator itself and it's repeatability. Before declaring what it is set for, shut the tank off, bleeding out the pressure, then bring the pressure back up and see if the setpoint changes. Three try's should be about what it is set for on average.

You do need to check the pressure when the system is operating, the furnace is a big draw and see how the regulator reacts and then when the furnace shuts off where the regulator comes back to. Make sure the pressure does not exceed 14" WC when the system is under load or at rest. If it does exceed 14" WC, and it started at 11" WC, then all you can do is get another regulator.

You may find, these RV main regulators may shift slightly on setpoint, even in a resting situation. They are only so good at repeatability for the price point they are made to. Remember, they are rated in 1" WC increments, not on the 0.1 or 0.2 "WC actual. Depending on the company you work for, when reading whole numbers on a gauge with no decimal point, you do not interpolate, you round up or down to the next whole number when the needle is slightly above or below. More then 1/2 way above, round up. More then half way under, round down. I'm not sure what the RV industry follows, but if it industry standard practice, you round up or down the next whole number.

Hope this helps.

John