More corrections to my
Post #10.
DO NOT get the Marshall Excelsior MEGR-253 with either an H or an L on the end. The H is a high flow regulator and is olive drab green on the large diaphragm housing, the L is a low flow regulator and is bright blue on the large diaphragm housing. The standard flow (what you want) is bare metal. and is a MEGR-253 (bulk package and Amazon will break it, they did mine) or a MEGR-253P which is a plastic blister pack and ships better. Marshall Excelsior is all USA made.
Fairview regulators are made in Mexico and have a history of being junk, and JR Products is marketing the Fairview regulator. Flame King is mostly China made crap, but I don't know for sure. Not sure who might be making the Camco regulator, though they have a reputation of making or having made for them a lot of products here in the US. There is an Italian made regulator, Cavagna Group that makes an auto switch over regulator, my travel buddy has one on the trailer he bought earlier this year. They are probably OK, I have not heard anything good or bad about them.
Charles
The use of the different Marshall Excelsior regulators is dependent on your max possible BTU demand in your RV and the average demand you place on it.
Your furnace is one of the largest variables, as they can vary from about 20K to 35K BTU/hr. The stove burners are very minor at about 6500 BTU/hr per burner at max. and possibly as much as 9000 BTU/hr for a larger main burner. The fridge is almost not worth talking about as it will only consume about 1500 BTU/hr. The water heater depending on size or brand will be 8000 to 10000 BTU/hr when running. If you have a "instant" water heater, now you are talking some serious BTU's, something on the order of 50K BTU for the time it is operating. Add to that grills, griddles, fire pits and portable generators (generators require about 20K BTU/hr per 1000 watts) that you can plug into your outside LP fitting and usage can vary wildly but since you are not going to be operating all of the appliances at once, you don't need to have a regulator to max out your possible total demand. Most of us are not hauling a 500 gallon LP tank behind our RV!
The flow specs for the Marshall Excelsior regulators are as follows.
MEGR-253
L Low flow, Blue 175000 BTU on the primary tank, 100000 BTU on the secondary tank.
MEGR-253 Standard flow, bare metal finish, 225000 BTU on primary and 150000 on secondary.
MEGR-253
H High flow, OD green finish, 350000 BTU primary and 200000 BTU secondary.
Primary tank is the one the selector handle is pointing at, while secondary is the other tank in use after an auto switch over. If it does an auto switch over, and you move the lever to the in use tank, that tank becomes primary and the flow rate increases.
Note that the tank connectors with the GREEN ACME nuts have flow limiters in them that limit to about 200000 BTU/hr. Pigtails with RED ACME nuts have flow limiters of 400000 BTU/hr
I'm going to put in a little plug for the Marshall Excelsior 1/4 inch pigtail hoses. Quoting from the catalog........
"Flexible thermoplastic UL and CGA approved hose. These hoses are rated up to 350 psig working pressure with a 400 pound pull test rating. Each hose comes with two ends and fully crimped brass ferrules." ..... "MEC non-leaching hoses are made with a specially formulated “oil free” hose which is designed to resist chemical contaminants within some LP Gas that can cause standard hose to break down and clog regulators or appliances"
Link to the very informative MEC 2021 RV and Camping LP catalog
Some numbers to know, a gallon of propane is about 92K BTU. A 20 lb propane tank, full holds 4.6 gallons, and a 30 lb tank holds 7.1 gallons. The 20 lb tanks you exchange at the stores (Blue Rhino for instance) are only 3/4 full, or about 3.45 gallons.
The next correction is about the Flame King regulators. They are clearly identical to the Winntec/Enerco/etc and I personally would not want to use one of them
The last correction is about the Cavagna Group regulators. I have a friend with one, it works well, has a clearly visible green/red change over indicator and manual knob. They are NOT Italian made. The company is based in Italy but none of their products are made there. From my research on their web site, the RV type regulators are most likely made in the plant in China. (they have a map of locations and a description of what is made or done at each location, they are a world wide company.)
I hope this fixes all of the errors I have made and helps someone understand the issues with these LP regulators.
Charles