Hi,
I had this same problem this past spring with a 2000 Forest River product. Marshall Gas Controls made the regulator also. I researched the propane regulator. It seemed as if the diaphram was leaking around the crimp of the housing in the selector area.
I researched this and I found the US Consusmer Product Safety Commission recalled / Many Many times.
See:
http://search.cpsc.gov/query.html?qt...rols&x=15&y=14
1995 recall pertaining to RV's:
http://www.cpsc.gov/CPSCPUB/PREREL/P.../95150org.html
I was debating sending this failed unit to the UnderWriters Labs since their approval appears on the unit. But I didn't. I still have the failed unit. A 2000 dual tank selector valve with built in regulator. (don't have it in front of me for more specific's)
I would Like to keep this thread alive and see how many people have issues with Marshall Gas Controls LP propane gas valves / regulators.
This isn't a minor problem / issue. People and pets lives are at stake. If and when the regulator fails releasing unburned propane gas into the atmosphere. One spark and its all over.