Propane experts

Thanks guys.

What Old-Bisquit said. Required by National Fire Protection Association standard for RVs.

Mine started leaking from the vent hole and I replaced it with a Marshall years ago. Better regulator than the OEM.

The high pressure regulator is required to prevent condensation of propane in the cross over line. Required when the connection is over 5' in length. If the RV is older than 5 years I would replace both regulators.

That is a 30# LP REg....diaphragm is cracked if propane is coming out of vent
Commonly called Red Top LP Reg

It is required due to long line across front of RV from side to side
Full cylinder pressure could condense in that line and cause liquid propane to flow to Changeover Reg destroying it and possibly putting liquid propane into RV Propane System

Marshall Excelsior MEGR-130-30 High Pressure Regulator
About $14 on Amazon

It is also a regulator, it reduces the pressure to about 10 psi. It is a safety item so that there is not full tank pressure in the line going across the unit. It has failed and needs to be replaced.