[A/S] Re: 1965 Overlander Plumbing question

["vrmanac" <andy@xxxxxxxxxxxxx>]

Hello Chuck & Lynn

I think what you are describing is the 60 PSI Releif Valve.  This was 
standard in all Airstreams from the start of demand water systems in 
1964 until 1979 (ANSI and CSA code people could not understand them 
so they were not allowed after that time).   It is there to releive 
excess pressure when the water heater is heating.  You don't need one 
in your house because your house does not have a check valve on its 
inlet.  The Airstream also came standard with a 40 PSI regulator so 
the only way the valve became active was when you heated water from 
cold to hot but never opened a tap.  

The releif valve is available from "WATTS", We actually install them 
in high usage newer trailers as well since without them the plumbing 
system has to withstand 125 psi on a regular basis.  WATTS also makes 
a variable valve that looks almost identical but you can adjust the 
pressure that it releases at.  This is great for cleaning out the 
seat of the valve and fine tuning when it works.  We usually set 
these at about 80 PSI.

You will not be able to take the valve apart but if it does not leak 
until 60 PSI then it is doing its job.

I hope this helps you out.

Andy