You are not thinking about the dynamic case we have here, but rather a
static case. When you open the gas valve the water starts moving. The
water has mass. Once in motion it wants to stay in motion. This can
cause the water to overshoot and read higher than the pressure really
is, depending on how abruptly the gas starts flowing and how large the
diameter of the clear tubing is. The other thing is, these campers have
a stove. It is important that the Westy regulator be able to supply
enough flow for everything that can be on at the same time. The stove
uses far more propane than the fridge. For testing the fridge this may
not matter but for a test of the Westy propane delivery system you need
to factor in the stove burners.

I am just a home driveway hack but I have tested and repaired quite a
few Westy propane systems as well as other RV propane systems.

Mark

Mike "Rocket J Squirrel" Elliott wrote:

> On 7/31/2007 2:09 PM Mark Drillock wrote:
>
>> You need an open bleed hole between the reg and the water while
>> measuring the levels.
>
>
> Am I correct to assume that one should not check to see if the bleed is
> working properly by holding a lighted match near it to catch a draft?
>
> But about that bleed thing: presumably the regulator is designed to work
> even when only the Dometic refrigerator is turned on. The orifice is
> effectively the "bleed" under those conditions, and that orifice is
> really really small. So the regulator must be able to regulate even with
> such tiny gas flow. If a fellow could put such a small bleed hole in his
> manometer I wager a bottle of good beer that the measured pressure would
> be the same whether that bleed was open or shut. Neil - you have a
> manometer rigged right now, wanna test my hypothesis? Put a pinhole in
> the input tubing for your bleed. To plug it, use a wad of gum or some
> old Bandaid.
>
> --
>
> Mike "Rocket J Squirrel" Elliott
> 71 Type 2: the Wonderbus
> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
> KG6RCR
>