Thanks for these thoughts.  You never get 100% conversion, even with a good
catalytic heater.  Even with them, there is some imperfect combustion,
though I think it is probably high 90's, or else there would be carbon
monoxide, which with these heaters, there isn't supposed to be any.

Paul

-----Original Message-----
From: Michael Elliott [mailto:camping.elliott@gmail.com]
Sent: Monday, June 18, 2007 8:10 AM
To: Paul Chubbuck
Cc: vanagon@GERRY.VANAGON.COM
Subject: Re: More propane capacity needed

Paul Chubbuck typed:
> A few years ago I installed an Olympian brand catalytic heater in my
> Vanagon.
[snip]
> The only problem is, the little 3 gallon propane tank wasn't really
> designed for this additional load, so on camping trips longer than
> about 3 nights, if I'm using the heater, I run out of gas.

Is it the Olympian 3100 heater? I have one of those and it does add a nice
spot of warmth in the morning and on a cold night before bed. As far as
propane consumption goes (I'm not a chemist, nor do I play one on TV so more
smarter guys correct me, please)one gallon of propane contains about 84,000
to 91,500 Btu of energy depending on what resource I look at. The 3100 is a
5800 Btu/hr unit when set to high, so one gallon of propane should last last
between 14 to 16 hours.* The Westy's
2-1/2 gallon tank would provide at least 36 hours heat if this calc is
anywhere close to accurate. On low (3000 Btu) you should have have more than
70 hours of heat in the tank.

So if you are leaving your heater on all night, then I reckon your
experience of running out of propane after three nights makes sense. Get a
warmer comforter or sleeping bag.

* Assuming 100% energy conversion. If all the LPG going into the heater is
not being converted to heat, then where are it going?

--
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