Date: Sun, 25 Sep 1994 12:23:39 -0700 (PDT)
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: David Garth <dgarth@cymbal.aix.calpoly.edu>
Subject: Catalytic Heater Review
Catalytic heater review
I have just completed the installation and testing of a catalytic space
heater in my 1986 Westfalia, and with winter coming up, I thought my
results might be of some interest. (Special thanks to Derek Drew for
information and inspiration.)
Two critical decisions must be made before proceeding with this project:
1. What type of heater. 2. Where to put it. After a great deal of
research, I decided to buy a vented catalytic heater from Thermal Systems,
Inc. (2757 29th St. Tumwater, WA 98512, 206-352-0539) I chose a catalytic
heater because it is much more efficient of both propane and 12 volt
current than any other type.
Catalytic heaters provide radiant heat, and most of the energy in the
propane is turned into useful heat. Typical RV forced-air heaters consume
4 amps of 12 volts when running, and send a lot of the heat out through
their vent.
Most catalytic heaters are not vented. These unvented ones dont meet the
RV or any building codes, and, cause the user to keep at least one window
open for safety ventilation. Carbon monoxide really does kill several
thousand people a year, and I would rather not take the chance. In
addition, products of combustion include a lot of water vapor. With an
unvented heater, the water vapor is trapped inside the van, making it
uncomfortably clammy, and causing ice on the inside widows and
condensation which eventually causes body rust. (To the vehicle, not you.)
The Cat from Thermal systems is a different type of animal. It uses a
small, quiet 1/2 amp motorized blower to collect the products of
combustion, and then vent them outside through up to 12 feet of 1 1/2"
flex hose or ridged ABS plastic pipe. The 12 volt connection also powers a
microprocessor controlled safety system that is really slick. If the vent
is obstructed, there is no gas supply, or there isnt enough oxygen, or the
heater gets too hot, or fails to light, or the 12 volt supply loses
voltage, the unit shuts down automatically
The unit is remotely thermostatically controlled, and lights itself
automatically. When the thermostat calls for heat, an electric heating
element lights the gas without flame or spark. (The presence of the
platinum catalyst allows gas to react with oxygen at less than normal
flame temperature.)
Where to put it? I choose the larger 6000 btu unit because Derek convinced
me that the 3000 btu unit (both $279) would be too small. I built a small
cabinet, 28 inches high, 16 inches wide and just 4 inches deep. I covered
it in Formica (Desert Beige is a perfect match) and installed it behind
the passenger seat.) This height lets the passenger seat fully recline
even when all the way back. The seat can still swivel, but the cabinet
will be slightly in the way when facing 100% backwards. The heater is
semi-recessed into this cabinet. The cabinet also hides the vent hose,
which goes up, left, down and through the vertical sheet metal panel below
the battery. The gas I teed off at the tank, and ran 3/8 tubing over the
gas tank to the right side, through the same panel. I ran a new 12 gauge
wire from the auxiliary battery to the heater. Even though it only takes
1/2 amp when running, it draws about 10 amps for about a minute when
starting. This isnt the only place one can put it, but I felt it was a
good compromise.
How well does it work? GREAT! It hasnt gotten cold enough here in
California to tell for sure, but the unit throws out LOTS of radiant heat,
with no odor and very little noise. Flick the switch on the thermostat,
wait about 2 minutes, and enjoy lots of clean heat. Radiant heat is like a
fireplace or camp fire, and seems more pleasant than warming all the air
in the vehicle. I would rate the quality of the unit's construction and
engineering as excellent, except the sheet metal case is light gauge and
somewhat flexible. After installation this doesnt seem to matter.
I'd be glad to answer questions: 805-543-2046
--David Garth
San Luis Obispo, CA
|