Date: Sat, 9 Jan 1999 19:35:25 -0800
Reply-To: Steven Johnson <sjohnso@JPS.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Steven Johnson <sjohnso@JPS.NET>
Subject: Re: Hot water system thoughts
In-Reply-To: <s695d165.049@parametrix.com>
Content-Type: multipart/mixed;
At 09:34 AM 1/8/99 -0800, Nathaniel Merrill wrote:
>Hello all,
>I have been contemplating this for a while and thought I would elicit
comments from the majority...
>I would like to have hot (if not at least warm) water in the westy for
these cold seasons. I am aware of the Zodi systems which look nice and
functional but they don't energy! Coolant temp is over the boiling point
of water so the potential for really hot water after a longish trip is good
I think.
>Any potential problems with the system? Water pump strain? material
incompatibilities? >Etc,etc, Any body already done this?
------------
Yes, someone already has. A gentleman that used to be on this list it's first
year developed and made such a system for his bus. His name is Dave Garth and
if you happen to search the archives for 'hot water' you'd find his
articles. I have included the articles in this mailing that describe his
system
in his own words. I'm not sure if he is still at the address listed as
this was
in late 1994 - 1995. I saw his system when I went to the very first CCC's
campout
at Pfeiffer Big Sur on the California coast. It is an impressive system.
you can
see some pictures of it at:
http://www.tiu.net/~des/vw/garth/index.html
This is David Schwarze's web site who is now only on the Type 2 list. One
of the
misfortunes of the list split.....
I think this system is what you're looking for.....
Steven Johnson
Sacramento
sjohnso@jps.net (formerly: sjohnson@calweb.com)
Date: Sun, 16 Oct 1994 11:03:51 -0700 (PDT)
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: David Garth <dgarth@cymbal.aix.calpoly.edu>
Subject: hot water...another way to do it.
As some of you may remember, recently I added hot water to my Westfalia.
That scheme, which involved using a heat exchanger and a pump worked
fine, but it did have a few disadvantages. As Derek pointed out, it would
be vulnerable to freezing. And I didn't like the fact that the water pump
had to run for 20 minutes to heat the water. So I've installed a new
system that I think is better, simpler, and more efficient. (As was the
case with my first try, this system heats all the water in the tank to
shower temperature, so another source of drinking water is necessary.)
I've now run a coolant loop, teed from the rear heater, through 1/4"
copper tubing to the water tank. Inside the tank is a 15 foot coil of
tubing, coiled small enough to fit through the top opening. The hot
coolant heats all 13 gallons in about 20 minutes of freeway driving.
The problem with set ups like this is usually not heating the water, but
keeping it from heating the water too much. Here's how I solved that problem:
>From a water bed heater control ($10 new) I removed the thermosat. I
adjusted it so it could be set at 105 degrees. From the W.W. Grainger, Inc.
industrial catalog(800-225-5994) I ordered a high temperature selenoid
valve (1a582) and 24 volt AC selenoid. ($90. From past experience I knew
that 24 volt AC selenoids work great on 12-14V DC).
It works like this. When the engine is running, 12 volts from the
refrigerator relay goes through the "water heater" switch, then through
the thermostat. If the water is less than 103 degrees, the 12 volts goes
to the selenoid valve, which opens, letting hot coolant flow though the
tank loop and heating it. As soon as the water temp reaches 105, the
valve closes, until the water temp drops below 103.
I tested various materials in the oven at 250 degrees to see if the hot
coolant line would cause problems. Neither rubber nor polyethylene seems
to be phased by it. So I used rubber grommets through the tank top for
the coolant loop tubing. The fail safe nature of the system is a plus. If
the selenoid valve fails, it will be closed.
Hot water and a pump powered hand shower really make the van more usuable
for us.
As before, I'd be glad to help anyone who wants to do this...either
e-mail or phone (805-543-2046 pacific daylight time) is fine.
Dave Garth
San Luis Obispo, CA
'86 Westfalia
---------------------------------------------------------
Date: Wed, 31 Aug 1994 09:41:50 -0700 (PDT)
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: David Garth <dgarth@cymbal.aix.calpoly.edu>
Subject: hot water and shower at last!
I've been experimenting for a few months with different hot water schemes
for my Westy. I finally have developed one which is safe and efficient,
and I thought I would share it in case anyone is interested.
I had already replaced the oem water pump with an RV type pressure
sensitive demand type. These pumps are only about $50, and are easy to
install in the compartment above the tank. New pressure water line needs
to be run to the compartment under the sink, and then teed into the
pressure line (grey) which goes up to the faucet. (Water will leak out of
the old non-pressure unneeded line unless you cap it.)
My previous experiments had convinced me that it was too difficult and
dangerous to run the coolant lines through the water tank. So instead I
built a small 8" water to water heat exchanger. It's just two tight flat
coils of 3/8 copper tubbing soldered together. Coolant flows through one
loop, water from the tank in the other loop. I located the heat exchanger
right behind the rear heater, so it was easy to tee from the heater hoses.
The trick is controlling the heat...and I'm quite proud of my solution.
For $10 I was able to get a new water bed heater control unit. This is a
mechanical one, not solid state. It was built to switch 110v, but it
works just great on 12v if you just use it as a switch. The temperature
probe goes inside the tank at the bottom. I set it to 100 degrees.
A small selenoid sprinkler control valve is connected to the water bed
controller. When I turn on a "water heater" switch, 12v from the ignition
switch goes to the valve, opens it. This turns on the pump, which pumps
water through the heat exchanger, and back to the tank. When the water
get to 100 degrees, the valve closes, and the pump shuts off. The water
stays at exactly 100 degrees as long as the engine is running. It stays
warm for many hours after shutdown.
I have also installed a hand shower in the little space at the rear
opening to the left of the A/C blower. 13 gallons of hot water is plenty!
--Dave Garth
San Luis Obispo
