Date: Sun, 10 Oct 1999 09:41:09 -0400
Reply-To: Bulley <gmbulley@BULLEY-HEWLETT.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Bulley <gmbulley@BULLEY-HEWLETT.COM>
Subject: HOT HEAT in an air-cooled van,
(VERY long) was: 12 volt heater suggestions
Dennis-
You don't need or want an electric heater. You already own a fantastic heat
system...what??? You don't believe me?
Well, a couple of years ago, my wife and I poured a heap of $$$ into a 1976
van to preserve and improve it. The least expensive aspect of the project
was making the stock heater WORK. When we were done, we were able to
comfortably sit in shirt sleeves in the van when it was 0 F degrees
outside. In our 1982, the heat coming out of the front ducts is now so hot,
you cannot hold your hand over it from more than a second or two. This,
without adding expensive or complicated furnaces, electric heaters, etc. I
have cc:d the type 2 list with this note, although I am not currently on
that list.
I built a website that chronicles to whole project
http://www.bulley-hewlett.com/VWindex . Since some of the early parts of
the project contributed to our heater's performance (like fully insulating
the body), I would recommend at least scanning the pages from start to f
inish, so you get the baseline info you need. You don't need to do all the
stuff to drastically improve your heater's performance. The "heat" portion
of the site is only partially complete, but I will fill in some details
below. There is a graphic (on the heat page) that shows all the components
of the stock system. And the changes we made. The text below relates to
that graphic.
First, here are the things that can prohibit the stock, VW air-cooled heat
from effectively heating your van (starting from the source, to the vents
(**items require modification):
1. **Failure in design to recycle heated air from inside cabin (all air
pulled into heater is ambient, COLD air)
2. (some models) Lack of blower speed (auxiliary blower) to push air
through heater boxes.
3. Leaks in ducting leading to heater boxes.
4. Leaks in heater boxes.
5. Leaky seams around heat riser tubes (run from boxes to heat valves
'flapper boxes').
6. **un-insulated heat riser tubes
7. Un-adjusted, leaky, or non-functional flapper box valves.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Now up to that point, if you have one, or many of these problems, you don't
actually have a complete heater. That is, you aren't actually capturing the
enormous amount of heat available from your exhaust system. Now here's the
rest of the list:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
8. **un-insulated heater duct mufflers (those black plastic accordion
looking things).
9. Leaky junctions in main pipe
10. Leaks or tears in main pipe
11. **un-insulated main pipe
12. **front auxiliary fan to suck heat forward
13. **un-insulated van, which allows ALL heat to leak directly back to the
atmosphere without impediment.
Some of the above call for complicated efforts. Some are quite inexpensive
and easy to accomplish. In the near future, our site will go into great
depth on ALL of the above with photos and diagrams just like on the rest of
our site. For now, here is a "quick hit" all air cooled folks can enjoy,
with nominal expense/effort.
The greatest impact you can have on your 1980 (Dennis) without heroic
expense and effort, is adjusting the flappers, and insulating the ducting.
It will cost about $19, and will take about 5-6 hours. Assuming that your
heater boxes/flappers are in good shape, this project will DRAMATICALLY
increase the heat in your van. Fair enough? Good.
What we are going to do: Adjust the flappers, insulate the entire ducting
system, from the heat noise mufflers to the front of the van. For those of
you who aren't Dennis, I am writing the instructions for a 1980 Vanagon.
Any type 2 van would be nearly identical, except the routing of the hose
over the fuel tank.
Here's what you need.
1. A 25' box of 4" Inside Diameter R-4.3 insulated Mylar(r)-cased flexible
household ducting. (you can get this at an HVAC specialist. Home Deep-ho
won't have the 4" ID, only 6". Remember, you want 4"!!!
2. A dozen 20" cable ties.
3. Jack stands
4. A partner (for about 10 minutes)
5. Scissors, wire cutters, goggles, a straight-blade screw driver, a pair
of pliers, and a 6mm open end/ring wrench
What to do.........
Jack up the van. Disconnect the battery. Get all your tools under the van.
Put on your goggles. Scoot under the van, and locate both flappers.
On the dashboard, have your partner fully open and fully close the heater
control lever in a continual oscillation so you can inspect the flappers.
On either side of, and just above the transmission, look for a thin cable,
connected to a short (2") control arm by a spring and barrel bolt
arrangement. The control arm should be moving forward and aft, with the
motion of the cable as your partner opens and closes the valves.
You want to make sure they FULLY OPEN when the cable is under tension, and
the control arm is FORWARD. You can be sure they are fully open if, when
your partner has the lever in the fully open (HOT) position, you see the
spring on the end of the cable compress against the control arm.
Alternatively, when the cable is under tension, make sure there is no more
than 1mm-2mm additional movement the control arm 'could' make, if the cable
were tighter. I have never seen a bus where these are properly adjusted,
unless the owner has recently done it.
If the control arm isn't opening the flappers enough, you aren't getting
all the heat available. Using the 6mm wrench, release the barrel bolts, and
adjust the cables so that when the dash lever is in the fully open
position, the flapper valves are fully open. Done? Great.
Next, let's insulate the ducting. Leave the van on jack stands. We will
start at the front.
Remove the spare tire from its carrier, and remove the front grill. Behind
the grill, release the clamp holding the top of the duct to the plastic
fitting that leads inside the van. Release or cut the cable ties that hold
the duct against the body, and pull the duct gently down into the area w
here the spare tire would normally lie. We will insulate from the front
edge of the fuel tank, to the fitting going into the dash. We won't
insulate the duct going over the fuel tank, as it would be too tight of a
squeeze, and would probably cause rusting by holding moisture against the
top of the tank when it rains...
Open the box of Mylar(r) ducting, and measure out the same length PLUS 8"
as the ducting under the van, from the tank, to the fitting...remember, ADD
8". Cut the ducting with scissors, and wire cutters. You will notice that
this ducting has four (or three, depending on manufacturer) layers:
LAYER 1: an inside tube of wire-reinforced Mylar,
LAYER 2: a thick bat of Fiberglas insulation surrounding,
LAYER 3: a mesh of reinforcing cords, some manufacturers don't use the
reinforcing mesh. It doesn't matter for our use. And
LAYER 4: a sturdy outside casing of thick Mylar.
This ducting will fit PERFECTLY over your existing paper ducting. Slide the
entire group (all four layers) of new ducting over the old ducting. Now
comes the IMPORTANT part. You MUST seal the new ducting so that water can't
seep in, and get to the fiberglass. At the fuel tank end, trim Layers 1, 2,
and 3 back to about 1" from the place where you will stop insulating
(probably just about over the front axle). This should leave about 3" of
layer 4 to seal against the original paper ducting. Neatly gather layer 4
so that all of the extra Mylar is at the bottom of the duct. Using your
cable ties, secure layer four against the dusting, and trim off any excess
Mylar.
On the other end of the duct, perform virtually the same sealing procedure,
trimming back the inside layer, leaving the outside protective layer. But
you can use the existing screw clamp to seal the ducting as it passes into
the body. Make sure you can feel fiberglass batting evenly around the
entire length of the duct, that there are no "bunches" and no bare spots.
Adjust the insulation as needed. Replace any cable ties that held the
ducting. The outside protective ducting should be smooth, not wrinkly and
slack, but not TIGHT. Tah-dah! That was easy, huh?
Follow the same procedure for the main duct, running from the junction box
(just in front of the transmission) to the rear of the fuel tank. Use cable
ties to seal the tank end, and the existing screw clamp at the rear. Make
sure you re-hang the duct securely with a couple cable ties.
The procedure is a little different for the black plastic heat noise
mufflers. Remove the mufflers completely by releasing the screw clamps, and
gently pushing the mufflers off the junction box, and the flappers. Make
sure you include the silicone rubber seals with the mufflers.
Again, cut ducting +8". This time, remove the inside tube (LAYER 1)
completely from the new ducting, leaving only the fiberglass batting, the
mesh, and the outside Mylar. Slide these three layers over the mufflers,
and neatly gather the Mylar to pass UNDER the screw clamps that hold the
mufflers to the flappers/junction box. Make sure the clamps are still loose
enough to allow you to fit the mufflers. Trim off the extra Mylar. I'm no
dope smoker, but if you do this right, the results will look like a couple
of big, fat joints.
Re-install the mufflers back on the van, and tighten the clamps.
Tah-Dah!!!!! That's it. You have just insulated most of your ducting.
Unless, you want to get REALLY gung-ho, and insulate the junction box,
which helps a lot, that is it. Take the van off the jack stands, take of
your goggles, and hook the battery back up.
Now here is the fun. Start the van, and go for a spin with the heat on. Did
you have to open a window? Next, WITH CAUTION, slide up under the van, and
feel the difference in temperature between the outside of the insulated
ducting, and the un-insulated portions (over the fuel tank, or at the
junction box). Amazing, huh? All the heat going to waste.
Don't throw that extra ducting away, as you will need some of it for the
next "phase" of this project, recirculating the heat...that is another day
though....
Hope this helps. Again, those of you on the type 2 list, I ain't on your
list, so, cc: me with questions, if need be.
G. Matthew Bulley
Director
Bulley-Hewlett & Associates
www.bulley-hewlett.com
Cary, NC USA
888.468.4880 tollfree
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The cold is comin'. I'm looking to supplement my 80's heat
situation.....and
it needs it. Thanks in advance.
Dennis
New Hampshire
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