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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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Posted: Mon Sep 01, 2014 8:36 am Post subject: Installing A Fresh Air Shut Off Flap |
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I'm rebuilding my front Heater Assembly, the normal stuff, clean lubricate the fan motor, new heater core, new foam on the heater doors and cleaning up all of the mouse piss and crap!
I'm trying to understand the air flow concept.
Four (4) levers.
1. Controls the hot water heater valve. On/Off/Partial
2. Controls the flap for the fresh air into the front crash beam that delivers air to the rear of the Van. Open/Closed/Partial
3. Controls air to the Defroster Vents. On/Off/Partial
4. Controls air to the front footwell in front of the gear shift (I don't have the floor duct to the rear passenger area but some do) On/Off/Partial
And then there is another Flap, two actually that swing free. They open into the Fresh Air Intake chamber.
EDIT: officially called the "Forced Air Flaps"
These confuse me.
It seems to me that whenever the Van is in motion, Air being rammed into the heater box will simply push these flaps open thus pressurizing the heater core and forcing air out of the various flaps that levers 2-4 control.
There is a third exit out of the incoming air box and that goes into the blower fan, there is no flap, just the squirrel cage for the fan.
It is obvious that There is no way to shut off fresh air flow just as there is no way to heat using cabin air.
My question....... What do these flaps control?
Is there enough force from the fan motor to blow them shut as the fan pushes air out of various controlled vents?
EDIT: I'm guessing that if you are stopped and the fan is running, these Forced Air Flaps will swing closed by gravity and your blower fan will not be blowing air back out of the Vans front grill but instead continue the flow of warm air to the passengers?
If it is true that these flaps swing open when in motion, the blower fan with it's assorted speeds is basically rendered useless except when stopped or when driving very slowly??
Just call me confused, I'm sure there is a logic to it all but right now it is eluding me.
Air box towards fresh air inlet, it's dirty and the mice have been in here!
Screw driver point resting on closed gravity air flap (there are two of these flaps but just one close up in photo).......
Handle of screwdriver holding open the same gravity air flap.....
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert
Last edited by djkeev on Sat Sep 13, 2014 2:42 pm; edited 6 times in total |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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Posted: Mon Sep 01, 2014 4:45 pm Post subject: |
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So I'm coming up with a theory.
I've been looking at, working on or walking by this heater box all day, puzzling quite a bit over the design with the free swinging Forced Air Flaps.
If the defroster flaps are closed, the crash Beam duct rear air flaps are closed and the Heater Flaps are closed air hasn't anywhere to go so it doesn't. There will be flap leakage, it's inevitable at speed, so is this VW continuos cabin ventilation that the Feds mandated? Controlled air infiltration?
As soon as you open a flap...... Any flap the air will come rushing in pushing open those flaps and flooding the cabin with cool or hot, air as the driver desires?
The pipe to the rear cannot produce heated air, only cool air can pass. The only heated air possible is forced into the dash area.
The fan is really only there to move air when forward motion has ceased.
How forceful the air comes out of vents is determined by how many vents are open and how fast you are traveling along the highway.
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
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https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
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adv rider Samba Member
Joined: September 09, 2012 Posts: 288 Location: Everett,wa
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Posted: Mon Sep 01, 2014 10:25 pm Post subject: forced air |
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I agree with your theory about the fan only being needed when stopped or moving slow. My van's blower stopped working 2 yrs ago-but I have no issues staying warm, or keeping windows defrosted.
Only when not moving, do I have fogging issues. So I just turn up my rear heater. I have a new blower, but since the forced air works fine. I am in no rush to pull the dash. _________________ 86' Wolfsburg weekender 2.1, 4spd, , merian brown |
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alaskadan Samba Member
Joined: January 09, 2013 Posts: 1849 Location: anchor pt. alaska
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Posted: Tue Sep 02, 2014 8:19 am Post subject: |
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I came to same conclusions when I had my heater box out. Seems what looked like a newer heater core started to let off a little coolant smell a couple months after doing my blower motor. When I get in there again I will look into a way to close those flaps when I want to. There has been a fair amount of discussion on this and some have closed them permanently. My reason is mainly to stop dust from getting in on a dirt road when someone is in front of you. Might be better to add a flap out in front of them that blocks the air intake "tunnel" while also opening an area that lets cabin air recirculate. |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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Posted: Sat Sep 13, 2014 5:19 am Post subject: |
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Sometimes, I think that I think too much and go getting myself in trouble or creating more work for myself!
My conclusion on this Heater/Fresh Air system is quite simply that it Sucks!
----------------------
So............
I've been pondering this uncontrolled fresh air infiltration problem for a long time now.
This post has thus far produced precious few if any solutions as well.
So, I'm thinking........
"There is a LOT of fresh air ramming into the heater box while driving, you cannot ask a few wispy foam rubber seals to totally stop this onslaught of air.
There has to be a way to stop the vast majority of the air BEFORE it hits the heater box, the foam seals CAN easily contain a little air......."
I'm looking and thinking that I need to come up with a way to EASILY ..........
1) shut off the air ram effect that does not involve stopping, getting out tools, remove the front grill, get a roll of Duct tape or what have you and tape over the air intake opening......
2) controlled remotely via Cable somehow........
3) this new flap when closed will be pushed tighter shut by the wind velocity rather than pushed open by the wind.......
4) the sheer volume of fresh air opening seems rathe large, why so many square inches? Is it so the rear fresh air system can really put out the blast?
If I were to reduce the square inches of fresh air say by half...... I don't see that would seriously alter the comfort of the front seat passengers.........
5) I also need to be able to easily recirculate interior air.....
6) be able to seasonally easily shut off the hot water flow to the heater core.....
7) be able to direct warm air out of the side dash vents......
Hmmmmmmmm..........
All the while using the factory Heater Box, not a HUGE amount of fabrication work and not spinning big numbers... $$$'s.........
I read this article awhile back with great interest, while I currently do not plan on in dash AC his concepts are good.......
http://www.thesamba.com/vw/forum/viewtopic.php?p=6540000
here is a quote from it that I find interesting...........
Howesight wrote: |
There is no sense in having a front AC system if hot air can still come in through the VW fresh air ducts, so I installed closing flaps that will be operated by a vacuum servo. The flaps are also need for cool-weather de-humidifier operation since I am ducting some (not a lot) of chilled air into the Vanagon air box. Here are some pics of the fresh air closure flaps:
img]https://www.thesamba.com/vw/gallery/pix/1011101.jpg[/img]
I used 9/32 steel dowel, sheet metal, my MIG welder and some POR 15 for rust resistance. |
_________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert
Last edited by djkeev on Sat Sep 13, 2014 5:45 am; edited 1 time in total |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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Posted: Sat Sep 13, 2014 5:34 am Post subject: |
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Surfing........ Looking........ Thinking...........
I stumbled upon this thread again.....
http://www.thesamba.com/vw/forum/viewtopic.php?p=6507871
While I wouldn't totally block fresh air off, as Beetsport has done (and he bemoans having done so), I do see utilizing his block off concept..........
I'm thinking that if I Block off the drivers inlet completely and then on the passenger side (Right for you backwards Nations ) create a moveable cable controlled flap opening OUT and swinging DOWN into the Vans intake air chute...... Why the Right Side? Room to create a cable control flap system, the Left side is so full of wires, hoses, brakes and crap! For you "backwards" folk, I'd do the mod on the left side, your passenger side for the same reasons.....
Anyway, some quotes and photos from the above link......
Beetsport wrote: |
.............. The fresh air is blocked off. Your windows now will be the fresh air point of entry If going through this again I would design a fresh air entry with another blend door separate from the Vintage Air unit to switch between fresh and recirculation air. My concern would be noise from the fresh air coming in.............
Large Fresh air opening.
Fresh air blocked off.
............ |
_________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
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http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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Gnarlodious Samba Member
Joined: September 28, 2013 Posts: 2312 Location: Adobe Jungle USA
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Posted: Sat Sep 13, 2014 7:05 am Post subject: |
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Fresh air blocked off is a bad idea unless you live in Death Valley. You are going to find that warmed outside air is necessary to defog the front window in humid weather. If you need more heat you are better off wrapping foam insulation tubes around your heater hoses. _________________ Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50261
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Posted: Sat Sep 13, 2014 8:45 am Post subject: |
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I always leave the air to the back open unless I need full flow to the front for some reason. This lessens the pressure in the box and stops it from whistling. |
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Vanagon Nut Samba Member
Joined: February 08, 2008 Posts: 10347 Location: Sunshine Coast B.C.
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Posted: Sat Sep 13, 2014 9:27 am Post subject: |
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I don't know if this is of any use to you but.....
While doing my engine conversion, I needed to modify the heater box to accept a heater core. Since I'd experienced driving with no heat (air cooled engine, defunct heater), with the heater box on my bench, it occurred to me that by removing the fresh air ram flaps and blocking the fresh air flap openings, the box would recycle cabin air if the fresh air intake was blocked. I did so. Box on bench, even with 1/2 of the fresh air intake blocked, the box would pull air in via the side vents.
For some reason I had it in my head that a flap needed to be installed at the opening of the fresh air ram. I attempted this but the shape of the ram was beyond my fabricating skills at the time so it never happened. There is no flap installed there. The main air control flap works fine. When driving, if I close the main intake flap, there is virtually no air flow. I had resealed the flaps some years ago with close cell foam tape. It has held up well.
Neil.
_________________ 1981 Westy DIY 15º ABA
1988 West DIY 50º ABA
VE7TBN |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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Posted: Sat Sep 13, 2014 10:15 am Post subject: |
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Thanks for the photo!
Ideas, ideas, ideas!
I learned long ago, start with cardboard!
It's cheap, easy to cut and manipulate and most importantly rarely cuts you while you work with it!
A template to block off air flow.......
The Right Inlet Drawn upon the Template......
A cardboard door to see how much door I can make and any obstacles to being able to swing. Also how can I operate the door using a cable? ........
Hmmmmmmmm.........
While I think that making two air control doors able to work simultaneously is completely doable if I link them with a single rod............ Let's be honest, there are some huge obstacles to overcome.
I think that if I use one door for now, it will tell me if I'm heading in the right direction with minimal effort put forth!
Pulling the Heater Box really isn't all THAT much work!
To pull the dash again for modifications isn't out if the realm of possibility at a future date.
Everything I'm doing for this modification is absolutely 100% reversable except for a hole or two drilled.....easily fixed if need be!
Hmmmmmmm ......... looking at the fresh air box.........
I have space next to the upper Right mounting bolt where I can drill a hole to run an operating cable.
If I fasten a rod to the back of the door I can make a loop of cable to slip over the rod........... I of course need to make an adjustable cable housing holder below the Wiper Motor somewhere....... _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert
Last edited by djkeev on Sat Sep 13, 2014 2:46 pm; edited 4 times in total |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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Posted: Sat Sep 13, 2014 10:39 am Post subject: |
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See, almost 1 1/2" of space in the upper right of the air duct behind the dash metal........ The Green Tape Arrow points to the approximate area that the operating cable would pass into the fresh air chamber to hook onto a rod on the operating door........
Here is the same area with the Heater Box in place, lots of room to add a cable and cable support..........
And LOOK!!!!
All here in the Shop waiting to be used.
The best is the piece of off white 1/4" ABS left over from a task years ago that I will make the operating door from, rigid, easy to work and easy to glue......
Sheet Metal, ABS, ABS Glue, small steel rod for the hinge and the operating lever......... Cable...... I've got a cable somewhere in my stash!
It's time to design the actual door, make it out of cardboard, tape the rod to the door, insert operating cable........
Hmmmmmmm
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert
Last edited by djkeev on Sat Sep 13, 2014 10:48 am; edited 1 time in total |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32433 Location: Reading Pennsylvania
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Posted: Sat Sep 13, 2014 1:42 pm Post subject: |
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Testing the ABS Flap fit....... The hinge right now is a simple piece of Tape......
Trying to figure out how much room I have for making a hinge, I removed the ABS Flap and traced the Fresh Air opening onto the Sheet Metal
The flap removed with two tracings on the Sheet Metal.
The outer one with arrows is the Air Box opening in the Van Body,
The inner one is where the air flap sets and works clearing the Body opening......
--------------
Now for the HINGE.........
I'm thinking of doing a simple rod and pivot point hinge.
It's easy to make, cheap and I already have the rod!
Just a basic 1/8" steel rod available at any hardware store USA.
I will cut out the bottom edge that sets against the sheet metal about 1/16" deep by 1/8" wide. I don't want flush ti the sheet metal for I will be putting on a foam gasket to seal out the air when closed........ (The black arrows are the trace of the heater opening I made while I was test fitting the ABS door.)
Unfortunately when I do this, because I enlarged the size of the ABS flap I've shorted myself on hinge space! I am too close to the bottom edges with my hinge rod.
To fix this I will need to cut away just a tad of the Body as noted by the Green Arrows pointing at the two black marks where the metal will be removed.....
_________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
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