Author Topic: Very little heat (again)  (Read 20936 times)

jeffc280sl

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Re: Very little heat (again)
« Reply #25 on: January 29, 2010, 22:50:59 »
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« Last Edit: January 30, 2010, 16:46:30 by jeffc280sl »

Largeowner

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Re: Very little heat (again)
« Reply #26 on: January 30, 2010, 00:57:10 »
Maybe we could conduct a straw poll. 

Everyone who cares to participate can select full hot on the dash (driver side).  Then pop your rubber firewall cover.....If the heater valve linkage is aft, your door is closed (horizontal).  Linkage forward equals door open (vertical).

I am curious how this will turn out.

Large

jeffc280sl

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Re: Very little heat (again)
« Reply #27 on: January 30, 2010, 02:23:03 »
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« Last Edit: January 30, 2010, 16:46:50 by jeffc280sl »

bpossel

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Re: Very little heat (again)
« Reply #28 on: January 30, 2010, 11:48:36 »
Jeff, you stated ..."When the flapper is in the down position the heater lever should be at the right stop and towards the smaller end of the red cone emblem.  The heater core valve should be in the off position resting against its CW stop.

As the heater lever is moved to the left and towards the larger end of the red cone the heater flapper will move to the vertical position.  As it moves to the vertical position the linkage arm attached to the flapper rotates the heater core valve 90 degrees or so CCW to the open position...."

Andy, you stated ..."one could say that when the flaps are "vertical" that air is directed directly down into the air distribution box, and that when the flaps are "horizontal" the air flows forward and then down to the heater core..."

So to summarize....  heat on, flap up.  heat off, flap down.  With the flap up there is no air directed down to the heater core?  Sorry to beat this one to death, but I want to ensure that I have my valve installed correctly.  Also will help solve Large's questions...

Thanks!
Bob

awolff280sl

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Re: Very little heat (again)
« Reply #29 on: January 30, 2010, 12:59:21 »
Bob, using your photo, you can make out the fins of the heater core in the space forward of and below the flap. The flap is in the horizontal position, thus closing air access to the distribution box from the top. In this position, the heater core valve should be open.
When I redid my entire system, I kept in mind the "heat in the cabin problem even with the valve closed" problem I was having. Among several other things I did to try to remedy this, I wanted to eliminate air flow across the core even with the valve closed. I did this because I think that the core remains warm even with the valve closed due to heat conduction at the valve. I also noticed that the rubber seals around the flaps are actually doubled-sided and are designed to seal off air flow both when the flaps are shut vertically as well as when shut horizontally. So with this in mind, I made sure to set up my cables and levers so that my flaps will seal tightly when vertical against the metal edges that define the opening for air to flow toward the heater core. The net effect of this is that when my flaps are vertical, the lever knobs are not fully max'ed out against the ends of their slots so that enough sealing pressure can be applied.
Andy   Sarasota, FL
'69 280SL 4speed
'06 Mitsubishi Evo

bpossel

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Re: Very little heat (again)
« Reply #30 on: January 30, 2010, 13:14:29 »
Andy,

Does this then mean that the picture of the heater core valve that Largeowner posted below is accurate?  When the flap is down, the metal rod would pull the valve CW towards the back of the car (heat on).

Correct?

Thanks,
Bob

awolff280sl

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Re: Very little heat (again)
« Reply #31 on: January 30, 2010, 13:24:25 »
Bob, you cannot rely on the picture because it doesn't tell you in which direction the hole in the valve is pointed. Someone on the forum once wrote that you can determine the location of the hole in the valve by removing the hose and passing a stiff wire through the pipe towards the valve. The wire will pass deeper when the hole is pointing forward, and this means that the valve is "open", and the flap should be horizontal (down).
Andy   Sarasota, FL
'69 280SL 4speed
'06 Mitsubishi Evo

bpossel

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Re: Very little heat (again)
« Reply #32 on: January 30, 2010, 13:35:24 »
Thanks Andy,

I took that picture, its my car prior to the restoration last year.  I know that the valve hole is pointed toward the front (open) when the "stop" is back in its CW position.

Jeff, what do you think?

bob

jeffc280sl

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Re: Very little heat (again)
« Reply #33 on: January 30, 2010, 16:31:36 »
Not wanting to rely on memory anymore I removed the cowl vent so that I could peer into the flapper valves and heater core.  I'm afraid my memory of how things were laid out is incorrect.  I thought the heater core was directly under the flapper valve.  I was wrong and I'm sorry for confusing the situation.

As Andy has stated, the heater core is forward of the flapper valves.  The flapper valves sit directly over the squirrle cage fan and distribution box.  Andy is correct again when he says the flapper valves seal air passages when they are up and down.  When vertical or up they seal the air passage way to the heater core.  When horizontal or down they seal the passage way to the fan and distribution box.  

When the drivers side lever is slid to the left, towards the large end of the red cone,  the heater core valve should be in the open position and the flapper door should be down or in the horizontal position.  It works the same way on the passenger side.  When the heat is off the flapper valve is vertical position the heater lever is to the left and towards the small end of the cone.  When the heater lever is slid to the right and to the larger end of the the cone the flapper valve moves to the horizontal position.

Again, I'm sorry for the confusion.  I hope this explanation is of use.

I have deleted my earlier posts so that they do  not confuse anyone in the future.
« Last Edit: January 30, 2010, 16:49:31 by jeffc280sl »

bpossel

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Re: Very little heat (again)
« Reply #34 on: January 30, 2010, 17:25:47 »
Hi Jeff,

Thanks for checking your setup.  That is what makes this forum great!  Good exchange of information.
I was ready to correct my setup if it was wrong and update the tech manual accordingly.
On to the next discussion...
Thanks Jeff & Andy!
Bob

Largeowner

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Re: Very little heat (again)
« Reply #35 on: February 01, 2010, 15:34:49 »
Thanks for the great discussion guys.  Looking forward to having some heat!

Large

jeffc280sl

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Re: Very little heat (again)
« Reply #36 on: February 01, 2010, 17:05:14 »
Large,

Now that we know how the heat is supposed to work what are your plans?

Largeowner

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Re: Very little heat (again)
« Reply #37 on: February 02, 2010, 14:55:45 »
Jeff,

The next stop is ducting.  I will look to see if I have any blockages.

Thanks again for the help,

Large