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Is there a "recirc" for heat?


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5 minutes ago, Doubletrouble said:

 But with the a/c on in max position it would at least still help to remove excess moisture from the cab.

Yes it would, but not all the time. And in spring and fall I hardly ever turn ac on, no point wearing out ac system for no reason. I run it enough through the year to exercise it.

Plus it gives me more selections without turning ac on

Next I need a switch to shut blower off, no need for it on the hwy

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1 hour ago, Dieselfuture said:

Make sense, the only problem is it still turns ac on. Now if you're like me and put a toggle switch on to shut off the ac compressor then it becomes a recirc. 

 

Almost true.  When the selector is placed in the Max AC position, two separate things happen.  1.  the AC compressor circuit is activated. (but the ac compressor does not necessarily turn on).   2.  the vacuum controlled door that controls whether fresh air enters the cabin or whether cabin air is recirculated within the cabin shifts to cabin recirculation mode and stays there regardless of whether the ac compressor is running or not.  

 

My point in my earlier posts is that once the outside air temperature falls well below freezing for several hours (and the engine has been shut down overnight)  the static refrigerant pressure will be so low that the low pressure switch likely will not allow the ac compressor to be turned on.  Even if it does turn on, the cycle will be so brief that it will have very little cooling effect.  So, @Dieselfuture, even if you turned on your AC compressor toggle switch under those conditions, the compressor still would not turn on and the air would still be recirculating in the cabin.

 

I am thinking that you may already know this - I am just trying to clarify.  Thanks for you patience.

 

On 12/15/2020 at 10:35 PM, Doubletrouble said:

Thought it might be useful on the really cold days. 

 

@Dieselfuture, I am basing  all my posts on above statement in the original post.  Unfortunately, the description "really cold days" can have different meanings for different people.  For me a 45 degree day does not fit that description - a 25 degree day does.  On a 25 degree day the compressor is not going to run, so warming up the cab in the recirc mode could work well.

 

1 hour ago, dripley said:

Itmdoes max ac but i believe that it has a little recirc arrow on it too.

 

No arrow on mine, just a snowflake symbol.

 

- John

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  • Staff

 I agree @Tractorman, a "really cold day" is a matter of perspective. I am in the same mind set as you, 45° isn't real bad but you get down into the 20's it gets a bit chilly. Mainly I was thinking using this to warm up the cab faster at the beginning of the day or trip then just running like you normally would any other time.

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I think that just might work.  It look like the nights are going to be dropping to around 12 degrees here in about five or six days from now.  I think I will park my truck outside one of those and test the theory when I start the engine the following morning.

 

1 hour ago, Doubletrouble said:

45°

 

How did you get the degree symbol in the 45 degrees?

 

- John

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1 hour ago, Doubletrouble said:

a "really cold day" is a matter of perspective.

45° is cold to me.  Heck, when it goes below 59° I'm getting cold.

 

28 minutes ago, Tractorman said:

How did you get the degree symbol in the 45 degrees?

I go to the character map pull up Cambria math font, find what I need select, copy and past..   

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4 hours ago, Tractorman said:

 

You're on the Board of Directors - can't you make him wait?

 

 

 

John

He aims his rocket launcher at my house when I do.

 

I will have to do this mod. Starting with my work truck. Thanks for the link.

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1 hour ago, Tractorman said:

I think that just might work.  It look like the nights are going to be dropping to around 12 degrees here in about five or six days from now.  I think I will park my truck outside one of those and test the theory when I start the engine the following morning.

 

 

How did you get the degree symbol in the 45 degrees?

 

- John

 On my android phone when you hit the button for the numbers the upper case key changes to =\> for symbols, hit that key and they come up.

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I was in a similar situation. I typically use the floor/vent combo almost exclusively. I just like it that way. Unfortunately in the winter, the AC would always run. I simply added a switch to the low pressure valve and can turn the AC off whenever I choose. Works great

 

Later

D

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9 hours ago, Tractorman said:

So, @Dieselfuture, even if you turned on your AC compressor toggle switch under those conditions, the compressor still would not turn on and the air would still be recirculating in the cabin.

Make sense, I still like the control like some older cars I had, all had bottoms for ac and fan. I really don't care for new cars how on most yore forced to like what they give you.

7 hours ago, JAG1 said:

 

I will have to do this mod. Starting with my work truck. Thanks for the link.

Are you talking to me :think: if you are make sure you read my post to the end, wire to cut and splice changed in my conversation with @IBMobile because it was all his thinking on that, I just asked a question on how to. I think you can see which wire to splice in the picture.

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8 hours ago, IBMobile said:

I go to the character map pull up Cambria math font, find what I need select, copy and past.. 

 

When I go to the character map, all I get is a list of the guys on the Board of Directors for this site! 

 

8 hours ago, Doubletrouble said:

On my android phone when you hit the button for the numbers the upper case key changes to =\> for symbols, hit that key and they come up

 

So it looks like you are using your phone to reply to posts. I am still using my laptop.  I did go on line and found out how to do it on a windows based computer.  So, with some ° of difficulty I can do it now.  I have to hold the ALT key and select 0176 on the numeric keyboard.  Someone with a ° must have thought  this up!

 

- John

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16 hours ago, Dieselfuture said:

Make sense, I still like the control like some older cars I had, all had bottoms for ac and fan. I really don't care for new cars how on most yore forced to like what they give you.

I am traditionally fond of more control vs less, why I like the old mechanical controls like my friends 54 Olds. 

 

Prius allows you to recirc or fresh air any of the vent settings and a has dedicated a/c button. Also has a filter button where it does a full recirc through the filter for a few minutes for smells. I never smell skunks or paper mill in that car. Neat system. 

 

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 I tried switching to the "max" setting yesterday to try the recirc theory. It works. The vent temp went up shortly after switching which was expected. Then slowly got warmer since it was reheating the same warm cabin air. So, this does work, I didn't not however hear the a/c compressor cycle but it was a chilly 25° outside.

 Just thought I'd update my findings.

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What you are reporting is what I would expect.  Good to know that it warms your cab faster.   I had the perfect opportunity to experiment with the recirc setting the other morning as it was down to  15°.  But..., I forgot to park the truck outside.  I should get another opportunity soon.

 

Thanks for reporting back.

 

- John

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On 12/17/2020 at 10:07 PM, Tractorman said:

 

You're on the Board of Directors - can't you make him wait?

 

In my opinion the "Max AC" label is a poor choice of words to describe the function that is being performed.  How about calling it "Recirc"? -  since that is what it does.  After all, that is what most other auto manufacturers call it.

 

John

Kinda funny, my Chevy has seperate MAX and A/C buttons. MAX lights up an icon that says RECIRC. Pressing one does not activate the other. Not sure why Chrysler and later Daimler thought that it would be better not to have a seperate button.

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  • Owner

Never had a reason for Recirc on heating positions. When its pouring 160*F to 170*F out the center vents when is ZERO outside is no problem. Never had a need for recirc on heat. I'm here in the subzero land too.

 

Dodge has had this vent control layout for YEARS! My 1976 Dodge Power Wagon, 1973 Dodge Charger, 1978 Dodge Magnum, 1996 Dodge Ram and even my 2002 Dodge. 

 

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  • Owner

Yes I've got grill inserts I bolt on in the winter but I've been forgetting to install this winter. My engine oil temp is now as low as 158 to 162*F which is getting to cold for my liking. Coolant is 188 to 195*F. MPG is down about 18 MPG without the winter fronts. Engine needs more heat to light the fuel off properly. 

 

Winter Front For Dodge Cummins - Truck Exterior - Mopar1973Man's Dodge  Cummins Forum

 

My winter front does not interfere with the radiator or the intercooler. If the coolant temperature rises too much the fan can still lock and pull the heat out. Same with the intercooler if there is heat generated the fan can still cool the charge air without a huge loss. Majority of the grill face is covered and the direct cold is not blowing direct through the face at 65 MPH. BHAF typically gains me about +10*F after the grill is covered. MPG should rises again.

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