Heater Core Air Distribution

[japollon]

Is the amount of heated air that flows out of the heater core box the same at all four ducts? I'm not installing the defroster vents. I'm in California and I don't think they will be necessary. It would be more convenient because of routing for me to use the upper, round ducts to supply the heater vents. Does it matter???

Thanks, Joel

[carlewms]

Joe,

I am assuming your using the standard FFR heater and I have not actually run my heater yet ... so this is not from experience but observation.

The size of the holes for all four holes are the same so the flow out of each should be close to the same and it should not matter to you. What would impact you is the resistance to flow in the individual lines ... the longer vents with more turns would have more flow loss.

In my still untested solution I have the two of the vents going to the PS ... one pointed down and one pointed out from the footbox. Two go to the DS but on one I have a "Y" connection to the defroster plenum (I live in Northern VA) with flow controlled by a blast gate ...

Here is a diagram of how I The number of outlets I prepared this diagram showing what I "think" i want to do or try.

https://im1.shutterfly.com/media/47a6d711b3127cceed69fd0d9ce900000030O09AaOGbRo2bA9 vPhg/cC/f%3D0/ls%3D00006064438420160930102505186.JPG/ps%3D50/r%3D0/rx%3D720/ry%3D480/

Here are the notes from the drawing since they are a little hard to read ...

Installation Notes

1. Red = 2" ducting.
2. Blue = 3" ducting for Outside Air
3. F = Forward Facing Round Louver
4. D = Down Facing Round Louver
5. 2"BG = 2" Aluminum Blast Gate controlled from DS of cockpit
6. 3"BG = 3" Plastic Blast Gate controlled from Heater Fan Control Knob

Operations Notes

1. Heat: Maximize heating by closing both blast gates.
2. Defrost: Maximize defrost by opening 2"BG and close louvers.
3. Cooling: Maximize cooling by keeping HCV shut during warmest months and opening 3"BG
set it up ...