Heat/AC caveat: 2000-2004 Ford Focus (public service announcement :)

[Josh Wyatt-2-2]

Hello all,

I thought I'd share a discovery (and its implication) I made while converting my 2002 Ford Focus.  This applies to 2000-2004 Ford focii, and possibly beyond, since they all have the same air box design.

In this vehicle, the airbox is mounted behind the center dash.  Inside the airbox are the evaporator for the air conditioning system, as well as the heater core.  Both the evaporator and the heater core are positioned horizontally, one over the other ("stacked"), such that the air flow moves vertically through them both.

The heater core is located directly beneath the AC evaporator core.  Under the heater core is a plastic "pan" of sorts.  At the edge of this pan is the drain hole for condensation from the AC evaporator.

It appears very likely that condensation from the evaporator core could drip directly into the area of the heater core.  If you install a ceramic heater element, or other pure electric solution, in place of the heater core (like I did), do NOT keep the air conditioning!  As we all know, water and high voltage electricity are incompatible.

Next summer, when restoring the AC in my car, I will be replacing the ceramic element with a heated water/heater core solution.

Thanks,
Josh


--
Bob Pease and Win Hill walk into a bar...

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[Dennis Miles-2]

On Thu, Nov 12, 2009 at 2:52 PM, Josh Wyatt <[hidden email]> wrote:

> Hello all,
>
> I thought I'd share a discovery (and its implication) I made while
> converting my 2002 Ford Focus.  This applies to 2000-2004 Ford focii, and
> possibly beyond, since they all have the same air box design.
>
> In this vehicle, the airbox is mounted behind the center dash.  Inside the
> airbox are the evaporator for the air conditioning system, as well as the
> heater core.  Both the evaporator and the heater core are positioned
> horizontally, one over the other ("stacked"), such that the air flow moves
> vertically through them both.
>
> The heater core is located directly beneath the AC evaporator core.  Under
> the heater core is a plastic "pan" of sorts.  At the edge of this pan is the
> drain hole for condensation from the AC evaporator.
>
> It appears very likely that condensation from the evaporator core could
> drip directly into the area of the heater core.  If you install a ceramic
> heater element, or other pure electric solution, in place of the heater core
> (like I did), do NOT keep the air conditioning!  As we all know, water and
> high voltage electricity are incompatible.
>
> Next summer, when restoring the AC in my car, I will be replacing the
> ceramic element with a heated water/heater core solution.
>
> Thanks,
> Josh
>
>
> --
> Bob Pease and Win Hill walk into a bar...
>
> _______________________________________________
> General support: http://evdl.org/help/
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> =================alternate solution=======================

Josh,    Why not just put the ceramic heater element above the AC
Evaporator? Then any condensation drips away from the heater element. I seem
to recall from A-Cond Class that First airflow should pass thru the
evaporator for humidity control. then be heated to comfort level, so we feel
warmed dry air...
Regards,
    Dennis Miles,    (Director / CEO)
Electric Vehicle Technical Institute Inc.
Tampa Bay Region, Florida, USA
       Phone (863) 289 - 0690
"Mentoring, Small Group Instruction,
and Hands-On training
for the EV Technicians:
Building, Converting, Repairing,
and Servicing the
Electric Vehicles of Today,
and the Future."
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[Josh Wyatt-2-2]

Dennis Miles wrote:
> On Thu, Nov 12, 2009 at 2:52 PM, Josh Wyatt <[hidden email]> wrote:
>> The heater core is located directly beneath the AC evaporator core.  Under
>> the heater core is a plastic "pan" of sorts.  At the edge of this pan is the
>> drain hole for condensation from the AC evaporator.

> Josh,    Why not just put the ceramic heater element above the AC
> Evaporator? Then any condensation drips away from the heater element. I seem
> to recall from A-Cond Class that First airflow should pass thru the
> evaporator for humidity control. then be heated to comfort level, so we feel
> warmed dry air...
> Regards,
>     Dennis Miles,    (Director / CEO)
> Electric Vehicle Technical Institute Inc.
> Tampa Bay Region, Florida, USA

Hi Dennis,

Without seriously re-engineering that air box, including relocating the evaporator, replumbing the refrigerant lines, etc, I doubt it's feasible, although I have not completely disassembled the air box to see what's above the evaporator.

It's worth pursuing at least in the shop manual, though.  Stay tuned.

Thanks,
Josh


--
Bob Pease and Win Hill walk into a bar...

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