| [GMCnet] Engine driven roof top AC to replace Dash AC [message #321319] |
Sun, 30 July 2017 17:06  |
Thomas Pryor
Messages: 143
Registered: January 2011
Karma:
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Senior Member |
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George Butts Wrote: We all know the dash AC does only a marginal job to
cool the front and forget the entire coach.
George "I believe you" when you made the comment that dash AC is
marginal. However, the cooling system is plenty "large enough" (capacity)
to handle "most" of our demands properly maintained. I do not believe
hanging more hardware on your coach is the answer.
The real issue is the HVAC (Heating, Ventilation, Air Conditioning) box AIR
FLOW . The Harrison Division of GM designed the system with no apparent
thought to air flow velocity .......OR..........the GM Truck & Bus guys
said "give me something that will fit into this space"! So we got a system
that only pressurizes the HVAC box and ignores air velocity and direction.
Most of us are aware that the blower on a traditional furnace located in
the basement of a home has a centrifugal fan that pushes air up
through the heating and AC coils to the registers on the 1st and 2nd
floors. That is what is most efficient. It is a Laminar Air flow model
with little Air Flow turbulence. Many Owners think that we have this
model for dash AC in our Coaches.
That is untrue.
Just think if, 1) a centrifugal blower fan in our home basement was
turned upside down and pushed air toward the basement floor 1st
..............and 2) was then was ducted to the right or left into the
chamber that housed the heating and AC coils! THAT CREATES TWO TURBULENT
AIR FLOW EVENTS! That is exactly the strategy our coaches have
employed..........no matter what year it was built and what attempts by GM
employed to rescue the design.
I have only minor exposure to "marginal AC" when traveling 5000 miles to
the Rally in South Dakota from Florida in my 23B. Yea it Sucks! I
recently posted on the GM Photo site a Modification that DOES NOT require a
complete revision of the HVAC Box or any of the controls. It is a one day
project for some, most will say a week end. It requires one Purchased
part ........a double centrifugal fan assembly and the construction of a
small duct from the floor of the coach to the HVAC box. If the
Centrifugal fan is used from my posting, removing wires from the existing
HI, Med, and Lo resistors on the driver side of the HVAC box and extending
them to the new Centrifugal Double fan is a trivial task. We now can look
forward to Laminar, not Turbulent air flow
SEE:
http://www.gmcmhphotos.com/photos/i-need-more-air/p63443-a-hvac-blower-modification.html
HOW CAN I HELP?
--
Regards,
Tom Pryor
4188 Limerick Dr
Lake Wales, Fl 33859
Cell 248 470 9186
Living on a waterfront is not a matter of life or death. Its more
important than that.
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