Front air conditioner

[Jeff Miller]

Personally, I like the dash A/C. If at all possible, I prefer to
repair it. The original compressor might or might not work with
R134a, it is likely worth replacing it as it is already old.

In the past I have tried a couple of different things with the dash
A/C, and have learned the hard way. There is no relay to power it in
the early FCs, so the dash switch powers it directly from an already
overloaded wire. Running a relay for the compressor and condensor
fans will help the load on the dash power.

There is also no high/low pressure switch, so running the compressor
dry will happen, and eventually the compressor can seize and throw
the A/C belt. Often that belt takes others with it.

Adding at least a low-pressure switch is IMO mandatory, a high/low is
better still.

My '77 worked well, modified with a 3-groove pully on the alternator
to drive the A/C compressor with a short 3rd belt. This eliminated
the long and problematic A/C belt. Not a difficult conversion, the
compressor had to be moved forward to match the new pully groove and
put on a pivot for belt adjustment. Worked great.

My justification has always been that I'm stuck sitting in the sun
for sometimes hours, and the cold coach freezes everone else while
I'm still uncomfortably warm. I liked running the dash A/C, and the
rest of the A/Cs off of the inverter or genset only if others in the
coach wanted the cooling.

The other side of that debate is the cost of resurrecting the dash
A/C, the concern that the engine is already short on power in the
early FCs and couldn't afford to lose more to the A/C, and that most
of the time the coach A/C is necessary anyway.

Give me dash A/C and I'm happy.

- Jeff Miller
http://www.wanderlodge.net
http://www.millercoachworks.com


--- In WanderlodgeForum@yahoogroups.com, "fred89sp"
wrote:
> As I see it is a matter of personal preference and willingness to
pay
> for the repair.
>
> I is my perception that many of the FC owners opt to abandon the
dash
> air and run the roof A/C with the generator. I find that running
the
> generator on my 89SP creates vibration and noise up front which I do
> not like, it is especially noticeable at lower speeds. I also like
to
> have the A/C blowing into my face. If you have that, the overall
> ambient temperature is less of an issue.
>
> First you need to diagnose the problem. If it must be recharged
then
> you need to convert to R134a. Blue Bird advised me that to do so I
> needed to thoroughly flush the lines and install a new compressor
and
> drier. I had it done (compressor was Sentec 488-46021, Fleetpride
> 5798; drier was Sentec, Fleetpride 7218) and promptly seized the
> compressor.
>
> On the redo we used another compressor and drier but also installed
a
> Binary Switch (Schrader) part # 4379-RD46400 ( I believe a Mack #)
> which was purchased at Albany Truck Sales, in Albany NY. It is
> described as a high /low pressure safety switch for A/C system and
was
> installed at the compressor (do not know which side but probably
high
> pressure). Could find no reason for the prior failure and this
switch
> was installed to protect the compressor from the higher pressures
that
> I understand are present with R134a. I has worked fine for a
year.
>
> It helps to have a knowledgeable A/C technician who is willing to
work
> with you on a job that can be a pain in the neck.
>
> If you abandon the dash A/C it is certainly cheaper, you need to
> decide which you prefer.
>
>
>
> --- In WanderlodgeForum@yahoogroups.com, "williamcharrison"
> wrote:
> > The front air conditioner on my 90 SP36 doesn't work. Can it be
> > repaired or should it be replaced?