[AT] WAY off topic HVAC question

[charlie hill]

Well I guess it's not off topic if I use the unit to cool my tractor
workshop.  grins. If anyone is interested and/or can help answer my question
please read on.  Others please ignore.

I recently acquired a Single Packaged Air Conditioning system.
It's one like you typically see on manufactured houseing units.  The
complete system sits out side and flex ducts serve as supply and return to
and from the house.  All of the labels are gone except the brand name but as
best I can figure out it is an Intertherm P3R A30.

Now here is the problem.   I test ran it today to make sure it was good
before I spend money to buy flex duct etc.   We wired it up and since we
didn't have a thermostat handy we just connected the two thermostat wires
together.  The compressor and fan both came on and it started to blow cold
air.  GOOD.  Then in about 10 seconds or so it stopped.

We fooled around with it for a while and could not get it to come back on
until we decided to put current to the accessory fan wire that would go to
the thermostat if the unit had accessory heat strips in it for winter use 
(purple wire).
We did that by connecting that control wire to the two thermostat wires.

Once the fan was running there was a delay of maybe 10 seconds and the
compressor came on.  It ran flawlessly as long as we had the accessory fan
control wire hooked to the two thermostat wires.  The delay makes sense
because there is a little circuit board that appears to be a delay circuit.
I just can't figure out what is wrong that requires that other fan control
wire to be connected.  Anyone have an idea what is going on?
Everything is just like the unit was disconnected from it's original 
location.  The purple wire was taped up and had never been connected before 
as far as we could tell.

Thanks

Charlie