Hi Geza,

    If the conversion was done right, it will have "quick" connect service
ports, and a information decal.
    If all you want to do is check the compressor operation, just hit the
low side with about 70 or 80 PSI of air! This will fool the low pressure
switch and let the compressor come on.
    If the system has a large leak you should be able to hear it easily. If
the leak is slow, mix some dish soap and water in a spray bottle and go
around the system spraying. Any slow leaks will show up as bubbles.
    The conversion to HC 134a is a little lengthy for the list. But if you
need to do that drop me a personal E-mail and I'll walk you through it.

Howard

>
>Subject: Need help on R-134 question

> Is there any obvious sign that an R-12 A/C system has been converted to
R-134?
>
> Anyway, I wanted to fill it full of R-134 and see if I can get the
> compressor to kick on, etc., but am not sure whether the system's been
> converted or not.