"Ignoramus31823" wrote in
message ...
On 2013-12-07, Jim Wilkins wrote:
Check valve from compressor to primary tank, another from secondary
to
primary. Normally-closed solenoid valve from compressor to
secondary,
opens when primary 90PSI. Can be switched off. Primary feeds shop
air
line....

jsw

This is EXACTLY what I wanted to do, except the filling valve should
open at 120 and close at 90. Thanks for explaining.

i

90PSI was a placeholder to simplify the explanation.

Your unloader may require another check valve going into the secondary
tank.
jsw