I need ballasts for eighteen F72T12CW not high output lamps for some old cooler doors. One door has 3 lites........one has 4...........one has 5 and one has six. I can find the high output ones but none other

Have you gone to the Advance Transformer web site?

Or Sylvania's web site?

try howard industries. we've found some weird cooler ballasts there.

The only ones I could find from Howard Ind were High Output

swap the sockets?

Some F96T12 ballasts could operate F72T12 lamps,will need to search further when more time is availible. (burning daylight )