IronDoc,

This is a tough problem. A LOR from your program director may not be required but it is usually understood that applicants will have one--questions will be raised if there is not one. On the other hand, you should never turn in an LOR if you are unsure of what it says.

I don't mean that you should read it (that's either illegal or dishonest if you sign the form saying you won't), but it's perfectly fair to ask the letter writer about the general flavor of the letter. If the chairman says he barely knows you and can't write a strong letter, you should be able to fix that. If he says he thinks you are a tool and the letter goes on and on about your toolness, try and find someone who thinks otherwise and get them to write a strong letter.

i feel like i have to weigh in here...

i was in a similar situation. a previous graduate from my school made mention of the fact that our chairman's letters were not always strong and were usually anonymous (he did not get to know us all that well).

i only sent his letter to programs that specifically requested it, and at my interviews i was only asked once why i didn't submit one (and that was because i didn't send any letters from my program at all to that residency -- i ended up matching at that program though).

so take this fwiw, which is one isolated incident amongst ~1100 applicants last year.

if you are a good enough candidate with other strong letters, i can't imagine it would be a problem