Keystoker sells furnaces as well
Just a heads up, the Keystokers are not ASME certified and may not be allowed in a commercial application. Check you local building codes,I know at least one state requires that for home installations as well. I know there was one forum member that run into difficulty after installing one and only got approval after the inspector got in contact with Keystoker.
All EFM boilers are certified, the AHS units come in certified or non certified version I believe... the difference is $2000 and the stamp.
I'm pretty sure the AA's are certified too. Check with them.