Bodgett has many controls and changes on the DFG. First you have to identify what control system you have and front panel. How many speeds etc. They have used everything from a simple mechanical to full solid state. And a mutitude of different wiring diagrams. Some used 24 volt to the centrifugal switch in the motor and with the many connections that can get resistance. Grounds are very important and also get high resistance. Not knowing what you have the best thing I can do for you is this manual; It will help you to identify what operating system you are working with.
https://techtown.partstown.com/external-link.jspa?url=http%3A%2F%2Fwww.blodgett.com%2Fwp-content%2Fuploads%2FDFG100-200-serv.pdf
download and save as it is being pulled down.
This is a previous one we covered about 6 months ago in detail.; https://techtown.partstown.com/message/6148-blodgett-dfg1xlaa-not-relighting
Now not knowing where you measured the 24 volts to the spark controller, do you lose it at the temp control , or at the gas control? If at the temp control, is the timer set? does the thermister test ok? At the spark control? Door or motor centrifugal. If not losing 24 volt to the THS and ground terminals at the spark control, do you get a blinking light on the Fenwal?
Make sure to check the igniter, flame detector, and it’s wiring to the spark control. It may not have the proper gas pressure to the pilot or the orifice is plugged. You should measure your gas pressure. to be in spec.
Hope this helps.