I am entered in an oldest furnace contest. I have a hallmark model HGL 95 serial 19741. My house was built in 1960 and I believe this to be the original furnace. Hallmark has no record of this furnace. Please help me. I do not think it is 1974.
I haven’t seen them up here.
It looks like Boyertown bought Hallmark:
You could contact them:
Contact John Bowman at Building Intelligence here…
He has a lot of contacts in the HVAC market…