[RCM78]

If they installed it then they're a Rheem dealer. It's just surprising that he didnt have parts on the truck.
I'd bet he is more of an install mechanic and not a service tech. The boss probably sent him out to satisfy you and order a part.
Since it's been cold most heating contractors are really busy. I know we are.

Your probably not considered a priority since you have two heaters in your house. After they catch up a real tech will show up and miraculously diagnose the problem and have the part on the truck.