I'm new to having an account on the forum but have been reading other peoples questions and answers for sometime now and decided to best describe my situation I should just sign up.
I have a one pipe steam heat system, with cast iron radiators that switch over from Iron pipe to copper in the basement. The problem is, it's only one zone so the upstairs does not seem to warm up as much as the downstairs. Our friend is staying with us and complains that it gets too cold at night. I have tried insulating the basement pipes, replacing the air pressure relief valve in the radiator itself and it still doesn't get warm enough.
I guess the problem is I'm trying to get the heat warmer without having to re-pipe the basement and put the upstairs on a new zone.
Are the upstairs radiators getting reasonably hot at all?
Over the years parts of the house may settle differently and steam pipes running horizontally sag in a manner so as to trap condensate. This impedes the flow of new steam to a radiator. You can sometimes fix this by jacking up the radiator gradually about an inch and inserting blocks of wood under its legs. Be sure that the pipe entering the radiator has some give to it; don't use force jacking.
You might try covering the downstairs radiators partly so the furnace can run longer and heat the upstairs without overheating the downstairs.
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.