Hot water baseboard, upstairs works, downstairs not
We have hot water w/ baseboard splitlevel. It's a 1962 home with hard water. Furnace, thermostat and pump is working. The upstairs baseboards are very warm but no heat to the downstairs. The pipes to the upstairs is hot but not the pipe after the split that goes to the main level.
If it's an air plug, might it work itself out over time-there is some knocking when the water starts circulating.
If it's a hardwater plug, could it work itself out over time?
It was working last spring.
Would turning up the heat so there is more circulation help or does it create a dangerous situation?
If it does not work itself out, do we need a plumber, furnace person or PSEG?