"Hydronic Heating System - What is Max Water Temperature at Furnace?"

 By Ron Stultz

Summary: with baseboard radiators, furnace should be set for 180 Fahrenheit (F) temperature.

Background:

I have a 3 floor, 3 zone, old closed expansion tank, baseboard radiator, hydronic heating system.

My system has a high pressure pop open valve at 30  pounds per square inch (PSI).

System pressure is set at 18 PSI cold water (3 floors).

Furnace has a Honeywell controller.

Inside Honeywell controller is a wheel that sets maximum furnace water temperature.

Wheel can be set to 200F and even above.

Maximum, normal, water temperature at furnace?

Most baseboard radiators are most effective when they have water at or near 180F.

Inside the Honeywell controller, the water temperature wheel has a special pointer at 180F that should be pointing right at mark on stationary pointer.