The baseboard water or steam line can be extremely hot. Also when properly functioning the Taco valve head can get very hot.
Taco makes a range of heating and cooling products, including a Taco zone valve. The zone valve works with hot water or steam-based baseboard heating systems. When a signal is sent from the zone's thermostat to the valve a wax piece inside the valve heats and expands. As it expands it puts pressure on a valve mechanism that -- as it pushes down -- allows water or steam through the valve and into the zone's heating lines. A zone is a section of building; for example, apartment buildings may classify each "zone" as one apartment with each having its own zone valve.
Remove the baseboard heater front panel closet to where the baseboard water line enters the zone. Identify this section by looking directly down into the baseboard heat housing for a rectangle shaped unit (the Taco valve) and a shut off lever next to it. Lift one end of the front panel out of the corner of the baseboard heat cover. Then lift the other hand out of the center section where one length of front panel meets the next section of front panel.
Grasp the small silver lever on the side of the Taco valve and push it all the way down going from "Auto" to "Manual." If there is resistance there is water flow going to the valve, if the lever moves with no resistance then the problem is with the water line (such as a leak or lack of boiler pressure) and not the Taco valve. Proceed to Step 3 if there is lever resistance to continue troubleshooting the valve head.
Move the valve lever back up to "Auto" and wait a few minutes. Go to the zone's thermostat, usually a wall mounted control that allows adjustment of the room temperature. Slide the thermostat lever or turn the control knob up to a higher temperature beyond what the "current temperature" indicator displays.
Wait a few minutes then go back to the Taco valve. Place your hand on the top of the Taco valve unit. If it is warm or hot to the touch the valve is functioning. If it is cold or room temperature the valve is not functioning. The heat indicates the wax piece inside if heating up and thus expanding to push the water flow valve open.
Maxwell Payne has been a freelance writer since 2007. His work has appeared in various print and online publications. He holds a Bachelor of Science in integrated science, business and technology.