How to Troubleshoot a Steam Heat Radiator

Radiators emit steam to heat a building.

Steam heating systems are comprised of a boiler that heats water to a high temperature and pushes steam through the pipes of a building. The steam is pumped into radiators in each room of the building to heat the room. There are a variety of things that can go wrong with a steam heating system. When malfunctions occur, a series of troubleshooting steps must be performed. The key is to narrow down the problem to a specific component of the system before attempting repair.

Things You'll Need

• Cotton swab
• Water
• Needle
• Paint thinner
• Steam release vent
• Wrench

Instructions

1. Make sure that the shut off valves on the radiators are fully open to eliminate loud banging noises emanating from the pipes. The banging is caused by trapped air bubbles that burst. The shut off valve is located on a pipe that enters the bottom side of each radiator. Turn the knob counterclockwise to open it fully.

2. Replace the steam release vent on the radiator if a single room is too hot. Rooms that are too hot are the result of too much steam emanating from the radiator. Close the shut off valve to the radiator and locate the steam release which is on the opposite side of the radiator from the shutoff valve. Grasp the vent cover and twist counterclockwise to remove it. Purchase a new vent cover at the hardware store that has a smaller opening. Install the new vent by twisting it on clockwise and then opening the shutoff valve.

3. Remove debris and calcification from the steam release vent if a room is too cold. Rooms that are too cold mean that not enough steam is getting out. Turn off the shut off valve to the radiator and unscrew the vent cover to remove it. Examine the vent hole and wipe away any dirt and debris with a damp cotton swab. Insert a needle into the opening of the hole to dislodge any calcification. If the valve has been painted over, dip the cotton swab in paint thinner to remove the paint. Screw the vent back on and open the shut off valve.

4. Look for leaks in the system if the water level indicator is frequently low. The water level indicator is located on the glass sight on the main boiler and only lowers if water is removed from the system. Look all around the boiler and each radiator in the home for evidence of a water leak. Have water leaks repaired by a professional immediately.

5. Eliminate hissing by lowering the pressure on the main gauge of the boiler. Hissing is a sign that the pressure setting it too high for the system. If hissing is only noticed in one room, use a wrench to tighten the metal nut located at the base of the steam release vent on the radiator.

References

• BBC: Single Pipe Steam Heat
• Fix it Club: Steam Boiler Repair