Radiator heating problems

Updated March 23, 2017

Steam-heat boilers and radiators are old ideas that still keep dwellings warm and cosy through cold winters. Their operation is simple and usually reliable, but a few things can go wrong. There's a short list of breakdowns and basic maintenance issues that can cause one or more radiators to lose their heat, leak water or operate noisily. When unsure of the cause, it's best to contact a qualified technician to examine the entire system.

No Heat from a Single Radiator

If the single radiator is not heating up, there could be air trapped in the radiator. When the radiator is cool, open the bleed valve at the top of the radiator; close again when water begins leaking or squirting from the valve. You might also have a faulty or clogged inlet valve at the radiator foot. The water pipe leading from the floor to this valve and then to the radiator baffles should be hot to the touch. If the pipe between the valve and the radiator is cold, the valve itself could be clogged or stuck in the closed position. Clogged valves should be replaced.

No Heat from a Boiler

You might have a tripped circuit breaker. Check the service panel or fuse box and reset the breaker or replace a blown fuse. Make sure the boiler's water level is correct by checking the water pressure, which should be between 5.44 and 6.8 Kilogram per square inch (psi). If the pressure is too low, open the fill valve until the pressure reaches 12 psi. Also check the pilot light, which may be out, or the electronic ignition if there is no pilot. Finally, check to make sure the thermostat is set to "heat," then try to reset the temperature.

Heat has Gradually Lessened

Check that water pressure in the boiler has not fallen below 12 psi, which could be caused by a leak. The expansion tank may be overfilled or mineral deposits may have built up in the boiler or water lines. A technician can check for and repair water leaks, check the expansion tank or flush the system out, if necessary.

Water on the Floor near Boiler

Water on the floor near the boiler could be a sign of a faulty circulator pump, faulty pressure valve or leaking pipes. A technician can repair the circulator or replace the pump seal. The pressure valve may also be fouled with sediment. This can be checked by turning off the boiler and operating the pressure relief lever. If water continues flowing after closing the lever, or no water is discharged at all, the valve should be replaced. Leaks can also be revealed through a visual inspection of the pipes and connections. Replacing rusted out or leaky pipe connections is for professionals.

Water on Floor Near Radiator

The cap nuts used to fasten the inlet valve may have come loose or be corroded. Turn the system off, then tighten the valve nuts; it this doesn't work, replace them.

Banging and Clanging Pipes

The coupling that links the circulator pump to the motor may be broken. Or, there may be a problem with the angle of the water return lines. Steam in the radiators condenses, then returns to the boiler via a downward-sloping pipe. The radiator should be angled slightly back towards the inlet pipe. This can be easily corrected by placing a shim or wedge of wood underneath the far end of the radiator. Also check the inlet valve to make sure it is completely open.

Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Founder/president of the innovative reference publisher The Archive LLC, Tom Streissguth has been a self-employed business owner, independent bookseller and freelance author in the school/library market. Holding a bachelor's degree from Yale, Streissguth has published more than 100 works of history, biography, current affairs and geography for young readers.