Why Are My Radiators Cold? Common Causes in Waukesha Homes

Cold Radiators in a Waukesha Home

Many older Waukesha homes heat with hot water through radiators or baseboard units. When one of them stays cold while the rest of the house is warm, it is usually one of a few familiar problems. Here is how to tell them apart and what to do about each.

Air Trapped in the Radiator

If a radiator is warm at the bottom and cool at the top, air is most likely trapped inside. Air in the loop keeps hot water from filling the radiator, so the room never fully warms up. Bleeding a radiator releases the air, but if it keeps coming back, something is letting air into the system and a technician should look at it.

A Stuck Zone Valve or a Zone Control Problem

When a whole zone is cold and the rest of the house is fine, the cause is often a zone valve that is stuck closed or a failed zone control. The boiler is running, but hot water never reaches that part of the house.

Low System Pressure

If you keep having to top off the pressure, the system has a leak somewhere, or the expansion tank or relief valve is not doing its job. Low pressure can also cause the boiler to shut itself down. A leak should be found before it turns into water damage.

The Circulating Pump

The pump pushes hot water out to every radiator. When it fails or gets clogged, the boiler can run while the whole house stays cold. A technician can test the pump and replace it if needed.

What You Can Safely Check Yourself

• Make sure the thermostat is set to heat and calling for heat
• Check that the boiler has power and is running
• Look for water around the boiler and shut it off if you can do so safely
• Note which radiators are cold, since that helps a technician find the cause

If a boiler will not fire, makes banging or gurgling noises, or you see a leak, call for service instead of restarting it yourself.

Get Help in Waukesha

See our Waukesha boiler repair page for what a service visit includes, or our boiler tune-up page to catch problems before winter. If your heat goes out, call (262) 671-8999 any hour, every day, and a real person answers.

Save on Repairs with the On The Dot Club

The On The Dot Club is $25 a month with a 6 month minimum commitment. Members get 20% off repairs, a $0 dispatch and assessment fee with no overtime or after-hours rates, priority service, a lifetime repair warranty while the membership is active, and two tune-ups a year.