Seeing the boiler light on but the house still feels chilly is frustrating. If you are wondering why is my boiler on but no heating, start with a few quick checks you can do in minutes. Mesa Plumbing is here to help Boulder neighbors get heat back safely. If anything below feels unclear, call our local team for same day support.
Five Checks Anyone Can Do
Confirm the thermostat is calling for heat
Make sure Heat is selected and the set temperature is above the current room temperature. Replace old batteries. If your thermostat uses schedules, try a temporary Hold so it keeps calling for heat.
This simple step solves many cases of how to fix boiler no heating issues.
Set the boiler to winter mode and reset once
Some systems have a summer or eco setting that only makes hot water. Switch to the normal heating mode. Press the reset button once if your manual allows it. Wait a couple of minutes to see if the burner fires and the system pump starts.
Check system pressure on the gauge
Look at the pressure gauge on the front of the boiler. Most systems like to sit around one to one and a half bar when cool. If the needle is near zero, the boiler may refuse to heat. Do not overfill. If you are unsure how to top up safely, call a pro.
Low pressure is a common reason for why is my boiler on but no heating in Boulder homes before winter.
Feel the pipes and radiators safely
Carefully touch the flow pipe near the boiler. If it warms up but the radiators stay cold, the problem could be with the pump, air in the system, or a stuck valve. If only the top of a radiator warms, it may be air bound and need a bleed. Use a bleed key and a small towel and stop if you smell gas or see dirty water spurting.
Rule out timer and power issues
Check the breaker and the service switch near the boiler. Verify the heating timer is set to On or to a current time slot. Smart plugs and power strips can also cut power to pumps or controls, so make sure anything in line is on.
When To Call A Boulder Pro
If you see fault codes, repeated lockouts, dripping pipes, a smell of gas, or the pressure keeps dropping, stop and call Mesa Plumbing. These signs point to parts that need trained service. Quick attention now prevents bigger repairs during the first deep freeze.
We offer friendly boiler repair near Boulder with clear pricing and local know how.
Pre Winter Prep Tips
Keep the area around the boiler clear so it can breathe. Replace or charge thermostat batteries. Note your normal pressure so you can spot changes. Run the heat for ten minutes each week in the fall to keep valves moving.
Also, It’s better to have a pre winter maintenance to prevent no heat guide.
Need Help Fast?
Call Mesa Plumbing at (720) 680 2303 or schedule at www.mesa-plumbing.com
Why is my boiler on but radiators are cold?
Air in the system, low pressure, a stuck zone valve, or a pump problem can stop heat from reaching radiators even when the boiler is on. Start with pressure and thermostat checks. If radiators stay cold, call Mesa Plumbing for a quick diagnosis.
How to fix boiler no heating without tools?
Confirm Heat mode, raise the set temperature, do a single reset, and check the timer. Look at the pressure gauge. If pressure is very low or the boiler shows a fault code, it is time for a pro.
Is it safe to bleed a radiator?
Light bleeding is usually safe if you have a radiator key and can stop when water appears. Do not bleed if pressure is already low or if you feel unsure. Over bleeding can drop pressure and stop the boiler from heating.