If your home uses a hydronic heating system, you rely on your boiler to provide the heat you need to keep you comfortable through the winter. With fall underway, you may be turning your heating on for the first time this season. Unfortunately, that first chilly night is usually when most people notice something is amiss with their home's heating system.
Once you put your thermostat in heating mode and turn the setpoint above the ambient temperature, the boiler should kick on and begin distributing hot water to your heaters relatively quickly. If your boiler doesn't seem to be firing up, it's likely due to one of these three common and straightforward problems.
1. Pilot Light Failures
Boilers are surprisingly durable appliances, so you may still have a relatively old one in your home. While many modern boilers use electric ignition, there's no shortage of boilers in service that still rely on pilot lights. If your boiler isn't providing heat, always check and, if necessary, attempt to relight your pilot light before performing additional troubleshooting or calling for help.
However, don't continually attempt to relight a pilot light that refuses to stay on. If your pilot light goes out, you may have one of several issues ranging from a faulty thermocouple to a clogged supply tube. While these parts are often easy to replace, you'll usually want professional help unless you're confident in your ability to identify the specific failure.
2. Faulty Rollout Sensor
Gas boilers require a flame rollout switch or rollout sensor like gas furnaces. Rollout refers to a condition where the burner flame exits the combustion chamber, "rolling out" into the main body of the boiler. Rollout is dangerous in and of itself since it can threaten non-heat-tolerant components, but it's also a sign of a more dangerous combustion problem.
While flame rollout is a serious issue, there's another potentially simpler problem: a faulty sensor. Sensors have a fail-safe, which means they will stop your boiler from running. If you have a modern system, you may also receive a rollout error code. Although rollout sensors are cheap and easy to replace, you'll still want a professional to confirm you aren't suffering from a genuine rollout condition.
3. Bad Thermostat
A faulty thermostat is always a possibility when dealing with any heating failure. If you don't typically use air conditioning or have separate window units or a mini-split system, your thermostat may go unused until winter arrives. In these cases, you're unlikely to notice a problem until you switch it to heating mode and start using it for the winter.
Thermostats are simple devices, but they're not always easy to diagnose. A faulty thermostat may stop your boiler from heating or cause it to turn on and off erratically. An incorrect temperature reading on the thermostat is a good indication that something is wrong, but there may be few, if any, outward signs of trouble.
While many simple problems can cause your gas boiler to stop working, it's still a good idea to rely on a professional to help you diagnose and solve your issues. An expert can help you get to the bottom of the problem on the first try and guarantee that the solution will safely and permanently resolve the issue.
Reach out to a boiler repair contractor to learn more.