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5 Common Boiler Problems

Your trusty boiler keeps your home and water at the perfect temperature, but sometimes things can go wrong. Whether your boiler won’t turn on or has a more complex problem, repairs are often an option to get your heat and hot water working properly. This article covers some of the most common problems that can plague boiler owners, including:

Contact Cooper Heating & Cooling to schedule fast boiler repair and replacement services today!

Our highly-trained technicians deliver expert advice, and all our heating installations come with renewable 1‑year labor warranties, so you can repair your current boiler or upgrade with peace of mind.

The boiler won’t turn on

There are several reasons why a boiler may not turn on, some of the most common include:

  1. Thermostat problems: The thermostat may not be set correctly, or the batteries may be dead.
  2. Power supply issues: The boiler switch or circuit breaker may have been turned off or tripped.
  3. Low pressure: The pressure gauge on the boiler may indicate low pressure, which can prevent the boiler from turning on.
  4. Blocked air vents: Air vents can become blocked with dust or debris, preventing the boiler from functioning properly.
  5. Pilot light: The pilot light may have gone out and needs to be relit.
  6. Faulty parts: Certain parts, such as the thermocouple, gas valve, or control module, may have failed and need to be replaced.
  7. Lack of maintenance: Boilers that haven’t been serviced in a while can develop issues that prevent them from turning on.
  8. Gas supply: If there is a problem with the gas supply, the boiler will not turn on.

It’s always recommended to call a qualified technician like Cooper Heating & Cooling to diagnose and fix the issue or learn more about high-efficiency boiler installations.

The boiler is leaking water

A boiler leaking water can be a serious problem and should be addressed immediately. One of the most common causes of a leaking boiler is pressure issues. If the pressure inside the boiler is too high, it can cause water to leak out through the pressure relief valve. This safety feature is designed to prevent the boiler from becoming damaged, but it can also indicate a problem with the pressure regulation system.

Another cause of a leaking boiler is corrosion. Over time, the internal parts of a boiler can become corroded, leading to leaks. This is more common in older boilers that have not been properly maintained. A broken seal or gasket is another problem that can lead to leaking. Seals and gaskets are used to keep the system water-tight, so when they break down, there is often seepage at places where pipes join. A cracked or damaged pipe is another possible cause for leaking. Most pipe leaks are readily apparent, but a small leak can be difficult to spot if you aren’t looking for it.

The boiler is short-cycling

A boiler short cycling refers to a situation where the boiler frequently turns on and off within a short period of time. This can be caused by issues such as:

  • Faulty thermostat: If the thermostat is not working properly, it can cause the boiler to turn on and off too quickly.
  • Obstructed flue: If the flue or chimney is blocked, it can cause the boiler to overheat and short cycle.
  • Failed control module: The control module is responsible for monitoring and controlling the boiler’s operation. A failed control module may cause the boiler to short cycle.

The boiler is heating radiators but not water

A boiler heating radiators but not hot water can have several causes.

  1. Priority settings: Some boilers have a priority setting that prioritizes heating the radiators over the hot water. A qualified technician can adjust this.
  2. Faulty diverter valve: The diverter valve directs hot water to the radiators or hot water tank. If the valve is faulty, it can cause the water to be directed to the radiators instead of the hot water tank.
  3. Airlock: An airlock can prevent hot water from flowing through the system.
  4. Low water pressure: This issue can cause limited water flow, leaving only enough to heat the radiators and not your water.
  5. Blocked heat exchanger: The side arm heat exchanger transfers heat from the boiler to the water. If it is blocked, it can prevent the hot water from being heated.
  6. Faulty thermostat: If the thermostat is not working properly, it can cause the boiler to turn on and off at the wrong times.

The boiler is making a banging noise

A boiler making a banging noise, also known as kettling,” is often caused by water heating to a boiling point within the system. Low water pressure, failed pumps, and closed valves can all cause the interior water temperature to reach the boiling point. Some other causes of noisy operations might include: 

  • A buildup of limescale: Limescale is a hard mineral deposit that can build up in the heat exchanger, causing a banging noise.
  • Air in the system: If air is trapped in the system, it creates bubbles that expand and contract, leading to clicking and other sounds.
  • Debris in the system: Debris, such as sludge or rust, can become lodged in the system and slam against the walls of the boiler or pipes.

Ready to Get Your Boiler Up and Running Again? Contact the Cooper Green Team Today.

At Cooper Heating & Cooling, we do more high-efficiency installations than any competitor in the Denver area. Our boiler installations come with higher-quality equipment, higher comfort, and higher long-term energy savings.

Luke Cooper