A good hot water boiler should serve you faithfully for 10-15 years. However, you might encounter problems along the way. If your boiler is malfunctioning, your family's supply of hot water will be disrupted, which is annoying and inconvenient. Even worse, some boiler problems can actually be dangerous.

Have any boiler trouble checked out right away. You may well save a substantial amount of money by avoiding a major water boiler repair further along the line. (While you're at it, you might want to schedule an annual preventive maintenance appointment for the future.)

Here are 9 common trouble signals to watch out for.

1. Failure to switch on -- The very first step, if your boiler does not seem to be working at all, is to check the power supply or pilot light. If the unit is plugged in, make sure that the circuit breaker switch has not been tripped.
   
   
2. Cold or inconsistent water temperature -- Freezing cold water in your shower is an obvious sign of boiler failure, but an excessively hot flow is problematic, too. In fact, any inconsistency in your water temperature is a sign of trouble. When you have no hot water at all, the electric heating element may not be functioning. Overly cold or hot water might be caused by a defective thermostat.
   
   
3. Leak -- Unusual amounts of water or moisture around the boiler indicate a leak. This will result not only in wasted water, but also in excessive fuel consumption. What is more, leakage will put a strain on your boiler since it will be forced to continually heat more cold water to replace what is being lost.
   
   
4. Odor of oil or gas -- The smell of oil or gas is a serious danger sign. Quickly open a window in the area where your boiler is located, switch off the control valve if possible, and go outside. Then call for emergency boiler repair. Also, always install a working carbon monoxide (CO) monitor if you operate any fuel-burning appliances  inside your home; should the monitor's alarm sound, get everyone out of the house ASAP and contact your local fire department.
   
   
5. Metallic odor or taste -- A metallic odor or taste to the water heated by your boiler is problematic too, although less dangerous to human beings. It does, however, indicate a serious issue with the boiler.
   
   
6. Rusty water -- When you turn on your hot water faucet and the water runs rusty, the rust may be coming from either the boiler or the pipes. Either one spells trouble that must be attended to.
   
   
7. Mud or increased sediment -- Water that is muddy or contains more mineral sediment than normal is another warning sign. To check the contents of your boiler, attach a hose to the drainage bib, turn off the power supply, and drain out the water.  
            
8. Noise -- A hissing sound is most likely caused by uneven water distribution due to deposits of iron or sludge, which can overheat your system and even cause it to stop working altogether. Popping or cracking means that mineral deposit in your boiler is interfering with the normal function of the heating element.
   
   
9. Water Pressure -- Hot water which does not flow at the same pressure as the cold may be due to scale build-up in the boiler itself or in the pipes. Another possible cause is a kink in the water line. Check, too, that the shut-off valve is completely open.

SAFETY PRECAUTIONS: Disconnect your boiler from its power source and allow the water inside to cool down before you attempt to move or fix it yourself. Unless you are very sure of what you are doing, play it safe and hire a licensed plumber for boiler repair.

Laura Firszt writes for networx.com.

Updated July 5, 2018.