As we approach the cooler months of the year it is worth considering some preventative hot water system maintenance to avoid costly repairs.
There are some simple things that every homeowner can do to potentially avoid a failure of your hot water system and minimise the likelihood of waking up to no hot water on a chilly morning.
- Winter in Australia is traditionally the most common time of year for electric hot water systems to fail.
- We use more hot water during winter as we tend to spend longer in the shower warming up in the morning.
- The cold water supplying the hot water system is colder which causes the hot water system to work harder and heat longer.
- The general temperature overnight is colder, the hot water system, its associated valves and pipes are cooler and this contributes to more work that the hot water system has to do to provide us with reliable hot water each morning.
Why Do Hot Water Systems Fail?
The most common hot water system repairs are due to the heating element and thermostat failure.
A heating element and thermostat in a hot water system is very similar to the working of an electric kettle. Depending on use, the heating element in a hot water system will cycles over 15,000 times in a decade. This is a repair that requires a licensed tradesperson undertake due to the requirement to disconnect electricity during the repair process.
The second most common repair of a hot water system is due to the failure of the tank itself. When water is heated inside of a hot water system it expands. The cooler the water prior to heating the greater the expansion. Over time the tank weakens by oxidising or rusting and expansion causes a weld or the cylinder within the tank to fail.
It is not widely known that inside of electric hot water cylinders there is a sacrificial anode. A sacrificial works by oxidising or rusting as the weaker metal rather than the steel tank. Sacrificial anodes are commonly found where mechanical components are in contact with water. Sacrificial anodes dissolve due to an electrochemical reaction inside the hot water cylinder and after 5 years they become spent and require replacement. This again is a task best left to a licensed tradesperson due to the different range of anodes and potential for incorrect fitting to damage the hot water service.
Another method to combat the failure of tank cylinders is with the fitting of Cold Water Expansion valves. Nowadays we are required by law to install Cold Water Expansion valves on any new hot water system installations. Cold Water Expansion valves are set to a lower release pressure than a Pressure and Temperature Relief valve. This allows the discharge of the expanded water from the cold supply pipes instead of hot water from the Temperature Pressure Relief valve. This is a saves wasting hot water which you have already paid to heat and discharges cold water instead.
Every homeowner can prevent the failure of their hot water system by regular operation of the Pressure and Temperature Relief valve. (Us older plumbers know them as TPR’s)
Pressure and Temperature Relief valves are essential to prevent devastating consequences such as the rupture or explosion of a hot water system if the thermostat fails and the hot water system continuously heats. PTR’s should be operated each 6 months to check their operation and to keep them in working order.
Most hot water cylinders have a warning from the manufacturer to replace the PTR valve at 5 year intervals. This is to ensure the reliable operation of the valve if it is required. If your PTR has begun to discharge water or leak, it is a sign that there is a problem and should inspected by a licensed tradesperson. There are other valves on the hot water system which fail and require replacement.
Put simply, preventative maintenance can avoid more serious hot water problems from occurring.
Hot Water System Maintenance Schedule
Hot Water System Maintenance (Every 6 months):
- operate the Pressure and Temperature Relief valve
- Operate the Cold Water Expansion valve (if fitted)
- Check the operation of the Isolator valve (which is also a non return valve)
Hot Water System Maintenance (Every 5 years):
- Replace Pressure and Temperature Relief valve
- Renew the Sacrificial anode
- Check Isolator valve
- Check Tempering valve
- Check Element and Thermostat for correct operation
I hope this hot water system maintenance advice helps you keep those hot showers running through the cooler months! If you already have hot water problems checkout our hot water system troubleshooting guide or get in touch!