Why Is My Hot Water Service Cutting Out?

Last Updated on October 16, 2019

The chances are that if you are reading this article it is because your hot water service keeps cutting out and you most likely you have a system which is the size of a small box (350mm wide X 550mm High) mounted to the wall and plugs into an external weatherproof power
point for ignition and combustion fan.

Power Flued Continuous Flow Water Heaters

Power flued continuous flow water heaters (also known as instantaneous hot water) have been on the market now for approximately 20 years in Australia. These styles of water heaters are predominantly powered by gas (either natural or propane (LPG)). All the major
manufacturers offer a model whether it be an AquaMax, Bosch hot water, Rinnai Infinity 26, DUX Endurance, Eternity by Chromagen, Thermann c7, Chofu, Takagi or a Rheem Metro or Rheem Integrity its likely you will have one of these brands or models.

Components Fail

Over time various components can fail with age and need replacing. One component if faulty will cause the water heater to cut out after short periods of use. This part is called the Thermal Fuse. It is a long piece of wire which its wrapped around the heat exchanger a  the top of the water heater. The task which the thermal fuse performs is that it will communicate the overall temperature of the heater exchanger back to the central processing unit. It is in place to protect the heat exchanger from over heating which can lead to a catastrophic fail.

Over time unfortunately the thermal fuse can break and relay false messages back to the CPU such as the heat exchanger is running to hot and cause the system to shut down when in fact this may not be the case it’s just a faulty component. If the hot water service is installed with temperature control pads these may also display error codes such as the number 11, 12 or 14.

Majority of manufacturers will sell this as spare part so that it can be replaced. The unfortunate trick with this is that in order to have the part replaced the entire hot water service must be dismantled and taken apart a monumental task and one that is never undertaken due to the huge amount of labour involved and not to mention the likelihood of other issues arising along the way.

Systems Have A Life Span

As a general guide we find that this problem will display towards the end of unit’s life around 8 or more years of age. What our clients have found that in the mornings when the unit has been off all night or in colder months they will get a longer run out of the system but when the hot water service has warmed up the periods of use will be very short (maximum of a couple of minutes), that’s usually when we get the phone call to help them.

With a fault such as this it will mean that it is time for a new hot water service and sometimes the temperature control pads will also need replacing. Nearly every time that we get called out to this fault (5 to 6 times a week minimum) there is lots or corrosion internally on other parts indicating the system is well on its way

to needing to be upgraded anyways. As we are the hot water specialists of Adelaide, we stock all the major brands such as Rheem water heaters and Rinnai heaters and their different sized models for your convenience and in most cases offer a same day emergency hot water change over service.