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Hot Water System Not Working?

Frequently Asked Questions Regarding Hot Water Systems

Why does the Pilot Light on my Hot Water System Keep Going Out Even After Relighting?

On gas hot water systems it can be one of the following issues:


  • Faulty thermocouple that needs either cleaning or replacing. A thermocouple is a wire-like probe that sits in the pilot light flame. Replacement of this requires a qualified gas fitter such as Jim’s Plumbing.


  • On storage hot water heaters it can be a faulty thermostat which is usually referred to as a unitrol or sit-valve. These units do fail, but not as regularly as a thermocouple.

SIT valve

  • Another issue could be a particle floating inside the pilot tube and blocking the small hole where the gas is. A qualified gas fitter is needed to clean out this pilot tube. Call 1300 068 480 today.

Why am I Getting Intermittent Cold and Hot Water in my Shower?

This is often a problem on continuous flow and instantaneous hot water systems and is the result of insufficient gas coming to the hot water unit.

The diaphragm on the gas meter may be faulty. This will require your gas authority to come and replace the diaphragm.

The showerhead that you have may need to be replaced or the restrictor removed as some hot water units are unable to function when restricted flow showerheads are in place.  The unit does not register that a tap is on resulting in hot water cutting in and out.

I Can’t Seem to Get my Pilot Light Lit

There are a few issues that may be at fault:

  • Not enough hot water.
  • If you find you are running out of hot water it could be:
    • Blocked flue or vent on service.
    • Faulty thermostat.
    • Thermostat may be set too low. Use the dial to raise the temperature.
  • Hot water unit may be undersized for gas needs. If you are running out of hot water, we can send one of our Jim’s specialist to advise about a larger model or continuous flow which best suits the amount of bathrooms and number of people in the household.

Why is Water Leaking from my Ceiling?

There are a number of reasons as to why water may be leaking from a ceiling from a roofing problem such as broken tiles right through to a burst pipe, or a leaking hot water tank located in the ceiling. Turn off the water meter at the front of the property and if the hot water meter is located outside, there should be an isolation tap that can be turned off. Call a qualified plumber such as Jim’s Plumbing as soon as possible to prevent further damage or injury as an issue such as this can result in the ceiling caving into the property.

I Think That Water May Be Leaking from My Hot Water Tank or Pipes. What Should I Do?

Firstly it is important that you go to the water meter and turn off the water. This way it gives you time to identify whether it is a hot water tank located in the roof space or a burst pipe itself. If your hot water unit is located outside, it will obviously indicate a hot water pipe that is leaking and not the unit itself.  Give Jim’s Plumbing a call for one of our hot water technicians to attend.

I am About to Have a Baby and am Worried About the Safety of My Children as the Water From the Hot Taps May Be Too Hot

This depends on the type of HWS that you have. If you have a Bosch instantaneous, there is often a dial at the front of the water section that can be turned clockwise for hotter and anti for cooler.

Some models has a small screw at the bottom of the water section that does the same thing. However, we would suggest that you use a gas fitter to change this.

Electronic models often have external keypads that are located in the kitchen and/or bathroom. This can pre-set the temperature through the LED display. Or you can contact a gas fitter if there are no keypads. He can remove the front cover of the hot water unit and replace the dipsticks which will reset the temperature of water coming from the hot water system to suit the customer’s needs.

With storage hot water systems, there is normally a dial on the unitrol or sit-valve which can be accessed by removing the front cover. The temperature settings are then visible and can be adjusted accordingly. Many hot water units have what are called tempering valves which ensure that scalding hot water is not delivered to the house. By regulation they are pre-set to 50 degrees Celsius. As this is located external to the unit, customers may dial this down if they require cooler hot water.  However, please note that not all hot water units have this in place.

My Continuous Flow Gas Hot Water Unit Seems to be Producing Less Water and the Water That is Produced is Cold

There are two things that can be done in this case:

  • Have a plumber or gas fitter check the strainer valve on the cold inlet to the hot water system as often this becomes blocked especially if there have been water works carried out on the street or you have had a burst pipe repaired.
  • Have a gas fitter come and check the thermostat on the hot water system

I am Only Getting Lukewarm Water from All My Taps. I Have a Continuous Gas Hot Water Service

This is a common issue with Bosch and Rheem instantaneous HWS and it requires the attention of a gas fitter.

Another reason is that the thermostat may be faulty.

Lastly, the diaphragm in the water section is in need of replacement. A diaphragm is a rubber compound that like any other over time deteriorates and when this is the case, the section is removed, replaced and, once repaired, delivers hot water to the taps.

My Fuse or Circuit Breaker on Hot Water System Keeps Tripping. What is the Cause of This?

This normally relates to one of 2 things.

The 1st is a faulty element inside the hot water system. This will need to be replaced by a plumber with a restricted electrical licence and it is advisable to do the thermostat at the same time.

2nd is it can be a faulty circuit breaker which will need to be replaced by a qualified A-class electrician.

No Hot Water From an Electric Hot Water System

This can be numerous thing including:

  • Faulty element
  • Faulty thermostat
  • Faulty wiring
  • Burnt out terminal block within the hot water unit.
  • Faulty time clock within the hot water heater.
  • Faulty tempering valve
  • Electrical wire between the switchboard and the hot water service has a short circuit often caused by rodents.

My Hot Water is Coming Out Milky in Colour

This is only air bubbles and is not dangerous. The hot water unit can still be used. This often happens in storage type hot water units if you put this water that is milky in colour into a glass to stand, it will disperse and will become clear.

There is a solution where we replace the sacrificial anode. However, personally we feel that it is not necessary as it is only an air bubble issue and it is completely safe.

The Overflow Pipe From My Hot Water Unit is Leaking Water

It is normal in the heating cycle only for the hot temperature relief valve to leak water from these overflow pipes as it is a way for the hot water to escape when it is heated inside a closed hot water cylinder. However, if it is continually running, this valve will need replacing and if left leaking it will result in quite a high water bill which is unnecessary. Most manufacturers recommend that these valves are replaced every 5 years.

While waiting for a plumber to attend you can turn off the isolation tap to the tank and this will result in less water loss.

My Hot Water Unit is Leaking Water

If water is coming out of the hot water unit or cylinder, unfortunately it means in most cases you are up for a new hot water system.

Near the hot water unit there is a stop valve for the unit which you can turn off and if it is a gas hot water system, there should be a gas isolation tap also near the unit. This should also be turned off. If the hot water system is electric, isolate the circuit breaker or fuse at the main power board. This is often marked with HWS meaning it is for the hot water service.

Water is Only Running at a Trickle From Hot Tap

This could be one of the following

  • Faulty tempering valve which is located external to the unit.
  • A faulty duo or trio valve which is the isolation tap and non-return valve located on the cold water inlet to the hot water unit.
  • The duo or trio valve or main water meter tap may have been turned off accidentally by children etc.

I Have an Electric or Gas Hot Water Unit and Only Slightly Warm Water Comes Out of Taps

On storage units, there is often a tempering valve located externally on the unit. This may be faulty and needs replacement. On electrical hot water systems it could be elements and thermostat. On instantaneous gas units such as Bosch it may require the diaphragm replaced on the water section kit.

How Do I Make My Storage Hot Water Unit Last Longer?

You can make both your gas and electric hot water systems last longer by replacing the sacrificial anode which is located at the top of the unit. In storage hot water systems, the tank that has a vitreous enamel lined coating are the only units where a sacrificial anode is installed. On a continuous flow, instantaneous or stainless steel tanks the anodes do not exist because there a no corrosion issues.

The sacrificial anode is a long probe that is installed into the top of the unit that is designed to corrode before the outside tank does. As it corrodes, we would recommend replacing this every 4 years to extend the life of the unit.

Top Showing Corroded and Bottom New Sacrificial Anodes

No Interest Ever!** payment plan options available on hot water heater replacements to help ease any financial stress this burden may cause. If your hot water heater is leaking, or you have no hot water, we can often have a plumber to you within the hour*.

Choosing the correct hot water system can be difficult, as there are so many options to choose from; Click on the links to find out more about these systems.

Please be advised that we have additional hot water system brands & models available.

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