Skip to main content

Residential Hot Water Systems

The following topics are discussed on this page:


Hot water affects our lives in one way or another, although we don’t really think about where it comes from until something goes wrong.


Common Hot water system Problems and solutions

Most hot water system brands are made very well and do generally stand the test of time. At some point though, components will start to fail.

The following table is designed to help you identify the problem and offer you some solutions.

Problem Fault Solution
No Hot Water Faulty Thermostat Replace Thermostat
Faulty Element Replace Element
Leaking TPR Valve Replace TPR Valve
Badly dripping hot water tap Service the taps
Hot water system on the wrong tariff Call your electrical provider and change to the correct tariff which suits your family.
Faulty Tempering Valve Clean out the tempering valve Strainers.

Replace Tempering Valve.

No Power to the unit Turn on power
Problem Fault Solutions
Hot Water Too Hot Tempering Valve set too high Locate the tempering valve and alter the adjustment thread until the desired temperature is reached.

Replace Tempering valve if the adjustment fails.

Thermostat set too high Lower the temperature on the thermostat dial
Problem Fault Solutions
Not Enough Hot water Hot water system leak Check tank for leaks
Ensure TPR Valve is not leaking
Check for any dripping taps
Hot water system too small Buy a larger hot water system.

Change to an instantaneous type so that you never run out of hot water again.

Problem Fault Solutions
Hot water discoloured Tank and pipe corrosion Flush out the hot water tank

Replace the tank Anode

Install a water filter on the hot water outlet and change periodically.

Problem Fault Solutions
Water at the base of the hot water system Hot water system leak Check to see if there is a tank rupture

Check to see if the element seals are worn (likely)

Check to see if there is a screw hole in the tank

Is there any steam coming from the outside of the tank?

Problem Fault Solutions
My hot water takes too long to reheat Your hot water system has too small recovery rate for its demand.

Electric storage hot water units take a lot longer than your gas hot water system.

Check your hot water systems recover rate – most suppliers give you reheat rate per hour.
Problem Fault Solutions
Low Hot Water Pressure Blockage in the tempering valve Check the tempering valve strainer and remove any debris.
Blockage in the tap aerator Remove any debris from the tap aerator
Hot water pipe too small for the demand Increase the pipe size of the hot water line.
Problem Fault Solution
Noisy Hot Water System Scale build-up on your heating element

Too much sediment build-up in the bottom of the tank.

Replace the heating element

Replace the anode

Flush out the hot water system


Hot Water System Sizing

There are several factors to be considered when choosing the correct hot water system size. Some of these factors are fixed and cannot be changed; others are at our discretion.

  1. Family Size and Demographic
    • We use 50 – 60 litres of water on average per day. So, daily water requirements of five people equal 250L to 300L. The demographic changes this. For example, the average 12-year-old boy uses – 70 – 80 litres per day. If you have three boys in this age group, plus two normal adults, you will certainly need 310L – 360L per day.
    • Our peak times could be affected too if we all needed to shower for school and work, all within the same hour. Peak demand is critical.


  1. Generally, the bigger the house, the more the number of bathrooms
    • The higher this number, the higher the amount of hot water we can draw at once, thus the faster we can run out of water during peak periods.


  1. Fuel Source
    • Gas has a much quicker recovery rate than electricity. Therefore, you could potentially install a slightly smaller hot water system.
    • Gas is cheaper to run and has a much better carbon footprint. These are all-important factors when sizing a new hot water system.


  1. Preferred Hot water system Type
    • Storage (Gas or electric)
    • Instantaneous
    • Heat Pump
    • Solar


  1. Hot water system Tariff.
    • If you have a tariff where the hot water system only heats through the night, then you may need to get a larger hot water system.


If you first work out your likely peak demand using the factors above, this gives you a starting point. You can then move onto hot water system type and fuel source and tariff to be used. An example is given below;

Peak Demand = 300L

Natural Gas Storage

Tariff = Night Only

Option 1 = 330L Gas Stellar Storage Hot Water System.


Hot Water System Pricing

For the purpose of this exercise, all these hot water system replacements are of a like for like nature and require little or no alteration of the existing pipe. Every existing pipework is of a legal nature. The tempering valve and ECV are both in good condition and in good locations and do not need to be replaced. All gas pipework is airtight and good for operation.

If any of these components were faulty or any of the pipework needed altering, this is where the prices can start to increase quickly. Take a  picture and send it to your preferred plumber with a description of what you would like.


New Installations price guide

Hot water System Type Size Cost Range (Estimate)
External Small Storage 50L – 125L $900 – $1200
External Medium – Large Storage 160L – 315L $1300 – $1600
Internal Storage 125L – 160L $1350 – $1550
External Instantaneous (Gas) 16L – 32L $1150 – $2550


Maintenance price guide

Problem Solution Cost Range (Estimate)
Faulty Thermostat Replace $179 – $219
Faulty Element Replace $179 – $219
Faulty Tempering Valve Replace $220 – $260
Faulty TPR Valve Replace $220 – $260


Hot Water System Types

Residential hot water systems fall into the following four categories.

  • Continuous Flow Hot Water System (outdoor and indoor)
  • Green Energy – Heat Pump, Solar Hot Water System
  • Gas Hot Water System
  • Electric Hot Water System


Hot Water System Brands

In Australia, these different categories of the hot water system are supported by the following leading brands

  • Rheem Electric hot water systems
  • Rinnai Electric hot water systems
  • Apricus Solar Ready Electric hot water systems
  • Aquamax Electric hot water systems
  • Dux Electric hot water systems
  • Everhot Electric hot water systems
  • Boosch hot water systems
  • Stiebel Eltron Electric hot water systems
  • Vulcan Electric hot water systems


Future Projects

As a previous client, you can now enjoy the benefits of being a Yates Plumbing and Gas Member. To view member benefits, go to our home page.



  • All our hot water system installations currently receive
    • 10% off our pricing calculator price (See Home Page)
    • 10% off all future work
    • and one free hot water system check