Hot Water Clinic: Overcoming Common Problems
WATER HEATER POSITION
More and more householders are becoming mindful of the delay in receiving hot water to fixtures – so much so that some people are actually measuring the water lost down the drain while waiting for heated water to arrive at the point of use. Some are also measuring heat energy lost when the fixture is then shut off after use.
With the average household using around 200L of heated water per day and activating a hot tap in the dwelling around 20 times per day, water consumption and energy losses are now top of mind with consumers more than ever.
The most energy efficient water heater cannot provide the customers expected energy consumption savings if the location of the system is such that the delay in receiving heated water is excessive.
In the majority of domestic dwellings, the kitchen sink is the most regularly used hot water outlet, requiring water at around 60 degrees for domestic sanitising purposes. It is common for heated water to be drawn to this point at least 10 times per day under average usage patterns.
Positioning the water heater as close to the kitchen sink as practical and within regulation requirements, will provide minimal delay for the most activated fixture and in so doing, will provide water volume consumption savings as well as minimising heat energy losses in distribution piping.
While a standard-sized house once had the kitchen, laundry and bathroom all within a close designated area, modern house designs generally include fixtures positioned at distances that cause delays in heated water reaching the various outlet positions.
A general allowance of one second per linear meter of piping is a good rule of thumb to determine the expected delay in having heated water delivered to the most frequently used fixture locations.
BALANCED FLUE TERMINALS
All external gas storage water heaters regardless of where the flue terminal is located on the system require the air pressure around the terminal to be balanced. This is to ensure correct function and operation of the gas water heater to draw incoming air for the process of combustion and to expel the products of combustion via the balanced flue.
Gas water heaters with this type of flue need to be positioned against a solid structure (wall) extending a minimum of 500mm above and 500mm either side from the edge of the flue terminal.
If the gas system is positioned in a way that sees the air pressure around the flue unbalanced, consequences may include:
– down draft into the primary flue causing component failure
– yellow tipped flame
– insufficient hot water
– pilot outages
WATER HEATER FILTER/STRAINERS
The full range of Rheem continuous flow gas water heaters have an inlet filter/strainer positioned on the cold water supply connection to the system that captures debris (particularly in new housing estate areas) before entering the water section of the unit. This is particularly important as debris entering this section can cause component/system malfunction.
If the system is failing to operate and no error code is shown on the LED display or on the indicator board, the cold water inlet filter may be blocked causing the unit to operate incorrectly or not at all.
By removing the filter/strainer and clearing any debris that may be lodged (and reducing flow) then reconnecting it back into the cold inlet, the system should operate correctly.
This check should be done in all new estate and construction areas.
COMMISSIONING TO THE CUSTOMER
In addition to the step-by-step commissioning procedures located in gas continuous flow water heater installation instructions, it is necessary to explain to the customer how the water heater actually works and how the customer has to operate fixtures to allow the minimum flow rate of water to be established so that the unit will function correctly.
This will often mean that the customer will have to activate a fixture at full flow to allow the gas continuous flow system to reach its designated flow requirements prior to backing off the flow at the fixture to their desired level.
Jon Palfrey is Rheem Australia’s Training Manager. He conducts training to plumbers and specifiers across the southern states, covering the latest water heater technology and key water heating issues facing plumbers.