Thursday, June 11, 2015

Relighting Rheem gas storage Hot Water Systems


Rheem stellar gas control valve


Most people cannot relight the Rheem Stellar gas hot water system because of one common mistake - They believe they will hear or see the pilot flame. In fact, you are not likely to hear or see the pilot flame because of its small size and location.

You will find the main GAS VALVE and PIEZO IGNITOR inside the cover at the base of the hot water system. Follow the full lighting procedure printed on the flip side of the cover. When you reach the stage of turning the thermostat up from the pilot symbol to 7 you should hear the woofing sound of the main burner when it ignites. This is how you will know if you were successful at relighting the pilot flame.

The PIEZO IGNITOR should make a clicking or a clunking sound every time you press it. Spray a little WD40 into it if it does not make a sound when you press it.

To relight the Rheem Stellar gas storage hot water system

  1. Turn the CONTROL KNOB so the PILOT symbol is at the front 
  2. Hold the CONTROL KNOB down with your left hand and keep it held down
  3. Press the PIEZO IGNITOR 20 times with your right hand (ensure it makes a sound every press)
  4. After pressing the PIEZO IGNITOR 20 times, release the CONTROL KNOB  and twist it until the number 7 is at the front. (This is when you should hear a woofing sound that is the indication that you lit the main burner which is also an indication that you have successfully relit the PILOT flame) 
  5. Once the hot water system is alight, turn the CONTROL KNOB to the desired temperature setting. The higher the number the longer you will get hot water from your taps.  

If you were unsuccessful at relighting your Rheem gas hot water system, for help or advice call 0448 844 911

We hope this easy to follow, how to guide to relight the pilot on your Rheem Stellar gas hot water heater in Canberra and Queanbeyan helps

Monday, June 8, 2015

Gas Hot Water Systems - Review Gas Storage


Review gas storage hot water systems. Know how they work- the pros and cons. Compare a storage hot water system to instantaneous / continuous flow systems.

There are two distinct types of gas hot water systems for domestic and commercial hot water installations in Canberra. These are the gas storage systems and the gas continuous flow systems (also incorrectly known as instantaneous).

Below is an explanation of how a high efficiency gas hot water system works.   You can learn about How continuous flow systems work.

How a gas hot water system works diagram 1



  1. Air for combustion is drawn into the combustion chamber (2) of the hot water heater. 
  2. Natural gas or LP gas is burnt in the combustion chamber. This creates super heated exhaust gases. 
  3. The hot exhaust gases from the combustion chamber (2) rise up through a central flue (3).  While in the central flue, some heat from the hot exhaust gases is transferred into the water in the hot water storage tank (5).
  4. Once the hot exhaust gases leave the central flue (3), the hot exhaust gases enter the exhaust shroud (4). The shroud envelops the hot water storage tank (5).
  5. More heat is transferred into the water in  the hot water storage tank (5) from the hot gases in the exhaust shroud (4).  Water in the hot water storage tank can stay hot for days without any heat input. This is because of the layer of insulation (7) between the outer casing (8) and the exhaust shroud (4).
  6. Cooler exhaust gases exit the flue terminal (6). These gases are mostly carbon dioxide and steam. 
  7. Once the water is heated, the layer of foam insulation between the outer casing  (8) and the exhaust shroud (4) will keep the hot water inside the hot water storage tank (5) hot for days without any further heat input. The continuous flow system has very little insulation and water inside goes cold very quickly.
  8. The outer casing is weather proof. It keeps moisture, dust and dirt out of the combustion chamber and exhaust shroud.  It also protects the layer of foam insulation.
  9. Cold water entering through the cold water inlet pipe (9) forces hot water out of the hot water storage tank (5)  through the hot water outlet (10) whenever a hot tap is turned on.
  10. Unlike continuous flow hot water systems, the water is always hot at the hot water outlet of the hot water storage tank.  This makes them more water efficient than continuous flow gas hot water systems.
In a high efficiency gas hot water system, up to 93% of the heat in the exhaust gases is transferred into the water inside the hot water storage tank.

ADVANTAGES AND DISADVANTAGES of gas storage hot water systems

As a plumber I am often asked if I would choose a gas storage system or a continuous flow hot water system.

These are the pros and cons of the gas storage system.

PROS
  • Water efficient. Owners do not have to wait as long as they would for hot water when compared to gas continuous flow / instant hot water. 
  • Gas storage systems deliver 3x more hot water in the first hour than a similar sized electric hot water system.
  • Domestic gas storage systems do not require electricity.
  • They come in a huge variety of commercial hot water systems.
  • They require a small gas line and use 80% less gas than a continuous  flow system when they are on.
  • Very quick recovery if you run out of hot water. 
  • Consistent hot water temperature.
  • Can be plumbed so 75°C water goes to kitchens and laundries and 50°C water goes to ablution areas as per AS/NZ 3500.
  • Easy to repair. 
  • You will have hot water during blackouts.
  • Long life expectancy. 
  • Because of the cost of water in Canberra, the high efficiency gas storage systems are likely to be cheaper to run than continuous flow hot water systems. 
  • Water will stay hot for days without any heat input
  • Cheaper to install than continuous flow and does not require an upgrade to 20mm gas pipe.
CONS
  • They take up more space than continuous flow hot water systems.
  • They do not provide an unlimited amount of hot water per hour.
  • There are no internal high efficiency storage systems available for the domestic market.
If you would like to know more, or get help with your storage gas hot water heater in Canberra or Queanbeyan you can contact us for help.

We hope our review of gas storage hot water systems and the pros & cons helped you to properly compare them to instantaneous / continuous flow systems.



Friday, June 5, 2015

Gas hot Water Systems - Review continuous systems

Review hot water systems, Discover the pros & cons of an instant continuous flow system. Learn how they work. Compare them with gas storage hot heaters.

There are two categories of gas hot water systems for commercial hot water installations and domestic installations. They are gas continuous flow/instantaneous (instant) and gas storage systems. Below is an explanation of how a continuous flow gas hot water heater works.   You can also learn about How gas storage systems work.

Diagram 1

1. All hot taps are closed. There is no flow. The 3 litres of cold water in the heat exchanger is stone cold.  The gas burner is off.

2. A hot tap is turned on and  cold water begins to flow through the heat exchanger. The gas valve opens and the gas is ignited.  The gas flame begins heating the heat exchanger. 300ml of the original cold water in the heat exchanger comes through the hot water outlet of the system. This water is not hot enough for use.

3. A hot tap is on and cold water continues to flow into the heat exchanger.  The cold water originally in the heat exchanger is moving through the system and is taking on heat.  Although not as cold, another 300ml of the original cold water in the heat exchanger comes through the hot water outlet of the system. The water at the outlet of the system is still not hot enough for use.

Diagram 2

4. A hot tap is on and cold water continues to flow into the heat exchanger. The cold water originally in the heat exchanger is moving through the system and is taking on more heat.  Although slightly warmer,  another 300ml of the original  water in the heat exchanger comes through the hot water outlet of the system. The water at the outlet of the system is still not hot enough for use.

5. A hot tap is on and cold water continues to flow into the heat exchanger. The cold water originally in the heat exchanger is moving through the system and is taking on more heat. Although slightly  warmer again,  another 300ml of the original  water in the heat exchanger comes through the hot water  outlet of the system. The water at the outlet of the system is still not hot enough for use.

6. A hot tap is on and cold water continues to flow into the heat exchanger. The cold water originally in the heat exchanger is moving through the system. Now much  warmer, another 300ml of the original  water in the heat exchanger comes through the hot water  outlet of the system. The water at the outlet of the system is still not hot enough for use.

Diagram 3

7. A hot tap is on and cold water continues to flow into the heat exchanger. The cold water originally in the heat exchanger is moving through the system. The water is about 45 degrees  and another 300ml of the original  water in the heat exchanger comes through the hot water  outlet of the system. Although very warm, the water at the outlet of the system is still not hot enough for use.

8. A hot tap is on and cold water continues to flow into the heat exchanger. The cold water originally in the heat exchanger has completely moved through the system. The water is about 50 degrees  and another 300ml of the original  water in the heat exchanger was lost through the hot water outlet of the system. The water at the outlet of the system is  now hot enough for use. Now the hot water must travel from the outlet of the system to the tap. The hot tap is typically 2 -20m from the hot water system.

ADVANTAGES AND DISADVANTAGES of gas continuous Flow/Instant/instantaneous hot water systems

As a plumber I am often asked if I would choose a gas storage system or a continuous flow hot water system.  These are the Pros and cons of the gas continuous flow.

PROS
  • They produce an unlimited amount of hot water. 
  • Take up minimal space.
  • They can be installed in roof spaces and under floors.
  • Are available in indoor and outdoor models.
  • Are available in a range of sizes for different uses.
  • Models are available for commercial hot water installations.
  • Suitable for inconsistent and extremely high hot water demand such as canteens, hotels and sporting fields.
  • Rheem and Rinnai make very reliable models.
  • Better for the environment than electric hot water systems.
CONS
  • Are not very well insulated so the water inside the system looses heat very quickly. 
  • Not very water efficient. Owners have to wait longer for hot water than they would for hot water from a gas storage system. 
  • Most require a 240 volt power supply for the electronics.
  • They require  80% more gas than a gas storage system when heating- this means larger gas pipes. Sometime they require a full upgrade to the gas meter and the gas piping from the meter.
  • They are more computer than plumbing. Therefore, they are not easy to repair and can  be expensive to repair. 
  • Some brands are not very reliable.
  • Inconsistent hot water temperature.
  • They are restricted to minimum and maximum flow rates.
  • Most will only lift the temperature 25 -35°C above the incoming water temperature. 
  • You will not have hot water during blackouts.
  • Because of the cost of water in Canberra, they are more expensive  to run than high efficiency gas storage systems.  
  • They are more expensive to install.
  • Because of the electricity they use and the energy involved in treating potable water, it is likely they are not as beneficial to the environment as people expect. 

We hope this review of hot water systems and the pros & cons of instant/continuous flow systems helps you to compare them with gas storage hot water heaters.

If you would like to know more or get help with your Continuous flow gas hot water in Canberra or Queanbeyan you can contact us on 61619417