LPG Instant Hot Water System: How Does LPG Instant Hot Water Work?
How does an LPG instant hot water system work?
An LPG instant hot water system (LPG instantaneous hot water) works by heating the water as it passes through the unit.
Also called an LPG instant hot water system, an LPG instant hot water system (LPG instant hot water) is the most popular type of gas hot water system in Australia.
The reasons are simple — an LPG instant hot water system (LPG instantaneous hot water) never runs out of hot water and they are energy efficient.
But how does an LPG instant hot water work?
How Does an LPG Instant Hot Water System Work?
An LPG instant hot water system (LPG instant hot water) works when you open a hot water tap and a sensor detects the water flow.
When the LPG instant hot water is working, the gas burner fires and the heat exchanger works to heat the water. See image.
Some models of tankless LPG instant hot water system (LPG instantaneous hot water) work with a secondary heat exchanger to pre-heat the water, using heat from the LPG instant hot water exhaust gases.
A thermostat works to regulate the amount of gas that goes to the LPG instant hot water system burner, maintaining the pre-set water temperature.
The gas burner fires and the heat exchanger warms the flowing water.
Computer Controlled LPG Instant Hot Water System (LPG Instantaneous Hot Water)
At the heart of an LPG instant hot water system (LPG instant hot water) is an Electronic Control Unit (ECU) that controls how the gas flows through the LPG instant hot water system.
The ECU controls all of the functions of a modern gas hot water system, including temperature control, ignition, gas flow, and modulation.
It is also responsible for safety, with a flame sensor and automatic gas cut-off in the event of a problem.
LPG Instant Hot Water System Getting Started
When you turn on a hot water tap anywhere in your home, a flow sensor connected to the ECU detects the water flow through the LPG instant hot water system, and the heating begins.
A slow leaking tap is not enough flow to start the LPG instant hot water system (LPG instantaneous hot water).
However, leaky water pipelines and continuous hot water system repairs require immediate inspection.
Some LPG instant hot water system (LPG instant hot water) models have a combustion fan that draws air for combustion.
At the same time, the ECU starts the gas flow via a solenoid gas valve and triggers the igniter.
The igniter sparks until the flame sensor detects a flame.
If the gas flow fails to light within a few seconds, the ECU shuts down the flow to prevent any unsafe accumulation of gas.
The LPG Instantaneous Gas Hot Water System Process
In an LPG instant hot water system (LPG instantaneous hot water), the gas burner applies heat to the heat exchanger that the water flows through.
The course of the instant gas hot water is typically a serpentine pattern, allowing the water to absorb as much heat as possible from the walls of the heat exchanger.
Some LPG instant hot water system (LPG instant hot water) models have a secondary heat exchanger to pre-heat the water, using the heat from the burner exhaust gases.
This is often called a “condensing” continuous hot water system model.
The advantage of these LPG instant hot water system (LPG instantaneous hot water) is that they provide even greater energy efficiency; however they tend to have a higher purchase price than standard LPG instant hot water system models.
Many non-condensing LPG instant hot water system (LPG instant hot water) models are already 6-star rated.
Controlling the Temperature of an Instantaneous Gas Hot Water System
As the flow rate and temperature of the incoming water can vary, the ECU modulates the amount of gas that goes to LPG instant hot water system (LPG instantaneous hot water).
This modulation of the gas keeps the instant gas hot water at a constant temperature.
This functionality is based on a water temperature sensor on the exit side of the heat exchanger.
Some LPG instant hot water system (LPG instant hot water) have temperature controllers that allow the user to select a temperature and others are factory pre-set.
These controllers can be located on the instant gas hot water or wired to a remote location like a kitchen or bathroom.
The ECU takes the controller’s input to modulate the gas flow, keeping the instant gas hot water at the user’s desired temperature.
Most models of LPG instant hot water system (LPG instantaneous hot water) come with their maximum temperature pre-set in the factory.
This is a safety precaution to help prevent possible scalding.
Gas Water Tank
Different from an LPG instant hot water system (LPG instant hot water), a gas water tank works by heating water and storing it until needed.
Hot water is drawn from the top of the gas hot water tank and replaced with cold water at the bottom because warm water rises.
When the gas water tank water temperature drops below the thermostat set point, the gas hot water tank works by having the burner run until the temperature recovers to the set point.
Power Supply to an LPG Instant Hot Water System (LPG Instant Hot Water)
To power the flame igniter, most LPG instant hot water units are connected to your home’s power supply.
However, there are some LPG instant hot water units that use energy created by the water flowing through a small water turbine to provide the power for ignition (see graphic).
Lastly, there are also some LPG instant hot water system (LPG instantaneous hot water) units that just use a simple battery.
The turbine and battery powered instant gas hot water units have a distinct advantage over the connected models, inasmuch as they will operate even during a power outage.
The disadvantage of the turbine powered LPG instant hot water system (LPG instant hot water) is that the entire unit is physically larger than a comparable plug-in model, as well as more expensive.
How an LPG Instant Hot Water System Works – Summary
Cold water flows into the LPG instant hot water system (LPG instantaneous hot water) when a hot water tap is opened inside your home.
The water flow is detected by an instant gas hot water sensor that ignites the gas burner, to heat the water in the heat exchanger.
The water typically follows a serpentine pattern through the instantaneous gas hot water system heat exchanger, absorbing as much heat as possible.
An electronic control unit modulates the gas burner to maintain a set water temperature.
This is the simple explanation of how an instant gas hot water works.
Many Manufacturers & Models of LPG Instant Hot Water System
Please note that there are many manufacturers and even more models of LPG instant hot water system, including both LPG and natural gas.
Therefore, there can be variations in features, functionality and operation from the general gas hot water system descriptions provided above.
You should always consult the specific manufacturer’s information when making an LPG instant hot water system (LPG instantaneous hot water) purchase selection or other decision.
You should also always consult your owner’s manual for advice on safe LPG instant hot water system operation and maintenance.