Vulcan DUOMAX 315L Electric Hot Water System - Installed Today
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Product Information Quick Specs & Benefits View sizing, power, warranty and key product details
Recommended Household Size 6 people
Make Vulcan
Model 661315G7
Volume 315L
Maximum Warranty 10 years
Height 1640 mm
Width 640 mm
Made In Australia
Main Cylinder Material Steel Enamel

Vulcan DUOMAX 315L Electric Hot Water System

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VULCAN ELECTRIC HOT WATER

Vulcan Duomax 315L Electric Storage Hot Water System

The Vulcan Duomax 315L Electric Storage Hot Water System is a large-capacity electric water heater designed for medium to large households with higher daily hot water demand.

With 315 litres of hot water delivery, a 3.6 kW single element, vitreous enamel lined cylinder and indoor or outdoor installation suitability, it is a practical option for homes replacing an existing large electric storage water heater.

Installed Today offers the Vulcan Duomax 315L as a supply-only hot water system or with supplied-and-installed options in selected Brisbane and Gold Coast service areas, where available.

Vulcan Duomax 315L at a glance: this is a 315L single-element electric storage water heater designed for medium to large households and higher hot water demand. It uses a 3.6 kW heating element, can be installed indoors or outdoors where suitable and can be connected to an off-peak tariff where the property's electrical arrangement supports it.
WHAT IT DOES

What Does the Vulcan Duomax 315L Do?

The Vulcan Duomax 315L stores and heats water inside an insulated vitreous enamel lined cylinder. The electric element heats the stored water so it is ready when showers, baths, sinks and other hot water outlets are used.

Its 315L capacity gives households more stored hot water than smaller common electric systems such as 125L, 160L or 250L models.

This makes it particularly relevant to households with multiple occupants, higher shower demand or an existing large electric storage unit that needs replacing.

WHO IT SUITS

Who Is the Vulcan Duomax 315L Best For?

Medium to Large Families

Designed for households that need a larger reserve of stored hot water for regular showers, kitchen use, laundry and other daily demand.

315L Electric Replacements

A practical option where an existing 315L or similar large electric storage heater is being replaced and the existing installation position remains suitable.

Off-Peak Hot Water

Suitable for connection to an off-peak tariff where the electrical setup and household usage pattern make controlled-load heating appropriate.

WHO IT HELPS

What Problems Can the Vulcan Duomax 315L Help Solve?

Smaller Tank Running Out

The larger 315L capacity provides more stored hot water than common smaller electric systems where household demand has outgrown the existing tank.

Ageing Electric Storage System

It provides a straightforward replacement pathway where an older large electric water heater has reached the end of its service life.

Higher Household Demand

Homes with several occupants, longer shower patterns or regular periods of concentrated hot water use may benefit from the larger stored capacity.

PRODUCT AT A GLANCE

Vulcan Duomax 315L Key Details

315L Hot Water Delivery
3.6 kW Single Element
Up to 9 Manufacturer Sizing Guide
10 Years Cylinder Warranty

The manufacturer household guide is based on stated usage conditions. Real household suitability depends on hot water demand, shower habits, climate and electricity tariff arrangement.

PRODUCT SUITABILITY

Is the Vulcan Duomax 315L Right for My Home?

A Good Choice If...

You need a larger electric storage system, have higher daily hot water demand or are replacing an existing 315L electric water heater.

Consider Another Option If...

Your household has modest hot water demand, installation space is limited or you want to change to a different hot water technology such as a heat pump.

Check Before Ordering

Confirm dimensions, access, electrical supply, valve condition, water pressure, drainage, pipework, base condition and whether the system will be installed indoors or outdoors.

HOUSEHOLD SIZING

How Many People Can the Vulcan Duomax 315L Suit?

Vulcan lists the 315L model as capable of servicing a maximum of 9 people under its stated usage conditions.

This should be treated as a manufacturer sizing guide rather than a guarantee for every household. Actual usage can vary substantially.

  • Number of people living in the home
  • Average shower duration
  • Shower flow rates
  • Bath usage
  • Kitchen and laundry hot water demand
  • Climate and incoming water temperature
  • Electricity tariff arrangement
  • When household hot water demand occurs
HOW IT WORKS

How Does the Vulcan Duomax 315L Work?

1. Cold Water Enters

Cold water enters the storage cylinder through the water supply connection.

2. The Element Heats the Water

The 3.6 kW electric element heats the stored water inside the cylinder.

3. Hot Water Is Stored

The heated water remains stored until it is required at showers, taps and other connected hot water outlets.

KEY FEATURES

Key Features of the Vulcan Duomax 315L

315L Hot Water Delivery

Provides substantial stored capacity for medium to large households and homes with higher daily hot water use.

3.6 kW Single Element

The selected model uses a single 3.6 kW heating element and can suit many conventional electric storage replacement installations.

Vitreous Enamel Cylinder

The storage cylinder uses a vitreous enamel lining designed to help protect the internal steel cylinder surface.

Indoor or Outdoor Installation

The system can be installed indoors or outdoors where the location meets the required plumbing, drainage, electrical and access conditions.

Off-Peak Tariff Suitable

The model is suitable for off-peak connection where the household's electrical setup and hot water usage are appropriate.

Left-Handed Connections

The Vulcan product specification identifies left-handed connections, which should be considered when planning replacement pipework.

TECHNICAL DETAILS

Vulcan Duomax 315L Specifications

Specification Details
Brand Vulcan
Range Duomax
Product Reference 661315G7
System Type Electric storage hot water system
Hot Water Delivery 315 litres
Element Type Single element
Element Rating 3.6 kW
Manufacturer Household Guide Up to 9 people under stated usage conditions
Installation Type Indoor or outdoor where suitable
Tariff Suitability Suitable for off-peak connection where appropriate
Cylinder Vitreous enamel lined steel cylinder
Connection Layout Left-handed
Water Connections Rp 3/4"
ECV Setting 850 kPa
Maximum Supply Pressure With ECV 680 kPa
Maximum Supply Pressure Without ECV 800 kPa
Relief Valve Pressure 1000 kPa
Height 1640 mm
Width 640 mm
Depth 680 mm
Empty Weight 89 kg
Shipped Weight 95 kg
Warranty 10 year cylinder warranty and 12 months parts and labour, subject to current Vulcan warranty conditions
INSTALLATION REQUIREMENTS

What Is Required to Install the Vulcan Duomax 315L?

The 315L Vulcan is a substantial storage water heater, so the installation position and delivery route should be checked before ordering an installed system.

  • Suitable stable installation position
  • Space for the 1640 mm x 640 mm x 680 mm unit
  • Safe delivery and lifting access
  • Suitable cold and hot water connections
  • Correct valve arrangement
  • Suitable incoming water pressure
  • Relief and expansion drainage
  • Electrical supply suitable for the 3.6 kW element
  • Suitable electrical isolation
  • Service and maintenance access
  • Safe tray and drainage where required indoors
  • Suitable outdoor position where installed externally
ACCESS & DIMENSIONS

Will the Vulcan Duomax 315L Fit in the Existing Location?

The unit measures approximately 1640 mm high, 640 mm wide and 680 mm deep and has a listed empty weight of 89 kg.

Both the final installation position and the delivery path should be checked. Narrow side access, stairs, raised platforms, tight laundries, cupboards and steep sites can affect installation requirements.

Check more than the final tank position. There also needs to be a practical route for getting the existing system out and the new 315L water heater safely into position.
ELECTRICAL REQUIREMENTS

What Electrical Supply Does the Vulcan Duomax 315L Need?

This model uses a 3.6 kW single heating element. The existing electrical circuit, wiring and isolation arrangement should be checked before installation.

Where the system is replacing a compatible electric storage heater, the existing electrical arrangement may be reusable if it remains suitable and compliant.

Any required circuit changes, isolator alterations or other electrical work need to be completed by an appropriately licensed electrical contractor.

OFF-PEAK HOT WATER

Can the Vulcan Duomax 315L Use Off-Peak Electricity?

Yes. The Vulcan 315L is suitable for connection to an off-peak tariff where the property's electrical arrangement supports it.

Storage systems can heat water during the available controlled-load period and hold that hot water for later use.

The tank still needs to be correctly sized for the household so enough hot water is available between heating periods.

WATER PRESSURE

What Water Pressure Limits Apply?

850 kPa ECV Setting

The listed expansion control valve setting is 850 kPa.

680 kPa With ECV

The listed maximum incoming water supply pressure is 680 kPa where an ECV is installed.

800 kPa Without ECV

The listed maximum incoming water supply pressure is 800 kPa where an ECV is not installed.

Incoming water pressure and the required valve arrangement should be checked as part of the installation.

INDOOR OR OUTDOOR

Can the Vulcan Duomax 315L Be Installed Indoors or Outdoors?

Indoor Installation

Indoor installation is possible where the position provides suitable access, drainage, leak protection, plumbing, electrical supply and any required safe tray arrangement.

Outdoor Installation

Outdoor installation is possible where the water heater has a stable base, suitable service access and compliant plumbing and electrical connections.

REPLACEMENT & UPGRADES

Can the Vulcan Duomax 315L Replace My Existing System?

The Vulcan Duomax 315L can be a practical like-for-like replacement where an existing large electric storage system occupies a suitable location and the existing plumbing, drainage and electrical supply are compatible.

Like-for-Like Replacement

The simplest installations are generally those where an existing large electric system is being replaced in the same suitable location.

Changing Tank Size

Moving from a smaller system to 315L can require additional space, altered pipework, a different base or changes to the surrounding installation.

Relocating the System

Moving the water heater to a new position can require additional pipework, drainage, electrical work and installation labour.

WHAT'S INCLUDED

What's Included With the Vulcan Duomax 315L?

Supply Only

Choose supply only if you already have the required licensed trades arranged and simply need the Vulcan Duomax 315L supplied.

Supplied & Installed

Eligible Brisbane and Gold Coast customers can choose a supplied-and-installed option where available and suitable for the property.

Possible Additional Work

Valve kits, electrical alterations, pipework, drainage, system removal, disposal, relocation and difficult-access work may be additional depending on the installation.

SUPPLY OR INSTALL

Choose How You Want to Order the Vulcan Duomax 315L

Supply Only

Choose the unit only if you already have a licensed plumber and the required electrical work arranged.

Brisbane Installation

Supply and installation may be available across selected Brisbane service areas, subject to site suitability and availability.

Gold Coast Installation

Supply and installation may be available across selected Gold Coast service areas, subject to site suitability and availability.

AUSTRALIA-WIDE SUPPLY

Buy the Vulcan Duomax 315L Across Australia

Installed Today can offer supply-only ordering to supported Australian locations, while eligible Brisbane and Gold Coast customers may also have supplied-and-installed options available.

Brisbane Gold Coast Sydney Melbourne Adelaide Perth
BRISBANE INSTALLATION

Vulcan Duomax 315L Supply & Installation Brisbane

The Vulcan Duomax 315L can suit Brisbane family homes replacing an existing large electric storage water heater where the current installation position, plumbing, electrical supply and drainage remain suitable.

Before installation, access, valves, water pressure, pipework, base condition, electrical requirements and old-system removal requirements should be checked.

GOLD COAST INSTALLATION

Vulcan Duomax 315L Supply & Installation Gold Coast

Gold Coast customers may be able to choose the Vulcan Duomax 315L with installation where service coverage and site conditions allow.

The model may suit family homes, rental properties and larger residences needing a conventional electric storage replacement. Final suitability depends on access, water pressure, drainage, plumbing and electrical requirements.

315L ELECTRIC STORAGE

Why Choose a 315L Electric Hot Water System?

A 315L electric system sits above common 250L storage sizes and provides additional stored hot water without moving to the larger 400L class.

It can be a useful middle ground for households that need more hot water than a smaller system can provide but do not necessarily need the physical size and additional storage of a 400L cylinder.

The correct choice should still be based on actual household demand rather than tank capacity alone.

COMPARE YOUR OPTIONS

Vulcan Duomax 315L vs 250L Electric Storage

Consideration 315L Electric Storage 250L Electric Storage
Stored Hot Water Greater stored capacity Lower stored capacity
Typical Application Medium to large households or higher demand Moderate household demand depending on usage
Physical Size Larger installation footprint Generally more compact
Consider 315L When... The household genuinely needs additional stored capacity The extra capacity of a 315L system is unnecessary
COMPARE TECHNOLOGIES

Vulcan Duomax 315L vs Heat Pump Hot Water

The Vulcan Duomax uses a conventional electric resistance element to heat stored water. A heat pump uses heat from the surrounding air and has different installation and operating characteristics.

Choose Electric Storage When...

You want a straightforward large-capacity electric replacement and the existing location, plumbing and electrical setup already suit this type of system.

Consider a Heat Pump When...

You are considering a change in technology and have a suitable installation position with the required airflow, drainage, electrical supply and space.

COMMON QUESTIONS

Questions About the Vulcan Duomax 315L

Can I Buy the Vulcan Duomax 315L Supply Only?

Yes. Supply-only ordering is suitable if you already have the required licensed trades arranged for installation.

Can Installed Today Install the Vulcan Duomax 315L?

Supply and install options may be available in selected Brisbane and Gold Coast service areas, subject to service coverage, site suitability and installation availability.

Is Installation Included in the Product Price?

No. The product-only price is for the water heater unless an installed option is selected. Site-specific installation extras may also apply.

How Much Hot Water Does the Vulcan Duomax 315L Deliver?

The listed hot water delivery is 315 litres.

How Many People Can the Vulcan Duomax 315L Suit?

Vulcan lists the model for a maximum of 9 people under stated usage conditions. Actual household suitability depends on hot water demand and heating arrangement.

What Size Element Does It Use?

The 661315G7 model uses a 3.6 kW single element.

Is the Vulcan Duomax 315L Twin Element?

No. This product is the single-element version.

Can It Run on Off-Peak Electricity?

Yes. The Vulcan 315L is suitable for connection to an off-peak tariff where the property and household requirements are suitable.

Can It Be Installed Indoors?

Yes, provided the location meets the required access, plumbing, electrical, drainage and leak-protection requirements.

Can It Be Installed Outdoors?

Yes, where the outdoor position provides a suitable base, service access and compliant plumbing and electrical connections.

What Are the Dimensions?

The listed dimensions are approximately 1640 mm high x 640 mm wide x 680 mm deep.

How Much Does the Vulcan Duomax 315L Weigh?

Vulcan lists the empty weight as 89 kg and the shipped weight as 95 kg.

What Water Connections Does It Use?

The listed water connections are Rp 3/4-inch.

What Is the ECV Setting?

The listed ECV setting is 850 kPa.

What Is the Maximum Water Supply Pressure?

The listed maximum supply pressure is 680 kPa with an ECV and 800 kPa without an ECV.

What Is the Relief Valve Pressure?

The listed relief valve pressure is 1000 kPa.

Can It Replace an Existing 315L Electric Water Heater?

Potentially, yes. A like-for-like replacement can be relatively straightforward where the installation location, connections, electrical supply, water pressure and drainage remain suitable.

Does It Need a New Valve Kit?

The existing valves should be assessed as part of the installation. Older, unsuitable or non-compliant valves may need replacement rather than being reused with the new water heater.

Does It Need Electrical Work?

The existing electrical installation should be checked for compatibility with the 3.6 kW element. Additional electrical work may be required where the existing circuit or isolation does not suit the new unit.

WARRANTY & MAINTENANCE

Vulcan Duomax 315L Warranty and Maintenance

The Vulcan 315L product information lists a 10 year cylinder warranty together with 12 months parts and labour warranty, subject to current manufacturer warranty conditions.

Correct installation, suitable water pressure, appropriate valves and ongoing maintenance all contribute to the long-term performance of an electric storage water heater.

Current warranty conditions should be checked against the documentation supplied with the specific unit.

WHY INSTALLED TODAY

Why Order the Vulcan Duomax 315L From Installed Today?

Supply-Only Ordering

Suitable for customers who already have the required licensed plumber and electrical arrangements in place.

Installation Options

Eligible Brisbane and Gold Coast customers can check available supplied-and-installed options.

Clear Installation Add-Ons

Valve kits, system removal, disposal, electrical work and other installation requirements can be separated from the unit price where applicable.

FINAL CHECK

Is the Vulcan Duomax 315L Right for You?

The Vulcan Duomax 315L is primarily suited to medium to large households wanting a conventional electric storage hot water system with substantial stored capacity.

Its key strengths are its 315L hot water delivery, 3.6 kW single element, indoor or outdoor installation suitability and compatibility with off-peak electricity arrangements where appropriate.

If you are replacing an existing large electric system, check dimensions, delivery access, valves, water pressure, drainage and electrical supply before ordering. Choose supply only if you already have licensed trades arranged, or check available Brisbane and Gold Coast installation options where applicable.

Tempering Valve and Element Information

*Element size information:
All electric hot water units are supplied as standard with a 3.6kW element unless otherwise stated on the product page, invoice, or order confirmation.

If a different element configuration is requested, such as 1.8kW or 2.4kW, the hot water unit may still arrive with the standard 3.6kW element fitted from the manufacturer. The requested 1.8kW or 2.4kW element will be supplied separately with the order for installation by a suitably licensed electrical contractor or licensed electrical licence holder.

Any element changeover, electrical connection, disconnection, wiring, testing, or modification must be carried out by a licensed electrical contractor or licensed electrical licence holder. Elements must not be changed, connected, modified, or tested by an unlicensed person.

Alternative elements supplied for non-standard configurations may be generic replacement elements and may not be the same brand as the hot water unit unless specifically stated. Generic elements are supplied to suit the requested element size and electrical configuration, but final suitability must be checked by the licensed installer before installation.

1.8kW and 2.4kW elements supplied separately with a hot water unit include a 12-month supply-only parts warranty from the date of purchase, provided the element has been correctly installed by a licensed electrical contractor or licensed electrical licence holder and used under normal operating conditions.

This element warranty covers the replacement supply of the element only. It does not include labour, call-out fees, electrical work, plumbing work, fault finding, removal, reinstallation, testing, travel, downtime, damage caused by incorrect installation, or any other associated costs. Warranty may be declined where the element has been incorrectly installed, dry-fired, modified, damaged, connected to incorrect voltage or wiring, affected by power issues, used in unsuitable water conditions, or installed by an unlicensed person.

Proof of purchase, installer details, electrical licence details, photos, and/or return of the faulty element may be required before a warranty claim is approved.

**Tempering valve information:
Where a hot water system is capable of delivering water above 50°C, a compliant tempering valve must be installed to control the temperature delivered to personal hygiene fixtures such as showers, baths, basins, and bathroom outlets. This helps reduce the risk of scalding and assists with meeting plumbing compliance requirements.

A tempering valve blends hot and cold water to deliver a safer controlled outlet temperature to required fixtures. The hot water unit itself may store water at a higher temperature, but the water delivered to personal hygiene outlets must be controlled where required by plumbing regulations.

If your property already has a suitable, compliant tempering valve installed, your licensed plumber can assess whether it is appropriate for use with the new hot water system. Existing valves may not always be suitable due to age, condition, compliance requirements, valve type, location, or system compatibility.

If a compliant tempering valve is not already installed, or if the existing valve is unsuitable, one must be supplied and installed by a licensed plumber as part of the hot water installation.

Tempering valves are not automatically included with every supply-only hot water unit unless specifically selected, listed as included, or purchased as part of a suitable valve kit. If a tempering valve is required, please purchase the appropriate valve kit with your order or arrange for your licensed installer to supply and install the correct tempering valve on site.

It is the customer’s responsibility to ensure the installation is completed by appropriately licensed trades and that all required valves, fittings, electrical work, plumbing work, and compliance requirements are allowed for as part of the installation.

A Simpler Way to Buy Hot Water, Filters, Pumps and Plumbing Products

Buying a new hot water system, water filter, pump or plumbing product should be clear, simple and easy to organise.

Installed Today helps you compare products, check supply-only pricing and, where available, build an optional installation package before checkout. That means you can choose the product, review the available options and order with more confidence, without the usual back and forth just to understand the starting price.

Whether you already know exactly what you need or you are still comparing options, Installed Today gives you a clearer way to buy the right product for your home, budget and timing.

Why Customers Choose Installed Today

Supply Only or Optional Installation

Choose the product on its own, or add installation where available on selected products and in eligible service areas. This gives you the flexibility to order the way that suits you best.

Clear Pricing Before Checkout

See the product price upfront, then review available installation options and common add-ons before placing your order. You can check the package total before checkout, instead of waiting on basic pricing just to get started.

Product Details That Actually Help

Key specs, sizing details, warranty information, product features and suitability notes are shown clearly, making it easier to compare products properly before you buy.

Common Installation Add-Ons Available

Where relevant, you can add common installation extras such as valve kits, bases, access-related items, removal, electrical options or other site-specific upgrades before checkout.

Built Around Brisbane and Gold Coast Homes

Our product and installation options are selected with common Brisbane and Gold Coast homes in mind, including local water quality, access issues, plumbing layouts, replacement requirements and typical installation conditions.

One Simple Order

Add the product and selected options to cart in one order, instead of trying to organise separate suppliers, installers, parts and payments yourself.

Practical Help Before You Buy

Not sure which size, model or installation option is right? Installed Today gives you a clearer path to compare your options before you order.

Designed to Make Your Decision Easier

Installed Today is built for customers who want a faster, clearer and more convenient way to buy.

Instead of guessing what is included, waiting for basic pricing or trying to work out which extras may be needed, you can review the product, compare your options and move forward with confidence.

Choose supply only if you just need the product.

Choose an optional supplied and installed package where installation is available and you want the product and selected install options organised in one order.

Add common extras before checkout if your job needs additional parts, removal, access support or site-specific options.

It is a simpler way to organise the product, the selected extras and the parts of the job that matter most.

Important Installation Note

Installation availability, inclusions and add-ons vary by product type, service area, site access, existing services, selected options and property requirements.

Some jobs may require additional work, upgrades or checks before installation can proceed. Final suitability may need to be confirmed based on site conditions, plumbing, electrical requirements, valves, drainage, access and compliance requirements.

Supply-only orders do not include installation, old unit removal, disposal, valve kits, electrical work, plumbing alterations or compliance upgrades unless these are clearly selected or included in your order.

Fast Delivery and Install-Aligned Shipping

Installed Today makes delivery simple, whether you are ordering supply-only or choosing an optional install package.

For supply-only orders, you can select from available delivery options at checkout. For eligible orders with installation selected, shipping is included and coordinated to align with your selected installation period where possible.

Delivery Options

Same Day Delivery

Same day delivery may be available for selected hot water systems in Brisbane and Gold Coast metro areas when ordered before 7:00am.

Availability depends on stock, courier capacity, delivery location, product type and safe transport conditions.

Express Delivery

Express delivery is available on selected products and locations, with an estimated delivery timeframe of 1–4 business days.

Standard Delivery

Standard delivery is available on selected products, with an estimated delivery timeframe of 2–8 business days.

Free Shipping with Installation

When you select an eligible installation package, delivery is included as part of the supplied and installed order.

Your product delivery will be organised to align with your selected installation period where possible, helping avoid separate courier timing, storage issues or delays between delivery and installation.

Fast Metro Delivery

Most hot water orders in metro areas are delivered quickly, with many arriving within 1 business day depending on stock, location, order time and courier availability.

Weather and Transport Delays

Hot water systems are large, heavy products and cannot always be transported safely during rain or unsafe handling conditions.

Delivery timeframes may be affected if wet weather impacts loading, unloading, transport access or safe delivery conditions.

Express Delivery Refund

If your express delivery order takes longer than the estimated 1–4 business day express timeframe, your order will move to the standard 2–8 business day delivery timeframe and your express shipping charge will be refunded automatically.

Order Tracking

We will send your delivery details once your order has been dispatched or scheduled.

For supplied and installed orders, delivery timing may be coordinated around your selected installation period rather than sent as a separate courier-only delivery.

Need Help with Delivery?

Not sure whether to choose supply-only delivery or an optional install package? Contact our team before ordering and we can help you understand the best option for your product, location and timing.

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