Rinnai Heavy Duty
VULCAN HOT WATER
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Australia's Leading Commercial Continuous Flow Solution
When commercial hot water demand requires uncompromising performance, Rinnai heavy duty continuous flow hot water heaters deliver industry-leading reliability. Rinnai pioneered the commercial heavy duty continuous flow water heater category in 2003, and today's HD28 represents the culmination of Japanese engineering excellence.
The HD28 series provides 48kW energy output with flow rates up to 28L/min at a 25°C temperature rise — perfect for commercial kitchens, ablution blocks, process equipment, healthcare facilities and hospitality venues. With 83% thermal efficiency and a 6-star energy rating, these units minimise operating costs while delivering endless hot water on demand.
PlumbingSales.com.au stocks the complete Rinnai HD28 range with same or next-day dispatch on stock items, free shipping on orders over $300, and expert advice backed by over 60 years of plumbing industry experience.
Browse our Rinnai heavy duty continuous flow range above or contact our team for sizing and manifold configuration assistance.
Rinnai HD28 Model Range
The HD28 series offers two installation configurations to suit different site requirements, with both models available in natural gas and LPG variants.
| Model | Installation | Controller | Status Monitor | Pre-Set Temps | Gas Types |
|---|---|---|---|---|---|
| HD28e | External | Remote compatible | Yes (built-in) | 50°C, 75°C | NG / LPG |
| HD28i | Internal | In-built controller | Via controller | 50°C, 75°C | NG / LPG |
External models (HD28e) feature a built-in status operation monitor displaying set water temperature and system status, ideal for plant rooms and outdoor installations. Internal models (HD28i) include an in-built controller for indoor mechanical rooms and enclosed spaces.
Both models are MECs (Manifold Electronic Control System) compatible, enabling seamless multi-unit configurations for high-demand commercial applications.
Key Features and Benefits
Rinnai HD28 heavy duty continuous flow water heaters combine proven Japanese engineering with commercial-grade performance:
- 48kW output capacity — Delivers up to 28L/min at 25°C rise or 37L/min maximum flow for high-demand applications
- 83% thermal efficiency with 6-star rating — Reduces gas consumption and operating costs compared to storage systems
- Heat exchange bypass technology — Maintains perfect temperature while reducing pressure loss through the unit
- MECs manifold compatibility — Connect multiple units for scalable hot water capacity in large commercial installations
- Anti-frost protection to -20°C — Ensures reliable operation in cold climates and exposed locations
- BMS fault option — Integrates with Building Management Systems for centralised monitoring and fault reporting
- Low pressure loss design — Minimises impact on water pressure across multiple outlets
Technical Specifications
| Specification | HD28e (External) | HD28i (Internal) |
|---|---|---|
| Maximum Capacity | 48.8 kW | 48.8 kW |
| Flow at 25°C Rise | 28.0 L/min | 28.0 L/min |
| Flow at 35°C Rise | 20.0 L/min | 20.0 L/min |
| Flow at 50°C Rise | 14.0 L/min | 14.0 L/min |
| Maximum Flow | 37.0 L/min | 37.0 L/min |
| Thermal Efficiency | 83.3% | 83.3% |
| Star Rating | 6.0 | 6.0 |
| Gas Rate (Max) | 210 MJ/h | 210 MJ/h |
| Min Operating Flow | 1.4 L/min | 1.4 L/min |
| Water Pressure Range | 220–1000 kPa | 220–1000 kPa |
| Pre-Set Temperatures | 42°C, 50°C, 75°C | 42°C, 50°C, 75°C |
| Max Temperature Setting | 85°C | 85°C |
| Dimensions (W × D × H) | 357 × 272 × 583 mm | 357 × 245 × 583 mm |
| Weight | 20 kg | 21 kg |
| Connection Size (Hot/Cold/Gas) | 20 mm | 20 mm |
| Sound Level | <52 dBA | <52 dBA |
| Electrical Consumption | 66 W | 95 W |
Choosing the Right Rinnai HD28 Configuration
1. Assess installation location — Select HD28e for external plant rooms, rooftops or weatherproof enclosures where the built-in status monitor provides at-a-glance system information. Choose HD28i for internal mechanical rooms where the in-built controller offers convenient temperature adjustment.
2. Calculate hot water demand — Use the flow rate table to match temperature rise requirements to your application. At a 25°C rise (typical for pre-heated inlet water), the HD28 delivers 28L/min. For cold inlet water requiring a 50°C rise, expect 14L/min per unit.
3. Plan for multi-unit manifolds — High-demand sites such as hotels, aged care facilities and industrial processes benefit from MECs-connected manifold configurations. Multiple HD28 units can be linked for scalable capacity with intelligent load sharing.
4. Confirm gas supply — Verify natural gas or LPG availability and ensure adequate supply pressure and pipe sizing for the 210 MJ/h maximum gas rate.
Typical Commercial Applications
| Application | Why HD28 Suits |
|---|---|
| Commercial kitchens | High-volume dishwashing and food prep with endless hot water |
| Hotels & hospitality | Multi-unit manifolds scale to meet peak guest demand |
| Healthcare facilities | Reliable supply for patient care and sanitation requirements |
| Aged care | Consistent temperature delivery with BMS integration |
| Industrial processes | Process water heating with precise temperature control |
| Ablution blocks | Mining camps, sports facilities and public amenities |
| Laundromats | Sustained hot water for commercial washing equipment |
Warranty and Support
Rinnai backs the HD28 heavy duty series with comprehensive warranty coverage:
- 12-year heat exchange warranty (commercial applications)
- 3-year parts and labour warranty (commercial applications)
- 3-year parts and labour warranty (domestic applications)
Rinnai National Customer Care Centre: 1300 555 545
For service, maintenance and technical support, Rinnai's national network ensures your commercial hot water system operates at peak efficiency.
Frequently Asked Questions
What flow rate does the Rinnai HD28 deliver?
The HD28 delivers up to 37L/min maximum flow, or 28L/min at a 25°C temperature rise. At a 50°C rise (cold inlet to 60°C outlet), flow rate is 14L/min per unit. Multiple units can be manifolded for higher combined flow rates.
Can multiple Rinnai HD28 units be connected together?
Yes, the HD28 is MECs (Manifold Electronic Control System) compatible, allowing multiple units to be connected in manifold configurations for scalable capacity. This is ideal for hotels, aged care facilities and industrial applications requiring high-volume hot water.
What is the difference between HD28e and HD28i models?
The HD28e is designed for external installation with a built-in status monitor, while the HD28i suits internal installation with an in-built controller. Both deliver identical 48kW output and 28L/min flow performance.
Is the Rinnai HD28 available in LPG?
Yes, both HD28e and HD28i models are available in natural gas and LPG variants. Specify your gas type when ordering to ensure correct factory configuration.
What warranty covers Rinnai HD28 commercial water heaters?
Commercial applications receive a 12-year heat exchange warranty and 3-year parts and labour warranty. Domestic installations receive a 3-year parts and labour warranty. Full warranty terms are available at rinnai.com.au.
Does PlumbingSales.com.au deliver Rinnai commercial hot water heaters?
Yes, we deliver Rinnai HD28 heavy duty continuous flow water heaters Australia-wide. Orders over $300 qualify for free shipping to most areas. Click & Collect is available from our Melbourne warehouse.
Related Hot Water Categories
Explore our complete hot water range and related installation products:
- Rinnai Hot Water Systems — Complete Rinnai range
- Hot Water Systems — All brands and fuel types
- Gas Spares — Gas fittings, regulators and components
- Valves — Tempering valves and pressure limiting valves
- Copper Products — Copper pipe and fittings for hot water installations
- Flexible Hoses — Water heater connection hoses
Shop Rinnai Heavy Duty Continuous Flow with Confidence
PlumbingSales.com.au makes sourcing Rinnai heavy duty continuous flow hot water heaters simple. As Australia's largest online plumbing store with over 60 years of industry experience, we stock genuine Rinnai HD28 units ready for same or next-day dispatch.
Why shop with us:
- Free shipping on orders over $300 to most areas Australia-wide
- Click & Collect from our Melbourne warehouse at 23–25 Marni Street, Dandenong South VIC
- Same or next-day dispatch on stock items
- Expert support for commercial sizing and manifold configurations
Browse our Rinnai HD28 heavy duty continuous flow range above and order online today, or contact our team for commercial project advice and multi-unit quotations.