Rheem AmbiPower MDc-180 Heat Pump Hot Water System
The Rheem AmbiPower MDc-180 is a compact integrated heat pump hot water system with a 178-litre storage capacity, designed for smaller households replacing conventional electric storage hot water.
Rheem lists the MDc-180 for households of up to four people based on its stated sizing assumptions. The system uses R513a refrigerant, wraparound microchannel heat-transfer technology and an electric backup element to provide stored hot water without relying on direct sunlight.
The current 551D180 family is available in hardwired 2.4kW-element and plug-and-lead 1.4kW-element versions, including optional blue-anode variants for appropriate water conditions.
Installed Today can offer the unit as supply only where available, or as part of an eligible supplied-and-installed package in Brisbane and Gold Coast service areas subject to site suitability and the exact electrical variant selected.
Which Rheem AmbiPower MDc-180 Version Do You Need?
The 551D180 family includes separate electrical and anode configurations. The correct version should be selected before installation rather than assuming every MDc-180 connects in the same way.
551D180C5
Hardwired model with standard magnesium anode and a 2.4kW electric backup element.
551D180C5/B
Hardwired model with the optional blue aluminium anode configuration and a 2.4kW electric backup element.
551D180C3P
Plug-and-lead model with standard magnesium anode, 1.4kW backup element and standard Australian 10A three-pin plug.
551D180C3P/B
Plug-and-lead model with the blue aluminium anode configuration, 1.4kW backup element and standard Australian 10A three-pin plug.
How Many People Does the AmbiPower MDc-180 Suit?
Rheem lists the 178L MDc-180 for up to four people.
Rheem's sizing note is based on seven-minute showers at 42°C, with appliances using hot water counted as an additional person.
Smaller Families
The 178L capacity is intended for small-family hot-water demand rather than the larger demand served by Rheem's 280L heat-pump models.
Townhouses & Compact Homes
Its smaller storage volume can suit homes where a larger heat pump would provide unnecessary storage capacity.
Electric Storage Replacement
Rheem specifically positions the MDc-180 for replacement of small-to-medium electric water heaters.
Actual suitability depends on shower length, bath use, fixture flow rates, daily timing of hot-water use and the electrical tariff available to the appliance.
Rheem AmbiPower MDc-180 Key Details
How Does the Rheem AmbiPower MDc-180 Heat Water?
The MDc-180 extracts heat from the surrounding air and transfers that energy into the stored water through a refrigeration cycle.
Rheem uses a wraparound microchannel heat-transfer design to provide a large contact area around the cylinder for water heating.
The system can operate during the day or night because it uses ambient air energy rather than direct sunlight.
An electric heating element provides additional heating when required, including operation outside the normal heat-pump ambient-temperature range.
Rheem AmbiPower MDc-180 Heat Pump Performance
Rheem's current March 2026 technical data lists an average COP of 4.9 at 19°C ambient air temperature for the R513a 551D180.
At the same test point, Rheem lists an average heat-pump heating capacity of 3.2kW and a recovery rate of approximately 61 litres per hour for a 45°C temperature rise.
| Ambient Condition | Average Heating Capacity | 45°C-Rise Recovery | Average COP |
|---|---|---|---|
| 6°C / 88% RH | 2.3kW | 45L/hr | 4.3 |
| 19°C / 66% RH | 3.2kW | 61L/hr | 4.9 |
Can the AmbiPower MDc-180 Reduce Water-Heating Energy Use?
Rheem states that the 551D180 can use up to 70% less water-heating energy than an electric water heater of similar size in Zone 3 under its stated modelling conditions.
The comparison uses government-approved TRNSYS modelling and assumes a minimum available electrical supply period of 16 hours per day.
Actual energy use and electricity-cost savings vary with climate, tariff, hot-water demand, operating schedule and the water heater being replaced.
Rheem AmbiPower MDc-180 Specifications
| Specification | Current 551D180 Details |
|---|---|
| Brand | Rheem |
| Range | AmbiPower MDc-180 |
| Model Family | 551D180 |
| Storage Capacity | 178 litres |
| Boost Capacity | 168 litres |
| Household Sizing | Up to 4 people |
| Tank Height | 1810mm |
| Tank Width | 532mm |
| Tank Depth | 576mm |
| Cartoned Weight | 116kg |
| Filled Weight | Approximately 284kg |
| Refrigerant | R513a |
| Refrigerant Charge | 875g |
| Manufacturer-Listed GWP | 631 |
| Rated Heat Pump Input | 683W |
| Hardwired Backup Element | 2.4kW |
| Plug-and-Lead Backup Element | Approximately 1.4kW |
| Hardwired Maximum Power Input | 3.5kW |
| Plug-and-Lead Maximum Power Input | 2.4kW |
| Hardwired Electrical Circuit | 15A |
| Plug-and-Lead Electrical Circuit | 10A |
| Plug Type | Standard Australian 10A three-pin plug on plug-and-lead version |
| COP at 19°C | 4.9 |
| Average Heating Capacity at 19°C | 3.2kW |
| Recovery at 19°C / 45°C Rise | 61L/hr |
| Sound Level | 47 dB(A) LA90 at 1 metre |
| Heat Pump Operating Range | -7°C to 43°C |
| Ingress Protection | IP24 |
| Water Connections | Rp 3/4 inlet and outlet |
| TPR Valve Setting | 1000 kPa |
| Expansion Control Valve Setting | 850 kPa |
| Maximum Mains Pressure With ECV | 680 kPa |
| Maximum Mains Pressure Without ECV | 800 kPa |
Hardwired or 10A Plug-and-Lead?
The current MDc-180 family gives customers two distinct electrical pathways.
Hardwired – 551D180C5
The hardwired model uses a 2.4kW backup element and requires its own electrical circuit capable of supplying at least 15A.
Rheem requires permanent wiring, an isolating switch at the switchboard and a second lockable isolating switch adjacent to the water heater.
Plug & Lead – 551D180C3P
The plug-and-lead model uses an approximately 1.4kW backup element and is supplied with a standard Australian 10A three-pin plug.
Rheem specifies a weatherproof switched GPO on a circuit rated at least 10A, located within 1.2 metres of the installation and clear of draining water and plumbing connections.
Does the MDc-180 Need Continuous Power?
Rheem recommends connection to an uninterrupted 24-hour continuous-tariff supply.
Depending on household demand and electricity-retailer requirements, Rheem states that an extended off-peak or time-controlled supply of at least 16 hours per day may also be suitable.
The appliance includes an onboard timer that can define one operating period within a 24-hour period.
Can the Rheem AmbiPower MDc-180 Be Installed Indoors?
No. Rheem's current installation instructions state that the 551D180 is designed for outdoor installation only.
The location should be close to frequently used hot-water outlets while also allowing for noise, safe access, condensate drainage and adequate heat-pump airflow.
Rheem advises considering nearby bedrooms, living-room windows and neighbouring properties when choosing the final position.
How Much Clearance Does the MDc-180 Need?
Rheem's current installation guide specifies minimum clearances to maintain heat-pump airflow and performance.
- 80mm minimum behind the water heater
- 500mm minimum on the left-hand air-inlet side
- 600mm minimum on the right-hand air-outlet side
- 700mm minimum above the water heater
- 500mm preferred front clearance for service access
- 600mm preferred clearance on both sides for servicing where possible
The air inlet and discharge should remain free of vegetation, walls and other obstructions that could restrict airflow.
What Installation Space Does the MDc-180 Require?
The tank measures approximately 1810mm high x 532mm wide x 576mm deep, before allowing for the required airflow and service clearances.
Rheem requires the unit to be installed at ground or floor level, vertically upright, on a level, stable and impervious base that avoids ponding.
Delivery and handling should also be considered before ordering because the packaged water heater is approximately 116kg and the filled operating weight is approximately 284kg.
Does the Rheem AmbiPower MDc-180 Need a Condensate Drain?
Yes. Condensate is produced during normal heat-pump operation.
Rheem supplies a condensate drain hose that must be securely connected to the rear condensate spigot.
The hose should maintain continuous fall to its discharge point without bends or distortion, and the outlet should remain visible so discharge can be checked.
The hot-water installation also requires compliant TPR-valve drainage and any other drainage required by the final plumbing arrangement.
What Water Pressure Limits Apply?
The MDc-180 uses a 1000 kPa temperature and pressure relief valve and Rheem specifies an 850 kPa expansion-control-valve setting where an ECV is fitted.
| Plumbing Arrangement | Maximum Mains Supply Pressure |
|---|---|
| Expansion Control Valve Fitted | 680 kPa |
| No Expansion Control Valve | 800 kPa |
Where incoming mains pressure exceeds the applicable limit, a suitable pressure-limiting arrangement is required.
Rheem also notes that supply pressure should be greater than approximately 350 kPa for true mains-pressure operation.
Is the MDc-180 Suitable for Harsh Water?
Rheem promotes the AmbiPower MDc-180 as suitable for harsh-water conditions and offers optional blue-anode models for appropriate water chemistry.
The blue-anode variants are 551D180C5/B for hardwired installations and 551D180C3P/B for plug-and-lead installations.
However, this should not be interpreted as unlimited water-quality tolerance.
How Fast Does the Electric Backup Element Recover?
The hardwired and plug-and-lead models use different electric elements and therefore have different element-only recovery rates.
| Element | 30°C Rise | 40°C Rise | 50°C Rise |
|---|---|---|---|
| 2.4kW Hardwired | 69L/hr | 52L/hr | 41L/hr |
| 1.4kW Plug & Lead | 44L/hr | 33L/hr | 26L/hr |
The electric element can also activate when ambient temperature falls outside the normal -7°C to 43°C heat-pump operating range.
What Temperature Can the MDc-180 Store Water At?
Rheem's current installation guide allows the hot-water temperature set point to be adjusted from approximately 60°C to 70°C.
Stored water at these temperatures can cause serious scalding, so the plumbing installation must include any temperature-control devices required for personal-hygiene fixtures.
What Maintenance Does Rheem Recommend?
Rheem recommends minor owner maintenance as described in the product guide and a major service every five years by qualified personnel.
The five-year service includes checks of the relief valve, expansion control valve where fitted, anode, electric element, heat-pump system, condensate drain and electrical connection.
Rheem also recommends the evaporator and refrigeration system be checked approximately every five years, with more frequent cleaning possible in particularly dusty locations.
Rheem AmbiPower MDc-180 Warranty
For qualifying single-family domestic installations, Rheem's current standard warranty specifies:
| Component | Supply / Parts | Labour |
|---|---|---|
| Inner Cylinder | 7 years | 3 years |
| Sealed Refrigeration System | 3 years | 3 years |
| Other Components | 1 year | 1 year |
The sealed system includes refrigerant-carrying components such as the compressor, condenser, expansion device, receiver/drier, evaporator and associated refrigeration pipework.
Rheem's current warranty also contains additional five-year whole-of-product provisions for certain installations associated with specified rebate or certificate programs, subject to the manufacturer's eligibility and evidence requirements.
Is the Rheem AmbiPower MDc-180 Eligible for STCs?
Rheem currently identifies the MDc-180 as eligible for Small-scale Technology Certificates where the installation satisfies the applicable scheme requirements.
The number and value of certificates can vary with installation date, climate zone and current program rules.
Any federal or state incentive should therefore be confirmed at the time of purchase rather than hard-coded as a permanent dollar saving.
Buy the Rheem AmbiPower MDc-180 Supply Only
Choose supply only where you already have appropriately licensed installation trades arranged and only require the heat pump supplied.
The supply-only price does not automatically include plumbing installation, valve kits, electrical work, condensate drainage alterations, old-system removal, disposal, base work or other site-specific requirements.
Confirm the exact electrical variant before ordering so the installer receives either the correct hardwired model or the correct plug-and-lead model for the property.
Rheem AmbiPower MDc-180 Supplied & Installed
Eligible Brisbane and Gold Coast customers can select a supplied-and-installed pathway where the property, product variant and required installation scope are suitable.
Plumbing Check
Existing valves, mains pressure, pipework, temperature control and drainage need to suit the replacement heat pump.
Electrical Check
The electrical installation must match the exact hardwired 15A or plug-and-lead 10A model being supplied.
Outdoor Location
The site needs a suitable outdoor position with the required airflow clearances, stable base, condensate drainage and future service access.
Brisbane & Gold Coast Installation Options
Installed Today can provide supplied-and-installed pathways across eligible Brisbane and Gold Coast service areas where the product and required installation scope are available.
Additional work may apply where the property requires a new electrical circuit or GPO, valve replacement, pipework changes, drainage alterations, relocation, base work or difficult-access handling.
Why Choose the Rheem AmbiPower MDc-180?
The MDc-180 combines a compact 178L cylinder with Rheem's current R513a heat-pump platform, wraparound microchannel heating and a choice of hardwired or plug-and-lead electrical configurations.
Its up-to-four-person manufacturer sizing and relatively compact tank dimensions make it particularly relevant where a 280L heat pump is unnecessarily large for the household.
The current plug-and-lead version also provides a standard 10A electrical pathway, while the higher-output 2.4kW backup-element version remains available for hardwired installations.
Questions About the Rheem AmbiPower MDc-180
What Is the Main Model Number?
The product family is 551D180.
What Are the Current Hardwired Product Codes?
The current standard-anode hardwired model is 551D180C5, with 551D180C5/B identifying the blue-anode version.
What Are the Plug-and-Lead Product Codes?
The current standard-anode plug model is 551D180C3P, with 551D180C3P/B identifying the blue-anode version.
What Is the Storage Capacity?
The MDc-180 stores 178 litres.
How Many People Does Rheem Size It For?
Rheem lists the model for up to four people under its stated sizing assumptions.
What Are the Dimensions?
Approximately 1810mm high x 532mm wide x 576mm deep.
What Is the Filled Weight?
Rheem lists approximately 284kg when full.
What Refrigerant Does It Use?
The current 551D180 uses R513a.
What Is the R513a Charge?
Rheem's current installation guide lists approximately 875g.
What GWP Does Rheem List?
Rheem lists a GWP of 631 for R513a.
What Is the Current COP?
Rheem's March 2026 data lists an average COP of 4.9 at 19°C.
Why Do Some Older Pages Say COP 4.5?
Earlier Rheem documentation and parts of the manufacturer website contain older figures. The current March 2026 MDc-180 datasheet lists 4.9 for the R513a 551D180.
What Is the Heat-Pump Heating Capacity?
At the current 19°C test point, Rheem lists an average heating capacity of 3.2kW.
What Is the Recovery Rate?
At 19°C ambient conditions, Rheem lists approximately 61 litres per hour for a 45°C temperature rise.
What Is the Sound Level?
The current March 2026 data lists 47 dB(A) LA90 at one metre.
Why Do Older Pages Say 48 dB(A)?
Older Rheem material listed 48dB(A). The current March 2026 MDc-180 technical sheet lists 47dB(A).
What Is the Operating Temperature Range?
The heat pump is designed to operate from approximately -7°C to 43°C.
Does It Need Direct Sunlight?
No. The heat pump extracts energy from the surrounding air and can operate during the day or night.
Is the Plug Version 10A or 15A?
The current plug-and-lead MDc-180 uses a standard Australian 10A three-pin plug and requires a suitable 10A circuit and weatherproof switched outlet.
Does the Hardwired Version Need 15A?
Yes. Rheem specifies that the hardwired 2.4kW-element model requires a supply capable of at least 15A.
Can the Plug Version Be Hardwired?
Rheem permits the plug and lead to be removed and the plug-model appliance permanently hardwired by a qualified person.
Can a Plug Be Added to the Hardwired Version?
No. Rheem specifically states that a plug and lead cannot be added to a water heater originally intended for permanent hardwired connection.
How Long Is the Plug-Model Lead?
Rheem's current guide lists a 1.9-metre supply cord.
How Close Must the GPO Be?
Rheem specifies a weatherproof switched GPO within approximately 1.2 metres of the installation for the plug-and-lead model.
Can It Be Installed Indoors?
No. Rheem's current 551D180 installation guide specifies outdoor installation only.
What Clearances Does It Need?
Key minimums are approximately 80mm behind, 500mm on the left air-inlet side, 600mm on the right air-outlet side and 700mm above.
Does It Need Condensate Drainage?
Yes. Rheem supplies a condensate drain hose that must run with continuous fall to a suitable visible discharge point.
What Is the TPR Valve Setting?
The TPR valve setting is 1000 kPa.
What Is the ECV Setting?
Rheem lists an 850 kPa expansion-control-valve setting.
What Is the Maximum Mains Pressure?
The limit is 680 kPa with an ECV or 800 kPa without an ECV.
Is It Suitable for Harsh Water?
Rheem promotes the model for harsh-water conditions and offers blue-anode variants, but the manufacturer's water-chemistry warranty limits still apply.
Can It Run on Off-Peak Power?
Rheem recommends an uninterrupted 24-hour supply, but states that an extended off-peak or time-controlled supply of at least 16 hours per day may also suit some households where the electricity retailer permits it.
Does It Have a Timer?
Yes. The display-panel timer can set one timed operating period within a 24-hour period.
What Is the Standard Cylinder Warranty?
For qualifying single-family domestic installations, Rheem lists 7 years cylinder supply and 3 years cylinder labour.
What Is the Sealed-System Warranty?
Rheem lists 3 years supply and labour on the sealed refrigeration system under the standard domestic warranty.
What Warranty Applies to Other Parts?
Other components are generally covered for 1 year supply and labour under the standard domestic warranty.
Is It Eligible for STCs?
Rheem currently identifies the MDc-180 as STC eligible where the installation and current scheme requirements are satisfied.
Is the Rheem AmbiPower MDc-180 Right for Your Home?
The Rheem 551D180 is designed primarily for smaller households wanting a compact heat-pump replacement for an electric storage water heater.
Its main strengths are its 178L storage capacity, up-to-four-person sizing, COP 4.9 performance at the current 19°C test point, R513a refrigerant and choice of hardwired or standard 10A plug-and-lead electrical configurations.
Before ordering, confirm household hot-water demand, outdoor installation space, airflow clearances, condensate drainage, water pressure, delivery access and whether the property is better matched to the hardwired or plug-and-lead version.
For supply only, arrange appropriately licensed installation trades. For eligible Brisbane and Gold Coast properties, select the matching supplied-and-installed pathway and any required electrical, valve, drainage, relocation or access add-ons before checkout.
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.
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Important Installation Note
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