Mitsubishi 11.2kW R32 1Ph Monobloc ASHP Outdoor Unit UQ Coastal Protection - PUZ-WM112VAA-BS

Description

The Mitsubishi Ecodan PUZ-WM112VAA-BS is an 11.2kW R32 monobloc air source heat pump outdoor unit, built for full-house space heating and domestic hot water in UK homes. The -BS coastal protection variant uses an enhanced anti-corrosion coating on the casing and heat exchanger fins, making it the correct specification for properties within a few miles of the coast where salt-laden air would otherwise shorten the working life of a standard unit.

As a monobloc design, all refrigerant components are sealed inside the outdoor unit at the factory — there is no refrigerant circuit to run into the building and no F-Gas handling on site. The unit connects to the heating system using water pipework only, which keeps installation quicker and more straightforward than a split (refrigerant-piped) system.

With an A+++ energy rating at 35°C flow and the ability to deliver hot water up to 75°C, the PUZ-WM112VAA-BS is equally suited to underfloor heating, radiator upgrades, and direct replacement of an oil or gas boiler. It maintains rated output down to -25°C ambient, so performance does not fall away during UK cold snaps.

11.2kW

Nominal Heating Output

A+++

ErP Rating (35°C)

SCOP 4.78

Seasonal Efficiency

45 dB(A)

Sound Pressure @ 1m

75°C

Max Flow Temperature

R32

Low-GWP Refrigerant

Please Note

This is the coastal protection (-BS) version of the PUZ-WM112VAA. It shares identical heating performance, efficiency ratings and dimensions with the standard PUZ-WM112VAA, but adds a corrosion-resistant casing and fin treatment for installations within around 3km of the coast, or in other high-salinity or industrial environments. Ordering the correct variant for the site location protects the manufacturer warranty — always confirm coastal exposure before specifying the standard unit as a lower-cost substitute.

11.2kW Monobloc Heat Pump

Self-contained R32 monobloc outdoor unit — all refrigerant is factory-sealed, so only water and electrical connections are needed on site, with no F-Gas certified engineer required for the refrigerant circuit.

A+++ Efficiency, SCOP 4.78

Rated A+++ at 35°C flow (SCOP 4.78) and A++ at 55°C flow (SCOP 3.34), delivering low running costs across both underfloor heating and radiator-based systems.

Coastal-Grade Corrosion Protection

The -BS casing and heat exchanger coating is designed to resist salt-air corrosion, extending service life in coastal and marine-exposed locations.

Full Output Down to -25°C

Maintains rated heating capacity in ambient temperatures down to -25°C, so performance is not compromised during UK winter cold spells.

Ultra-Quiet Operation

Sound pressure of just 45 dB(A) at 1 metre, making it suitable for close-boundary installations and noise-sensitive sites.

MELCloud Remote Control

MELCloud app connectivity (with optional Wi-Fi adaptor) gives remote scheduling, monitoring and diagnostics from a smartphone.

Up to 75°C Water Temperature

Can deliver flow temperatures up to 75°C, supporting direct boiler replacement onto existing radiator systems without needing to upsize emitters.

MCS Certified

MCS certified for compliance with UK installation standards and eligibility for government renewable heating incentive schemes.

Model & Refrigerant

Model Code

PUZ-WM112VAA-BS

Type

Ecodan R32 monobloc air source heat pump, coastal protection

Refrigerant

R32 (GWP 675)

Refrigerant Charge

3.00 kg (2.03 t CO₂ equivalent)

Heating Performance

Nominal Heating Capacity (A7/W35)

11.2 kW, COP 3.73

Heating Capacity (A-7/W35)

11.2 kW output at low ambient

ErP Rating — 35°C Flow

A+++, SCOP 4.78 (ƞs 191%)

ErP Rating — 55°C Flow

A++, SCOP 3.34 (ƞs 134%)

Combination Heater Rating (Large Profile)

A+, ƞwh 148%

Maximum Flow Temperature

Up to 75°C

Operating Range & Sound

Operating Ambient Temperature

-25°C to +35°C DB

Sound Pressure Level @ 1m

45 dB(A)

Sound Power Level

60 dB(A)

Water Circuit

Water Pipe Connections

1" BSP (G1)

Water Flow Rate (A7/W35)

24.0 L/min

Water Pressure Drop

28 kPa

Electrical

Electrical Supply

220–240V, 50Hz, single phase

Nominal Running Current [Max]

10.9 A [28 A]

Fuse / MCB Rating

32 A

Dimensions & Weight

Width

1050 mm

Depth

480 mm

Height

1020 mm

Weight

119 kg

Important Safety Information

This is an outdoor unit only. To complete a working heating system you also need a compatible Ecodan hot water cylinder (which houses the plate heat exchanger, circulating pump and safety valves that link the outdoor unit to your wet heating circuit and hot water supply), plus a wired or wireless Ecodan controller for day-to-day operation. Installation and commissioning must be carried out by an MCS-certified installer in accordance with Mitsubishi Electric's design guidance and current Building Regulations.

What's Included

The PUZ-WM112VAA-BS outdoor unit complete with factory-charged R32 refrigerant circuit, anti-corrosion coastal casing and fin coating, mounting feet, and manufacturer installation and commissioning documentation. No hot water cylinder or indoor controller is included.

What You Need for a Complete Installation

A compatible Ecodan hot water cylinder to store domestic hot water and house the system pumps and safety valves, a wired or wireless Ecodan controller, water pipework and insulation between the outdoor unit and cylinder, a weatherproof isolator and dedicated electrical supply, a suitable outdoor mounting base or anti-vibration feet, and system components such as an expansion vessel, filter, and buffer volume as specified by the installer's heat loss and system design calculations.

Do I need the -BS coastal version, or will the standard PUZ-WM112VAA work?

Choose the -BS coastal protection variant if the installation site is within roughly 3km of the coast, or exposed to salt spray, de-icing salt, or industrial airborne contaminants. For inland sites without this exposure, the standard PUZ-WM112VAA is suitable and the coastal coating is not required.

Does this unit include the hot water cylinder or indoor controls?

No. The PUZ-WM112VAA-BS is the outdoor unit only. A separate Ecodan hot water cylinder and a wired or wireless controller are required to connect the heat pump to your wet heating system and hot water supply.

What refrigerant handling is required on installation?

None on site. This is a monobloc unit — the R32 refrigerant circuit is fully sealed and factory-charged, so installation only involves water pipework, electrical connection, and mounting.

How cold can it get before the heat pump loses performance?

The unit maintains its rated heating capacity down to -25°C ambient temperature, so it is designed to perform reliably through UK winters without a loss of output.

Can this heat pump provide domestic hot water as well as space heating?

Yes, when paired with a compatible Ecodan hot water cylinder, the unit can deliver flow temperatures up to 75°C, sufficient for both space heating and domestic hot water production.

Is this heat pump eligible for UK renewable heating incentives?

The PUZ-WM112VAA-BS is MCS certified, which is generally a prerequisite for UK renewable heating incentive schemes — confirm current eligibility criteria with your installer at the time of purchase.

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Room Dimensions

Length (in m):

Width (in m):

Height (in m):

Room Type

Living Room

Bedroom

Kitchen

Bathroom

Conservatory

Hallway

Glazing Type

Single Glazed

Double Glazed

Triple Glazed

External Walls

0 Wall

1 Wall

2 Walls

3 Walls

4 Walls

Insulation Level

Poor

Average

Good (New Build)

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