The Mitsubishi Ecodan PUZ-WZ50VAA-BS is the coastal-protection version of Mitsubishi's 5 kW R290 monobloc air source heat pump — single-phase, ultra-quiet, and built on the next-generation natural refrigerant platform. With a GWP of just 3 and the ability to deliver flow temperatures up to 75°C, it's the most future-proof choice for UK properties, now with enhanced corrosion resistance for coastal installations. This listing is the outdoor unit only; pair it with a Mitsubishi FTC7 pre-plumbed cylinder or hydrobox for a complete system.
SCOP 4.62
35°C seasonal efficiency
75°C
Max flow temperature
-25°C
Guaranteed operation
BUS grant eligible
Eligible for the UK Boiler Upgrade Scheme grant when installed by an MCS-certified installer in an eligible property. The grant is paid directly to your installer and discounted from your quote.
-BS coastal protection
The -BS suffix denotes Mitsubishi's coastal-protection specification: enhanced corrosion-resistant casing treatment designed for installations exposed to salt-laden air near the sea. Functionally identical to the standard unit in output, efficiency and control compatibility — choose -BS specifically for coastal or otherwise corrosive environments.
R290 outdoor unit siting
R290 is an A3 flammable refrigerant. UK installation requires the outdoor unit to maintain minimum clearances from openings, drains and ignition sources per Mitsubishi's technical manual — always check the current installation manual rather than an older cached PDF.
MCS-certified installer required
To claim the BUS grant and validate full Mitsubishi manufacturer warranty, this heat pump must be installed and commissioned by an MCS-certified heat pump installer.
Property fit
The 5 kW Ecodan R290 typically suits: 2 to 3 bedroom well-insulated UK homes. Sizing should always follow a calculated heat loss assessment — Quality Heating offers free heat loss calculations.
Key features
R32 refrigerant
Lower GWP than legacy R410A units, with a sealed factory-charged circuit — no on-site F-Gas brazing required at install.
True monobloc
All refrigerant work happens inside the outdoor unit at the factory. The installer only connects water pipes indoors, reducing install time and risk.
Coastal corrosion protection
The -BS casing treatment is specifically designed to resist salt-air corrosion — extending outdoor unit lifespan in coastal and other harsh environments.
MELCloud enabled
Built-in MELCloud connectivity for remote control, monitoring, maintenance and technical support — no separate Wi-Fi module required to get started.
Ultra-quiet operation
Engineered for low sound levels suited to boundary-sensitive sites — see the sound pressure and power figures in the specification table for this exact model.
UK manufacturer warranty
Backed by Mitsubishi's UK warranty when commissioned by a Mitsubishi-approved engineer. Warranty registration documentation is supplied in the box.
Technical specification
| Model code |
PUZ-WZ50VAA-BS |
| Quality Heating SKU |
MITS-682515 |
| Rated heating output |
5 kW |
| Refrigerant |
R290 (GWP 3) |
| Refrigerant charge |
0.6 kg |
| Heating capacity (A7/W35) |
6.2 kW, COP 5.12 |
| Heating capacity (A2/W35) |
5.8 kW, COP 2.95 |
| Heating capacity (A-7/W35) |
5.2 kW, COP 2.68 |
| ErP rating — 35°C flow |
A+++, SCOP 4.62 |
| ErP rating — 55°C flow |
A++, SCOP 3.53 |
| Maximum water outlet temperature |
75°C |
| Guaranteed operating range |
-25°C to +46°C ambient |
| Electrical supply |
220-240V, 50Hz, single phase |
| Maximum current |
13 A |
| Fuse rating |
16 A |
| Sound pressure level at 1m |
40 dB(A) |
| Sound power level |
56 dB(A) |
| Water flow rate |
14 L/min |
| Water pressure drop |
18.16 kPa |
| Water pipe connections |
22 mm |
| Dimensions (W × D × H) |
1020 × 480 × 1050 mm |
| Weight |
89 kg |
| Coastal protection |
Yes (-BS specification) |
| Compatible control platform |
Mitsubishi FTC7 |
| Smart connectivity |
MELCloud enabled (built in) |
| BUS grant eligibility |
Yes, when MCS-installed |
What's in the box
- Mitsubishi Ecodan R290 outdoor monobloc unit (PUZ-WZ50VAA-BS)
- Manufacturer installation and commissioning documentation
- Mitsubishi UK warranty registration card
What you'll also need (sold separately)
- FTC7 indoor controller (PAC-IF082B-E) or a pre-plumbed FTC7 cylinder
- Outdoor unit wall bracket or floor stand
- Anti-freeze valves on primary flow and return
- Magnetic system filter on the primary return
- Insulated flexible primary hoses and isolation valves
Frequently Asked Questions
What does the -BS suffix mean?
-BS denotes Mitsubishi's coastal protection specification — an enhanced corrosion-resistant casing treatment for the outdoor unit. Output, efficiency and control compatibility are identical to the standard PUZ-WZ50VAA; only the casing durability differs.
Do I need to be MCS-registered to install this heat pump?
The Ecodan can technically be installed by any competent heating engineer, but to claim the UK Boiler Upgrade Scheme grant the install must be carried out by an MCS-certified installer.
Is R290 safe for domestic use?
Yes. R290 is widely used across Europe in domestic heat pumps and refrigeration. The refrigerant is sealed inside the outdoor unit. UK installation rules govern minimum siting clearances to ensure safety.
Does this include the indoor cylinder?
No — this listing is for the outdoor unit only. You'll need either a Mitsubishi FTC7 pre-plumbed cylinder, or a third-party cylinder with the FTC7 Master Controller.
How far from the coast should I be to need the -BS variant?
Mitsubishi don't publish an exact distance threshold — the -BS spec is generally recommended for installations within a few kilometres of the coast, or anywhere exposed to salt-laden air. If you're unsure, ask your installer or contact us for guidance based on your exact location.
