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SEIYA 2 (R32)
- 3.3 kW
- Wi-Fi
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from 6,547 zł · incl. installation
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Mitsubishi Heavy Industries
Diamond
The Mitsubishi Heavy Industries Diamond SRK35ZSX-W is a white 3.5 kW wall-mounted air conditioner with Jet Air technology, a double flap and an Allergen Clear filter, rated A+++.
- Wi-Fi
- White
- Heating function
- Japanese technology
- Low noise
- Anti-allergen
- Cooling capacity
- 3.5kW
- Indoor unit noise
- from19dB(A)
- Heats in outdoor frost
- down to−20°C
Price incl. installation
Price on request
What installation includes
- Installation of the indoor and outdoor unit
- Up to a few metres of refrigerant, electrical and condensate routing
- Wall penetration and neat routing of the installation
- Carrying out the vacuum and checking the system for tightness
- Charging with refrigerant and starting the unit up
- Checking the operating parameters and configuring the controls
- Operating instruction and handover of the warranty documents
The Mitsubishi Heavy Industries Diamond in the 3.5 kW version is the SRK35ZSX-W indoor unit paired with the SRC35ZSX-W outdoor unit. The manufacturer describes the series as an elegant, timeless unit with rounded contours, intended for small and medium rooms. The white -W version we describe has no built-in Wi-Fi; connecting to a phone requires an optional adapter, which we cover in the controls section. In practice this means buyers in Warsaw get a unit with top-shelf parameters for the wall-mounted category, with one deliberate omission: the network connection has to be chosen separately.
The technical data is specific. Nominal cooling output is 3.5 kW (from 0.9 to 4.5 kW) and heating output is 4.3 kW (from 0.8 to 6.8 kW). Seasonal coefficients are SEER 9.5 and SCOP 5.1, which gives class A+++ in both modes. The heating operating range reaches -20°C, and in cooling the unit works from -15 to 46°C. The indoor unit measures 920 x 220 x 305 mm (width, depth, height), weighs 13 kg and produces from 19 to 43 dB; the outdoor unit produces 48 dB. The refrigerant is R32. Indoor noise goes down to 19 dB, which makes it a sensible choice for a bedroom, and the wide modulation range keeps temperature steady without constantly revving the compressor.
What sets the Diamond apart among models of similar output is its elaborate airflow control. Jet Air technology, a double damper and the 3D AUTO function decide how air travels around the room, not just how much of it there is. It suits someone who likes to influence the direction of the stream and wants a filter that limits allergens. Keep in mind that our description rests on the manufacturer's data, and we check the real match of power to the room on site. We quote the installed price after a free assessment.
Overview and positioning
The Diamond series (SRK-ZSX) is the top wall-mounted unit for flats and houses in the Mitsubishi Heavy Industries range. In its 2026 RAC catalogue the manufacturer aims it at small and medium rooms, so the 3.5 kW version fits a living room, a large bedroom or a day room with a kitchenette. We see the main argument as the combination of high seasonal efficiency with extensive control of air direction. For the customer it also matters that the manufacturer lists R32 with a low GWP and features that keep the inside of the unit hygienic, such as Self Clean. These are solutions that help most when the unit runs many months a year.
This description concerns only the -W version: white, without a built-in Wi-Fi module. The series also has variants with Wi-Fi as standard and in other colours, but those are separate products with different equipment and are not covered by this text. If you want a dark or titanium casing, or connectivity without buying extra parts, tell us at the assessment and we will go through the available options. The advantage of the -W version is a simpler set: you pay only for what you use, and you can add Wi-Fi if you really will control the unit from a phone. That approach suits people who know their needs and prefer to choose elements deliberately.
The manufacturer bets on a rounded, compact body and quiet operation. Together with class A+++ in cooling and heating, this gives the profile of a unit for someone who uses air conditioning all year, not just a few hot weeks. We describe the technical details in the following parts, together with what the model does not do.
Cooling and heating technology
The system is built around a DC PAM inverter and a twin-cylinder DC rotary compressor. The manufacturer links this to low noise, little vibration and high efficiency. The 3.5 kW nominal cooling output can vary between 0.9 and 4.5 kW, and the 4.3 kW heating output between 0.8 and 6.8 kW. The upper heating value is clearly higher than for cooling, which is useful in a Polish winter when the air conditioner also serves as a supplement to heating. The twin-cylinder rotary compressor runs calmly and limits vibration passed to the casing and the wall, which in a flat in a block matters more than it seems before purchase.
Seasonally the model reaches SEER 9.5 and SCOP 5.1, that is A+++ in both directions. The outdoor temperature range is from -20 to 24°C in heating and from -15 to 46°C in cooling. Three sensors (room temperature, room humidity and outdoor temperature) watch over comfort, and the working refrigerant is R32 with a low GWP. These ranges refer to the outdoor temperature, not the room, and heating output falls as temperature drops, so we do not promise that the air conditioner will replace a whole heating system.
The maximum installation length for the 35 model is 25 m according to the manufacturer's table; other models of the ZSX series allow a longer route, but we do not carry that over to the 3.5 kW version. We measure the real route on site, because it determines both the scope of work and possible surcharges, which we discuss before installation starts. The visit is also a chance to agree the position of the outdoor unit and to check whether the wall can be drilled at a sensible point.
Comfort and air quality
This is the strongest area of the model. Jet Air technology, designed with CFD simulation, is meant to give quiet operation and a long airflow throw. The double damper sets the direction of the stream: horizontal in cooling, strongly downward in heating, and the 3D AUTO function selects the air distribution automatically. In cooling this is the Cool Breeze mode, in heating floor warming. The left and right louvres can be controlled independently, in 8 airflow patterns. Air distribution matters much more for felt comfort than power alone, because the same kilowatt works differently with a stream aimed at the bed than with one sweeping along the wall.
For air quality the manufacturer provides an Allergen Clear filter, in which an enzyme and urea deactivate allergens, bacteria, moulds and viruses, and a photocatalytic washable deodorising filter, according to the catalogue sheet. The Allergen Clear Operation function, started with a button on the remote, lasts 90 minutes. Self Clean dries the indoor unit with the flaps closed, which limits mould growth, and the fan has an antibacterial coating. This does not replace cleaning the filters, it only complements it.
Additional modes add everyday usefulness: High Power runs for 15 minutes, quiet mode lowers the noise level by 3 dB(A), Night Setback keeps 10°C, and Fireplace is a separate mode for rooms with a fireplace. The unit goes to stand-by after an hour without movement in the room. Indoor noise is from 19 dB at the quietest speed to 43 dB at the highest, and the outdoor unit is 48 dB. We quote noise values as the manufacturer gives them; in a room they also depend on reflections from walls, furniture and finishes.
Controls and Wi-Fi
In the -W version Wi-Fi is not built in. The manufacturer provides wireless control with the Smart M-Air app, but in this variant it requires the optional WF-RAC adapter, which is not part of the set we describe. If you want to control the air conditioner from your phone, state that when ordering and we will include the adapter in the quote as a separate item. For anyone who likes to run everything from a phone, it is important to know that this variant needs an extra investment.
The Smart M-Air app lets you switch the unit on and off, change modes and temperature, set timers, use Home Leave Mode and view an energy cost chart. Outside the app, the remote offers a weekly timer and a sleep timer, a Comfort Start-up function, remembered settings, LED brightness adjustment and a child lock. Fuzzy Auto selects the operating mode on its own. This gives a lot of freedom in settings, but also more options to learn, so we take the briefing seriously.
During commissioning we configure the controls together with the customer: we show the basic modes, the airflow direction settings and how to set a timer. If you order the adapter, we help with the first pairing with the app. We finish the briefing so that you know which settings you can change yourself and which are better left alone. The remote remains the basic tool even when the adapter is not fitted.
Design and build
The indoor unit is white, with rounded contours, and measures 920 x 220 x 305 mm (width, depth, height). A depth of 220 mm is little, so the unit does not protrude from the wall more than necessary. A weight of 13 kg means a solid wall or a well-chosen mounting is needed, and we decide that after seeing the installation place. A flat body with rounded corners looks calm even up close, which matters in small rooms where the unit is near a bed or desk.
The manufacturer describes the look as elegant and timeless. In practice a white casing with gentle lines blends into a light interior and does not draw attention, and adjustable LED brightness lets you dim the display in a bedroom. The series also offers black-and-white and titanium variants, but those are other products that we do not describe here. The manufacturer says the Diamond is meant for small and medium rooms, so the proportions do not overwhelm an interior.
As for build, the deodorising filter is washable, the Allergen Clear filter needs regular care, and the fan has an antibacterial coating. Such solutions make it easier to keep the unit clean, provided you actually clean the filters as the manual recommends. That is why during the briefing we show where the filters are and how to take them out. It is also worth thinking about how the unit will look against the wall after a few years, because a white casing sometimes needs wiping.
Installation and service
For this model we mount both units, run refrigerant pipes, electrical cables and the condensate line over a stretch of a few metres, make the wall passage and lay the installation neatly. Then we evacuate the system, check it for leaks, charge it with refrigerant and start the air conditioner. During the work we keep the area tidy, and afterwards we clean up the work spot and leave the area by the wall clean.
We finish with a check of operating parameters, setting up the controls, a briefing and handing over the warranty documents. Before work we discuss possible surcharges: a longer route, drilling through concrete or reinforced concrete, wall chasing, a condensate pump and work from a lift platform. We settle the scope at the free assessment, and the list of quote items is made after it, so there are no surprises on installation day. For this version the maximum installation length is 25 m.
In use, remember to wash the filters and to have a periodic service. The Self Clean and Allergen Clear Operation functions help keep the inside clean but do not replace servicing. We recommend a check before the cooling season and before winter, when the unit is to support heating. We quote the installed price after a free assessment.
Who this model is for — summary
The Diamond 3.5 kW is for a person who wants control over how air spreads around the room: the double flap, 3D AUTO and separate control of the left and right louvre offer more than a simple stream in one direction. It will work well in a living room or bedroom where quiet modes and an allergen-limiting filter matter, and where in winter the air conditioner should support heating at temperatures down to -20°C. Most benefit goes to people who value silence at night, because from 19 dB in the indoor unit the operation is barely audible.
It suits less someone who expects built-in Wi-Fi with no add-ons, because the -W version needs the optional adapter. Nor is it a choice for a person looking for a dark casing. In such cases it is better to ask about other variants of the series or about models in our catalogue that have Wi-Fi as standard. For someone who needs the simplest unit for a few summer weeks a year, the rich functionality of this series may simply be unnecessary.
A well-chosen unit is one whose functions you actually use, not one that has the longest list in the catalogue. The best step is a free assessment: we will measure the route, check the wall and the place for the outdoor unit, and then price the installation. We quote the installed price after a free assessment.
Technical data
Specifications
| Model (indoor / outdoor unit) | SRK35ZSX-W / SRC35ZSX-W |
|---|---|
| Cooling capacity (nom.) | 3.5 kW (range 0.9–4.5 kW) |
| Heating capacity (nom.) | 4.3 kW (range 0.8–6.8 kW) |
| SEER (cooling) | 9.5 — class A+++ |
| SCOP (heating) | 5.1 — class A+++ |
| Refrigerant | R32 |
| Noise level (indoor, min.–max.) | 19–43 dB(A) |
| Noise level (outdoor) | 48 dB(A) |
| Indoor unit dimensions (W/D/H) | 920/220/305 mm |
| Indoor unit weight | 13.0 kg |
| Operating range (cooling, outdoor) | -15°C to +46°C |
| Operating range (heating, outdoor) | -20°C to +24°C |
| Max. pipe length | 25 m |
Questions
Frequently asked questions
Does the MHI Diamond heat in frost?
The heating operating range reaches -20°C and heating output is 4.3 kW (from 0.8 to 6.8 kW). SCOP 5.1 corresponds to class A+++.
How loud is this model?
The indoor unit runs from 19 dB at the quietest speed to 43 dB at the highest, and quiet mode lowers the level by 3 dB(A). The outdoor unit is 48 dB.
Does the Diamond SRK35ZSX-W have Wi-Fi?
Not as standard. In the -W version, control with the Smart M-Air app requires the optional WF-RAC adapter. The -WF version has Wi-Fi built in, but it is a different product.
What are the dimensions and the maximum installation length?
The indoor unit measures 920 x 220 x 305 mm and weighs 13 kg. The maximum installation length is 25 m. We settle the installation scope at a free assessment.
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