All three models ship with the E51.33D controller in the box. The unit mounts flat inside a suspended ceiling and connects to ducted supply and return layouts. It also fits MENRED WUHENG Climate System projects, where it works alongside radiant heating and cooling, buffer tanks, and AI pump stations.

Three Sizes, One 230 mm Body

Start small. The N5.150A delivers 150 m³/h at rated speed, 180 m³/h flat out, and draws 100 W doing it. Move up to the N5.250A and those figures become 250, 300, and 160 W. The N5.350A tops the range at 350 m³/h rated, 400 m³/h maximum, 260 W.

Height never changes. All three units stand 230 mm tall and run 990 mm long. Only the width moves, from 520 mm to 620 mm to 720 mm. A designer can resize the airflow late in a project without redrawing the ceiling void. Duct connections are φ100 mm on the N5.150A and φ160 mm on the other two.

Down to 34 dB(A)

Twin centrifugal fans drive all three models. They move a lot of air for the power they draw, and they stay quiet doing it. The N5.150A runs at 34 dB(A). Step up to the N5.250A and you get 38, then 39 on the N5.350A.

Put the N5.150A above a bedroom ceiling and it will run all night without waking anyone.

76% Enthalpy Exchange Efficiency in Heating

All three models use a Dow enthalpy membrane heat exchange core. Enthalpy covers heat and moisture together, not heat alone. Measured to GB/T 21087-2020, enthalpy exchange efficiency in heating is 76% on the N5.150A, 73% on the N5.250A, and 71% on the N5.350A. In cooling the figures are 63.1%, 60.3%, and 58.5%.

The core is washable and never needs replacing. It resists damp. It resists frost. Mould-resistance testing returned Grade 0, which means no visible growth. Rinse it, dry it, slide it back.

Three-Stage Filtration, 97% to 98%

On all three models, air crosses the same three barriers before it reaches a room.

• Washable mesh screen: stops insects, pollen fluff, and leaves. Rinse it once a month.

• G4 coarse filter: captures particles above PM10. Replace every 6 months.

• H11 filter: traps PM2.5. High dust-holding capacity, low airflow resistance. Replace every 6 months.

Overall filtration efficiency is 97% on the N5.150A, 98% on the N5.250A, and 97% on the N5.350A, all under manufacturer test conditions.

E51.33D Controller, Included as Standard

The E51.33D is an LCD wall controller. It comes in the box, so there is no separate order to place and no extra line on the quotation.

Two modes. Manual sets the fan speed by hand, and that is all it does. Auto runs the schedule you build, block by block, across the day. You also choose how many speeds the controller offers: two, or three.

Then there is the cleaning reminder. The controller counts running hours in the background and flags the filters once the count runs out. You pick the interval, anywhere from 1,008 to 2,016 hours. Each step is 168 hours. That is one week. Out of the factory it sits at 2,016.

The rest is quick. It draws 2 W. It switches up to 3 A. Temperature reads from 0 °C to 99 °C, displays to 0.1 °C, and calibrates ±5 °C. The housing is flame-retardant PC, rated IP20. Backlight either stays on or fades after 60 seconds. If a sensor fails, the screen shows Err and the unit stops until someone clears the fault.

Core Technologies & Benefits

Six engineering decisions shape how these units perform and how much work they make for the installer.

• Twin Centrifugal Fans: high airflow for the power drawn, and low noise from 34 dB(A) upward.

• Dow Enthalpy Membrane Core: recovers heat and moisture in both directions. Washable, replacement-free, and Grade 0 in mould-resistance testing.

• Three-Stage Filter Train: mesh, G4, and H11 in series, for 97% to 98% filtration efficiency under manufacturer test conditions.

• One Footprint, Three Airflows: 990 mm long and 230 mm tall across the range. Only the width changes.

• E51.33D Controller in the Box: scheduling, filter reminders, and fault display included from day one.

• Front-Access Service Panel: filters, core, fans, and control board all reach through a single 810 × 450 mm opening.

Installation and Maintenance

Hang the unit from threaded rods inside a removable suspended ceiling. Leave an 810 × 450 mm service opening on the door-panel side. Two things must stay reachable: the electrical box has to open fully, and the control board has to come out. Wiring is fixed, so the circuit needs an all-pole switch with at least 3 mm contact separation, plus reliable earthing. Where the unit sits high, keep the fan blades at least 2.3 m above the floor.

Maintenance is quick. Rinse the mesh monthly. Replace the G4 and the H11 every six months. Wash the core when it looks dirty. The controller counts the hours for you and puts the reminder on screen, so nobody has to keep a diary.

Technical Specifications

Rated airflow starts at 150 m³/h on the N5.150A and climbs to 350 m³/h on the N5.350A, with the N5.250A sitting between them at 250 m³/h. Maximum airflow adds roughly a fifth on top: 180, 300, and 400 m³/h. Power at rated speed follows the same curve, at 100 W, 160 W, and 260 W. Noise rises with size, from 34 dB(A) to 38 and then 39. Weight goes 23 kg, 27 kg, 31 kg.

Efficiency moves the other way. The smallest unit is the most efficient of the three, at 76% enthalpy exchange in heating against 71% on the largest. Dimensions barely move at all. Every model runs 990 mm long and 230 mm tall. Width is the only figure that changes.