FCU platforms that still ship three-speed motors need a wall face that speaks relays, not a retail Nest tone. A 3-speed FCU OEM thermostat is the buyer guide sentence: 230 VAC contacts for speed 1 / 2 / 3, heat and cool, Modbus on the copper pair, and your logo on the glass.
3-SpeedFCUOEMHVACRelayWhite Label
Alledio’s OEM Thermostat is built for that line. Designed in Slovenia and manufactured in the EU, it keeps the plant language on contact closures. Occupants see your brand. Commissioning sees a known relay map. When the same relays must speak Modbus on RS-485, pair this buyer guide with the fan coil thermostat 3-speed AC fan Modbus install checklist.
Who still ships three-speed FCU platforms
This guide is for FCU OEM product managers and BMS partners who still specify three-speed motors in hotels, offices, and residential coils. It is not for installers hunting a webshop SKU.
The commercial model is high-MOQ OEM. The usual MOQ is 1,000 pcs, and it is negotiable. Samples ship with demo or test firmware under NDA. If your coil has moved to analogue EC fans, stop and open the Room Controller conversation instead of forcing this RFQ.
Name the end markets you ship into. Hotels care about quiet schedules and glass that matches the corridor. Offices care about a Modbus map the BMS already knows. Residential coils care about a simple Auto fan path. Those are brand packs on one board, not three electronics projects. Write them as one NRE conversation.
If your current indoor unit is a private-label wall thermostat from a catalogue house, treat this as a swap of the wall face and the relays, not a swap of the fan-coil chassis. The occupant only ever sees your glass. The plant still sees contact closures for fan speeds and heat or cool.
Selecting a 3-speed FCU OEM thermostat without assuming EC
Start with the motor you actually ship. Three-speed induction fans want relays. EC fans want a voltage or bus command that this SKU does not publish as the default fan path. Write relays in the RFQ when the coil is three-speed.
Relay fans vs EC 0–10 V decision
The glass shows temperature and humidity and takes a setpoint. Fan speed is manual or Auto. A weekly schedule with intervals is listed. Optional air-quality and CO2 sensors are orderable. An external NTC is listed. None of that turns the fan path into analogue control.
Baud, parity, and framing to put beside the coil note
Hotel packs usually want a quiet night schedule and a colourway that matches the corridor. Office packs usually want the same three-speed relays plus a Modbus map the BMS already expects. Write those as two brand packs on one electronics revision — one NRE conversation, two faces, one relay map.
Ask for baud rates from 9600 to 115200, with 4800 also in the Modbus table if you need it; parity none / even / odd; address 1–247 (default 1). The page lists 8 data bits and 2 stop bits. Put those numbers next to your existing FCU controller note so the first sample does not fail on a framing mismatch.
Wi-Fi 2.4 GHz (802.11 b/g/n) STA is listed for connected SKUs; the technical table notes update support. MQTT is named for cloud or web services. That path does not replace the copper pair when the BMS is already on RS-485. Write the split as a SKU decision.
Thermostat vs Room Controller for 3-speed FCU
A branded FCU thermostat on this platform keeps 230 VAC relays as the published fan path. Logo, UI, colourway, optional sensors, packing and docs are the NRE surfaces on /oem.
If the next platform generation needs 0–10 V fan or more universal I/O in the wall, that is the Room Controller family — quote it as a separate line, not as a hidden option on this thermostat. For coils with separate 0–10 V heating and cooling valves, the 4-pipe fan coil room controller 0–10 V guide shows how that RFQ is written.
Power is 230 VAC. Mechanics: 98 × 98 × 14 mm, 150 g, IP20, EU flush box Ø 60 mm. Display: 3.5" capacitive 480 × 320. Compliance listed: CE, EN 60730-1, EN 60730-2-9, EN 300 328 V2.2.2. Security updates are listed as 5 years.
Colourways are white, black and silver, plus custom on the OEM path. Ambient on the page is −10 to +50 °C, max. 85% rH non-condensing. Those numbers belong next to your corridor elevation. They are not a licence to invent a second thickness or a surface-mounted retail brick. Keep the language of a flush OEM wall thermostat.
Related reading on the same relay class: white label FCU thermostat with relays for the branding pack, OEM Modbus relay thermostat for the Modbus and AHU framing, and the 230VAC OEM HVAC thermostat for Europe when supply voltage is the gate. For host-driven glass without relays, keep the RFQ on the white label HVAC room display. Keep display and thermostat RFQs separate.
I/O on the wall and what the RFQ must name
Ask for the ICD with the mechanical drawing. Specify the RS-485 cable class you already pull, the slave-ID plan, baud, parity, and whether the host expects holding registers, input registers, or both. Alledio can ship a map that matches a map you already use.
Four I/O models sit on top of fan-speed relays and heat/cool contacts. Name the model in the RFQ. Do not invent EC curves, BTL listings, or a KNX catalogue SKU on this page. Those are out of scope unless quoted as OEM work.
Name the sample count you need under NDA and whether demo firmware or test firmware is required for the first bench. Write who owns the artwork and who owns the register map. Those two owners should sign the same RFQ so NRE does not split into two silent projects. That is how OEM programmes stay honest on MOQ.
If several brand versions share electronics and only differ in logo and colour, say so in the RFQ. Combined quantity over 1,000 pcs may open a path down to 500 on a version — confirm that rule for this thermostat SKU on the OEM page; do not assume Room Unit or Room Controller quantity logic applies automatically.
Do not promise an installer webshop, a Nest-style retail box, or a catalogue KNX SKU in the same sentence as this thermostat. Those promises break channel strategy and force a redesign. Alledio sells to OEMs. Your channel sells to installers. Keep that split as a commercial rule.
Keep the RFQ language precise on units: 230 VAC, 98 × 98 × 14 mm, 3.5" glass, RS-485 half-duplex, Modbus address 1–247. Short paragraphs beat brochure tone. Specifiers should be able to paste the product-proof table into an internal pack without rewriting every cell. That is the point of a defensible OEM page.
When you compare this SKU to a catalogue private-label thermostat, ask what changes on the glass and what stays on the coil. If only the logo changes and the relay map stays honest, you are in the right RFQ. If you need analogue fan or a different power class, stop and open the matching Alledio family page before you invent a hybrid SKU.
Product proof
| Topic | Published spec |
|---|---|
| Product | Alledio OEM Thermostat (Modbus / relay) |
| Power | 230 VAC |
| Fan relays | Speed 1 / 2 / 3 / Auto / off |
| H/C relays | Heating / cooling |
| Display | 3.5" LCD, 480 × 320, capacitive touch, auto brightness |
| Sensors (standard) | Digital temperature and humidity |
| Sensors (optional) | VOC, CO2, external NTC |
| Bus | RS-485 Modbus RTU, half-duplex |
| Wi-Fi | 2.4 GHz (802.11 b/g/n) STA |
| Mechanics | 98 × 98 × 14 mm, 150 g, IP20, EU flush box Ø 60 mm |
| Origin | Designed Slovenia, manufactured EU |
| Standards | CE, EN 60730-1, EN 60730-2-9, EN 300 328 V2.2.2 |
| Security support | 5-year update window |
Attach this table to the FCU controls pack, then add logo artwork and the exact colour codes for housing. Leave unpublished current cells blank until the datasheet catches up.
FAQ
Can an installer buy one unit from a webshop?
No. Alledio sells to OEMs only.
Does the thermostat run the whole plant?
No. It switches fan and heat/cool relays. Plant sequences stay on the controller you certify unless you quoted the Room Controller.
Should we assume EC fan control?
No. Do not assume EC. The published fan path is three-speed relays.
Can we get samples?
Yes. Samples with demo firmware or test firmware are available under NDA via /oem.
What is the MOQ?
The usual MOQ is 1,000 pcs, and it is negotiable.
Is white label available?
Yes. Logo, UI, colourway, optional sensors, packing and docs — NRE on the OEM programme.
What to do next
Start on the Alledio OEM Thermostat page, compare the Room Controller only if your fans are analogue, then open /oem for samples. Bring motor type, 230 VAC, Modbus map, MOQ, and glass artwork. That is how a 3-speed FCU OEM thermostat becomes a line item your coil can ship.
