24V White Universal Touch LCD Screen Heat Pump Programmable Smart Air Conditioner Thermostat for AC (STN855) For Floor Heating Parts
STN855 is the universal unit in the range. One part number covers up to 2 heat and 2 cool on conventional equipment and up to 3 heat and 2 cool on heat pumps, with auto changeover between modes. The interface is an LCD touch screen rather than a button keypad, and the switching side uses Omron relays rated 6 A with 2 A inductive load. For a contractor holding stock across mixed equipment, this is the model that replaces several.
Key Benefits
- Universal staging removes the need to stock separate conventional and heat pump stats
- Auto changeover switches between heating and cooling without user intervention
- Omron relays rated 6 A, 2 A inductive, give a predictable contact life
- Touch screen keeps the front face clean, which matters in hotel and office fit-outs
- Power consumption of 2W allows 24V or battery operation
Problems It Solves
- Holding four or five stat variants to cover one building
- Wrong stat sent to site because the equipment type was misreported
- Button keypads wearing and discolouring in public rooms
- Manual mode switching in shoulder seasons
Who It Is For
- HVAC contractors covering mixed equipment estates
- Facility managers who want one spare part for the whole site
- Distributors consolidating a fragmented stat range
- OEM buyers needing a touch screen flagship for their catalogue
Technical Features
- Universal control, up to 2 heat 2 cool conventional and 3 heat 2 cool heat pump
- Auto changeover between heating and cooling
- 5/1/1 programmable schedule with wake, leave, return and sleep icons
- Display accuracy +/-1 C at 20 C, range 32 F to 99 F (1 C to 40 C)
- Switchable current 6 A with 2 A inductive load, Omron relay
- NTC sensor with room temperature calibration adjustment
- 5 minute compressor delay protection and filter change indicator, both selectable
- Anti-flammable PC and ABS housing, CE and RoHS, 2W power consumption
Specifications
| Model | STN855 |
| Programmability | 5/1/1 programmable |
| Power Supply | 24V power or battery |
| Switchable Current | 6 A (2 A inductive load) |
| Temperature Range | 32℉-99℉ (1℃-40℃) Power Consumption 2W |
| Display accuracy | ±1°C (at 20°C) |
| Sensor | NTC |
| Relay | Omron |
| Screen | LCD Touch |
| Backlight | White/Blue/Green |
| Color | White/Customixed |
| Material | Anti-flammable PC +ABS |
| Dimension | 120 x 98 x 28 mm |
| Installation | Mounts on wall or junction box |
| Consumption | 2W |
| Type | Floor Heating Parts |
| Feature | Save Energy |
| Certification | CE ROHS |
Specifications are taken from the manufacturer data for this model. Confirm the exact configuration with us before you order.
Application Scenarios
- Commercial buildings running a mix of conventional and heat pump equipment
- Hotels standardising one control across different room types
- Underfloor heating zones combined with air conditioning in the same room
- Service companies carrying one universal stat on the van
Quality Control
- Touch panel response tested point by point on every unit
- Relay switching verified at rated inductive load
- CE and RoHS material declarations kept on file for each production batch
Customisation Options
- Backlight in white, blue or green and custom housing colour
- Screen layout and icon set adapted for ODM projects
- Staging defaults preset for the buyer's most common equipment
- Logo and language specific instruction sheet
How It Compares
Installing And Commissioning
Step 1
Isolate the 24V supply and record the existing terminal assignments
Step 2
Mount the universal sub-base to the wall or junction box
Step 3
Select conventional or heat pump staging in the installer menu
Step 4
Enable auto changeover and set the deadband between heating and cooling
Step 5
Confirm compressor delay and filter indicator settings, then run each stage
24V White Universal Touch LCD Screen Heat Pump Programmable Smart Air Conditioner Thermostat for AC: Buyer Questions
How many stages can the STN855 drive?
Up to 2 heat and 2 cool on conventional systems, and up to 3 heat and 2 cool on heat pump systems.
What relay is fitted?
Omron, with a switchable current of 6 A and 2 A on inductive load.
Does it need a common wire?
It can run from 24V power or from batteries, so a missing common wire does not stop the installation.
Which approvals does it carry?
CE and RoHS. Ask us for the test report covering your destination market.
Can the touch screen be re-skinned for our brand?
Yes. Screen layout, icons and firmware defaults are part of our ODM service.
What is the power consumption?
2W, which keeps it within the budget of most 24V control transformers.
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