STN855 Premier 24V auto changeover thermostat, multiple product views

Premier Thermostat 24V Premier Thermostat HVAC Thermostat Heat Pump Thermostat Electric and Gas Thermostat Programmable Thermostat Non-Programmable Thermostat

24V 2Heat 2Cool Auto Changeover Thermostat STN855

Name: 24V 2Heat 2Cool Auto Changeover Thermostat STN855
Brand: Smart Therm

This is STN855 in the Premier range specification: a universal auto changeover thermostat covering up to 2 heat and 2 cool conventional and up to 3 heat and 2 cool heat pump, in a PP housing with white, blue or green backlight. Programming is selectable between 7 day, 5/1/1 and non-programmable, and the operator controls are here in full, namely keypad lockout, setpoint limits and a selectable compressor delay.

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Key Benefits

Universal staging with auto changeover across conventional and heat pump plant
Three programme modes from one Premier part number
Keypad lockout and setpoint limits together give full operator control
Mounts on a wall or a junction box, on battery or 24V power
Premier PP housing with white, blue or green backlight

Problems It Solves

Several part numbers to cover one building's plant
Occupants forgetting to switch between heating and cooling
Settings changed by anyone with access to the room
Compressor restarts too soon after a supply interruption

Who It Is For

Facility managers reducing the spares list
HVAC contractors on mixed equipment estates
Distributors stocking a Premier range universal model
OEM buyers needing the widest staging in the range

Technical Features

Universal control, up to 2 heat 2 cool conventional and 3 heat 2 cool heat pump
7 day, 5/1/1 or non-programmable, with auto changeover
Easy menu driven programming with wake, leave, return and sleep icons
Electric or gas configurable, room temperature calibration adjustment
Separate heating and cooling swing (cycle rate) adjustments
Keypad lockout and heating and cooling setpoint limits
5 minute compressor delay protection, selectable on or off
Mounts on wall or junction box, battery or 24V power, PP housing, 400 g

Specifications

Model	STN855
Programmability	7 Day,5/1/1 or
Color	White/Blue/
Material	PP
Weight	400g
Package Included	1Premier Thermostat 1Instruction

Specifications are taken from the manufacturer data for this model. Confirm the exact configuration with us before you order.

Application Scenarios

Buildings running both conventional and heat pump plant
Shoulder seasons where mode switching would otherwise be manual
Shared spaces needing keypad lockout
Projects mixing scheduled and unscheduled rooms

Quality Control

All staging outputs exercised across conventional and heat pump modes
Auto changeover deadband verified during the functional test
Keypad lockout and setpoint limits checked on every unit

Customisation Options

Default programme mode and setpoint limits preset at the factory
Backlight white, blue or green
Swing defaults set for the buyer's plant
Manual and carton in the buyer's language

Comparison

How It Compares

The touch screen STN855 configuration

This Premier build uses a PP housing and adds selectable 7 day, 5/1/1 and non-programmable modes with keypad lockout and setpoint limits.

STN805 Premier

STN855 carries the wider staging, up to 2 heat 2 cool conventional and 3 heat 2 cool heat pump, where STN805 is 1 heat 1 cool.

Use guide

Installing And Commissioning

Step 1

Isolate the supply and land the conductors on the colour coded terminals

Step 2

Mount on a wall or a junction box

Step 3

Select conventional or heat pump staging and the programme mode

Step 4

Enable auto changeover and set the deadband

Step 5

Set the setpoint limits and enable keypad lockout before handover

Answers