The SolaX Thermal R290 1-Phase Hydraulic Unit (STN1-C02) is the wall-mounted indoor unit for the SolaX Thermal R290 heat pump range, for single-phase systems (220-240V) with an existing or separately installed hot water cylinder. It combines the indoor control board and a 4 inch high-resolution touch panel with the hydraulic components in one compact unit.
Inside are a 3kW + 6kW backup heater, an 8 litre expansion tank and a solenoid 3-way valve. Connections are G1 inch and G1-1/4 inch, and it communicates over WiFi, Ethernet and RS485, so the SolaX Smart App can provide remote monitoring, operation and OTA updates.
It measures 420 x 700 x 265mm and weighs 33kg empty, and it works with the STU1 R290 outdoor units from 8kW to 16kW to give heating, cooling and domestic hot water from a monobloc system.
STN1-C02
SolaX Model Code
3kW + 6kW
Backup Heater
8 litre
Expansion Tank
39.5A
Rated Current
4 inch
Touch Panel
33kg
Weight (Empty)
You Still Need a Hot Water Cylinder
This unit is for homes with an existing or self-installed hot water cylinder. It does not include one. If you want the cylinder supplied with the indoor unit, SolaX's Hydraulic Integrated Unit has a 190-litre cylinder built in, and if you only need the controller there is the Control Unit.
Check Your Electrical Supply
The rated current is 39.5A on a 220-240V supply. The supply cable and protective device must be sized by a qualified electrician to BS 7671, and the outdoor unit has its own supply requirements, so check both in the SolaX installation manuals.
Important Safety Information
Installation must be carried out by suitably qualified engineers, with electrical work to BS 7671 and Part P. The system uses an outdoor unit charged with R290 (propane), so follow the SolaX manuals on flammable refrigerant, and follow MCS standards for MCS-certified installs. Any unvented hot water cylinder connected to the system must be installed in line with Part G of the Building Regulations by a G3-qualified installer.
1-Phase and 3-Phase Versions
This is the single-phase STN1-C02. The three-phase STN3-C02 (380 to 415V, 13.5A per phase) has the same size, weight and specification, and differs only in supply and rated current.
Backup Heater Built In
A 3kW + 6kW electric backup heater is built into the unit.
Hydraulic Components Included
An 8 litre expansion tank and a solenoid 3-way valve are built in alongside the control board.
4 Inch Touch Panel
A 4 inch high-resolution touch panel gives local control of heating, cooling and hot water.
Connected & Updatable
WiFi, Ethernet and RS485 connections, with remote monitoring, operation and OTA updates through the SolaX Smart App.
For Existing Cylinders
Designed for homes with an existing or self-installed hot water cylinder, so you keep your current storage.
Compact Wall Mounting
420 x 700 x 265mm and 33kg empty, mounted on the wall rather than taking floor space.
Indoor Unit
Rated Current
Installation
Size (W x H x D)
Weight
Hot Water Cylinder
Control Unit STN1-C01
0.1A
Wall
340 x 400 x 80mm
6.5kg
Existing or separate
Hydraulic Unit STN1-C02 (this product)
39.5A
Wall
420 x 700 x 265mm
33kg
Existing or separate
Hydraulic Integrated Unit STN1-C03
52.3A
Floor stand
595 x 1875 x 700mm
186kg
190 litres built in
About the Table
The single-phase indoor units are shown. The Control Unit is a compact wall-mounted controller with a rated current of only 0.1A. Weights for the Hydraulic Unit are without water.
Electrical
Product code
STN1-C02
Power supply
220 to 240V / 1N~ / 50Hz
Rated current
39.5A
Backup heater capacity
3kW + 6kW
Hydraulic
Expansion tank
8 litres
Valve
Solenoid 3-way valve
Piping connections
G1" / G1-1/4"
Interface & Communication
User interface
4 inch high-resolution touch panel
Communication
WiFi / Ethernet / RS485
Installation & Mechanical
Installation
Wall mounting
Dimensions (W x H x D)
420 x 700 x 265mm
Weight (empty)
33kg
System
Compatible outdoor units
STU1-C08R290 to STU1-C16R290 (single-phase, 8 to 16kW)
Functions
Heating, cooling, domestic hot water
What does the hydraulic unit do?
It is the indoor unit of the SolaX Thermal R290 system. It holds the indoor control board and touch panel, a 3kW + 6kW backup heater, an 8 litre expansion tank and a solenoid 3-way valve, and it links the outdoor unit to your heating and hot water circuits.
Do I need a separate hot water cylinder?
Yes. The hydraulic unit is for homes with an existing or self-installed hot water cylinder. The floor-standing Hydraulic Integrated Unit is the version with a 190-litre cylinder built in.
Which outdoor units does it go with?
The STU1 R290 series: STU1-C08R290 to STU1-C16R290 (single-phase, 8 to 16kW). Confirm the exact pairing for your outdoor unit in the SolaX installation manual before ordering.
What is the difference between the STN1-C02 and STN3-C02?
Supply and rated current only. The single-phase STN1-C02 runs on 220 to 240V at 39.5A, and the three-phase STN3-C02 runs on 380 to 415V at 13.5A per phase. Size, weight, heater capacity and connections are the same.
How big is the backup heater?
The unit contains a 3kW + 6kW backup heater. SolaX lists it as the backup heater for the system.
How is it controlled and monitored?
Locally on the 4 inch touch panel, and remotely through the SolaX Smart App, which supports monitoring, operation and OTA updates. The unit connects by WiFi, Ethernet or RS485, and the SolaX Thermal R290 range supports Modbus TCP/RTU and is SG Ready.
Does it include a circulation pump?
The contents listed for the hydraulic unit are the control board, touch panel, backup heater, 8 litre expansion tank and solenoid 3-way valve. Check the SolaX installation manual for the circulation pump arrangement in your system.
Where can I install it?
It is wall mounted indoors and measures 420 x 700 x 265mm. It weighs 33kg empty, so make sure the wall can carry it once it is filled with water.
