The Passiv Smart Thermostat can be installed alongside both heat pumps and heat interface units. When installing alongside heat interface units, there are some things to consider that differ from heat pump installations. This page will guide you through how to install the Passiv Smart Thermostat on a heat network, as well as some of the difference in the product.
Installation
Installing the Passiv Programmer
The Passiv Programmer should be installed somewhere accessible to the homeowner, as this is where they can set their schedules and other settings for the Passiv Smart Thermostat.
Prior to installation, open the Programmer's connection bay by loosening the two screws on the right hand side - these should not be unscrewed completely. The Programmer can be surface mounted to a wall, or using a vertical 2-gang pattress box, using the two slotted screw holes.
The Programmer requires a fused protected spur supplying 230v AC. An internal fuse rates at T3.15A 250v prevents excessive currents from damaging any connected valves. The total current of connected valves and pumps must NOT exceed 3 Amps. Power connections for the Programmer can be found at the top of the connection bay - see the diagram on the back of the connections bay cover for details.
Installing the Passiv Hub
The Passiv Hub should be installed somewhere where cables could be run to the Programmer. It should also be installed somewhere where an ethernet cable can be run from the Hub to the homeowner's broadband router.
The Hub is provided with a wall bracket, which can be fixed directly to the wall of a 1-gang pattress box. The Hub is powered by attaching the provided cable to the power socket on the underside of the Hub, and then into a standard 3-pin socket. Connect an ethernet cable to the RJ45 port on the underside of the Hub and to the homeowner's broadband router.
Installing the Passiv Thermostat(s)
The Passiv Thermostat is where homeowners can control their heating for that zone. The Passiv Smart Thermostat supports either one or two heating zones. Each Thermostat should be located approximately 1.2-1.5m above the floor, positioned away from radiators or direct sunlight, and situated where they can accurately represent the heating zone temperature. They must also be accessible to the homeowner.
Each Thermostat requires a 1-gang pattress box or a small recess to accommodate the wall bracket profile. To remove the Thermostat from the wall bracket, use a flat headed screwdriver, insert and twist at each of the two tags on the bottom edge. Gently prise the Thermostat off the wall bracket and the connection pins. The wall bracket can then be screwed into the wall or the pattress box. To fit the Thermostat, hook on at the top edge of the wall bracket and then press the bottom edge of the Thermostat towards the wall, until the Thermostat clips into place.
Connections
Hub to Programmer
Cable type: Twisted pair cable. Screening recommended. Ethernet cable is suitable, but only one of the four twisted pairs should be used.
On the backside of the Passiv Hub, you can find two connectors labelled A and B. Connect the twisted pair cable to each - we recommend using ferules on each core, where they can simply be pushed into place for a secure connection.
Cores A and B on the Passiv Hub
On the Programmer, connect the twisted pair cable to the 'RS485' section of the connections bay. This can be found using the diagram on the back of the cover. Make sure that the connecions to cores A and B are consistent with the Passiv Hub - i.e. A to A and B to B. Again, ferrules are recommended to enable quick push-fit connections. Ensure that the RS485 termination jumper is connected, mounting the jumper on both pins.
Programmer to Thermostat(s)
Cable type: 2-core SP24 speaker cable
The Thermostats are powered by a 24V supply from the Programmer. On the back of each Thermostat, you can find a port for the speaker cable. These then connect to ports at the bottom of the Programmer's connections bay - see below.
Wired Thermostat connections on the Programmer
Programmer to Heat Interface Unit
Cable type: Standard relay cable
Connections to the Heat Interface Unit will differ dependent on model. Find manufacturer specific guidance on how standard thermostats should be connected to the unit. The Passiv Smart Thermostat should not differ from that guidance.
On the Programmer, you can find a 'Voltfree 1' set of connections in the middle of the connections bay. These are labelled 'NC1', 'COM1' and 'NO1'. The exactly ports necessary with differ depending on manufacturer, but it is likely that COM1 and NO1 will be required to be wired into the corresponding ports on the heat interface unit.
Control differences
As heat interface units behave very differently from heat pumps, there are some key differences to be aware of regarding the operation of the end user's heating.
With a heat interface unit, Passiv Smart Thermostat users will be able to:
- Control their room temperature from the Passiv Thermostat(s)/Passiv app
- Set up schedules on the Passiv Programmer/Passiv app
- Activate Away Mode and Summer Mode on the Passiv Programmer/Passiv app
- Turn on ecoHeat for smart pre-warming in the Passiv app
However, users will not be able to:
- See their heating usage
- Control their hot water
- Optimise their heating to tariffs or solar PV
- Benefit from smart flow temperature optimisation
Depending on the app version the user is on, they may see some screens that are not relevant to their Passiv Smart Thermostat installation. These screens should be left alone.