What type of boiler do you have
One zone valve is for the upstairs heatingWhat is the zone valves function
The problem is the OP wants to use a Baxi Usense stat not sure if it is one stat for each heating zone or one stat for both unfortunately the information on the Usense stat and the gateway if needed is very limited, I suspect this might be one for Baxi tech support although from past experience a few customers with Baxi smart controls have asked me to install alternative smart heating controllersIf I've understood the question correctly, there will need to be two thermostats, one for upstairs to operate the upstairs zone valve, and another thermostat downstairs for the downstairs zone valve.
As far as I can see the Usense is a single zone (whole house) programmer and doesn't have 2 zone capability, but could be wrong!
Update: Apparently the Baxi Usense 2 can control 2 zones, but you need an additional thermostat and gateway. Seems buried in here:
Yes, It would be a thermo stat for upstairs heating and another for downstairs heating.If I've understood the question correctly, there will need to be two thermostats, one for upstairs to operate the upstairs zone valve, and another thermostat downstairs for the downstairs zone valve.
As far as I can see the Usense is a single zone (whole house) programmer and doesn't have 2 zone capability, but could be wrong!
Update: Apparently the Baxi Usense 2 can control 2 zones, but you need an additional thermostat and gateway. Buried in here:
Seems to be all done with wireless communication and setting it up in the app, but the hard wiring of the zone valves, which appears to be directly from the boiler, escapes me -so far - sorry!
View attachment 121703
The wiring for two heating zones is described by John Ward below. It requires zone valves with the brown and orange wires for their microswitches.Yes, It would be a thermo stat for upstairs heating and another for downstairs heating.
They just aren’t clear enough with the information, it’s straight forward if it was just
If I've understood the question correctly, there will need to be two thermostats, one for upstairs to operate the upstairs zone valve, and another thermostat downstairs for the downstairs zone valve.
As far as I can see the Usense is a single zone (whole house) programmer and doesn't have 2 zone capability, but could be wrong!
Update: Apparently the Baxi Usense 2 can control 2 zones, but you need an additional thermostat and gateway. Buried in here:
Seems to be all done with wireless communication and setting it up in the app, but the hard wiring of the zone valves, which appears to be directly from the boiler, escapes me -so far - sorry!
View attachment 121703
You’re absolutely right, I’m wanting one room stat for each zone.The wiring for two heating zones is described by John Ward below. It requires zone valves with the brown and orange wires for their microswitches.
Combination Boiler with 2 Heating Zones, 230V Switching
Wiring diagrams for two heating zones with a combination boiler that uses 230V switchingflameport.com
I'm guessing, but don't know, that each Usense gateway "on/off mains switch" connections could provide the equivalent to thermostat terminals 1 and 3 shown in John Ward's diagram.
Yes that was my thought.You’re absolutely right, I’m wanting one room stat for each zone.
After looking further into this I’m assuming the brown from the valve is what sits in this terminal,
There are obvious warnings about not applying mains to the bus connections etc, but the on/off terminals are mains rated volt free terminals. See pic below.I’ve also emailed Baxi technical regarding a clearer picture. Just precautious with it stating to not connect 230v.
That would have helped greatly. Perhaps Baxi installation engineers are sworn to secrecy!Thought putting in here there would of being someone who has experienced this with these stats before who then could of relayed a clearer picture for me.
It’s just a shame a Baxi engineer isn’t around this forum to help me outYes that was my thought.
What I don't know is whether you can use the bus connection to the boiler (eg Opentherm or whatever) as well/ at the same time.
There are obvious warnings about not applying mains to the bus connections etc, but the on/off terminals are mains rated volt free terminals. See pic below.
That would have helped greatly. Perhaps Baxi installation engineers are sworn to secrecy!
View attachment 121741
If I remember correctly Baxi uses R-Bus and not Opentherm control, I believe there is a conversion module for Opentherm control but speaking to Baxi technical recently this is only available in a couple of EU countriesWhat I don't know is whether you can use the bus connection to the boiler (eg Opentherm or whatever) as well/ at the same time.
I suspect the answer is they don't know Baxi technical seemed very poor when I spoke to them a few months agoThat would have helped greatly. Perhaps Baxi installation engineers are sworn to secrecy!
That is a useful bit of information that none of my searches found. It looks like a stat and gateway would be needed for each zone and some research suggests the bus connections can be daisy chained
The problem is heating controls are evolving from the traditional on / off to the many levels of smart control which can modulate the boiler firing and optimise the heating profile to achieve the required set point at the given time and a lot of these controls are developed by third parties with little boiler manufacturer involvementIt’s just a shame a Baxi engineer isn’t around this forum to help me out![]()
The wiring diagram Avo Mk8 posted suggests a gateway is needed for each zone valve overall the Baxi setup seems quite poor against some of the other smart heating controls available that can control individual rad valves and therefore individual room temperaturesI’m assuming it must have the capability to switch separate zones with the use of 2 stats, if not, they are missing out on the money![]()