5070THB

Very little info on here about these.

Do they have a temperature sensor built-in? If so, can these be used to open/close a relay to turn my boiler on and off? If so, is there a way to adjust hysteresis to stop it rapidly cycling on/off?

Thanks!

 

The thermostat will control a cbus group address either in heating or cooling mode. It has built in hysteresis, plus you can also set minimum on and off times. You just need to associate that group address with a cbus relay. I currently have 8 in my house controlling a ducted Daikin inverter aircon system which gives me individual temperature control in 8 zones.

 

Perfect, thanks!

 

Thinking further.. how is yours set up?

I read some posts on here about these not working with Heating application as it's deprecated. So how does it all work? I don't have any logic in my C-bus network.

 

With heating my thoughts are you should use the original thermostat for most scenarios to keep whatever safety systems are built into the equipment then add some CBus/automation control on top.

 

Cheers for the reply mate. I have a Hive smart thermostat (might just be a UK thing) that basically switches the central heating boiler on and off to keep the house at a set temperature. I just want to be able to set the temperature from either of the 3x EDLTs I have round the house. Seems impossible to trick the Hive into speaking to C-Bus without some kind of complicated logic and I don't have the money to spend thousands on software unfortunately.

Any ideas welcome!

 

I use logic in a Touch Screen to convert to HVAC temperature, stepoint and mode data into measurment application data. Code in an SHAC then reads the measurment data and controls the Diakin aircon via a modbus gateway. The thermostats control each zone motor directly.

There's quite a lot of code

 

Yikes.

 

Sorry I don't know how to setup your particular equipment but as a general rule I think you don't want to reinvent the wheel and should use existing equipment safety systems where possible.
It seems there is an integration for the hive thermostat in Home Assistant.
I'm not using CBus at all right now but I am using Home Assistant for other devices.
It may be worth a look.

 

There's one for Homebridge too, but I just can't get the data out of C-bus in the first place.

 

Just revisiting this as I've finally got Home Assistant running with all my C-bus kit integrated to it, along with my Hive heating controls.

Planning to have 3 zones with a different set temperature in each.

I have a PAC on order, should be here in a few days so here's what I'm thinking:

Is there a way to control the set temperature for each zone using a separate eDLT for each zone?

Note: I would need to have the current actual temperature displayed on the eDLT (not sure how to get that data into C-bus), and would also need the set temperature level displayed too.

Thanks!

 

Can you describe your heating system as it stands. What controls does it have?
How are the zones operated (i.e. damper motors). And are you continuing to use the Hive or moving to the Cbus thermostats completely.

If the rooms have individual damper control, you can certainly have independent control with the Cbus thermostats. It's a bit tricky to set up, but certainly possible.

I can send you the PICED test project I created to get you going.

 

So at the minute it's just a central heating boiler (Worcester Greenstar 30i) switched at mains voltage by a relay of a single zone Hive smart thermostat. No dampers, no zones, nothing fancy at all. The display unit of the Hive has a temperature sensor built in. I keep it mounted in the hall in the middle of the house, with all the doors open, so the whole house stays at a constant 17.5°C usually.

I bought a 4 zone C-bus thermostat as I had planned to simply keep the setup the same, with a single zone, and then be able to adjust the temperature at night time from the eDLTs in the bedroom, or living room. I like it a bit cooler when I go to bed, can't sleep if it's too warm.

Then I thought I would add additional temperature sensors to the C-bus 4 zone thermostat, and dampers so I could have the bedroom as a seperate zone, and maybe my office too. Finding the parts has proved impossible so far.

So back to the Hive. Adding additional thermostats and TRV dampers is very easy, the only downside is that they are all wireless and battery powered. I really don't like the thought of replacing batteries on the TRVs all the time. Also, not sure how to get the current zone temperature from Hive / Home Assistant back into C-bus so the eDLTs will show current temperature in the different zones.

So now I'm completely stuck, not sure which direction to take. I think the C-bus route would be much better but just can't get the parts.

What would you do?

Thanks for all your help by the way, you're an absolute legend!

 

While I do use Home Assistant , I don't use it for anything I need to rely on. Just too many failure points. So while it would be possible to get Home Assistant to take the Hive data and send it back to Cbus where the PAC can interface to the eDLT's , that's a lot to go wrong.

If you replace the Hive with the Cbus thermostat, it will control the boiler directly, and you can program the PAC to allow you to show and set the temperature on your eDLT's. You just need a spare mains rated Cbus relay channel which I gather you have. The main issue here is the Cbus thermostats are out of production so if it fails getting a replacement could be an issue. However, I installed 4 in 2005 (currently running 8 zones) and have never had a problem.

The 4 zone thermostat is equivalent to a single thermostat (like the Hive) with 4 switches for the zones. It is not capable of modulating the temperature of each zone even if you have temperature sensors in each zone. To do this you need a Cbus thermostat in each zone. The 4 zone thermostat then becomes the master and controls the boiler based on the demand of the other thermostats.

With 4 Cbus thermostats and cbus controllable dampers (via a relay in each zone), you can set individual temperatures for each zone. This is reasonably straight forward to set up. You can get Cbus thermostats with inbuilt relays that can control low voltage loads. There are a couple of limitations though:
1/ Cbus thermostats support a maximum of 4 zones.
2/ You can't turn off an individual zone from the thermostat. If the system is off, pressing any thermostat main button will turn the system on. If the system is on, pressing any button will turn the whole system off. To disable a zone you either have to set it's temperature so it won't activate, or use a separate Cbus switch (and a bit of programming in the PAC).
You can get around both of these with a bit (quite a bit!) of logic in the PAC.

 

It sounds like Hive is the only option then as it was hard enough just getting a single C-bus thermostat.

How can you get the data back into C-Bus from Hive using logic? I think that's the only way I can achieve what I need.

 

An update to this:

Turns out the Hive wireless system is quite temperamental, so I'm removing it and going with the single C-bus 4 zone thermostat to control the whole house as a single zone.

How do I get the C-bus thermostat to show in Home Assistant? I had a working C-bus to HA setup, but it only integrated the lighting. I'm replacing my server so starting again from scratch.

 

Quick question:

For my boiler on/off dry contact, can I use a relay on an existing 12 channel relay module that is currently being used for lighting? Or do I need to have a dedicated relay module running the HVAC application? Can't figure it out.

Thanks.

 

If you currently aren't using the secondary application on the relay, you can set that to the HVAC application which will allow you to select the boiler ga. I'm assuming here the boiler is mains switched as mixing mains and low voltage on a relay is a bad idea.

 

Hi mate. Brilliant, thanks for that. Yeah 230v switched.

The very last hurdle is controlling the heating remotely through Home Assistant. I suppose I could set a dummy lamp to be an on/off switch for the whole system, but would be great if I could see and control the actual temperatures on Home Assistant somehow.

I ordered a further two thermostats today, so I'm going all-in on this. Some may think I'm mad but I really love C-bus.

 

Given you have a PAC it wouldn't be that hard to put some logic in it to convert the HVAC data from the thermostats into lighting data that HA already understands. If you want to give it ago I can post you some code examples..