Glow worm Ultracom 2 sxi with zones


I'm new to this forum, so hello!

I'm looking to replace my old Glow Worm controller and thermostats with a Tado system. I was drawn to Tado because of the Smart TRVs, which I will slowly replace my manual TRVs with after I install the main Tado thermostat.

Currently our house has two heating zones, controlled by separate thermostats, each operating a Honeywell v4043h zone valve, our boiler is a Glow Worm Ultracom 2 sxi. See my crude diagram below!

My question is, are these zone valves still necessary if I plan to put Smart TRVs on all the radiators, or could I just lock them open permanently? And if they are still needed, how would the Tado unit control them? Would I need an extra thermostat for the 2nd zone or can I get away with one? We are not fussed about have seperate zones, just the house is plumbed that way, especially if we will be using Smart TRVs going forwards.

Any other advice?

Many thanks, Dan


  • johnnyp78
    johnnyp78 ✭✭✭
    If you can short the heating zone valves so they’re permanently open that might be the easiest solution. By using smart trvs you’re effectively creating multi zones anyway. If you want to keep the zone valves in operation you’ll need one wireless receiver for one zone valve and hot water and one smart thermostat wired to the other zone valve.
  • @dandanknight are you aware that the SystemPro is an Ebus multi zone controller? Tado can use Ebus for communication to the boiler, but it cannot normally do multi zone with a low voltage interface. You might need an electrician to switch your system to 230V relay control to use Tado with multiple zones. The Ebus interface manages the flow temperature for heating and hot water. With the traditional relay interface it will be a fixed flow temperature, meaning your new setup is less efficient.

    It's worth asking customer support if you can wire Tado thermostats directly to the SystemPro Ebus connectors. A wireless connection won't be possible as it's a proprietary protocol.

    You might be better off with smart TRVs to schedule each radiator, but retain the SystemPro to control the overall system.

  • dandanknight
    edited March 14

    @GrilledCheese2 & @johnnyp78 Many thanks for the replies, it's very helpful indeed thanks. I read on another thread here that Tado can talk to the boiler to control flow temperature via the bus (I think the guy had some communication issues to start but got it working in the end).

    Could we then control the 2 CH valves in parallel to turn on off the CH, as we are not fussed about the 2 zones, then fit Smart TRVs to the rads?

  • @GrilledCheese2 looking at the thread I mentioned, seems you were a major contributor to it, so you'd know better than me! ;-)

    Not overly worried having ebus control over switched, the primary purpose of this exercise is to be able to remotely control the heating via home automation, and to be able to turn off 8 of the 10 rads when it's just me at home working.

  • GrilledCheese2
    GrilledCheese2 ✭✭✭
    edited March 15

    You can connect the control wires for the CH zone valves together so that they both turn on/off together. Leaving you with a single CH zone and the HW zone that can be controlled with the wireless receiver starter kit. The radiator valves then do your zoning.

    The System Pro can also do Weather Compensation, so check if you have an external weather sensor wired in to one of the Ebus ports. To go from Ebus to relay control is a significant change to the wiring. You may not get much help from Tado if they consider this not to be a DIY install.

  • dandanknight
    edited March 15

    @GrilledCheese2 Tado have said they are not aware of the SystemPro product. I'm sent them further details (manual etc), and replied that it is not supported for UK version.

    So where does this leave me, I think options are ...

    1) As you said, leave SystemPro & ClimePro2s, fit Smart TRVs (but no Tado thermo), but then I'd be unable to completely switch off heating remotely, only individual rads. Meaning there would always be a couple of rads on (the ones without the TRVs)

    2) Remove SystemPro, fit Tado thermo and TRVs, bridge the two zones to act as one. With relay only control I'd lose flow temp control, but have complete control over heating and rooms. May be less efficient without flow temp control, but would it outweigh the efficiency I'd gain by putting automation in to disable rooms/heating when rooms/house is empty. Difficult.

    3) Ditch the system boiler and get a Combi!

  • GrilledCheese2
    GrilledCheese2 ✭✭✭
    edited March 15
    If I was in your position I'd purchase a few smart TRVs and evaluate their performance on your current system. Do they maintain accurate temperature, level of motor and water noise, battery performance, saving energy etc. Be a shame to rip out the System Pro and then decide the Tado performance does not meet your needs.

    I wouldn't recommend removing your cylinder. The next generation of heating systems to replace gas/oil often don't have the ability to heat large quantities of cold water on demand. As a result many homes will have to make space for a hot water cylinder.