Combi boiler wiring: Multiple radiators in 1 room

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Apologies this maybe a silly set of questions.

I have searched and couldn’t find an answer to the below

I have a wiring question on radiator plumbing. I have multiple radiators in a room, I imagine/believe they are connected in series not dissimilar to this wiring diagram here
https://www.the50plus.co.uk/tech_support/Modern-Central-Heating/combi3.jpg

All my existing radiators have trv’s - in one room I have 2 radiators:

1) can I get away with just having one TRV? Would the smart radiator be the temp control for the room and as they are in series the water would go to the 2nd radiator? If so how do I work out which one is the 1st in the series.

2) a wireless temp sensor but no trv’s in the room would be pointless I imagine? It’s just there to be the main temp sensor?

Answers

  • johnnyp78
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    I’m not a plumber but I thought uk radiators were plumbed in parallel, not series. You would need a smart trv on each radiator.

    A wireless temp sensor would fulfill the same role as having trvs on the radiators in that room, however it would be less precise if the Tado is wired in using relay (on/off) rather than a modulating connection like opentherm.
  • nkm3837
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    Ah that could be my bad in terms of wiring @johnnyp78 / that diagram I found might be wrong - assuming you have a uk setup do you have openthern support on your wireless sensor? I did a quick Google and it looks like opentherm is not supported?

    https://community.tado.com/en-gb/discussion/8508/open-term-vs-relay-connection-to-boiler
  • johnnyp78
    johnnyp78 ✭✭✭
    edited September 2022
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    Wireless temperature sensors support opentherm, as do wired/wireless thermostats. Uk wireless receivers, which connect to the boiler for use with wireless temp sensors or thermostats, do not. If you want Opentherm support you need to either get an EU version of the wireless receiver or the discontinued extension kits, or use a wired thermostat into your boiler.

    If you have a system boiler (with external hot water tank) you are unlikely to be able to use a digital connection, but there are a few exceptions.