Questions about Radiator TRV and Smart TRVs

[Dan_P]

Hi all,

A recent post in the "images of items i have purchased" thread about buying smart Thermostatic radiator valves for their home got me thinking... We have been adding smart features to our home recently (lamps, light switches, sockets etc) and we were previously looking into getting a smart thermostat.

After doing some research i think smart TRVs could be an option for us, however, i have a few questions as im quite confused sorry (and one general heating question too) i hope you can help with.

1. The radiator in our hall has no TRV despite every other room (except the towel radiators) having one. Is this right? Is this why our hallway is always cold (newbuild and good seal on door from what i can tell) (thermostats are in our lounge and our bedroom if it matters)
2. Can we fit TRV/Smart TRVs to our towel radiators to help with drying towels/clothes.
3. Will a Smart TRV override the thermostat in the lounge or bedroom (depending on the radiator) to heat that room up regardless of the mode (detail below) and if the thermostat room is up to set temperature. e.g lounge thermostat set to 20c, kitchen TRV set to 25c.
4. Will the TRV heat in every thermostat mode (info below) or only in certain modes. Will the TRV turn the heating on for that specific radiator even if the thermostat is off?
5. Do we also need to buy a smart thermostat (hive etc) or can we use our existing thermostats.
6. If we get smart TRVs for the whole house, what additional feature would a smart thermostat offer as i believe i can set schedules and temperatures on the TRV app?

Thermostat info.
1 on ground floor lounge
1 on top floor (second) master bedroom.
4 modes, OFF, NIGHT, AWAY, HOME each with their own temperature and timing.

Thermostat schedule:
OFF - NEVER (used manually in summer)
NIGHT - 10PM - 6AM (5 degrees c)
HOME - 6AM - 8AM and 4PM - 10PM (20 degrees c)
AWAY - 8AM - 4PM (15 degrees c)

If it matters i am looking at the Tapo TRVs.

TIA
Dan

 

[LuckyBenski]

Can't answer all points but I'll chuck what I know in. There's a tldr at the end!

1. A TRV can only restrict flow - without one, your hallway radiator will either be maximum flow and heat, or the valves on it need adjusting. Side note, most central heating systems require one radiator to be always on and not bypass-able, so the boiler can't overheat the system. Maybe the hall loses heat fastest, and you should put the thermostat there?

2. TRVs won't lead to any more heat coming out, only less if set up to do so.

3 and 4. No, you need the boiler to be firing. The thermostat makes the boiler fire. A TRV can only restrict heat output, and a smart TRV can also demand heat - but you need a smart gadget to receive that demand and tell the boiler to fire i.e. a smart thermostat.

5. It's up to you - you could have the boiler run 24/7 and allow all TRVs to permit flow/heat as needed. Or you could have the boiler run in your existing time windows and set all thermostats and TRVs to control their own space as needed. Note in this case you'll need the thermostats to be set higher than any other TRV locations. Or... Whatever the approximation would be given different rooms store heat differently. Or you could get the smart gadget that fires the boiler, and then all TRVs can demand the boiler fires independently through it.

6. As covered above, TRVs alone can't fire the boiler up, so it depends on your chosen strategy.

tl;dr You've only got one boiler and one loop of CH water supply. It needs to be firing to supply heat, then TRVs can slow or restrict that heat. So you need to plan out how you ensure the supply is triggered. Hope this makes sense

 

[gc123]

just to add we are in the process of getting the boiler replaced/upgraded and the company are also fitting trvs they quoted for 7 when we have 8 rads and 2 towel rails . they responded with you dont need them on the rails (fair enough) and the last (or the first cant remember ) radiator doesnt have a trv fitted , something to do with flow?

strangeley its our hallway rad that they arnt due to fit a trv too as well?