How to thermostats work

[C0mbat]

Hi all,

I have a gas boiler than is for underfloor heating and hot water (on demand) on the ground floor, heating and a hot water tank on the first floor, and then heating on the second floor. The first and second floor heating and the hot water tank are managed by a Timeguard TRT038N 3 channel programmer plus the 1st and 2nd floors also have a single on wall thermostat for the heating.

I'm lazy and don't want to always walk from my office on the second floor to the programmer on the ground floor to boost the heating for an hour during the winter and I can't really understand what my options are.

For example, do I have an energy efficient way of doing it without buying anything? What I mean is that can I have the Timeguard set the 2nd floor to be on for 8 hours of the day and then just control whether the heating is on via the thermostat? What I can't work out is if by doing this the programmer actually heats the pipes around the house and the thermostat actually just controls the radiators on the second floor? If that is the case then I assume that for the 8 hours a day that I have it on the boiler will be on to heat the pipes? Or does the thermostat actually control the boiler via the Timeguard?

It my above option does end up using energy even when I have the radiators off (because it's heating the pipes) then I think my only other option is the Wiser Kit 3 as that includes a 3 channel programmer as well as the smart thermostats. Or is there a cheaper and less complex option of a smart 3 channel programmer that replaces the Timeguard and I just leave the existing wired thermostats as is?

 

[Agile]

Heat will only flow into pipes if there is a water flow through them.

If any motorised valve along the pipe is closed then there will be no water flow and so they will remain cold and not lose any heat.

However any heat loss from heating pipes is generally low and in an occupied house must contribute to the overall heating in the house.

 

[RandomGrinch]

What I mean is that can I have the Timeguard set the 2nd floor to be on for 8 hours of the day and then just control whether the heating is on via the thermostat?

Yes, even with the programmer set to on, the boiler shouldn't be using any energy until the thermostat calls for heat - try it!

 

[C0mbat]

Heat will only flow into pipes if there is a water flow through them.

If any motorised valve along the pipe is closed then there will be no water flow and so they will remain cold and not lose any heat.

However any heat loss from heating pipes is generally low and in an occupied house must contribute to the overall heating in the house.

Thanks @Agile and @RandomGrinch

This sounds promising

So does that mean that I could just get two wired Tado (or any other smart wired brand) thermostats to replace my existing wired thermostats and then keep set the Timeguard to be on for large parts of the day and use the Tados to control things? Obviously I'd still need to have the water on a timer or to manually hit boost but my heating would be "smart"?

 

[RandomGrinch]

So does that mean that I could just get two wired Tado (or any other smart wired brand) thermostats to replace my existing wired thermostats and then keep set the Timeguard to be on for large parts of the day and use the Tados to control things?

Depending on your existing stats wiring, it should be possible - i.e. if your existing stats are battery powered, there may not be the wiring to support a mains powered stat - this could limit your choices.

You would also be missing out slightly on having a truly integrated system like the Wiser; completely replacing your existing programmer, it would add smart control of the water, as well as the ability to introduce smart TRV's later on, should the budget allow.

If you're comfortable showing us the wiring behind your existing stats, we may be able to advise further.

 

[C0mbat]

Depending on your existing stats wiring, it should be possible - i.e. if your existing stats are battery powered, there may not be the wiring to support a mains powered stat - this could limit your choices.

You would also be missing out slightly on having a truly integrated system like the Wiser; completely replacing your existing programmer, it would add smart control of the water, as well as the ability to introduce smart TRV's later on, should the budget allow.

If you're comfortable showing us the wiring behind your existing stats, we may be able to advise further.

I didn't get around to doing this but it then turned out that one of the thermostats seems to have malfunctioned and given up the ghost this week. What's annoying about that is that it's preventing the heating from coming on at all on the second floor where I work so I do now need a solution.

Screwfix have the Tado V3+ Wireless Heating & Hot Water Smart Thermostat Starter Kit on offer for £85 so I'm wondering whether I can do what you suggested and replace the Timeguard programmer with the receiver that you get with this kit. Then you get one temperature sensor that would do the job of the wired thermostat (I'd need to buy another one separately to replace the second thermostat on the first floor).

https://www.screwfix.com/p/tado-v3-wireless-heating-hot-water-smart-thermostat-starter-kit-white/141kt

What's not clear is whether the Tado receiver can handle three channels (two heating zones and the hot water) in the same way the Timeguard does. And then if it does, is it an issue if I still have the old thermostats wired in? Will the Tado receiver/programmer just bypass them and communicate only with the wireless temperature sensors?

I've attached photos of the existing thermostats. This is the one that has given up the ghost. It's got three wires: white, black and brown.

 

[C0mbat]

Please ignore this thread as I've created a new one