Do I need a wired thermostat?
Hi All,
I have 6 Tado TRVs and a Glow Worm combi boiler Essential 28c. I set them all up yesterday and they're great.
The weird thing about my combi boiler is that there is no attached thermostat currently and hasn't been since I lived here, although the support team for Glow Worm said it can only run with one. The bloke who installed the boiler (before I purchased this property) waffled on about it not being connected and it was easier to operate the heating by using the thermostatic rad valves that were already in this property. There is a thermostat on the wall, but he says it's not connected and I certainly can't get it to fire the boiler, so I think he's correct. We've been using it in this config for for over a year.
I just replaced all the existing rad valves with Tado ones.
However I read on here somewhere, I think, that I should be running a Tado wired thermostat to fire up the boiler, just having the boiler on the heating setting and waiting for the valves on the rads to open to draw the hot water and in turn cause the boiler to fire up is the wrong way to do it and could damage my boiler under some circumstances.
Can someone help me understand what to do? I'm happy to buy the wired thermostat, but it'll just be wired and perched on top of the boiler and only the TRVs will be controlling the radiators. I don't want to buy the thermostat if it's not needed.
Many thanks.
Comments
-
Your boiler has an internal Auto Bypass Valve which will open (relieving pressure) when all the TRVs have closed. So you don’t need to worry about causing catastrophic damage to the boiler.
Without a wall thermostat the boiler is relying on its internal water thermostat to turn the boiler on and off. So every time the water in the heating circuit cools the boiler will re-ignite its burner and will continue to heat until the water exceeds a pre-defined temperature. This will waste energy and will cause some premature wear of the pump and fan. Installing a wall thermostat to control the boiler would certainly be a benefit and should save you money in the longer term.
Because you have a Glow Worm boiler it makes me think you are located in the UK, which means your boiler has to comply with Part L of the building regulations. Both new and replacement boilers must have Boiler Interlock, which is a technical way of saying it must be controlled by a wall thermostat.
1 -
Thank you so much @GrilledCheese2 - that is really helpful. I'll get a thermostat and have a crack at installing it myself. I am in the UK, you're correct.
Could you help me understand the purpose of the wired thermostat a little please? I understand what you say about the water temp dropping as the valves open, and so the internal boiler thermometer will fire up the boiler to bring it back up to temp. And of course if all valves are closed it's almost like a car idling in neutral, slowly ticking away and bringing it up to temp as necessary, albeit less frequently and using much less gas than if valves are open. Even so, there's energy being wasted, so how does the wired thermostat alter that behaviour?
0 -
The wall thermostat simply works as a switch to turn the boiler on when there is a demand for heat. The wall thermostat will be what Tado define as a Zone Controller. If you link the smart TRVs to the zone controller then each TRV will request the zone controller to switch on the boiler when a radiator needs to be heated. You don't have to link all of the TRVs to the zone controller - they can work Independently as they do now. A TRV in independent mode will measure temperature but won't make the call for heat.
This help article gives more complete information on zone controllers.
Tado will provide users with wiring instructions to replace an existing thermostat, but I don't think they will provide you with the instructions for opening up your gas boiler and attaching the necessary wires to the circuit board. You may need to get a qualified engineer to make the necessary changes before you can connect the new Tado thermostat.
1 -
Really really helpful. Thank you so much @GrilledCheese2.
0
