Home heating automation

I've a tado extension. Will I be able to just replace what's there with it or do I need to do some rewiring?

Current control connections in photos below. Thanks

Yes, assuming your existing timer is for HW and CH, the two wires from the terminals marked NO, normally open, go to the same two terminals on the V3 ext kit, but you will have to link the Live to the COM terminals of each relay on the ext kit, as the relays are volt free. If you have the older V2 extension kit, when it is configured for two zones, the live is internally connected to the Common terminal for both relays, so its almost a straight swap.

You will need to determine which channel on your current timer is used for HW, as these are not specifically assigned.

On the other hand, if this existing timer is for two CH zones, the extension kit can only connect one thermostat wirelessly, as the other terminal is for HW timing only. You don't say what if any wall thermostats you have, but if your system is two CH zones rather than one CH and one HW, you will need at least one Tado stat to be wired for one zone, the other wireless via the ext kit.

Thanks for the reply.

How do I link the live to the com on the ext kit.

Currently don't have a wall stat but have one with the tado kit.

There are 2 zones. HW and CH

Yes, mains electricity and volt free mechanical relay contacts don't mind which way you wire between two switch terminals. There are some circumstances, such as when using a switch with both NO and NC used, that the Live should enter on Com.

A Tado thermostat or other brands will provide temperature/humidity readings and graphs without actually wiring it in. A WiFi or smart hub/Bluetooth enabled remote temperature/humidity sensor only will cost less with lots of options on Amazon, but it depends on your house setup, is your WiFi always on, have you a smart hub device, etc. There are 4g and 5g options also, but battery life will be the biggest issue in an unoccupied location, so either a mains powered WiFi or lo power wireless to a hub device is best.

This is a typical Tado temperature/humidity graph

This SONOFF sensor is cheap if you already have a ZigBee hub.

https://www.amazon.co.uk/dp/B08BFW697F/ref=cm_sw_r_awdo_navT_g_3H9F7B9Q4CTPMS58VZTM

13 stats sounds unmanageable, unless you're running a small hotel. Would you consider grouping some of the UFH zones, but having a single stat operate more than one UFH zone valve. Group some rooms, open areas, etc. Say two groups of beds, all bathrooms, living, dining and other day rooms. This will reduce the complexity of your system.

There is the other issue of UFH capable thermostats, which should have an element of predictive or second order control. UFH heating has a slow response rate, and will continue to heat for a longer time after flow is cut. Ordinary mechanical stats will often have high cycling as a result, overshoot and undershoot of the target room temperature. There are certain electronic stats optimised for UFH, some will have a floor temperature sensor as well as the ambient room temperature sensor. Heat miser have a few types with optional sensors, locally programed or ones with optional hub and app control. Pricey enough.

Smart stats have learning algorithms which track the heat up cycle and modulated flow as target temperature approaches in order to keep a steady state temperature in the room. Tado are suitable for UFH control even without a floor sensor as their 'smarts' will calculate the on off cycles to reach and hold ambient temperature steady.

You may find other cheaper app controlled devices will operate purely as on/off devices, never quite getting the fine control of target temperature without significant over and undershoot.

An inexpensive remote solution would be to install SonOff relays with ambient temperature sensors. These would give remote programmable control of each UFH zone for only €20 per zone plus the Internet hub. The only disadvantage would be lack of a local controller, it would be entirely app operated. You can get these for a fiver on Aliexpress, customs and vat probably not included.

I had a quick read of the bumpf and a look at this video.

the kit consists of 4 ch. receiver and a single main stat/programmer. You will need an extra wireless stat or sensor to control the second CH zone. HW is just timer control as per the H37XL. It can accommodate existing wired thermostats on the 2nd (and 3rd) CH zones, but temperature setting of these will not be available on the app or on the main stat/programmer. For remote temperature setting of CH2 you will need an additional temperature sensor wirelessly paired to the unit. This will give app and main stat setting of the zone, but no wall controls are built into this sensor for manual control. For app access away from the home you will also need the WiFi Internet link unit

The addition of these units will add another €150 to the €200 price of the main Secure kit. From looking at the user manual, you can set schedules for up to 6 time slots per day. In all other respects it appears to be a basic programmable stat with app access, but there's no mention of any advanced or smart features such as geolocation, learning, modulated burning, graphs and data, TRV integration etc.

If you already have wired wall stats, a far smarter and simpler solution is to substitute them with a wired smart stat such as Tado or Netatmo. There is no need to remove the existing Horstmann, just set the CH zones to always on, retaining the HW timing.

Yesterday, I replaced the two mechanical wall stats in a new build with two wired Tado, leaving the three channel controller untouched. The whole job took an hour. The kit cost €212 during black Friday, starter kit plus extra wall stat, nothing else needed.

If you want to replace the controller, the Drayton wiser kit three is a simple enough install, the two fully equipped wall stats are wireless, and the Internet WiFi hub is integral to the drayton 3 channel controller, not an optional extra. I would consider both these brands superior to the Secure, which is at best a single wireless stat upgrade on one zone, with the additional zones and Internet access requiring additional kit, and I'm not seeing any option for a manual controlled second zone stat, just a temperature sensor. With Tado or Drayton, you get two fully functioning wall stats, plus all the extra smart features.

Yes, got it in one. Set Danfoss controller CH zones to always on, keep using HW zone timer. Great price of the wired start kit, grab it. Extra wired stat is £85 on Amazon.uk, free postage, about €105 with vat difference and exchange. Pity Currys.ie haven't the extra stat with a pro rata reduction.

That bix is called the extension kit, It gives you Tado app control of HW timing, and (optional) wireless connection of ONE of your wired stats. Bit more wiring involved as you would likely remove you own electronic timer, wire in CH1 and HW to the two relays, then you'd need to wire the CH2 SL directly to live, so that it sends live to the CH2 wired Tado. A little trickier than just subbing in the stats, but you'll have a 3 channel timer controller to flog on Donedeal.

I wouldn't be bothered, I still have my old 2 zone timer working the HW timing, CH is on constant. I've never seen the need to adjust HW timing, its set for a morning burst, an afternoon burst then off in the evening to give the solid fuel stove a go in Winter, and the yet to be installed solar panels a heat sink in summer. (Some day...)

Thanks for taking the time to respond, a lot of good info.

The other system I was looking at was the Honeywell evohome, what do you think of that? I'd have the option to add TRV's like the tado but could control hot water (if we forgot to turn off when away or something).

For the heating zones, I take it all these systems will work with existing zonal valves, as they just send a signal to the valve to open?

If I leave the H37XL installed, and go for the tado, do I need to wire in the tado to the H37XL or how does that work?

I'm beginning to get my head around it now, the tado thermostats give the signal back to the H37XL to say if they are at temperature.

So I just need to get a tado wired starter kit and a tado wired extension, replace existing stats and then if I want add TRVs for greater control.

Thanks for your patience. I'm sure it's all in this thread already, but it's just so big and only started looking into the area in the past week.

Final question!

Much difference between tado and netatmo in your opinion? I've never heard of the latter so will look them up now.

Thanks again, this was a great help!

That's again. I haven't moved into the house yet. Hopefully getting keys this week, I took a photo of the heating system when I was there. However in the 3d tour that's available online i can't find any stars anywhere so I'll contact the current owner through estate agent Monday. I assumed that they would be using zones, it's a new heating system and the house has had an extension and a refurb in the past few years so I'd hope they'd have stats. If they are electronic does that change the plan much?

On a positive note I did notice the radiators in the bedrooms have manual TRV's so at least they'll be handy to upgrade!

Yeah I'm too eager! I'll see what the set up is and I might check again with you before I do anything! Thanks for the help

You operate the boiler I assume by throwing the switch over the timer on and off, and as the timer is set to always on, the boiler burns until you turn it off or until the jacket temperature inside the boiler is reached, which is set by the white insert thermostat inside the boiler, which is as you state, set to the minimum. I'd expect that the timer is wired inside the boiler to the switched live terminal, SL, while the main switch provides power directly to the boiler circuits. There's a distinction between firing the boiler on and off by just turning its power on and off, as against leaving the boiler power on, but controlling the firing by turning the Timer on and off which powers the SL connection to the boiler. The latter is the correct method of operation, as it means the boiler is always powered even when not firing, or when the timed period finishes, and can properly complete the firing cycle by running the fan when the oil burning is turned off, and also allows the pump to continue circulation for a period. Cutting the power in the middle of a burn will not purge the flue gases properly, so all firing should be done by applying power to the SL lnput, while the boiler is left powered on but in standby.

I just wanted to get that out of the way so that I could advise you how to correctly connect a smart stat to your system. It is as easy as running a wired thermostat from the living room to where the old timer is, or if this presents problems getting the wire pair from the stat to there, an easier solution is to use a wireless stat with a receiver relay to supply the SL to the boiler. The receiver relay can replace the Flash timer, and the stat can be wall or stand mounted in the living room. For your setup, I'd recommend the Hive, Drayton Wiser, Netatmo, Tado or Nest as the easiest option. The Hive or Drayton single zone would be an easy install, and probably the best value. The Tado wireless kit costs a bit more than the wired. All of these stats are battery operated, (except Nest, it's powered by a USB mains adapter), while the receiver's (aka hubs, extension kits, heatlinks. etc) are powered from the mains currently supplying the Flash timer, (again, except the Nest E heatlink, which uses a pair of AA batteries).

You don't mention HW, and I notice a manual switch for a back boiler pump, but I won't comment on dual source systems as all you're looking for is a reliable means of replication of the timer switch with a smart stat and app control.

You can get the Netatmo installed free if you switch to Energia, the Hive if you dual fuel switch to Bord Gais, and Electric Ireland will bang in the Nest 3rd Gen stat for €130 ( plus a free Nest mini) if you choose them.

Live comes in at 1 on the top. SL out at 4 on the bottom, 2 and 3 are linked Neutrals. With the Nest E you just connect L and SL to the Com and NO terminals of the heatlink. No need for neutral as it runs on batteries.