Home heating automation

When you say you use an electric shower, are you talking about one which heats the water by electricity, or just a "power' shower which contains an electric pump but is supplied by hot and cold from your existing cold tank and HW cylinder. Such a shower might not behave perfectly with combi boiler sourced HW, where the HW is only supplied on demand by the boiler. If however you install a combi as a sealed system, no large cold supply tank and all hot and cold at relatively high regulated pressure with an expansion tank, then you should get great flow from normal shower mixer bars without the need for a local pump.

When I moved in to a bungalow many years ago it had the standard attic cold tank on the ceiling rafters, and HW cylinder. It had an all electric shower in the ensuite. This pumped and powered 8kw electric shower had poor flow at the best of times, and feeble in the winter as it tried to heat near 0° attic tank water to comfortable temperature. Turning down the flow knob obviously increased the temperature of the water passing the 8kw element, but it was a piddling trickle. Meanwhile I had a cylinder full of scalding water unconnected to the ensuite shower, and I had only 4-5 feet of head pressure from the attic tank sitting on the rafters to the top of the bath shower head mounted just a few feet below the ceiling, so it had poor flow through the bath tap mixer, and even less when I installed a thermostatic shower mixer.

The cost effective solution was simple. Dump the electric en suite powered shower, fit two proper wall hot and cold inlet thermostatic shower bar mixers in each location, and intercept the hot and cold flows to these with a booster pump in the hot press. It works a treat.

The booster pump is a pretty basic domestic Stuart Turner, it can handle both showers at the same time, plenty of pressure. It's been running for over 22 years, only needed a new €10 motor starting capacitor last year. Both showermixers are still perfect also. I had toyed with the idea of combi boilers, but this was an instant and cheap upgrade, a new condenser boiler and modern insulated cylinder came many years later. I did raise the attic tank about 1.2 M to improve non pumped H&C taps in the rest of the single story house.

I guess the combi sounds attractive, but I was surprised when doing Tado on two brand new 2021 family house purchases with all the new A rated tricks, that both developers, one of them the biggest name here, had opted for traditional cylinder and single flow/return system boilers, albeit with a sealed system and a single cold source pressure pump from a vented storage tank, which is on the ground floor in one house. I was expecting cylinderless combi boiler but there you go. Both houses over three floors btw, so the pumped and sealed system removes gravity from the equation, and gives solid pressure on all floors, with all shower bars performing with gusto. The cold tank gives cover in the event of water mains outage.

As regards upgrading your CH, Tado will zone heat your CH as before, and you can determine if your new/old house cylinder HW is heated constantly during a boiler CH call or if it has its own zone valve. Not a huge issue if you have Tado TRVs on the rads.

Hope this rambling tale helps you decide.

Gas combi boilers are virtually instantaneous due to the small capacity needed for the HW heat exchanger, and can have a pre heat setting turned on to keep this chamber hot. I'd expect the equivalent in an oil combi to be a bit slower. Modern HW cylinders are almost lossless, so making them very efficient as a souce of preheated water for instant showers. Don't forget the electric shower costs 4 to 5 times more to heat HW than than oil, 3 to 4 times more than gas.

The combi provides direct HW on a seperate circuit, so external zone valves only for CH. These would be 2 port valves, three port are used generally to zone HW and 1 CH zone, with the option of priority flow. There is an internal diverting valve usually in a combi boiler to direct the heated flow to the HW heat exchanger when a tap is opened.

3 port valves are not popular as the logic of wiring and switching is difficult to understand, involving use of both NO, normally open and NC, normally closed terminals on the zone thermostat zone controller receiver, I.e the Tado ext kit. An all TRV setup with a main stat to call the boiler from a single NO Terminal won't require any zone valve, just TRVs on all rads, with the rad in the main stat location generally left open, but it can also have a TRV and use the main stat as its temperature measuring device. This allows any TRV to trigger the boiler using the main stat as a relay, while the colocated rad to the main stat remains closed if the scheduled temperature there is satisfied.

Depending on the combi boiler you choose, (gas or oil?), you can connect the main stat via its opentherm connection. If it has one. This will allow the stat to read flow temperature of the CH and modulate firing to achieve steady state heating with the lowest possible flow temperature, ensuring maximum efficiency at the boiler condenser. Tbh, I've not seen an OT installion of a Tado including TRVs except when asked to look at one abroad a few months ago, and the TRVs were passive, not communicating to the main stat as there was no bridge installed, no app control. The entire thing was manual, yet the stat and boiler could talk via the two wire digital connection. It was a rented house, so the landlord obviously kept the bridge, wouldn't want tenants locking the devices to their app account.

I'm assuming that a TRV can call the boiler via OT in the same way it can by SL from the stat rela. If OT sounds a bit risky to you, just use SL. OT does give the app the opportunity to communicate HW settings to an OT equipped combi, such as temperature and preheat on/off, but you'd have to know if your boiler offered these options by OT, and if it started behaving erratically, I doubt you'd find an installer who could trace the configuration of the stat and the combi to resolve it.

The valves are well priced compared to established brands like Tado, Hive, Drayton wiser. They're passive valves, they can't operate or 'call' the boiler when they open for heat, so some other device ( your timer) must simultaneously be on for the CH, or CH zone if you have separate upstairs and downstairs timers.

The hub is WIFI connected and battery powered, which is less than ideal as WiFi consumes greater power for communication. The hub communicates to the TRVs via Z-wave, which is a lower powered smart device protocol. You may be able to automate the boiler call using a mains powered z-wave compatible relay device, and schedules using the app, or other smart apps that can see the TRV's, such as Google, Alexa, etc.

Because your radiators have only standard twist valves, these will need to be replaced with TRV push pin valve heads. The installation cost may run to well over the price of the Kasa TRVs, I think someone here manged to get it done in the region of €80 per rad, doing all the radiators at one time. It's DIYable for those who know how and are confident.

Given the cost associated with the radiator valve body upgrade, the additional cost of a TRV brand which has a mains power hub/bridge/ and receiver relay to operate the boiler would be a better all in one solution. Particularly for installations where there are no wall thermostats, and just a two or three zone timer, the Drayton Wiser system is almost drop in, with wireless wall stats, giving 3 zone smart temperature/time control of 2 CH and one HW zones. This is easily upgraded to include smart TRVs at a later stage, giving some or all of the rads their own control, and the ability to call the boiler on demand.

You're welcome dude, lots of users here of the various brands are pleased/happy/ecstatic even with their smart systems. Post image of your timer for further comment if you want.

What make is your current timer, is it a three zone electronic timer?

If you intend installing full TRV control on the radiators, then you will be able to simplify the wiring by leaving ttheuo/down zone valves fully open at all times. Firing of the boiler can then take place from a smart thermostat relay, which can be triggered by either a HW timer event or any of the smart TRVs timed events. In this case, the wireless two zone receiver of a smart stat with HW control can operate in gravity mode, with a single output for any CH or HW event firing the boiler. Tado, Hive or Drayton two zone system would be ideal, all have linked TRVs. The wireless receiver would sit in place of the current timer.

Does anyone here know of a system that can be used to control older wired home heating systems?

I have underfloor heating with individual zone thermostats controlled by a Heatmiser wired system (NetmonitorPlus) - 15 thermostats controlling different manifold zones in different rooms/halls etc.

The Heatmiser control unit's ethernet board is now playing up, so I get intermittent access to the app to control all the room thermostats. Generally after switching it off and rebooting, I get about 5 minutes of access! Heatmiser no longer support the unit and have only suggested replacing with their current system, which would involve changing all the thermostats and purchasing a Neo controller. Frankly, I don't trust them as there is no guarantee they will support Neo in the future if something goes wrong; plus, it would cost a small fortune! Typically, they did not make Neo backwards compatible to all of my wall thermostats 😡

Does anyone know of a system that could connect to the heatmiser controller (or replace it) that would allow me to access all thermostats through a single app or web page, without having to change all the thermostats too?

Note: my system is less than 10 years old, so not exactly ancient!

Thank you

I'll have a read of the Netmoniterplus installation and wiring, but if the 15(!) Thermostats are hard wired directly to the manifold valves. then its possible, though expensive, to replace with wired smart wall stats. I presume the stats all terminate in a wiring centre, so it may be a case of leaving this. I'll have a readup later, then comment.

I recall digging through this heatmiser mire before. If I'm correct, the individual stats are wired to the individual room manifold valves. At the simplest, you turn up a stat and that room ufh warms up. The stats are not wired via the NetMonitor box, though it does have a large amount of wired inputs and outputs. This box communicates with the individual stats wirelessly, enabling programming of each stat via the box and Internet access to each stat and it's schedules. The detail I'm not fully certain of is if this box via a relay output is providing any SL (switched live) control voltage to boilers and pumps which supply the UFH manifolds, or if this control is happening in a passive UFH wiring centre or lex box. I think it the latter.

A few years ago I encountered a new Three zone S plan heatmiser system, with schedules built in into the 2 CH and HW wall thermostats controllers. To bring this system online required nothing more than an additional hub device which paired to the wall stats. There was no additional wiring required.

I'm thinking the NetmonitorPlus is similar,it has no wired function in this respect, but this would have to be established, as it does have relay outputs. I think the NetmonitorPlus is just overlaid on a local wired system, requiring only comms with the correct model of stats. I presume if you power off the NetmonitorPlus only, you heating will still work manually.

If this is the case, then each heatmiser stat can be replaced by a wired smart stat, or the receiver of a wireless stat. These stats will report to their own local bridge or hub, which will enable Internet app control of your system. It still won't be cheap, as you will require 15 smart thermostats, such as wired Tado, wired Netatmo, wireless Hive and others. You could be looking at at least 100€ for each stat, plus the Internet bridge. Before you do anything, can you post the model of the heatmiser stats used, an image perhaps, and an image of the wiring behind the one of these units. A shot of the NetmonitorPlus too.

Thank you... I've found a couple of documents that may explain the set-up better than me taking photos of the system, but let me know if you need photos.

The first doc shows that the Netmonitor+ is separate to the stats and manifolds. So you are correct, when I power off the Netmonitor, everything still works. Each stat and manifold actuator is connected to an Optiflo LV (three Optiflo LVs in total, one for each manifold per floor). The Netmonitor+ is simply connected to one of the Optiflo LVs - it does not connect to anything wirelessly. The only data connection is to my router via an open port - which enables communication via a webpage or an app.

The second doc shows the wiring to the low voltage push button stats within the Optiflo LV (I do not have wireless stats). I do recall each thermostat having a temperature sensor wire under the floor nearby, so that floor temp is monitored.

Having seen these docs, I can't believe Heatmiser were unable to simply swap out the Netmonitor+ with an upgrade!!

When I spoke to someone at Heatmiser, they said a Control4 (?) unit may be used to replace the Netmonitor+, but as it is a 3rd party device, I would have to seek help elsewhere!! 😣

I'm not keen to spend on new stats - mine all work fine, it's just I have to set and program them individually if the app is not working. At the moment, I can get short bursts of life out of it, so I'm able to program centrally if needed, but if it fails and there is no reasonable replacement for the Netmonitor +, I will simply have to program each stat manually!

Thank you again for your help.

Just to help for those considering options.

I've the heatmiser neo stats and the neohub, included in my heat pump install but I'm a big fan of them. Can be set individually at the wall, via the app with templates applied to multiple stats and visible and controllable in home assistant via homekit or a HACS integration depending on your preference....

The schedules just work so my long planned switch to manage the temps via home assistant schedules / automations instead of the heatmiser app is consistently on the long finger.

Turning them off to prevent calls for heat (without impacting schedule) if a window sensor is open is as far as I've gotten. Will change the schedules over to home assistant at some point.

I'd second this. The neohub works well, and even though the Home Assistant integration has to be installed via HACS, it has been very solid. I never use their app and do everything via Home Assistant.

Installation was very simple too, though they are slightly smaller than the non smart heatmiser stats they replaced, so I need to do some small touch ups around the wall boxes.

Sorry for my ignorance in advance 

We have a oil burner which heats the house (rads and water) using a pressurized system.

We had two zones one upstairs and one down stairs .

The heating control switch we have currently is the grasslin towerchron qe2 . Which heats the rads and water separately but when you have it timed for heating it will heat the water.

One of the rads upstairs never heated correctly . When we got the bathroom renovated the plumber with them said if he removed the valves and created one zone it would solve the problem. He did and it did solve the problem, all the rads heated fully.

 Problem now is the switch doesn't work, once the burner fires , whether the switch is timed or not it stays on constant .

So we want to get a new smart system with zones for each radiator . 

Question is which system should we get / do we need pick back in the valves or will the ones on each rad do the job 

Thanks in advance, reposting this in this forum as it more placed here

Someone recommended the tado system

Here are a few photos of the system , might give a better idea