Emmeti Actuators + Neo Stats

**Jambo** · 17 January 2014, 11:38 AM

Neo Hub installed last night and the thermostat for the underfloor heating connected up.

Pairing up the hub and stats and getting it all working with the iPhone app could not be easier, it takes literally seconds.

My air sensor is not really in the right place, it's above head height near the door. Will lower it and try to move it into the room a bit.

Noticed the following:
- Neo App is iPhone only. You can install the iPhone app on the iPad but a dedicated iPad app would be really nice!
- Terminals in the back of the stat will not take two pieces of 2.5mm wire. Not a criticism of the stat, just something to consider in your planning.

Still trying to figure out these radiator valves. Slightly concerned that the on/off nature of them may not be ideal. Perhaps best to leave the TRVs in place and get zone valves fitted, and then just use the Neo as a time switch, with frost protection also?

**Jambo** · 30 January 2014, 07:23 PM

Surprised to have had so many views and so few replies!

So a couple of nights ago I wired in the main neo stat to control the boiler - this is situated in my hall. I've also hooked up the neo controller for the hot water. As before, very easy to pair up and the wiring is easy too, and all controllable from my iPhone from anywhere!

More comments on the neo app:
- It would be nice to have a time stamp for the last update of the temperatures etc.
- There was chat of an API, I'm thinking it would be possible to add a remote temp sensor to one of these and run that outside for some smarter weather compensation?

**Jambo** · 22 August 2014, 11:55 AM

Updates on this project - I have added two new zones to my system by way of more Neo stats with Emetti actuators on the radiators, replacing the TRV heads. Works very well although these things are quite slow to open and close. They are also either on or off so overshoot may be a problem, I don't know if the Neo can calibrate itself against that. Would be a straightforward software solution I would have thought.

Dedicated App for iPad is now available and works well.
A software update that would be good would be to be able to see from the home screen of the Neo if the hot water is in standby or not.

**brentwood** · 22 October 2014, 12:18 PM

I'm doing something very similar. Emmeti actuators controlled by Heatmiser 12V networked stats and a UH1. My rationale for this is that we have a large stone built house which has very poor thermal performance, so trying to heat the whole thing to a constant temperature is just not practical. When we moved in all there was by way of controls was a single ancient thermostat in the hall, not even any TRV's. We basically used the stat as an on-off switch... We will of course try to improve the insulation in the house but it will never reach modern standards.

Last winter we converted downstairs. We had the opportunity to re-plumb so I put in an emmeti manifold and plumbed the radiators individually back to it. This avoids having TRV's/actuators on show and allowed us to use nice decorative valves on our lovely new cast irons rads.

I'm now in the process of doing upstairs. We've put drayton TRV bodies on all the rads which are a perfect match for the emetti actuators, so as I work my way around each room its a very simple case of unscrewing the head and attaching the actuator. I work from home so I'm really looking forward to being able to turn on the heat in just my study during the day without wasting heat on a mostly unoccupied house.

I've used 4 wire actuators with all the microswitches wired in parallel to form the heat demand. We have a thermal store as our heat source so the heat demand just runs the pump on the radiator circuit from the store. The boiler charges up the store based on the store's own thermostats independently of what the house heating is doing. I use the HW output from the UH1 as the timer control on the boiler although really you might need heat any time depending on how the room stats are programmed.

The idea with the store is to act as a buffer between the varying demands from the house and the output of the boiler. Boilers generally aren't too happy supplying intermittent small loads such as when the stats in individual rooms click on and off so you could find yourself using more gas to supply one room than it would take to supply several. The store will also allow us to combine multiple heat sources as and when we get around to that. Solar in the summer and wood in the winter so we can wean ourselves off of fossil carbon.

At some point I plan to interface to the RS485 bus on the heatmiser and build an integrated house control system. Things iike automatically putting the stats on holiday when the alarm is armed and so on.

All the best, Alan

**Jambo** · 26 December 2014, 11:55 PM

Howdy,

Brentwood, great to see someone else is using this setup, seems very Evohome dominated on here otherwise! Awesome that you've re-plumbed with a manifold, simplifies the wiring a little I expect. The heat store is an interesting point - how big is it? My combi is ancient and incorporates a 4 gallon heat store - not sure if this is still normal on oil fired combis?

If you get anywhere with the 485 please let me know.

A few other things I've found lately - Screwfix's dirt cheap TRVs have the right thread for the Emmeti actuators. The heads are probably crap but you don't need them!

Geolocation has been added to the App, I haven't played with it much but my feeling is it needs some tweaks.

I've got a stat controlling the towel rail in my bathroom (using a remote probe). I want it to heat the room, but also warm/dry towels for a few hrs per day. Issue I'm struggling with here is that neither thermostat nor time switch mode on the neo is perfect for this application, with the towel rail remaining off on warm days on thermostat mode and either using too much energy or not getting the room warm enough in time switch mode. I feel a 'towel rail' mode which is a mixture of the two could be useful.

**brentwood** · 8 January 2015, 02:56 PM

So I had another go at tinkering with the RS485 over the holidays after Jambo's message reminded me about it. This is a bit of a hijack of this thread's title so I hope no one objects.

I have a generic IP to serial converter off of ebay that I wired in to the spare bus connectors on the UH-1 and I found a little perl module on the web that sends a status message to a thermostat and parses out the reply. Got absolutely no where with it.

First off my linux box was unable to open a TCP connection to the converter. I could see the syn's going out but nothing came back. The sun/solaris box fared a bit better and was able to connect and write out the request string but it timed out waiting to read a response.

Too many variables -- what if the converter doesn't do what it claims? Is it wired in and configured correctly? I always thought the Y/B connections on the UH-1 are all commoned but sticking the meter on them showed they aren't. Each must be treated as one leg of a star with its own termination resistors so maybe there is more to it than just connecting it up.

So I went looking for a netmonitor as it basically does what I want in a shrink wrapped box, but at a price point I was hoping to avoid. None to be had. It seems that heatmiser only supply the touchpad now. Wonder how much longer the N-series stats will last now that the whole world seems to be going to z-wave? An online retailer was offering 10% off the touchpad so I ordered one. Still much more pricey than I would have liked, its probably doubled my outlay on heatmiser kit.

It arrived yesterday and I immediately got it hooked up directly to the UH-1 in the Harry Potter room under the stairs. First impressions good, it detected the kitchen and study thermostats and gave me all the current readings, but not the living room one. Now, the living room stat suffered a bit of collateral damage when it was first installed resulting in a bit of an acrid smell and some charring around the terminals. The stat itself still works fine but it wasn't too surprising that it wasn't detected by the touchpad.

Then things went decidedly downhill. The kitchen thermostat disappeared. The study thermostat became very unresponsive. Sometimes it would take several seconds for a new setting to take effect, but often it just seemed to ignore it. Looking into the settings/statistics screen I was getting about a 30% success rate talking to the study.

Yikes - maybe its the cabling, I thought. Heatmiser recommend screened CAT cable but I used the unscreened stuff I use for ethernet and HDMI. It performs flawlessly for those so how hard can a piddly little RS485 bus running at 4800bps be? Our alarm system has the same kind of bus and it runs on crappy aluminium alarm cable thats as thin as spider silk without any worries. The cables have all been carefully kept separate from mains so I really didn't imagine I was going to have problems with it.

Fortunately the solution turned out to be simple. Disconnecting the Y/B of the living room restored normal service and its all working brilliantly. Looks like I'll need to replace that stat. By coincidence the kitchen stat backlight has started flickering. Not sure what brought that on other than it being unceremoniously pulled off the wall a few times last night whilst checking for bad connections. I may be able to fix it by canabalising the living room one.

I also need to find a space to mount the touch pad. I'd like to put it in the kitchen instead of the stat there as it has all the same functions for controlling the kitchen so having both on the wall is a bit redundant, but of course the touchpad lacks an actual temperature sensor. I'm toying with the idea of wiring a remote sensor back to a thermostat hidden under the stairs instead. Would have to move the HW function to another room though but thats ok as the touchpad has a dedicated icon for it.

Next step will be to reintroduce the IP-serial converter and see if any more progress can be made now that I have known good messages flowing on the bus. The touchpad appears to poll all the stats continuously so there is plenty of traffic to see. For now pretty happy with the touchpad and got to admit its a lot more non-techy friendly than an IP based solution which I think will be an advantage if we ever sell up.

I also tried the USB on the touchpad. I believe it will show up as a storage device and both a mac laptop and the linux box see it as a block device but neither is able to mount a filesystem. The linux box gets quite upset with it actually, spitting out constant error messages whilst its connected. Not a great loss as I can't really see it being used once its mounted on the wall.

-Alan

**brentwood** · 8 January 2015, 03:45 PM

Jambo, you asked about the size of the heat store. It holds 250l but with an integrated header tank and lots of insulation the whole thing is about 2.5m high and maybe a little over 1m in diameter. I shudder to think how much it all weighs once filled... Its in the shed on the back of the house so space isn't a problem.

The motivation for it is to combine different heat sources, preferably non-fossil carbon ones. Its actually a bit on the small side for that. If we were serious about heating with a wood burner for example we'd need something more in the 1000-2000l range. But it should allow me to get a bit of solar going, either from a thermal collector or PV driving immerser heaters to cover our hot water needs in the summer.

As well as a gas boiler we also feed our oil fired Aga into it, which is decidedly not non-fossil. But the Aga will happily carry on without electricity for about 3 months on a full tank so we can be somewhat self sufficient in heat should we lose utilities. Generally the Aga is off except around this time of year. Before we started renovating it had to be on 24x7 as it was our only means of cooking and heating water, so we've already done the planet a big favour. I'm also looking at adding a medium sized wood burning stove with back boiler to supplement things when the weather is at its coldest. The great thing about the store is that it doesn't matter where the heat comes from, you can take it out to the taps or the radiators in exactly the same way.

The store can run the radiator in my study for a good 2 or 3 hours before the boiler comes in to recharge it. You want a gas boiler to run in a good long blast rather than lots of short ones so that it gets into condensing mode and stays there. I've been doing quite a bit of tinkering getting the controls for the heat supply of all this just right. The heatmiser hw output is used as a timer input to the boiler, so you have to sort of second guess when the radiators are likely to be running and need heat. If the heat runs out then a thermostat shuts off the pumps to avoid pumping cool water around the house. Its a chicken and egg problem really, you want the store to be up to temperature and ready to go before the heat demand arrives, but having all that hot water sitting around if its not going to be used is wasteful.

I let the temperature in the store vary between about 45 and 60 degrees, the two ends of the range being controlled by a pair of thermostats. Once it drops below the lower end a relay clicks in and the boiler runs until the top thermostat is satisfied. A single thermostat usually only has about 5 degrees of hysteresis so you get too much short cycling again from the boiler as it comes on almost immediately after you start taking heat out.

Its been an interesting voyage of discovery and taken about a year to get the whole thing ticking over nicely. We currently have about three quarters of our radiators under heatmiser control although not every room has its own stat yet. A bit more floorboard lifting and knocking of holes in walls and I should be done. I'm rewiring the mains as well as putting in ethernet, TV and alarm cabling so the extra disruption of doing the heatmiser is minimal by comparison.

-Alan

**Jambo** · 9 January 2015, 12:08 PM

Thanks for the info Brentwood - certainly sounds fun what you're doing. I had a woodburner installed recently and looked at integrating it with my heating, but as I don't actually have a good supply of wood at a decent price, I wasn't convinced there was a financial incentive to do it, especially with the oil price falling through the floor.

I had a search online and some guys here seem to have got the Neo to do some stuff:

heatmiser

https://www.npmjs.com/package/heatmiser

A node.js app that talks to Heatmiser WiFi and Neo thermostats. Latest version: 2.0.0, last published: 10 years ago. Start using heatmiser in your project by running `npm i heatmiser`. There are 4 other projects in the npm registry using heatmiser.

This just goes into the Neo hub over wifi, much easier than going over 485 link I imagine. Not sure if and when I'll get time to play with this. You could maybe use it to have the stats come on and off based on the temperature of your store.

Regarding all the knocking holes in walls etc., I suggested to Heatmiser that they update the firmware to allow one Neo in a system to be set up beside the boiler as a 'Neo Slave'. All it does it short its contacts when another 'stat in the house is asking for heat. It would save so much hassle with cabling, 4 wire actuators, valves etc. They seemed to like the idea but remains to be seen if it will happen. Also suggested that the firmware be updated to allow the user to toggle the use of the slave on and off for each stat - don't want my electric underfloor heating firing up the boiler

Emmeti Actuators + Neo Stats

Emmeti Actuators + Neo Stats

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