Home Automation - Heating

[unclebob1]

Afternoon all,

I'll be looking to reinstall (ie remove old cast iron boiler + pipework and fit a new boiler in) in the near future, and am toying with the idea of having thermostats in individual rooms, and zoning each room for plumbing as well.

Plumbing side i have a fairly good idea of what I'm aiming for, was looking at the electrical side - replacing bog standard thermostats with a computer/brain of some description. Initially i looked at using a RaspberryPi but need to figure out how to get it to control 240v. Bit of searching and i stumbled across these guys:

http://www.controlbyweb.com/

Now looks like their kit will basically do the whole lot for me, measure the temperature and when it hits pre-defined values/times etc it will connect the wiring on the zone valve to a) open that valve, and b) fire up the boiler and pump).

All in all, heating wise, I'm looking to have 18 zones for heating (inc hot water and solar water) so also 18 relays/outputs... possibly if programmable, also door contacts, which can be used to figure out if a room door is open/closed and heat an area adjacent according...

Question i have is, has anyone come across these guys, or anyone similar who does this sort of thing?

 

[bernardgreen]

The company are located in America, fine until you need some on site support.

The first problem you will have is finding a boiler that can cope with the varying load you will be putting on it. Some boilers adapt ( modulate ) the amount of heat they are putting into the water to try and match the load. If the returning water is too hot they reduce the amount of fuel being burnt. The range of modulation is small in the average domestic boiler. The system you are looking at might need to have two or more boilers to cover the range from one room heating to several rooms heating.

Do you need the added complexity of it being "web" connected ?

I am designing a system for my cottage ( hardware and software ). All valve and boiler controls hard wired to a single control board. Simple RS485 comms from temperature sensors to the control board. The boiler has a range ( equivalent ) of 4 kw to 16 kw

It is a learning curve to develop the control algorythm that you will need for the complexity you are looking at. The "door open so heat the next room" will be a nightmare to configure. If the door is only open for a minute do you heat the room. ? Or if the door is open and then shut do you then turn off the heating to one of the rooms ( which one ) simply because the door has been shut.

 

[ericmark]

My son was telling me how he had found TRV which were wireless linked and he would be able on the HMI (Human Machine Interface) to select temperature for each room and time for each room and that there was no longer any point in using motorised valves.

However I did not pay too much attention. He did say cheaper than motorised valves but he would be fitting it. He wanted a wired system all through the network but seems could only find a wireless version.

 

[ericmark]

P.S. he also said it would connect to his alarm system so when he set the alarm the temperature would auto reduce but not off so saving money when no one in the house.

 

[unclebob1]

Thanks for the reply bernardgreen, the fact that they are in the states is the main reason for me asking, is there alternatives which don't do the web bit, which are based here in the uk etc. I don't mind the web bit, but control through a local network device(pc/tablet/phone etc) is prefered. And tbh i am thinking along the lines of two boilers, one combi for kitchen sink, and the "downstairs"rooms, with a second for upstairs and hot water tank.

Door wise i was thinking along the lines of a time'd period - if a door has been open for say 5 min, then heat the room to a temp close to the room it is connected to. If it is closed, then use whatever has been programmed for it already... That way if i leave the landing door open to a room which is not used, I'm not heating the room by heating the air in the hall way... and if the door is closed, then use the pre-programmed time/temp config of keep it at x degrees instead of say 20 or 21 in the rooms which are being used.


What is your setup for the cottage? Software side I can happily manage, I'm struggling with the hardware interface. As i stated, initially i looked at using the Pi, i am happy to code, recode, adjust and recode till it works. i just cant find suitable off the shelf interfaces for 5v to 240v control!
Is your setup something that can be bought off the shelf and then programmed and connected to your needs or is it something which you have made/had made? Is it connectable over network so can be easily reconfigured or is it a case of re-coding? (e.g. can a non technical person come along and turn the temperature up if the are cold?)


ericmark - i looked at those, i don't feel comfortable with wireless in my heating! I have had a lot of interference issues with wireless alarms etc, in the past so I've always preferred using hard wired which i can test/diagnose and if need be by-pass!

 

[pukka]

have a look at http://heating.consumers.danfoss.com/Content/519BEC7A-71D7-4736-8634-DE6E293E91BA.html

it supports zwave for home automation.

Thanks

Paul

 

[ericmark]

My son was also not happy with wireless. Also with my dads death we look at his house and scratch our heads to work out what he had done. This without any computer links. And my son is worried if he was ill who could repair the system? We have not been impressed with so called heating engineers to date. Can't even read a book and fit right size drain for condensate so what chance is there for them repairing your system if you for any reason could not DIY?

 

[disinfo]

Have you looked at the Arduino as well?

 

[unclebob1]

Pukka, Thanks for the link - will look at their products and see if they will be suitable,

ericmark, unfortunately, that will forever be the case while people do DIY - My dad wired up the house we live in 20 odd years ago, and any time i want to do any works in the house, he scratches his head thinking what did i do here, or where does this go etc...

I guess the best we can do is document what we do! Circuit diagrams, schematics etc as well as follow industry standards so someone has a fighting chance of picking it up and being able to maintain it.

Disinfo - are you able to recommend me any suitable temperature sensors and 240v relays that are compatible with or easy to use with the Arduino?

 

[bernardgreen]

Hardware
PCB with 7 ports for controlling shoe valves.
valves can be full open, half open and closed.
Boiler control port
RS485 port for remote temperature sensing
Real time clock with off air MSF decoder
key board and display ( 4 by 20 ) interface.

Shoe valves driven by 12 volt DC motors with positional feedback.

I would avoid using combi boilers. They are too complex, for plumbers they are easy to install but with pressurised radiators and direct heating of hot water they are not as easy to maintain.

 

[unclebob1]

Hardware
PCB with 7 ports for controlling shoe valves.
valves can be full open, half open and closed.
Boiler control port
RS485 port for remote temperature sensing
Real time clock with off air MSF decoder
key board and display ( 4 by 20 ) interface.

Shoe valves driven by 12 volt DC motors with positional feedback.

I would avoid using combi boilers. They are too complex, for plumbers they are easy to install but with pressurised radiators and direct heating of hot water they are not as easy to maintain.

Was the PCB for the shoe valves custom?

 

[bernardgreen]

Was the PCB for the shoe valves custom?

Yes, and with experience it may need to be altered in terms of the mechanics of detecting the angular position of the shaft to get a more accurate half open indication.

 

[david3456]

Plumbing side i have a fairly good idea of what I'm aiming for, was looking at the electrical side - replacing bog standard thermostats with a computer/brain of some description. Initially i looked at using a RaspberryPi but need to figure out how to get it to control 240v.

My solution might be a bit over the top for 18 devices but I recently realised there is a very simple way of controlling mains devices. Obviously opto couplers would give the necessary isolation but the mains side circuitry is fairly awkward. I do not need microsecond response times and wanted to avoid building from scratch.

An electronic room thermostat (I had an old Drayton Digistat) contains a thermistor likely to be a nominal 47K. It also happens to be the middle of the range of a light dependant resistor. http://www.maplin.co.uk/light-dependent-resistors-35962

It's a direct substitution. Make a hole for some light to shine in and point an led at it. No wiring needs to go inside the housing so no worries about isolation. On mine, 100 microamps through the led is enough to make it swing from end to end. I hold the led on the side of the housing with velcro to make a "connector". I get a response time of about 90 seconds.

 

[bernardgreen]

For reasonable cost and highly reliable opto isolated mains control from ELV computor based controllers I frequently use Opto22 G4 modules.

http://www.opto22.com/site/documents/doc_drilldown.aspx?aid=1649

Opto22 G4OAC5A
Contact Form: SPST (1 Form A)
Contact Current-Max: 3 A
Output Voltage: 24 to 280 V
Control Voltage: 4 to 8 V
Isolation Voltage-Max: 4000 V

Mounting PCBs are needed but these are available from several suppliers.

 

[xdave]

Have you looked at the Heatmiser products? (http://www.heatmiser.com/web).

Their v3 12v network products can be installed using standard CAT 5e FTP cables and you can chain up to 32 zones together. You can use their netmonitor to connect to your network/internet and can interface it with alarm systems, etc, via the generic IOs. I use their network thermostats to control actuators in place of TRVs and to control the electric UFH and towel radiators in my bathrooms. I also use their network timers to provide connected switching of things like outside lights, a mister on my pond, etc. You can hide the timers away and use a single touch screen controller to manage them, which also gives you one place to manage all of the attached thermostats/timers and group them, copy schedules across, etc.

I have no experience of using their 230V or wireless products so I don't know what you can or can't achieve with them.