WebBrick InstallationHere's a step by step 'photo' guide to installing a WebBrick to control a Central Heating and Hot Water system.
Getting StartedHere's a before photo:
and here's the pre-existing timeswitch:
The first step is to isolate from the mains - of course you shouldn't do this unless you know what you're doing - our advice would be to get a Part P qualified electrician to help.
If you are going to use an electrician, it would help if you have all the networking side complete first, since the electrician's jobs will be straightfoward, in fact you could make a cuppa just after disconnection and be ready to test once its finished!
This next stage could be prepared before an electrician arrives. It consists of getting the housings ready for both the WebBrick and the Solid State relays that will be used to control the mains side.
We suggest this route because it makes a very clean and safe separation between the low voltage WebBrick side and the main voltage control side. It also makes a very convienent point for an electrician to perform a part P test.
We next bond a temperature sensor to the 'flow' side of the boiler CH feed.
We used modelers 5 minute epoxy and a cable tie to do the job. This glue is good at high temperatures and doesn't mind a bit of differential expansion. We removed the cable tie after ten minutes or so.
You could chose the return side, but in this case its helpful to have an early indication that the boiler is generating heat.
This next photo shows the WebBrick in place along with the network and 12V supply:
Here we can see the installation of the Solid State Relays. We're using two here, one for Hot Water and one for Central Heating:
Our final installation photo shows the WebBrick and SSR's boxed up:
Note that we've added a couple of switches and LEDs these are used for mainly manual control, and could prove useful if the network was down for any reason.
The Control SideObviously the control that you put in place depends on the sort of use you need. In this particular case the boiler supplies heat and hot water to a room above a garage that is used by children as a music room.
The Children have lessons during the week at more or less set times, and they pop over at random times for practice.
This means that the schedule is driven from lLinux CRON jobs and that there is a button that will provide heat for 2 hours.
Let's consider the WeBrick Configuration:
Here we can see that triggers 0 and 1 are used to toggle the boiler functions. These are infact connected to the local toggle switches and provide any bail-out local control should there be network or system problems.
Trigger 4 will provide heating for 2hours; This is connected to the hard and 'soft' buttons that the children can use if they decide they want to pop in a practice.
The beauty of this approach is that they cannot leave the heating on forever! |