Central Heating Zoning

Xennon

Hi all,

Just looking for some advice, I'm splitting up my house into 4 zones including hot water tank.

pipework would be as follows:



Any help would be appreciated on the following:

Im looking for a programmable timer for each zone that I can have different temperatures at different times. So say in zone 1 from 7-8 its 19 degs and from 8-10 its 17 degs etc etc

Does it matter if the control valves are on the send or return from the boiler?

Wired or wireless control?

Any input, dos or donts welcome.

freddyuk

A programmable room thermostat wired (or wireless) for each valve will give you 6 times per day 7 days per week with all the other functions you would expect such as holiday mode and override etc. You can pick these up quite cheaply but stick to known brands. Wireless are more expensive so go hard wired if possible.
I use Honeywell CM707 which I have picked up off the web very cheaply.
http://www.honeywelluk.com/Products/Programmable-Thermostats/TPI/CM707/
This allows you to fine tune your heating controls to suit your lifestyle.
For DHW I use a simple timed 24/7 day programmer. Also we have an immersion programmer so this can be used in summer if required to support the solar or for instant hot water for shower /washing up thus minimising waste by firing the boiler for small amounts of water.
If you want to control your heating from your Iphone then this will be of no use but then why would anyone want to do that when it can be done automatically with simple zoned programmed controllers. Adding an outdoor sensor would switch the heating on at a set point but this is only really useful for underfloor which needs a longer warm up time.

kanji

Just as an add on to that I would replace the "valve one turn open" bypass with an automatic bypass valve which you can set the spring pressure to only open when all zone valves are off.

antoinolachtnai

I zoned my house recently into two heating zones. There is a diverter valve built into the boiler that deals with the hot water side of things.

The controller is my own thing. I have a small computer, a raspberry pi, attached to a relay board, which turns on the heat and everything else. I have a schedule which is based on the outdoor temperature taken from a weather website. It turns the heat on for longer as the temperature falls. I don't have thermostats around the house, though I do have one temperature sensor. I could use the sensor to turn the heat on and off, but I don't.

Xennon

@freddy. Thanks for that, exactly what Im looking for.
@kanji. Sounds like a good plan I'll go that route.
@anto. Yeah I could go the Pi or some other SBC route, but I need to get everything up and running by next month. I could stick rudimentary controls in each zone and hook them up to the Pi but by the time I've it all working...meh...just as easy get something that does the job. And like freddy, Im not buying into the controlling your heating from the net malarkey, I dont need it.

On the wiring of the heating control system, would you have the boiler always on or on a seperate timer and only enable the pump when you what to circulate water, or leave the boiler to be switched on with the circulating pump when a stat requires heat.

Im thinking that the heat would be more instant if the boiler was on a separate timer, or would I be loosing heat un-necessarily ... hmmm bit of an apples/oranges question?

antoinolachtnai

The way the zone valves are generally wired, what you do is you activate the zone valve, and then a switch on the zone valve switches on the heating. So then there is just one wire to make 'live' in order to turn on a particular zone.

See this link and reference to the auxiliary switch: http://www.honeywelluk.com/documents/All/pdf/974.pdf

Doing it this way ensures the boiler never runs unless there is a zone valve open somewhere. If a zone valve fails, no problem, the failed zone valve won't call for heat if it can't actually open. It obviously means you need to run wires back from the boiler to the zone valve. There are some drawbacks to this way of doing it, but it's the standard way and it will meet your needs.

You are going to have to buy 3 of those 707's and put one in each zone, and you'll need a timer for the HW (you might have something suitable already).

AndyBoBandy

Hi Folks,

I am looking into adding an extra zone to my house, and a better control system (currently have a daily timer with only 2 on/off's per day)
With the current control though, I can separate between 'heating' & 'water' (with 'heating' also heating the water cylinder, 'water' heating the cylinder only).

Is this 2 zones as it is?

I would like to separate upstairs from downstairs, and create the 2 heating zones, while also retaining the 'water zone',
The pipes into my downstairs radiators are coming from the walls, and not the floor. Does this indicate it will be hard to create the 2 heating zones?

All my rads have TRV's, but I would much rather have the 2 independent zones (or possibly more) that I can easily control.

In my case would it be a big job?

Also, due to an upcoming attic conversion, I will be moving & replacing my current copper 'blanketed' water cylinder for a larger factory insulated cylinder, so I presume that would be the ideal time to make any potential changes to the overall system.

Cerco

Op,
Have you considered what would happen if the pump jammed?
I'm not a plumber so I maybe be raising a non-issue. Maybe there is protection on the boiler ?

Xennon

Hi Cerco,

yeah the Boiler has a blowoff valve, and temp cut off.

Xennon

Thanks Antoin, thats the way Im heading. Got the 707s, running cabling is not a problem, and I can use my old timer for the tank.

Now If I can just get myself to cut the floorboards in the hall so the plumber can get to work

Eggs Omlettes etc etc.

Dtp1979

Xennon wrote: »

Hi Cerco,

yeah the Boiler has a blowoff valve, and temp cut off.

I think he means an automatic bypass valve

freddyuk

Pressure relief valve.........it is a safety device. Bypass valve is something different

Dtp1979

freddyuk wrote: »

Pressure relief valve.........it is a safety device. Bypass valve is something different

he was asking what would happen if all the TRV's shut off