Changing thermostat to heating controller advice pls

[Mattyxr66]

Hi,

I'm no plumbing expert but i need to replace the thermostat with a controller so we can manage the heating better.

The thermostat is quite old as far as i can tell, the boiler we have is a ariston combi a/23.

I was wanting to replace the thermostat with a Honeywell ST9100C.

From the images attached does this look possible without installing new wiring? The thermostat is currently located in the hall way about 6 meters from the boiler and its the only thermostat in the house.

The picture of the corroded pipe is just for advice, we have a problem with the hot water supply if you put a tap on but not fully on the pressure seems to drop and the pipes start vibrating and banging, if you put the hot water taps on full it doesnt come out as hot as not opening the tap fully.

I have since disconnected the pipe and put PTFE tape in the corroded connection to stop it leaking as bad and is manageable now till i can get a permanent solution

Many thanks in advance!!

Matt

[Mattyxr66]

After doing more research i believe I've come up with a solution.

The boiler uses volt free connection for the thermostat, so if i replace the old thermostat with a honeywell DT90E thermostat and install a honeywell ST9100C inside the boiler cupboard.

I can use the power connected to the boiler to power the controller, and as the cable from the thermostat is in the cupboard connect it in series with the thermostat.

Do this sound correct?

[martyn.wendon]

What (if anything) does the boiler currently use for scheduling / time control?

You might be better with a complete replacement scheduler / controller with thermostat built in - something wireless that you could install in the most common used room. At the boiler end you would remove the current time clock and thermostat and fit the partner to the aforementioned wireless unit - usually a controlling relay that is powered from the mains but connects volt-free to the boiler to operate it.

[Mattyxr66]

The boiler has its own scheduler but its rubbish so currently just use the thermostat in the hall way.

Wireless sounds good, though can the scheduler be battery powered? I dont want to chase wiring up a perfectly good wall

[martyn.wendon]

Most manufacturers of Thermostats / Controllers do wire-free versions.

Honeywell, Heatmeiser, Horstman all do various types.

If you wanted something with future possibilities such as remote control and integration with other Home Automation equipment, you could take a look at some of the Z-Wave offerings. The new Secure SCS317 is pretty good, a "wired" Receiver / relay for the Boiler end (single or two channel available) and a battery powered Thermostat / Scheduler that can be sited anywhere within range of the Receiver. This can operate stand-alone and also be integrated into a Z-Wave system at a later date, for example with a PC based system such as HomeSeer or a standalone controller such as a Zipato Zipabox, or a Raspberry Pi / Razberry solution - lots of possibilities.

[Mattyxr66]

Just had a slap head moment, the wire from the boiler to the thermostat is normal electrical cable so i can use it to power the scheduler.

Ill look at possible wireless and maybe wifi solutions if the budget allows

Thanks