Replacing Basic Dial Room Thermostat with Digital programmable version

matelodave

SuiDreams wrote: »

I currently have one of those horrid cheap dial Thermo stats, would the wiring for the existing one be correct for the new stat and therefore would I be able (or get someone else to) just swap them over?

Assume if using a programmable room stat it would best to have the programmer set to constant for CH and let the stat control the boiler for heating and just leave the timer setting on for the HW on the programmer?

It's hard to know without actually looking at the stat & wiring, it depends on whether its got two or three wires (plus an earth). If it's just got two then you'd probably need a battery powered stat as it won't have a neutral - it's just switching the live from the programmer.

If it's got three then it's likely that its got what's called an accelerator and should then have a live, neutral and switched output and almost any stat will do. If there's more than three then you've probably got a motorised valve as well somewhere and it gets a bit more complicated. Make sure you've isolated the mains before mucking about with the wiring.

Depending on which stat you've actually got and which one you buy you might find that the backplates are the same and the replacement might just plug straight on without any wiring changes at all - have a look inside the existing stat and see if its got a make and model number and see how the wiring is configured (which wire colour goes to which terminal and if there are any terminals connected together with a short link), that should give enough info to see what would be suitable and easiest to fit

You are right about the existing programmer, just set it to permanent CH and let the programmable stat control the heating times & temperatures and just use the programmer clock to turn the hot water on & off

macman

SuiDreams wrote: »

Finally getting round to buying one of these, but have a question, both state Ideal for Combi Boilers. I still have a standard Non Condensing (non Combi) boiler, would these still be suitable or am I better off with an older model with my elderly boiler

If you want to control the hot water as well from one unit then you need a twin channel programmer. Ones for combi's are single channel.

matelodave

Don't confuse it Macman - Sui is just changing her thermostat, hopefully not reconfiguring the system. A simple programmable stat should be all that is required unless there is a complex system installed (and even then it shouldn't be difficult)

SuiDreams

macman wrote: »

If you want to control the hot water as well from one unit then you need a twin channel programmer. Ones for combi's are single channel.

Happy to keep existing programmer for HW, so just need the thermostat for the different CH temps/times

SuiDreams

matelodave wrote: »

Don't confuse it Macman - Sui is just changing her thermostat, hopefully not reconfiguring the system. A simple programmable stat should be all that is required unless there is a complex system installed (and even then it shouldn't be difficult)

Yes just want something simple thats better that the horrid BG dial Thermostat that I currently have (which seems to need changing every few years as they just don't last), and that will also let me change the temperature at different times of day etc.

Sounds like its safer to buy one that has a battery.

SuiDreams

Mine is similar to this (probably the sameone but has BG stamped on instead of Brand name).

http://www.ebay.co.uk/itm/Drayton-RTS1-Room-Thermostat-NEW-Bagged-10-30-Deg-/230994997230?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item35c85fefee

even though it states it operates down to 10 degrees I do not believe my previous ones have ever worked if set below 15, even when temperatures have dropped well below that overnight.

matelodave

If its one of those then you should find it has three connections, a neutral, live and terminal 3 which is the switched output, almost any thermostat would do, you might find yours has got another connection on terminal 1.

Almost any stat should work, try the Salus RT500, which is battery powered anyway and would just be connected to the L wire and terminal 3 wire of your existing stat (tape up the neutral a tuck it out of the way), or if you want a wireless one because you want to put the stat somewhere else the Salus RF500 would do the trick, just install the receiver unit where the existing stat is located.

I'm only advocating the Salus units because they are inexpensive (£35-40 from Amazon), they are easy to install, they do the job and both of my daughters have them installed and they seem to work OK.

SuiDreams

Thank you for your help. Going to get that purchased tonight. Was thinking of wireless, but as house is so small, probably not much benefit as it most likely would only get moved between 2 rooms.

matelodave

Make sure you turn the power off before taking the lid off the existing one and if it's not obvious what you need to do, put the lid back on and ask for help.

Sirmaggie

Hi all, thread is old but I thought I would try my luck....


I have replaced my old dial 3 wire thermostat with a digital two wired one. (Just a generic brand)


I have wired up the live and the earth and left the Neutral wire disconnected.


I have clearly done something wrong though as now radiators only get warm to the touch rather than 'proper hot' and the house does not very often reach the desired temperature.


I have a standard boiler with radiators and a hot water tank.


Can you give me any advice or do I need to get a professional in to do the job.